Objective: The popliteal artery is, after the aorta, the most common site for aneurysm formation. Why the popliteal artery is more susceptible than other peripheral muscular arteries is unknown. An important factor may be differences in arterial wall composition as compared with other peripheral muscular arteries, which in turn affect wall properties. These are however unknown. We studied the mechanical wall properties of the popliteal artery in healthy subjects. Material and Methods: An ultrasound echo-tracking system was used to measure pulsatile changes in popliteal diameter in 108 healthy subjects (56 female, 52 male, age range, 9-82 years). In combination with blood pressure, stiffness (β), strain, cross-sectional artery wall compliance coefficient (CC), and distensibility coefficient (DC) were calculated. Intima-media thickness (IMT) was registered with a Philips P700 ultrasound scanner. Results: The popliteal diameter increased with age, and was larger in male subjects than in female subjects (P < .001). Fractional diameter change (strain) decreased with age (P < .001), and strain values were lower in male subjects than in female subjects (P < .01). Accordingly, stiffness increased with age (P < .001), with higher stiffness values in male subjects (P < .01). DC decreased with age (P < .001), with lower DC values in male subjects (P < .01). CC decreased with age, with no difference between genders (P < .001). IMT increased with age (P < .001), with higher IMT values in male subjects (P < .001). The increase in IMT did not affect distensibility. Conclusion: The wall properties of the popliteal artery are affected by age and gender, not only with an increase in diameter, but also with an age-related decrease in distensibility, with male subjects having lower distensibility than in female subjects. This seems not to be the behavior of a true muscular artery, but of a central elastic artery, such as the aorta, and might have implications for susceptibility to arterial dilatation, as well as the association of aneurysm formation between the aorta and the popliteal artery.

Introduction: The popliteal artery (PA) is, after aorta, the most common site for aneurysm formation. Why the PA is more susceptible than other peripheral muscular arteries is unknown. We hypothesised that the wall composition, which in turn affects wall properties, as well as the circumferential wall stress imposed on the arterial wall, might differ compared to other muscular arteries. The aim was to study the circumferential wall stress of the PA in healthy subjects with the adjacent muscular common femoral artery (CFA) as a comparison.

Material and Methods: Ninety-four healthy subjects were included in this study (45 males, range 10-78 years and 49 females, range 10-83 years). The lumen diameter (LD) and intima-media thickness (IMT) in the PA and CFA were investigated with a Philips P700 ultrasound device. Together with blood pressure the circumferential wall stress was defined according to the law of Laplace adjusted for IMT.

Results: The diameter increased with age in both PA and CFA (P<.001), with males having larger diameter than females (P<.001). IMT increased with age in both PA and CFA (P<.001), with higher IMT values in males only in PA (P<0.001). The calculated wall stress was unchanged with age in both arteries, but lower in PA than in CFA in both male and female subjects (P<0.001).

Conclusion: This study shows that the popliteal and common femoral artery wall stress is maintained during ageing, probably due to compensatory remodeling response with an increase in arterial wall thickness. However, the stress imposed on the popliteal artery wall is quite low, indicating that other mechanisms than wall stress contribute to the process of pathological arterial dilatation in the popliteal artery.

Objective: A genetic polymorphism in the angiotensin-converting enzyme gene (ACE I/D polymorphism) has been associated with abdominal aortic aneurysm and a link between aortic aneurysm and aortic stiffness has been suggested. The aim of this study was to explore the links between ACE I/D polymorphism, circulating ACE, and abdominal aortic wall integrity as reflected by abdominal aortic wall stiffness.

Material: The study population consisted of 406 subjects (212 men and 194 women) aged 70-88 years.

Methods: The mechanical properties of the abdominal aorta were determined 3-4 cm proximal to the aortic bifurcation using a Wall Track System. ACE-genotype was determined by PCR followed by gel electrophoresis, and circulating ACE level was measured by ELISA.

Results: Men carrying the ACE D allele had lower distensibility coefficient than II carriers (ID/DD 8.09 vs II 10.38, P=0.017). Multiple regression analyses showed additional associations between the ACE D allele and increased stiffness β as well as reduced cross-sectional compliance.

Conclusion: This study showed that men carrying the ACE D allele have stiffer abdominal aortas compared to II carriers. Deranged abdominal aortic stiffness indicates impaired vessel wall integrity, which along with other local predisposing factors, may be of importance in aneurysmal disease.

Aortic stiffness is a predictor of cardiovascular mortality. The mechanical properties of the arterial wall depend on the connective tissue framework, with variation in fibrillin-1 and collagen I genes being associated with aortic stiffness and/or pulse pressure elevation. The aim of this study was to investigate whether variation in fibrillin-1 genotype was associated with aortic stiffness in men. The mechanical properties of the abdominal aorta of 79 healthy men (range 28-81 yr) were investigated by ultrasonographic phase-locked echo tracking. Fibrillin-1 genotype, characterized by the variable tandem repeat in intron 28, and collagen type I alpha 1 genotype characterized by the 2,064 OT polymorphism, were determined by using DNA from peripheral blood cells. Three common fibrillin-1 genotypes, 2-2, 2-3, and 2-4, were observed in 50 (64%), 10 (13%), and 11 (14%) of the men, respectively. Those of 2-3 genotype had higher pressure strain elastic modulus and aortic stiffness compared with men of 2-2 or 2-4 genotype (P = 0.005). Pulse pressure also was increased in the 2-3 genotype (P = 0.04). There was no significant association between type 1 collagen genotype and aortic stiffness in this cohort. In conclusion, the fibrillin-1 2-3 genotype in men was associated with increased aortic stiffness and pulse pressure, indicative of an increased risk for cardiovascular disease. Copyright © 2005 the American Physiological Society.

Objective: Fibrillin-1 is an important constituent of the vascular wall and earlier studies have indicated an effect of the Fibrillin-1 (FBN1) 2/3 genotype on blood pressure as well as aortic stiffness in men. The aim was to determine if the FBN1 2/3 genotype was associated with presence of carotid plaque and incident cardiovascular morbidity and mortality in middle-aged subjects.

Material and Method: The FBN1 genotype was characterized in 5765 subjects (2424 men, 3341 women; aged 45-69 years) recruited from the Malmö Diet and Cancer Study Cardiovascular Cohort, Sweden. Plaque occurrence and intima media thickness (IMT) of the carotid artery were assessed by ultrasound. Incidence of first cardiovascular events (myocardial infarction and stroke) and cause-specific mortality was monitored during a mean of 13.2 years follow-up.

Results: The most common FBN1 genotypes were 2/2, 2/3 and 2/4 which accounted for 92.2% (n=5317) of the subjects. There were no differences between the three genotypes regarding age, blood pressure, glucose, lipids, smoking habits, CCA diameter and IMT in men and women. Presence of plaque in the carotid artery was higher in men with genotype 2/3 as compared to the 2/2 and 2/4 genotypes, (55% vs. 46% and 50%, p=0.007). No similar difference was observed in women. No significant relationship was observed between FBN1 genotypes and incidence of CVD or all-cause mortality.

Conclusions: The increased prevalence of plaque in the carotid artery of middle-aged men with FBN1 2/3 genotype indicates a pathological arterial wall remodeling with a more pronounced atherosclerotic burden.