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  • 1.
    Dyverfeldt, Petter
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Trenti, Chiara
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ziegler, Magnus
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bjarnegård, Niclas
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindenberger, Marcus
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Helical flow in tortuous aortas and its relationship to turbulence: A whole-aorta 4D flow MRI study2023In: Frontiers in Cardiovascular Medicine, E-ISSN 2297-055X, Vol. 10, article id 1124604Article in journal (Refereed)
    Abstract [en]

    BackgroundIncreased vascular tortuosity is a hallmark of ageing of the vascular system, including the aorta. However, the impact of tortuosity on aortic blood flow is unknown. We hypothesized that increased tortuosity would be associated with increased blood flow helicity and with decreased degree of blood flow turbulence as measured by the turbulent kinetic energy (TKE).Methods4D Flow MR images covering the entire aorta from the aortic valve to the iliac bifurcation were acquired in 23 normal volunteers aged 18-30 years ("Young") and 23 normal volunteers aged 66-76 years ("Old") without aortic disease. The aorta was segmented and divided into four regions: the ascending, descending, suprarenal abdominal and infrarenal abdominal aorta. Tortuosity, helicity, TKE, flow velocity, and Reynolds number were computed for the whole aorta and for each section.ResultsTortuosity and helicity were higher whereas TKE, velocity, and Reynolds number were lower in Old than in Young, for all aortic regions (p < 0.05) except for helicity in the descending aorta. Tortuosity correlated positively with helicity and negatively with TKE for all aortic regions (Spearman rho=+/- 0.45-+/- 0.72, p < =0.002) except for TKE in the ascending aorta. Further, helicity correlated with TKE in the descending, suprarenal abdominal and infrarenal abdominal aorta (Spearman rho=-0.56--0.77).ConclusionTortuosity increases with age and blood flow in tortuous aortas is more helical. Increasing helicity, in turn, is associated with decreasing TKE.

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  • 2.
    Ekerstad, Niklas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Medicine and Health Sciences. NU NAL Uddevalla Hosp Grp, Sweden.
    Pettersson, Staffan
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Alexander, Karen
    Duke Clin Res Inst, NC USA.
    Andersson, David
    Linköping University, Department of Management and Engineering, Economics. Linköping University, Faculty of Arts and Sciences.
    Eriksson, Sofia
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Janzon, Magnus
    Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Swahn, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Frailty as an instrument for evaluation of elderly patients with non-ST-segment elevation myocardial infarction: A follow-up after more than 5 years2018In: European Journal of Preventive Cardiology, ISSN 2047-4873, E-ISSN 2047-4881, Vol. 25, no 17, p. 1813-1821Article in journal (Refereed)
    Abstract [en]

    Background There is a growing body of evidence on the relevance of using frailty measures also in a cardiovascular context. The estimated time to death is crucial in clinical decision-making in cardiology. However, data on the importance of frailty in long-term mortality are very scarce. The aim of the study was to assess the prognostic value of frailty on mortality at long-term follow-up of more than 5 years in patients 75 years or older hospitalised for non-ST-segment elevation myocardial infarction. We hypothesised that frailty is independently associated with long-term mortality. Design This was a prospective, observational study conducted at three centres. Methods and results Frailty was assessed according to the Canadian Study of Health and Aging clinical frailty scale (CFS). Of 307 patients, 149 (48.5%) were considered frail according to the study instrument (degree 5-7 on the scale). The long-term all-cause mortality of more than 5 years (median 6.7 years) was significantly higher among frail patients (128, 85.9%) than non-frail patients (85, 53.8%), (P amp;lt; 0.001). In Cox regression analysis, frailty was independently associated with mortality from the index hospital admission to the end of follow-up (hazard ratio 2.06, 95% confidence interval 1.51-2.81; P amp;lt; 0.001) together with age (P amp;lt; 0.001), ejection fraction (P = 0.012) and Charlson comorbidity index (P = 0.018). Conclusions In elderly non-ST-segment elevation myocardial infarction patients, frailty was independently associated with all-cause mortality at long-term follow-up of more than 6 years. The combined use of frailty and comorbidity may be the ultimate risk prediction concept in the context of cardiovascular patients with complex needs.

  • 3.
    Ekerstad, Niklas
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Health Sciences.
    Swahn, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Löfmark, Rurik
    Stockholm Centre for Healthcare Ethics, LIME, Karolinska Institutet, Sweden .
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping. Ryhov County Hospital, Jönköping, Sweden .
    Andersson, David
    Linköping University, Department of Management and Engineering, Economics. Linköping University, Faculty of Arts and Sciences.
    Carlsson, Per
    Linköping University, Department of Medical and Health Sciences, Division of Health Care Analysis. Linköping University, Faculty of Health Sciences.
    Frailty is independently associated with 1-year mortality for elderly patients with non-ST-segment elevation myocardial infarction2014In: European Journal of Preventive Cardiology, ISSN 2047-4873, E-ISSN 2047-4881, Vol. 21, no 10, p. 1216-1224Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: For the large population of elderly patients with cardiovascular disease, it is crucial to identify clinically relevant measures of biological age and their contribution to risk. Frailty is denoting decreased physiological reserves and increased vulnerability. We analysed the manner in which the variable frailty is associated with 1-year outcomes for elderly non-ST-segment elevation myocardial infarction (NSTEMI) patients. METHODS AND RESULTS: Patients aged 75 years or older, with diagnosed NSTEMI were included at three centres, and clinical data including judgment of frailty were collected prospectively. Frailty was defined according to the Canadian Study of Health and Aging Clinical Frailty Scale. Of 307 patients, 149 (48.5%) were considered frail. By Cox regression analyses, frailty was found to be independently associated with 1-year mortality after adjusting for cardiovascular risk and comorbid conditions (hazard ratio 4.3, 95% CI 2.4-7.8). The time to the first event was significantly shorter for frail patients than for nonfrail (34 days, 95% CI 10-58, p = 0.005). CONCLUSIONS: Frailty is strongly and independently associated with 1-year mortality. The combined use of frailty and comorbidity may constitute an important risk prediction concept in regard to cardiovascular patients with complex needs.

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  • 4.
    Ekerstad, Niklas
    et al.
    Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
    Swahn, Eva
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Cardiology UHL.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Cardiology UHL.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Cardiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Cardiology UHL.
    Löfmark, Rurik
    Stockholm Centre for Healthcare Ethics, LIME, Karolinska Institutet, Stockholm.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Carlsson, Per
    Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
    Frailty as a Predictor of Short-Term Outcomes for Elderly Patients with non-ST-Elevation Myocardial Infarction (NSTEMI)Manuscript (preprint) (Other academic)
    Abstract [en]

    Background – For the large and growing population of elderly patients with cardiovascular disease it is important to identify clinically relevant measures of biological age and their contribution to risk. Frailty is an emerging concept in medicine denoting increased vulnerability and decreased physiologic reserves. We analyzed how the variable frailty predicts short-term outcomes for elderly NSTEMI patients.

    Methods and Results – Patients, aged 75 years or older, with diagnosed NSTEMI were included at three centers, and clinical data including judgement of frailty were collected prospectively. Frailty was defined according to the Canadian Study of Health and Aging (CSHA) Clinical Frailty Scale (CFS). Of 307 patients, 150 (48.5%) were considered frail. Frail patients were slightly older and presented with a greater burden of comorbidity. By multiple logistic regression, frailty was found to be a strong independent risk factor for inhospital mortality, one-month mortality (OR 3.8, 95% CI 1.3 to 10.8) and the primary composite outcome (OR 2.2, 95% CI 1.3 to 3.7). Particularly frail patients with a high comorbidity burden manifested a markedly increased risk for the primary composite outcome. By multiple linear regression, frailty was identified as a strong independent predictor for prolonged hospital care (frail 13.4 bed days, non-frail 7.5 bed days; P<0.0001).

    Conclusions - Frailty is a strong independent predictor of in-hospital mortality, one-month mortality, prolonged hospital care and the primary composite outcome. The combined use of frailty and comorbidity may constitute an ultimate risk prediction concept regarding cardiovascular patients with complex needs.

  • 5.
    Ekerstad, Niklas
    et al.
    Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
    Swahn, Eva
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Janzon, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Alfredsson, Joakim
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Löfmark, Rurik
    LIME, Karolinska Institutet, Stockholm, Sweden.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Carlsson, Per
    Linköping University, Department of Medical and Health Sciences, Health Technology Assessment and Health Economics. Linköping University, Faculty of Health Sciences.
    Frailty is independently associated with short-term outcomes for elderly patients with non-st-segment elevation myocardial infarction2012Conference paper (Refereed)
  • 6.
    Ha, Hojin
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Kangwon Natl Univ, South Korea.
    Ziegler, Magnus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Welander, Martin
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Bjarnegård, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Carlhäll, Carljohan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Age-Related Vascular Changes Affect Turbulence in Aortic Blood Flow2018In: Frontiers in Physiology, E-ISSN 1664-042X, Vol. 9, article id 36Article in journal (Refereed)
    Abstract [en]

    Turbulent blood flow is implicated in the pathogenesis of several aortic diseases but the extent and degree of turbulent blood flow in the normal aorta is unknown. We aimed to quantify the extent and degree of turbulece in the normal aorta and to assess whether age impacts the degree of turbulence. 22 young normal males (23.7 +/- 3.0 y.o.) and 20 old normal males (70.9 +/- 3.5 y.o.) were examined using four dimensional flow magnetic resonance imaging (4D Flow MRI) to quantify the turbulent kinetic energy (TKE), a measure of the intensity of turbulence, in the aorta. All healthy subjects developed turbulent flow in the aorta, with total TKE of 3-19 mJ. The overall degree of turbulence in the entire aorta was similar between the groups, although the old subjects had about 73% more total TKE in the ascending aorta compared to the young subjects (young = 3.7 +/- 1.8 mJ, old = 6.4 +/- 2.4 mJ, p amp;lt; 0.001). This increase in ascending aorta TKE in old subjects was associated with age-related dilation of the ascending aorta which increases the volume available for turbulence development. Conversely, age-related dilation of the descending and abdominal aorta decreased the average flow velocity and suppressed the development of turbulence. In conclusion, turbulent blood flow develops in the aorta of normal subjects and is impacted by age-related geometric changes. Non-invasive assessment enables the determination of normal levels of turbulent flow in the aorta which is a prerequisite for understanding the role of turbulence in the pathophysiology of cardiovascular disease.

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  • 7.
    Hallman, Daniel
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Neider, Daniel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Zachrisson, Helene
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Diameter and compliance of the greater saphenous vein - Effect of age and Glyceryl trinitrates.2007In: Kardiovaskulära vårmötet,2007, 2007Conference paper (Other academic)
  • 8. Order onlineBuy this publication >>
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Cardiovascular responses to hypovolemic circulatory stress in women: With special reference to venous compliance and capacitance2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Acute haemorrhage is a leading cause of death in trauma. Young women (YW) seem more susceptible to hypovolemic circulatory stress than young men (YM), but the underlying mechanisms are not clear. Elderly subjects are more vulnerable to haemorrhage, with a decreased defence of central blood volume in elderly men, but the defence has not been evaluated in elderly women  (EW). The aims were to assess differences in cardiovascular responses to hypovolemic circulatory stress, emphasizing compensatory mechanisms to maintain central blood volume in YW, EW and in women prone to vaso‐vagal reaction (VW).

    Lower body negative pressure (LBNP) was used as a model for haemorrhage and to create acute hypovolemic stress. Volumetric techniques were used to assess venous compliance, capacitance and capillary fluid exchange both caused by LBNP in the calf and the response to maintain central blood volume.

    LBNP induced a comparable hypovolemic stimulus in YW and YM, with lower calf venous compliance and capacitance but higher net capillary fluid filtration in YW. YW responded with smaller vasoconstriction without association between P‐NE and peripheral vascular resistance in contrast to YM. Venous capacitance response was decreased with time in YW. Further, net capillary fluid absorption from peripheral tissues to central circulation was decreased in YW in response to hypovolemic stress. All in all, this indicates less efficiency to defend central blood volume in young women.

    Calf venous compliance and capacitance was maintained in EW compared to YW but capillary filtration was decreased, implying reduced capillary function with age. With increasing transmural pressures however, filtration and capillary filtration coefficient (CFC) increased indicating increased capillary susceptibility to transmural pressure load in dependent regions with age. Heart rate increase was attenuated in EW while peripheral vascular conductance was maintained suggesting reduced cardiovagal baroreceptor function in response to hypovolemia with age. Venous capacitance response and fluid absorption from peripheral tissues to central circulation were decreased with age, indicating less efficiency to defend central blood volume.

    LBNP induced a slower hypovolemic stimulus in VW compared with nonvagal women. Further, the cardiopulmonary baroreflex was less efficient, and the venous capacitance response from peripheral tissues to central circulation was decreased, which may explain their susceptibility to orthostatic challenge.

    List of papers
    1. Sex-related effects on venous compliance and capillary filtration in the lower limb
    Open this publication in new window or tab >>Sex-related effects on venous compliance and capillary filtration in the lower limb
    2007 (English)In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 292, p. R852-R859Article in journal (Refereed) Published
    Abstract [en]

    Recent studies in humans have suggested sex differences in venous compliance of the lower limb, with lower compliance in women. Capillary fluid filtration could, however, be a confounder in the evaluation of venous compliance. The venous capacitance and capillary filtration response in the calves of 12 women (23.2 ± 0.5 years) and 16 men (22.9 ± 0.5 years) were studied during 8 min lower body negative pressure (LBNP) of 11, 22, and 44 mmHg. Calf venous compliance is dependent on pressure and was determined using the first derivative of a quadratic regression equation that described the capacitance-pressure relationship [compliance = 1 + (2·2· transmural pressure)]. We found a lower venous compliance in women at low transmural pressures, and the venous capacitance in men was increased (P < 0.05). However, the difference in compliance between sexes was reduced and not seen at higher transmural pressures. Net capillary fluid filtration and capillary filtration coefficient (CFC) were greater in women than in men during LBNP (P < 0.05). Furthermore, calf volume increase (capacitance response + total capillary filtration) during LBNP was equivalent in both sexes. When total capillary filtration was not subtracted from the calf capacitance response in the calculation of venous compliance, the sex differences disappeared, emphasizing that venous compliance measurement should be corrected for the contribution of CFC.

    Keywords
    Lower body negative pressure, capillary filtration coefficient, venous capacitance
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-15416 (URN)10.1152/ajpregu.00394.2006 (DOI)
    Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2017-12-14Bibliographically approved
    2. Decreased capillary filtration but maintained venous compliance in the lower limb of aging women
    Open this publication in new window or tab >>Decreased capillary filtration but maintained venous compliance in the lower limb of aging women
    2007 (English)In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 293, p. H3568-H3574Article in journal (Refereed) Published
    Abstract [en]

    There are sex-related differences in venous compliance and capillary filtration in the lower limbs, which to some extent can explain the susceptibility to orthostatic intolerance in young women. With age, venous compliance and capacitance are reduced in men. This study was designed to evaluate age-related changes in venous compliance and capillary filtration in the lower limbs of healthy women. Included in this study were 22 young and 12 elderly women (23.1 ± 0.4 and 66.4 ± 1.4 yr). Lower body negative pressure (LBNP) of 11, 22, and 44 mmHg created defined transmural pressure gradients in the lower limbs. A plethysmographic technique was used on the calf to assess venous capacitance and net capillary filtration. Venous compliance was calculated with the aid of a quadratic regression equation. No age-related differences in venous compliance and capacitance were found. Net capillary filtration and capillary filtration coefficient (CFC) were lower in elderly women at a LBNP of 11 and 22 mmHg (0.0032 vs. 0.0044 and 0.0030 vs. 0.0041 ml·100 ml–1·min–1·mmHg–1, P < 0.001). At higher transmural pressure (LBNP, 44 mmHg), CFC increased by 1/3 (0.010 ml·100 ml–1·min–1·mmHg–1) in the elderly (P < 0.001) but remained unchanged in the young women. In conclusion, no age-related decrease in venous compliance and capacitance was seen in women. However, a decreased CFC was found with age, implying reduced capillary function. Increasing transmural pressure increased CFC in the elderly women, indicating an increased capillary susceptibility to transmural pressure load in dependent regions. These findings differ from earlier studies on age-related effects in men, indicating sex-specific vascular aging both in the venous section and microcirculation.

    Keywords
    Capillary filtration coefficient; lower body negative pressure; age
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-15417 (URN)10.1152/ajpheart.00725.2007 (DOI)
    Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2017-12-14Bibliographically approved
    3. Lower capacitance response and capillary fluid absorption in women to defend central blood volume in response to acute hypovolemic circulatory stress
    Open this publication in new window or tab >>Lower capacitance response and capillary fluid absorption in women to defend central blood volume in response to acute hypovolemic circulatory stress
    2008 (English)In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 295, p. H867-H873Article in journal (Refereed) Published
    Abstract [en]

    Acute hemorrhage is a leading cause of death in trauma, and women are more susceptible to hypovolemic circulatory stress than men. The mechanisms underlying the susceptibility are not clear, however. The aim of the present study was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in women and men. Twenty-two women (23.1 ± 0.4 yr) and 16 men (23.2 ± 0.5 yr) were included. A lower body negative pressure (LBNP) of 11–44 mmHg induced experimental hypovolemic circulatory stress. The volumetric technique was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as to assess net capillary fluid transfer from tissue to blood in the arm. Plasma norepinephrine (NE) and forearm blood flow were measured before and during hypovolemia, and forearm vascular resistance (FVR) was calculated. LBNP created comparable hypovolemia in women and men. FVR increased less in women during hypovolemic stress, and no association between plasma NE and FVR was seen in women (R2 = 0.01, not significant), in contrast to men (R2 = 0.59, P < 0.05). Women demonstrated a good initial capacitance response, but this was not maintained with time, in contrast to men [e.g., decreased by 24 ± 4% (women) vs. 4 ± 5% (men), LBNP of 44 mmHg, P < 0.01], and net capillary fluid absorption from tissue to blood was lower in women (0.086 ± 0.007 vs. 0.115 ± 0.011 ml·100 ml–1·min–1, P < 0.05). In conclusion, women showed impaired vasoconstriction, reduced capacitance response with time, and reduced capillary fluid absorption during acute hypovolemic circulatory stress, indicating less efficiency to defend central blood volume than men.

    Keywords
    Gender, orthostatic tolerance, baroreceptor sensitivity
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-15418 (URN)10.1152/ajpheart.00332.2008 (DOI)
    Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2017-12-14Bibliographically approved
    4. Reduced defense of central blood volume during acute hypovolemic circulatory stress in aging women
    Open this publication in new window or tab >>Reduced defense of central blood volume during acute hypovolemic circulatory stress in aging women
    2012 (English)In: Shock, ISSN 1073-2322, E-ISSN 1540-0514, Vol. 37, no 6, p. 579-585Article in journal (Refereed) Published
    Abstract [en]

    Elderly men respond with decreased defense of central blood volume during hypovolemic stress, but this response has not been evaluated with age in women. The aim was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in elderly compared to young women. Cardiovascular responses in 34 women, 12 elderly (66.4±1.4 yr) and 22 young (23.1±0.4 yr) were studied during experimental hypovolemic circulatory stress induced by lower body negative pressure (LBNP) of 11-44 mmHg. Volumetric technique was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as to assess net capillary fluid transfer from tissue to blood in the arm. LBNP created comparable hypovolemia in elderly and young women. Heart rate increased less in elderly women (LBNP of 44 mmHg: 20±2 vs. 37±4 %, P < 0.01), but with similar decrease in forearm vascular conductance (FVC). Mobilization of capacitance blood from the peripheral circulation was both slower and decreased by ~60 % in elderly, and net capillary fluid absorption from surrounding tissues was reduced by ~40 % (LBNP of 44 mmHg). In conclusion, during acute hypovolemic circulatory stress elderly women responded with less increase in heart rate but with an equal change in FVC, implying decreased cardiovagal baroreceptor sensitivity. Furthermore, both capacitance response and net capillary fluid absorption were reduced, indicating less efficiency to defend central blood volume in elderly than in young women.

    Place, publisher, year, edition, pages
    Lippincott Williams & Wilkins, 2012
    Keywords
    Female, trauma, baroreceptor sensitivity, orthostatic tolerance, adrenergic receptor response
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-15419 (URN)10.1097/SHK.0b013e31824fbb3e (DOI)000304202200004 ()
    Note

    funding agencies|Medical Faculty, Linkoping University||Futurum-The Academy of Health Care, Jonkoping County Council||Medical Research Council| 12661 |Heart and Lung Foundation||

    Available from: 2008-11-06 Created: 2008-11-06 Last updated: 2017-12-14Bibliographically approved
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  • 9.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Reduced Venous Compliance in Young Women with Type 1 Diabetes - Further Aggravated by Prolonged Elevated Levels of HbA1c2016In: Frontiers in Endocrinology, E-ISSN 1664-2392, Vol. 7, no 126Article in journal (Refereed)
    Abstract [en]

    Background: Young patients with diabetes present with reduced compensatory responses to hypovolemic stress. Less compliant veins could be a contributing factor, since roughly two-thirds of the blood volume resides in the venous system as a blood reservoir, adjusting proper venous inflow to the heart. The aim of this study was to measure venous compliance and lower limb blood pooling during hypovolemic stress, and to correlate them to indices of diabetes severity and glucose control. Methods: Fifteen young women with type 1 diabetes (DW) and 18 healthy age-matched women (C) were subjected to lower body negative pressure (LBNP) (11-44 mmHg), creating hypovolemic stress. Lower limb blood pooling was measured with strain gage technique and venous compliance calculated as the relationship between Delta V/Delta P. Results: DW presented with reduced blood pooling (e.g., blood pooling during LBNP of 44 mmHg, DW, 1.69 +/- 0.10; C, 2.10 +/- 0.08 (ml/100 ml), and P = 0.003). Calculated venous compliance was also reduced in DW (e.g., compliance at 20 mmHg, DW, 0.046 +/- 0.003; C, 0.059 +/- 0.002 (ml/100 ml/mmHg), and P = 0.002). A progressive reduction in both venous compliance (P amp;lt; 0.007) and blood pooling (P amp;lt; 0.005) was seen with increasing level of HbA(1c), and furthermore, less strongly associated with presence of microvascular disease (signs of retinopathy). Conclusion: Women with type 1 diabetes present with both reduced venous compliance and blood pooling. The reductions were particularly present in patients with long-standing poor glycemic control.

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  • 10.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Fedorowski, Arthur
    Lund Univ, Sweden; Sickle Univ Hosp, Sweden.
    Melander, Olle
    Lund Univ, Sweden.
    Gallo, Widet
    Lund Univ, Sweden.
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Skoog, Johan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Cardiovascular biomarkers and echocardiographic findings at rest and during graded hypovolemic stress in women with recurrent vasovagal syncope2019In: Cardiovascular Electrophysiology, ISSN 1045-3873, E-ISSN 1540-8167, Vol. 30, no 12, p. 2936-2943Article in journal (Refereed)
    Abstract [en]

    Introduction Vasovagal reflex is the most common type of syncope but its etiology is not fully elucidated. Venous return and cardiac output are key in hemodynamic control. The aim of the study was to assess cardiovascular biomarkers and echocardiographic measures at rest and during hypovolemia in women with and without a history of vasovagal syncope. Methods Fourteen women (aged 18-30) suffering from recurrent vasovagal syncope and 15 age-matched healthy women were included. Graded lower body negative pressure (LBNP) was used to create central hypovolemic stress until signs of presyncope occurred. Echocardiography was applied at rest and throughout LBNP. Cardiovascular biomarkers: copeptin, mid-regional proadrenomedullin, mid-regional pro-ANP, C-terminal proendothelin-1, and plasma norepinephrine were measured both at rest and throughout graded hypovolemia to presyncope. Results Women prone to vasovagal syncope presented with a narrower right ventricle (RV) (29 +/- 1 vs 32 +/- 1 mm, P amp;lt; .05), smaller left atrium (36 +/- 2 vs 47 +/- 3 cm(3), P amp;lt; .01) and lower cardiac output at rest (3.1 +/- 0.2 vs 3.7 +/- 0.2 L/min, P amp;lt; .05) and during graded hypovolemia (P amp;lt; .05). Copeptin was elevated at rest (4.3 +/- 0.8 vs 2.5 +/- 0.2 pmol/L, P amp;lt; .05) and increased more in women with vasovagal syncope during progression of LBNP (P amp;lt; .01). At rest, lower C-terminal proendothelin-1 (35 +/- 5 vs 46 +/- 2 pmol/L, P amp;lt; .05) and higher norepinephrine levels (1.1 +/- 0.1 vs 0.8 +/- 0.1 nmol/L, P amp;lt; .01) were seen in women with vasovagal syncope. Conclusion Women prone to vasovagal syncope demonstrate reduced cardiac preload, lower cardiac output, as well as increased release of vasopressin in rest and during hypovolemic challenge. The results emphasize the importance of venous return and cardiac output in the pathogenesis of vasovagal syncope.

  • 11.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology.
    Kjellberg, Margareta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Karlsson, Erling
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Cardiology. Östergötlands Läns Landsting, Heart Centre, Department of Cardiology.
    Wranne, Bengt
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Pericardiocentesis guided by 2-D echocardiography: The method of choice for treatment of pericardial effusion2003In: Journal of Internal Medicine, ISSN 0954-6820, E-ISSN 1365-2796, Vol. 253, no 4, p. 411-417Article in journal (Refereed)
    Abstract [en]

    Background. Percutaneous pericardiocentesis guided by 2-D echocardiography has been used at Link÷ping Heart Centre since 1983. Aim. To evaluate our experience of this method including a follow-up and also to determine the aetiology of pericardial effusion. Methods. A retrospective study including 120 of 252 consecutive patients punctured. Results. The two most common aetiologies were cardiac surgery (77% valve surgery), followed by malignant disease. The postsurgical effusions became clinically important a median of 12 days after surgery (range 0-56 days). The median survival in the group with malignant disease was 89 days (30-day survival 87%, 1-year survival 10%). Indwelling catheter was used in 93% of the patients. There was no mortality but one patient needed a second pericardiocentesis after an accidental puncture of the right ventricle. Nine patients had rhythm aberrations. Recurring effusion that needed puncture was seen in 8%. Conclusion. Pericardiocentesis guided by 2-D echocardiography is a safe and efficient method to treat pericardial effusion and also valuable as palliative treatment for patients with malignant aetiology of the effusion.

  • 12.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Lindström, Torbjörn
    Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Decreased circulatory response to hypovolemic stress in young women with type 1 diabetes2013In: Diabetes Care, ISSN 0149-5992, E-ISSN 1935-5548, Vol. 36, no 12, p. 4076-4082Article in journal (Refereed)
    Abstract [en]

    OBJECTIVE:

    Diabetes is associated with hemodynamic instability during different situations involving acute circulatory stress in daily life. Young men with type 1 diabetes have been shown to have impaired circulatory response to hypovolemic stress. The effect of type 1 diabetes on cardiovascular response to hypovolemia in young women is unknown, however.

    RESEARCH DESIGN AND METHODS:

    Lower body negative pressure of 30 cm H2O was used to create rapid hypovolemic stress in 15 young women with type 1 diabetes (DW) and 16 healthy women (control subjects [C]). Compensatory mobilization of venous capacitance blood (capacitance response) and net fluid absorption from tissue to blood were measured with a volumetric technique. Overall cardiovascular responses and plasma norepinephrine levels were measured.

    RESULTS:

    Capacitance response was reduced (DW, 0.67 ± 0.05; C, 0.92 ± 0.06) and developed slower in DW (P < 0.01). Capacitance response was further reduced with increasing levels of HbA1c. Fluid absorption was almost halved in DW (P < 0.01). The initial vasoconstrictor response was reduced and developed slower in DW (P < 0.05). Arterial vasoconstriction was further reduced in the presence of microvascular complications (P < 0.05).

    CONCLUSIONS:

    DW present with decreased and slower mobilization of venous capacitance blood and decreased net fluid absorption from tissue to blood during hypovolemic circulatory stress. Collectively, this indicates that DW are prone to hemodynamic instability, especially in the presence of microvascular complications and poor glycemic control.

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  • 13.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Lindström, Torbjörn
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Endocrinology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Type 1 diabetes in young women is associated with decreased circulatory response to hypovolemic stress.2012In: Experimental biology, 2012Conference paper (Refereed)
  • 14.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Reduced defense of central blood volume during acute hypovolemic circulatory stress in aging women2012In: Shock, ISSN 1073-2322, E-ISSN 1540-0514, Vol. 37, no 6, p. 579-585Article in journal (Refereed)
    Abstract [en]

    Elderly men respond with decreased defense of central blood volume during hypovolemic stress, but this response has not been evaluated with age in women. The aim was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in elderly compared to young women. Cardiovascular responses in 34 women, 12 elderly (66.4±1.4 yr) and 22 young (23.1±0.4 yr) were studied during experimental hypovolemic circulatory stress induced by lower body negative pressure (LBNP) of 11-44 mmHg. Volumetric technique was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as to assess net capillary fluid transfer from tissue to blood in the arm. LBNP created comparable hypovolemia in elderly and young women. Heart rate increased less in elderly women (LBNP of 44 mmHg: 20±2 vs. 37±4 %, P < 0.01), but with similar decrease in forearm vascular conductance (FVC). Mobilization of capacitance blood from the peripheral circulation was both slower and decreased by ~60 % in elderly, and net capillary fluid absorption from surrounding tissues was reduced by ~40 % (LBNP of 44 mmHg). In conclusion, during acute hypovolemic circulatory stress elderly women responded with less increase in heart rate but with an equal change in FVC, implying decreased cardiovagal baroreceptor sensitivity. Furthermore, both capacitance response and net capillary fluid absorption were reduced, indicating less efficiency to defend central blood volume in elderly than in young women.

  • 15.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Sex-related effects on venous compliance and capillary filtration in the lower limb2007In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 292, p. R852-R859Article in journal (Refereed)
    Abstract [en]

    Recent studies in humans have suggested sex differences in venous compliance of the lower limb, with lower compliance in women. Capillary fluid filtration could, however, be a confounder in the evaluation of venous compliance. The venous capacitance and capillary filtration response in the calves of 12 women (23.2 ± 0.5 years) and 16 men (22.9 ± 0.5 years) were studied during 8 min lower body negative pressure (LBNP) of 11, 22, and 44 mmHg. Calf venous compliance is dependent on pressure and was determined using the first derivative of a quadratic regression equation that described the capacitance-pressure relationship [compliance = 1 + (2·2· transmural pressure)]. We found a lower venous compliance in women at low transmural pressures, and the venous capacitance in men was increased (P < 0.05). However, the difference in compliance between sexes was reduced and not seen at higher transmural pressures. Net capillary fluid filtration and capillary filtration coefficient (CFC) were greater in women than in men during LBNP (P < 0.05). Furthermore, calf volume increase (capacitance response + total capillary filtration) during LBNP was equivalent in both sexes. When total capillary filtration was not subtracted from the calf capacitance response in the calculation of venous compliance, the sex differences disappeared, emphasizing that venous compliance measurement should be corrected for the contribution of CFC.

  • 16.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Slower lower limb blood pooling in young women with orthostatic intolerance.2015In: Experimental Physiology, ISSN 0958-0670, E-ISSN 1469-445X, Vol. 100, no 1, p. 2-11Article in journal (Refereed)
    Abstract [en]

    NEW FINDINGS: What is the central question of this study? Orthostatic stress is mostly caused by venous blood pooling in the lower limbs. Venous distension elicits sympathetic responses, and increased distension speed enhances the cardiovascular response. We examine whether lower limb blood pooling rate during lower body negative pressure is linked to orthostatic intolerance. What is the main finding and its importance? A similar amount of blood was pooled in the lower limb, but at a slower rate in women who developed signs of orthostatic intolerance. The difference in blood pooling rate increased with orthostatic stress and was most prominent at a presyncope-inducing level of lower body negative pressure. The findings have implications for the pathophysiology as well as treatment of orthostatic intolerance. Vasovagal syncope is common in young women, but its aetiology remains elusive. Orthostatic stress-induced lower limb blood pooling is linked with central hypovolaemia and baroreceptor unloading. Venous distension in the arm elicits a sympathetic response, which is enhanced with more rapid distension. Our aim was to study both the amount and the speed of lower limb pooling during orthostatic stress and its effects on compensatory mechanisms to maintain cardiovascular homeostasis in women with orthostatic intolerance. Twenty-seven healthy women, aged 20-27 years, were subjected to a lower body negative pressure (LBNP) of 11-44 mmHg. Five women developed symptoms of vasovagal syncope (orthostatic intolerant) and were compared with the remaining women, who tolerated LBNP well (orthostatic tolerant). Lower limb blood pooling, blood flow and compensatory mobilization of venous capacitance blood were measured. Lower body negative pressure induced equal lower limb blood pooling in both groups, but at a slower rate in orthostatic intolerant women (e.g. time to 50% of total blood pooling, orthostatic intolerant 44 ± 7 s and orthostatic tolerant 26 ± 2 s; P < 0.001). At presyncope-inducing LBNP, the mobilization of venous capacitance blood was both reduced (P < 0.05) and much slower in orthostatic intolerant women (P = 0.0007). Orthostatic intolerant women elicited blunted arterial vasoconstriction at low-grade LBNP, activating only cardiopulmonary baroreceptors, while orthostatic tolerant women responded with apparent vasoconstriction (P < 0.0001). In conclusion, slower lower limb blood pooling could contribute to orthostatic intolerance in women. Mobilization of venous capacitance blood from the peripheral to the central circulation was both slower and decreased; furthermore, reduced cardiopulmonary baroreceptor sensitivity was found in women who developed orthostatic intolerance. Further studies including women who experience syncope in daily life are needed.

  • 17.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Venous compliance and capillary filtration in the lower limb of women - the effect of ageing2007In: Experimental Biology,2007, 2007Conference paper (Other academic)
  • 18.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Vascular surgery.
    Olsen, H
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Increased susceptibility to acute hypovolemia in ageing females2004In: Svenska Läkaresällskapets Riksstämma,2004, 2004Conference paper (Other academic)
  • 19.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Vascular surgery.
    Olsen, H
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Indications of increased susceptibility to hypovolemic circulatory stress in ageing females2004In: 14th meeting of Hypertension,2004, 2004Conference paper (Other academic)
  • 20.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Olsen, H
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Indications of increased susceptibility to hypovolemic circulatory stress in females than in males2003In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 21, p. S126-S126Conference paper (Other academic)
  • 21.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences.
    Olsen, H.
    Helsingborg Hospital.
    Länne, Toste
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Lower capacitance response and capillary fluid absorption in women to defend central blood volume in response to acute hypovolemic circulatory stress2008In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 295, p. H867-H873Article in journal (Refereed)
    Abstract [en]

    Acute hemorrhage is a leading cause of death in trauma, and women are more susceptible to hypovolemic circulatory stress than men. The mechanisms underlying the susceptibility are not clear, however. The aim of the present study was to examine the compensatory mechanisms to defend central blood volume during experimental hypovolemia in women and men. Twenty-two women (23.1 ± 0.4 yr) and 16 men (23.2 ± 0.5 yr) were included. A lower body negative pressure (LBNP) of 11–44 mmHg induced experimental hypovolemic circulatory stress. The volumetric technique was used to assess the capacitance response (redistribution of peripheral venous blood to the central circulation) as well as to assess net capillary fluid transfer from tissue to blood in the arm. Plasma norepinephrine (NE) and forearm blood flow were measured before and during hypovolemia, and forearm vascular resistance (FVR) was calculated. LBNP created comparable hypovolemia in women and men. FVR increased less in women during hypovolemic stress, and no association between plasma NE and FVR was seen in women (R2 = 0.01, not significant), in contrast to men (R2 = 0.59, P < 0.05). Women demonstrated a good initial capacitance response, but this was not maintained with time, in contrast to men [e.g., decreased by 24 ± 4% (women) vs. 4 ± 5% (men), LBNP of 44 mmHg, P < 0.01], and net capillary fluid absorption from tissue to blood was lower in women (0.086 ± 0.007 vs. 0.115 ± 0.011 ml·100 ml–1·min–1, P < 0.05). In conclusion, women showed impaired vasoconstriction, reduced capacitance response with time, and reduced capillary fluid absorption during acute hypovolemic circulatory stress, indicating less efficiency to defend central blood volume than men.

  • 22.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Olsen, Henrik
    Helsingborg Hospital.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Impaired compensatory response to hypovolaemic circulatory stress in type 1 diabetes mellitus2011In: DIABETES and VASCULAR DISEASE RESEARCH, ISSN 1479-1641, Vol. 8, no 2, p. 136-142Article in journal (Refereed)
    Abstract [en]

    Diabetes mellitus is associated with decreased haemodynamic stability and reduced tolerance to hypovolaemia. Compensatory haemodynamic responses during experimental hypovolaemia in type I diabetes patients with (DMR+) and without (DMR-) retinopathy as well as healthy controls (C) were studied. Lower body negative pressure created hypovolaemic circulatory stress. Volumetric techniques were used to assess the compensatory capacitance response (redistribution of peripheral venous blood to the central circulation) and to assess capillary fluid absorption from tissue to blood. The compensatory capacitance response was 1/3 lower in DMR+ compared with C (p = 0.002) and DMR- (p = 0.01). Net capillary fluid absorption was reduced by one-third in DMR- and DMR+ compared with C (each p less than 0.05). Type I diabetes patients with retinopathy demonstrate reduced mobilisation of peripheral venous blood to the central circulation. Furthermore, type I diabetes patients present with impaired capillary fluid absorption, which in combination with potentially decreased sympathetic vasoconstriction impedes cardiovascular homeostasis during acute hypovolaemic stress.

  • 23.
    Lindenberger, Marcus
    et al.
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences.
    Toste, Länne
    Linköping University, Department of Medicine and Health Sciences, Physiology . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Decreased capillary filtration but maintained venous compliance in the lower limb of aging women2007In: American Journal of Physiology. Heart and Circulatory Physiology, ISSN 0363-6135, E-ISSN 1522-1539, Vol. 293, p. H3568-H3574Article in journal (Refereed)
    Abstract [en]

    There are sex-related differences in venous compliance and capillary filtration in the lower limbs, which to some extent can explain the susceptibility to orthostatic intolerance in young women. With age, venous compliance and capacitance are reduced in men. This study was designed to evaluate age-related changes in venous compliance and capillary filtration in the lower limbs of healthy women. Included in this study were 22 young and 12 elderly women (23.1 ± 0.4 and 66.4 ± 1.4 yr). Lower body negative pressure (LBNP) of 11, 22, and 44 mmHg created defined transmural pressure gradients in the lower limbs. A plethysmographic technique was used on the calf to assess venous capacitance and net capillary filtration. Venous compliance was calculated with the aid of a quadratic regression equation. No age-related differences in venous compliance and capacitance were found. Net capillary filtration and capillary filtration coefficient (CFC) were lower in elderly women at a LBNP of 11 and 22 mmHg (0.0032 vs. 0.0044 and 0.0030 vs. 0.0041 ml·100 ml–1·min–1·mmHg–1, P < 0.001). At higher transmural pressure (LBNP, 44 mmHg), CFC increased by 1/3 (0.010 ml·100 ml–1·min–1·mmHg–1) in the elderly (P < 0.001) but remained unchanged in the young women. In conclusion, no age-related decrease in venous compliance and capacitance was seen in women. However, a decreased CFC was found with age, implying reduced capillary function. Increasing transmural pressure increased CFC in the elderly women, indicating an increased capillary susceptibility to transmural pressure load in dependent regions. These findings differ from earlier studies on age-related effects in men, indicating sex-specific vascular aging both in the venous section and microcirculation.

  • 24.
    Lindenberger, Marcus
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Zachrisson, Helene
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Neider, Daniel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Venous compliance and wall distensibility in the venous compartments of the lower limb in man2008In: Experimental Biology,2008, 2008Conference paper (Refereed)
    Abstract [en]

      

  • 25.
    Neider, Daniel
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Hallman, Daniel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Zachrisson, Helene
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Clinical Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Physiology. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Venous compliance in the Superficial Femoral Vein and Greater Saphenous Vein in health males.2007In: Kardiovaskulära vårmötet,2007, 2007Conference paper (Other academic)
    Abstract [en]

      

  • 26.
    Nilsson, Lena
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping. Östergötlands Läns Landsting, Anaesthesiology and Surgical Centre.
    Goscinski, Tomas
    Linköping University, Department of Medical and Health Sciences, Pharmacology. Linköping University, Faculty of Health Sciences.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Johansson, Anders
    Linköping University, Department of Biomedical Engineering, Physiological Measurements. Linköping University, The Institute of Technology.
    Respiratory variations in the photoplethysmographic waveform: acute hypovolaemia during spontaneous breathing is not detected2010In: Physiological Measurement, ISSN 0967-3334, E-ISSN 1361-6579, Vol. 31, no 7, p. 953-962Article in journal (Refereed)
    Abstract [en]

    Recent studies using photoplethysmographic (PPG) signals from pulse oximeters have shown potential to assess hypovolaemia during spontaneous breathing. This signal is heavily filtered and reports are based on respiratory variations in the small pulse synchronous variation of PPG. There are stronger respiratory variations such as respiratory synchronous variation (PPGr) in the baseline of the unfiltered PPG signal. We hypothesized that PPGr would increase during hypovolaemia during spontaneous breathing. Hemodynamic and respiratory data were recorded together with PPG infrared signals from the finger, ear and forearm from 12 healthy male volunteers, at rest and during hypovolaemia created by the application of a lower body negative pressure (LBNP) of 15, 30 and 60 cmH(2)O. Hemodynamic and respiratory values changed significantly. From rest to the LBNP of 60 cmH(2)O systolic blood pressure fell from median (IQR) 116 (16) to 101 (23) mmHg, the heart rate increased from 58 (16) to 73 (16) beats min(-1), and the respiratory rate increased from 9.5 (2.0) to 11.5 (4.0) breaths min(-1). The amplitude of PPGr did not change significantly at any measurement site. The strongest effect was seen at the ear, where the LBNP of 60 cmH(2)O gave an amplitude increase from 1.0 (0.0) to 1.31 (2.24) AU. PPG baseline respiratory variations cannot be used for detecting hypovolaemia in spontaneously breathing subjects.

  • 27.
    Nilsson, Lena
    et al.
    Linköping University, Department of Medical and Health Sciences, Anesthesiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Hahn, Robert
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Surgery.
    The effect of positive end-expiratory pressure and tripled tidal volume on pleth variability index during hypovolaemia in conscious subjects A volunteer study2013In: European Journal of Anaesthesiology, ISSN 0265-0215, E-ISSN 1365-2346, Vol. 30, no 11, p. 671-677Article in journal (Refereed)
    Abstract [en]

    BACKGROUNDThe pulse oximeter measurement pleth variability index (PVI) can detect hypovolaemia during positive pressure ventilation.OBJECTIVESWe studied whether PVI can detect a hypovolaemic state in spontaneously breathing humans and whether better discrimination is obtained by modifying the breathing patterns.DESIGNExperimental study.SETTINGClinical physiology department in a university hospital.PARTICIPANTSFourteen healthy volunteers aged between 18 and 27 (mean 21) years.INTERVENTIONSA hypovolaemic state was induced by lower body negative pressure (LBNP) of 40mmHg (LBNP40) and 15mmHg (LBNP15). Data were collected in four separate series with normal breathing and application of positive end-expiratory pressure (PEEP) 5cmH(2)O, with and without tripling of the tidal volume.MAIN OUTCOME MEASURESPVI (meanstandard deviation), heart rate, arterial blood pressure and cardiac index (CI).RESULTSCardiac index decreased from 2.4 to 1.7 and 2.1 lmin(-1)m(-2) at LBNP40 and LBNP15, respectively (Pandlt;0.001). The mean PVI for the four breathing modes increased with the degree of LBNP, from 23.55.9% at baseline to 27.9 +/- 9.3% at LBNP40, and to 25.2 +/- 6.9% at LBNP15 (Pandlt;0.01). The greatest increase in PVI, to 31.7 +/- 12.3%, was recorded for the PEEP and tripled tidal volume breathing mode when hypovolaemia was induced by LBNP40. However, there was considerable overlap between the LBNP levels.CONCLUSIONThe PVI increased significantly for higher LBNP, but overlap was common regardless of breathing mode. The PVI can be used to indicate a hypovolaemic state during spontaneous breathing in groups but not in individuals.TRIAL REGISTRATIONClinicaltrials.gov identifier NCT01456559

  • 28. Olsen, H
    et al.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Impaired compensatory capacitance response from muscle and skin during hypovolemic circulatory stress - Importance for the cardiovascular morbidity/mortality in type 1 diabetes mellitus?2003In: Journal of Hypertension, ISSN 0263-6352, E-ISSN 1473-5598, Vol. 21, p. S86-S86Conference paper (Other academic)
  • 29.
    Shlimon, Kristian
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Lindenberger, Marcus
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Welander, Martin
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Thoracic and Vascular Surgery.
    Dangardt, Frida
    Department of Paediatric Radiology and Clinical Physiology, The Queen Silvia Childrens Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden; Department of Molecular and Clinical Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
    Bjarnegård, Niclas
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Radial artery lumen diameter and intima thickness in patients with abdominal aortic aneurysm2022In: JVS-Vascular Science, ISSN 2666-3503, Vol. 3, p. 274-284Article in journal (Refereed)
    Abstract [en]

    Objective: Abdominal aortic aneurysm (AAA) is associated with dilatation of central elastic arteries, while it is uncertain whether peripheral muscular arteries are affected. The aim of this study was to investigate radial artery diastolic lumen diameter (LD), wall thickness, and circumferential wall stress (CWS) in patients with AAA. Methods: We included 130 men with AAA (mean age, 70.4 ± 3.5 years) and 61 men without AAA (mean age, 70.5 ± 3.2 years) in the study. High-frequency ultrasound examination (50 MHz) was used to measure radial artery diameter, wall thickness, and CWS was calculated. Results: Men with AAA exhibited smaller radial artery LD (2.34 ± 0.42 mm vs 2.50 ± 0.38 mm; P &lt;.01), thicker intima (0.094 ± 0.024 mm vs 0.081 ± 0.018 mm; P &lt;.001), similar intima-media (0.28 ± 0.05 vs 0.26 ± 0.05 mm; P = NS), and lower CWS (42.9 ± 10.2 kPa vs 48.6 ± 11.4 kPa; P &lt;.001), compared with controls. Subgroup analyses including all patients showed smaller LD and thicker intima in patients on statin therapy versus no statin therapy and current/ex-smoking versus never smoking. Individuals with hypertension versus no hypertension also presented with thicker intima, but with no difference in LD. Conclusions: AAAs demonstrated a smaller LD and thicker intima in the radial artery, in contrast with the theory of a general dilating diathesis of the arteries. Apart from AAA, other factors such as atherosclerosis, smoking habits, and hypertension might also be determinants of radial artery caliber and thickness. Clinical Relevance: The clinical relevance of this study is the added insight into the pathophysiology of abdominal aortic aneurysm (AAA). Today, the management of AAA is focused on reduction of general cardiovascular risk factors and treatment is based on surgical approaches when the AAA is already manifest. By shedding light on unknown pathophysiological aspects of AAA, it will eventually be possible to develop targeted pharmacological treatments to prevent the formation of AAA, to halt disease progression, and to find early cardiovascular markers of AAA. © 2022 Society for Vascular Surgery

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  • 30.
    Skoog, Johan
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Ekman, Mikael
    Ekman Biomed Data, Sweden.
    Holmberg, Bengt
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Reduced venous compliance: an important determinant for orthostatic intolerance in women with vasovagal syncope2016In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 310, no 3, p. R253-R261Article in journal (Refereed)
    Abstract [en]

    The influence of lower limb venous compliance on orthostatic vasovagal syncope (VVS) is uncertain. The most widespread technique to calculate venous compliance uses a nonphysiological quadratic regression equation. Our aim was therefore to construct a physiologically derived venous wall model (VWM) for calculation of calf venous compliance and to determine the effect of venous compliance on tolerance to maximal lower body negative pressure (LBNP). Venous occlusion plethysmography was used to study calf volume changes in 15 women with VVS (25.5 +/- 1.3 yr of age) and 15 controls (22.8 +/- 0.8 yr of age). The fit of the VWM and the regression equation to the experimentally induced pressure-volume curve was examined. Venous compliance was calculated as the derivative of the modeled pressure-volume relationship. Graded LBNP to presyncope was used to determine the LBNP tolerance index (LTI). The VWM displayed a better fit to the experimentally induced pressure-volume curve (P &lt; 0.0001). Calf blood pooling was similar in the groups and was not correlated to the LTI (r = 0.204, P = 0.30). Venous compliance was significantly reduced at low venous pressures in women with VVS (P = 0.042) and correlated to the LTI (r = 0.459, P = 0.014) in the low pressure range. No correlation was found between venous compliance at high venous pressures and the LTI. In conclusion, the new VWM accurately adopted the curvilinear pressure-volume curve, providing a valid characterization of venous compliance. Reduced venous compliance at low venous pressures may adversely affect mobilization of peripheral venous blood to the central circulation during hypovolemic circulatory stress in women with VVS.

  • 31.
    Skoog, Johan
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Shlimon, Kristian
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Bjarnegård, Niclas
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Lindenberger, Marcus
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Assessment of Upper Extremity Venous Compliance in Patients With Abdominal Aortic Aneurysms2020In: European Journal of Vascular and Endovascular Surgery, ISSN 1078-5884, E-ISSN 1532-2165, Vol. 60, no 5, p. 739-746Article in journal (Refereed)
    Abstract [en]

    Objective: Abdominal aortic aneurysm (AAA) is associated with morphological and functional changes in both aneurysmal and non-aneurysmal arteries. However, it remains uncertain whether similar changes also exist in the venous vasculature. The aim of this study was to evaluate global venous function in patients with AAA and controls. Methods: This experimental study comprised 31 men with AAA (mean +/- standard deviation age 70.0 +/- 2.8 years) and 29 male controls (aged 70.6 +/- 3.4 years). Venous occlusion plethysmography (VOP) was used to evaluate arm venous compliance at venous pressures between 10 and 60 mmHg in steps of 5 mmHg. Compensatory mobilisation of venous capacitance blood (capacitance response) was measured with a volumetric technique during experimental hypovolaemia induced by lower body negative pressure (LBNP). Results: The VOP induced pressure-volume curve was significantly less steep in patients with AAA (interaction, p &lt; .001), indicating lower venous compliance. Accordingly, the corresponding pressure-compliance curves displayed reduced venous compliance at lower venous pressures in patients with AAA vs. controls (interaction, p &lt; .001; AAA vs. control, p = .018). After adjusting for arterial hypertension, diabetes mellitus, hyperlipidaemia, chronic obstructive pulmonary disease, and smoking, VOP detected differences in venous compliance remained significant at low venous pressures, that is, at 10 mmHg (p = .008), 15 mmHg (p = .013), and 20 mmHg (p = .026). Mean venous compliance was negatively correlated with aortic diameter (r = -.332, p = .010). Mobilisation of venous capacitance response during LBNP was reduced by approximately 25% in patients with AAA (p = .030), and the redistribution of venous blood during LBNP was negatively correlated with aortic diameter (r = -.417, p = .007). Conclusion: Men with AAA demonstrated reduced venous compliance and, as a result, a lesser capacity to mobilise peripheral venous blood to the central circulation during hypovolaemic stress. These findings imply that the AAA disease may be accompanied by functional changes in the venous vascular wall.

  • 32.
    Skoog, Johan
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Zachrisson, Helene
    Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Ekman, Mikael
    Ekman Biomed Data AB, Gothenburg, Sweden.
    Ewerman, Lea
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Thoracic and Vascular Surgery. Linköping University, Faculty of Health Sciences.
    Calf venous compliance measured by venous occlusion plethysmography: methodological aspects.2015In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 115, no 2, p. 245-56Article in journal (Refereed)
    Abstract [en]

    PURPOSE: Calf venous compliance (C calf) is commonly evaluated with venous occlusion plethysmography (VOP) during a standard cuff deflation protocol. However, the technique relies on two not previously validated assumptions concerning thigh cuff pressure (P cuff) transmission and the impact of net fluid filtration (F filt) on C calf. The aim was to validate VOP in the lower limb and to develop a model to correct for F filt during VOP.

    METHODS: Strain-gauge technique was used to study calf volume changes in 15 women and 10 age-matched men. A thigh cuff was inflated to 60 mmHg for 4 and 8 min with a subsequent decrease of 1 mmHg s(-1). Intravenous pressure (P iv) was measured simultaneously. C calf was determined with the commonly used equation [Compliance = β 1 + 2β 2 × P cuff] describing the pressure-compliance relationship. A model was developed to identify and correct for F filt.

    RESULTS: Transmission of P cuff to P iv was 100 %. The decrease in P cuff correlated well with P iv reduction (r = 0.99, P < 0.001). Overall, our model showed that C calf was underestimated when F filt was not accounted for (all P < 0.01). F filt was higher in women (P < 0.01) and showed a more pronounced effect on C calf compared to men (P < 0.05). The impact of F filt was similar during 4- and 8-min VOP.

    CONCLUSIONS: P cuff is an adequate substitute for P iv in the lower limb. F filt is associated with an underestimation of C calf and differences in the effect of F filt during VOP can be accounted for with the correction model. Thus, our model seems to be a valuable tool in future studies of venous wall function.

  • 33.
    Skoog, Johan
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Reduced compensatory responses to maintain central blood volume during hypovolemic stress in women with vasovagal syncope2017In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology, ISSN 0363-6119, E-ISSN 1522-1490, Vol. 312, no 1, p. R55-R61Article in journal (Refereed)
    Abstract [en]

    Although vasovagal syncope (VVS) is a common clinical condition, the underlying pathophysiology is not fully understood. A decrease in cardiac output has recently been suggested as a factor in orthostatic VVS. The aim was to investigate compensatory mechanisms to maintain central blood volume and venous return during hypovolemic stress in women with VVS. Fourteen VVS women (25.7 +/- 5.0 yr) and 15 matched controls (22.8 +/- 3.2 yr) were investigated. Single-step and graded lower body negative pressure (LBNP) to presyncope were used to create hypovolemic stress. Peripheral mobilization of venous blood from the arm (capacitance response and net capillary fluid absorption) and lower limb blood pooling (calf capacitance response) were evaluated using a volumetric technique. Cardiovascular responses and plasma norepinephrine (P-NE) were measured. Resting P-NE was elevated in VVS women (P amp;lt; 0.01). Despite a similar hypovolemic stimulus, the increase in P-NE was blunted (P amp;lt; 0.01) and the maximal percent increase in total peripheral resistance was reduced (P amp;lt; 0.05) during graded LBNP in VVS women. The arm capacitance response was slower (P amp;lt; 0.05) and reduced in VVS women at higher levels of LBNP (P amp;lt; 0.05). Capillary fluid absorption from extra-to intravascular space was reduced by similar to 40% in VVS women (P amp;lt; 0.05). Accordingly, the reduction in cardiac output was more pronounced (P amp;lt; 0.05). In conclusion, in VVS women, mobilization of peripheral venous blood and net fluid absorption from tissue to blood during hypovolemic stress were decreased partly as a result of an attenuated vasoconstrictor response. This may seriously impede maintenance of cardiac output during hypovolemic stress and could contribute to the pathogenesis of VVS.

  • 34.
    Skoog, Johan
    et al.
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine.
    Zachrisson, Helene
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Slower Lower Limb Blood Pooling Increases Orthostatic Tolerance in Women with Vasovagal Syncope2016In: Frontiers in Physiology, E-ISSN 1664-042X, Vol. 7, no 232Article in journal (Refereed)
    Abstract [en]

    Background and Aim: Slower lower limb blood pooling and associated blunted sympathetic activation has been detected in healthy women prone to orthostatic syncope. Whether these findings are true also for patients with vasovagal syncope (WS) is unknown. The aim was to investigate initial blood pooling time (pooling(time), time to 50% of total blood pooling) together with hemodynamic responses and orthostatic tolerance during lower body negative pressure (LBNP) in WS and healthy controls. Methods and Results: Fourteen WS women (25.7 +/- 1.3 years) and 15 healthy women (22.8 +/- 0.8 years) were subjected to single-step and graded LBNP to pre-syncope. Lower limb blood pooling (ml 100 ml(-1)), poolingtime (s), hemodynamic responses and LBNP-tolerance were evaluated. LBNP induced comparable lower limb blood pooling in both groups (controls, 3.1 +/- 0.3; WS, 2.9 +/- 0.3 ml 100 ml(-1), P = 0.70). In controls, shorter pooling(time) correlated to higher LBNP-tolerance (r = -0.550, P amp;lt; 0.05) as well as better maintained stroke volume (r =-0.698, P amp;lt; 0.01) and cardiac output (r = -0.563, P amp;lt; 0.05). In contrast, shorter poolingtime correlated to lower LBNP-tolerance in VVS (r = 0.821, P amp;lt; 0.001) and larger decline in stroke volume (r = 0.611, P 0.05). Furthermore, in controls, shorter poolingtime correlated to baroreflex-mediated hemodynamic changes during LBNP, e.g., increased vasoconstriction (P amp;lt; 0.001). In VVS, poolingtime was not correlated with LBNP-induced baroreceptor unloading, but rather highly correlated to resting calf blood flow (P amp;lt; 0.001). Conclusions: Shorter poolingtime seems to elicit greater sympathetic activation with a concomitant higher orthostatic tolerance in healthy women. The contrasting findings in AS indicate a deteriorated vascular sympathetic control suggesting well-defined differences already in the initial responses during orthostatic stress.

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  • 35.
    Trenti, Chiara
    et al.
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ziegler, Magnus
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Bjarnegård, Niclas
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Clinical Physiology in Linköping.
    Ebbers, Tino
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lindenberger, Marcus
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Dyverfeldt, Petter
    Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Wall shear stress and relative residence time as potential risk factors for abdominal aortic aneurysms in males: a 4D flow cardiovascular magnetic resonance case-control study2022In: Journal of Cardiovascular Magnetic Resonance, ISSN 1097-6647, E-ISSN 1532-429X, Vol. 24, no 1, article id 18Article in journal (Refereed)
    Abstract [en]

    Background Abdominal aortic aneurysms (AAA) can lead to catastrophic events such as dissection or rupture, and are an expression of general aortic disease. Low wall shear stress (WSS), high oscillatory shear index (OSI), and high relative residence time (RRT) have been correlated against increased uptake of inflammatory markers in the vessel wall and may improve risk stratification of AAA. We sought to obtain a comprehensive view of WSS, OSI, and RRT in the whole aorta for patients with AAA and age-matched elderly controls and young normal controls. Methods 4D Flow cardiovascular magnetic resonance images of the whole aorta were acquired in 18 AAA patients (70.8 +/- 3.4 years), 22 age-matched controls (71.4 +/- 3.4 years), and 23 young subjects (23.3 +/- 3.1 years), all males. Three-dimensional segmentations of the whole aorta were created for all timeframes using a semi-automatic approach. The aorta was divided into five segments: ascending aorta, arch, descending aorta, suprarenal and infrarenal abdominal aorta. For each segment, average values of peak WSS, OSI, and RRT were computed. Students t-tests were used to compare values between the three cohorts (AAA patients vs elderly controls, and elderly controls vs young controls) where the data were normally distributed, and the non-parametric Wilcoxon rank sum tests were used otherwise. Results AAA patients had lower peak WSS in the descending aorta as well as in the abdominal aorta compared to elderly controls (p &lt;= 0.001), similar OSI, but higher RRT in the descending and abdominal aorta (p &lt;= 0.001). Elderly controls had lower peak WSS compared to young controls throughout the aorta (p &lt; 0.001), higher OSI in all segments except for the infrarenal aorta (p &lt; 0.001), and higher RRT throughout the aorta, except the infrarenal aorta (p &lt; 0.001). Conclusions This study provides novel insights into WSS, OSI, and RRT in patients with AAA in relation to normal ageing, highlighting how AAA patients have markedly abnormal hemodynamic stresses not only in the infrarenal, but in the entire aorta. Moreover, we identified RRT as a marker for abnormal AAA hemodynamics. Further investigations are needed to explore if RRT or other measures of hemodynamics stresses best predict AAA growth and/or rupture.

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  • 36.
    Waldreus, Nana
    et al.
    Linköping University, Department of Social and Welfare Studies, Division of Health, Activity and Care. Linköping University, Faculty of Health Sciences.
    Hahn, Robert G.
    Linköping University, Department of Medical and Health Sciences, Division of Drug Research. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Anaesthetics, Operations and Specialty Surgery Center, Department of Anaesthesiology and Intensive Care in Linköping. Sodertalje Sjukhus, Sweden .
    Engvall, Jan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Skoog, Johan
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences.
    Ewerman, Lea
    Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Health Sciences.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Cardiology in Linköping.
    Thirst response to acute hypovolaemia in healthy women and women prone to vasovagal syncope2013In: Physiology and Behavior, ISSN 0031-9384, E-ISSN 1873-507X, Vol. 120, p. 34-39Article in journal (Refereed)
    Abstract [en]

    The present study measured self-perceived thirst and plasma angiotensin II (ATII) concentrations during graded hypovolaemic stress, induced by lower body negative pressure (LBNP), to elucidate the dependence of thirst on haemodynamics. A total of 24 women aged between 20 and 36 (mean age, 23) years rated their thirst on a visual analogue scale, graded from 0 to 100, when LBNP of 20,30 and 40 mm Hg was applied. Half of the women had a history of vasovagal syncope (VVS). The results showed that the thirst score increased three-fold when LBNP was applied, from 11 (median; 25th-75th percentiles, 9-25) to 34 (27-53; P andlt; 0.001). The women in the VVS group had twice as great an increase as those without a history of VVS (P andlt; 0.02). The plasma ATII concentration increased significantly in response to LBNP, both in the VVS group and in the control group, but the changes did not correlate with thirst. Application of LBNP decreased systolic and mean arterial pressures, cardiac output and pulse pressure (P andlt; 0.001 for all), but thirst correlated only with increase in heart rate and, independently, with reduction of mean arterial pressure. In conclusion, thirst and ATII increase in response to hypovolaemic stress, but are not statistically related. The haemodynamic parameter that was most strongly related to thirst was tachycardia.

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  • 37.
    Zachrisson, Helene
    et al.
    Linköping University, Department of Medical and Health Sciences, Clinical Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Clinical Physiology UHL.
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Hallman, Daniel
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Ekman, M.
    Biomed Data AB, Gothenburg, Sweden.
    Neider, Daniel
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences.
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Physiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Thoracic and Vascular Surgery in Östergötland.
    Diameter and compliance of the greater saphenous vein - effect of age and nitroglycerine2011In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 31, no 4, p. 300-306Article in journal (Refereed)
    Abstract [en]

    Objectives: The greater saphenous vein (GSV) is commonly used in autologous vein graft surgery. GSV diameter has proven to influence graft patency, and furthermore venous compliance might be of importance. The purpose of the study was to evaluate the effect of age on GSV diameter and compliance, and to evaluate the effect of nitroglycerine (NTG). Methods: The diameter and compliance of the GSV, with and without NTG, were examined with B-mode ultrasound in 12 elderly (70.3 +/- 1.2 year) and 15 young (25.1 +/- 0.6 year) men. The GSV diameter at the thigh and calf level was measured at rest, after 6 min of venous stasis (60 mmHg) and after NTG administration. Pressure-area curves during a linear venous pressure decrease were produced. Venous compliance was calculated using the quadratic regression equation (area) = beta(0) + beta(1) (cuff pressure) + beta(2) (cuff pressure)(2). Results: GVS diameter between the groups showed significant lower diameter in elderly compared to young men (Pless than0.05). Venous occlusion increased GSV diameter in elderly men (Pless than0.01) as well as young men (Pless than0.001). NTG increased GSV diameter in elderly men (Pless than0.01) with an equal trend in young men. During venous occlusion, after administration of NTG, GSV diameter increased further in both elderly (Pless than0.01) and young men (Pless than0.001). GSV compliance was decreased in elderly (beta(1), 0.037 +/- 0019, beta(2), -0.000064 +/- 00017) versus young men (beta(1), 0.128 +/- 0.013, beta(2), -0.00010 +/- 000018) [Pless than0.001 (beta(1)), Pless than0.02 (beta(2))]. Conclusions: Baseline GSV diameter as well as GSV compliance is decreased in elderly men compared to the young subjects. As reduced GSV diameter as well as reduced compliance is related to decreased graft patency, these findings might be of importance for the uses of GSV as graft material in cardiovascular bypass surgery. The clinical value has to be clarified in future studies.

  • 38.
    Zachrisson, Helene
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Clinical Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Clinical Physiology.
    Lindenberger, Marcus
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology .
    Hallman, Daniel
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences.
    Länne, Toste
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Physiology . Östergötlands Läns Landsting, Heart Centre, Department of Thoracic and Vascular Surgery.
    Diameter and compliance of the great saphenous vein2008In: Experimental Biology,2008, 2008Conference paper (Refereed)
  • 39.
    Ziegler, Magnus
    et al.
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Welander, Martin
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Lantz, Jonas
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lindenberger, Marcus
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Cardiology in Linköping.
    Bjarnegård, Niclas
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ebbers, Tino
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Clinical Physiology in Linköping. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Länne, Toste
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Heart and Medicine Center, Department of Thoracic and Vascular Surgery.
    Dyverfeldt, Petter
    Linköping University, Department of Medical and Health Sciences, Division of Cardiovascular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Visualizing and quantifying flow stasis in abdominal aortic aneurysms in men using 4D flow MRI2019In: Magnetic Resonance Imaging, ISSN 0730-725X, E-ISSN 1873-5894, Vol. 57, p. 103-110Article in journal (Refereed)
    Abstract [en]

    Purpose: To examine methods for visualizing and quantifying flow stasis in abdominal aortic aneurysms (AAA) using 4D Flow MRI. Methods: Three methods were investigated: conventional volumetric residence time (VRT), mean velocity analysis (MVA), and particle travel distance analysis (TDA). First, ideal 4D Flow MRI data was generated using numerical simulations and used as a platform to explore the effects of noise and background phase-offset errors, both of which are common 4D Flow MRI artifacts. Error-free results were compared to noise or offset affected results using linear regression. Subsequently, 4D Flow MRI data for thirteen (13) subjects with AAA was acquired and used to compare the stasis quantification methods against conventional flow visualization. Results: VRT (R-2 = 0.69) was more sensitive to noise than MVA (R-2 = 0.98) and TDA (R-2 = 0.99) at typical noncontrast signal-to-noise ratio levels (SNR = 20). VRT (R-2 = 0.14) was more sensitive to background phase-offsets than MVA (R-2 = 0.99) and TDA (R-2 = 0.96) when considering a 95% effective background phase-offset correction. Qualitatively, TDA outperformed MVA (Wilcoxon p amp;lt; 0.005, mean score improvement 1.6/5), and had good agreement (median score 4/5) with flow visualizations. Conclusion: Flow stasis can be quantitatively assessed using 4D Flow MRI. While conventional residence time calculations fail due to error accumulation as a result of imperfect measured velocity fields, methods that do not require lengthy particle tracking perform better. MVA and TDA are less sensitive to measurement errors, and TDA generates results most similar to those obtained using conventional flow visualization.

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  • 40.
    Östring, Robert
    et al.
    Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Lindenberger, Marcus
    Linköping University, Faculty of Medicine and Health Sciences. Linköping University, Department of Health, Medicine and Caring Sciences, Division of Diagnostics and Specialist Medicine. Region Östergötland, Heart Center, Department of Cardiology in Linköping.
    Kvitting, John-Peder
    Oslo universitetssykehus, Rikshospitalet, Norge.
    ABC om akut aorta­dissektion2022In: Läkartidningen, ISSN 0023-7205, E-ISSN 1652-7518, Vol. 119, article id 21168Article in journal (Other academic)
1 - 40 of 40
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