Background Supplementary oxygen is administered during anaesthesia to increase oxygen delivery and prevent hypoxia. Recent studies have questioned this routine. In this pilot study, our main aim was to investigate if 21% oxygen compared to >= 50% reduces the risk of postoperative complications and myocardial injury. Methods In this pragmatic, multicentre, single-blind study, patients undergoing vascular surgery were randomised to receive a fraction of inspired oxygen (FiO2) >= 0.50 and oxygen saturation determined by pulse oximetry (SpO(2)) >= 98% (group H) or FiO2 of 0.21 and SpO(2) > 90% (group N) oxygen perioperatively. The primary outcome was a composite outcome of major pre-defined postoperative complications assessed at 30 days. Myocardial injury was determined by serial troponin measurements. Data were analysed using generalised estimating equation, Mann-Whitney U test or chi-squared test, as appropriate. Results The 191 patients were randomised, and per-protocol principle was used for analyses. At 30-day follow-up, 43 out of 94 patients (46%) had a postoperative complication in group H and 36 out of 90 patients (40%) in group N, p = .46. New myocardial injury was seen in 27% versus 22% in Groups H and N respectively (p = .41). No differences in other outcomes were observed between the groups. Twelve patients (13%) in Group N had SpO(2) < 90%, six recovered spontaneously and six required supplemental oxygen. At 1-year follow-up, one patient in group H had died. Conclusion In this pilot study, postoperative complications were similar between the groups in patients randomised to FiO2 of 0.21 or >= 0.50 and no difference was found in the incidence of new myocardial injury. Larger, prospective adequately powered studies are needed.

Mechanical circulatory support technology is continually improving. However, adverse complications do occur with devastating consequences, for example, pump thrombosis that may develop in several parts of the pump system. The aim of this study was to design an experimental clot/thrombosis model to register and analyze acoustic signals from the left ventricular assist device (LVAD) HeartMate II (HMII) (Thoratec Corporation, Inc., Pleasanton, CA, USA) and detect changes in sound signals correlating to clots in the inflow, outflow, and pump housing. Using modern telecom techniques, it was possible to register and analyze the HMII pump-specific acoustic fingerprint in an experimental model of LVAD support using a mock loop. Increase in pump speed significantly (P less than 0.005) changed the acoustic fingerprint at certain frequency (0-23 000 Hz) intervals (regions: R1-3 and peaks: P1,3-4). When the ball valves connected to the tubing were narrowed sequentially by similar to 50% of the inner diameter (to mimic clot in the out-and inflow tubing), the frequency spectrum changed significantly (P less than 0.005) in P1 and P2 and R1 when the outflow tubing was narrowed. This change was not seen to the same extent when the lumen of the ball valve connected to the inflow tube was narrowed by similar to 50%. More significant (P less than 0.005) acoustic changes were detected in P1 and P2 and R1 and R3, with the largest dB figs. in the lower frequency ranges in R1 and P2, when artificial clots and blood clots passed through the pump system. At higher frequencies, a significant change in dB figs. in R3 and P4 was detected when clots passed through the pump system. Acoustic monitoring of pump sounds may become a valuable tool in LVAD surveillance.

Cardiotoxicity is a multifactorial problem, which has emerged with the improvement of cancer therapies and survival. Heart transplantation is relatively contraindicated in patients with breast cancer, until at least 5 years after complete remission. We present a case where a young woman who in 2001, at the age of 31, was diagnosed with breast cancer. She was considered cured, but 4 years later she suffered a relapse. During her second treatment, in 2006, she suffered from severe heart failure. She received a HeartMate II, as a long-term bridge to transplantation and 6 years later she was successfully transplanted. In this case report we discuss the use of mechanical circulatory support in cancer patients with drug-induced heart failure.

Objectives. The presence of a mechanical prosthesis has been regarded as an increased risk of thromboembolic complications and as a relative contraindication for a left ventricular assist device (LVAD). Five patients in our center had a mechanical aortic valve at the time of device implantation and were studied regarding thromboembolic complications. Design. Five patients operated upon with an LVAD (1 HeartMate I (TM), 4 HeartMate II (TM)) between 2002 and 2011 had a mechanical aortic valve at the time of implantation. The first patient had a patch closure of the aortic valve. In four patients, the prosthesis was left in place. Anticoagulants included aspirin, warfarin, and clopidogrel. Results. The average and accumulated treatment times were 150 and 752 days, respectively. Three of the five patients showed early signs of valve thrombosis on echo with concomitant valve dysfunction. Four patients were transplanted without thromboembolic events during pump treatment. One patient died from a hemorrhagic stroke after 90 days on the LVAD. Conclusions. The strategy of leaving a mechanical heart valve in place at the time of LVAD implantation in five patients led to valvular thrombosis in three but did not provoke embolic events. It increased the complexity of postoperative anticoagulation.

Implantable mechanical left ventricular assist devices (LVADs) are used as a bridge or alternative to heart transplantation. Peroperative transesophageal echocardiography is commonly applied during implantation. Significant air embolism may occur as a result of air leakage at connections and anastomoses when LV filling becomes inadequate, and this must be prevented. Early suspicion and detection of air is mandatory to avoid negative circulatory effects. We hypothesized that monitoring of heart chamber size and occurrence of single air bubbles using second harmonic imaging (SHI) echocardiography may prevent risk for significant air embolism. After implantation of the LVAD in 10 calves, invasive hemodynamic monitoring and epicardial SHI were performed while increasing pump speed. Air bubbles in the ascending aorta were monitored and the left heart visualized for off-line dimensional analysis. Detection of air bubbles in the ascending aorta preceded their appearance in the left ventricle. They occurred exclusively but not always after a decrease in left atrial (LA) size. Decrease in LA pressure did not predict bubble detection or reduction in LA size. We conclude that SHI detects spontaneous ultrasound contrast during implantation of a LVAD and that a decrease in LA size is a warning that air embolism is imminent.

Objectives. Left ventricular assist devices (LVAD), used in the setting bridge-to-transplantation and destination therapy, for patients with deteriorating severe heart failure are continuously developing. The second generation, the axial flow pumps, have been introduced since some years. Design. Eleven consecutive patients, seven male, with severe heart failure due to ischemic cardiomyopathy (n = 5), dilated cardiomyopathy (n = 5) and cytotoxic ethiology (n = 1) were implanted with the HeartMate-II (TM). They were preoperatively treated with inotropic support (n = 9), ventricular assist device (n = 2) and mechanical ventilation (n = 4). Results. Eight patients were bridged to transplant after median 155 days (range, 65 to 316 days). One patient is ongoing for 748 days, intended for destination therapy. Ten of eleven patients were discharged after median 64 days (range, 40 to 105 days). Four patients were reoperated due to bleeding. Two embolic events were recorded. One perioperative death. Conclusion. Eleven HM-II (TM) LVADs have been implanted in our institution with good early results. Eight patients were successfully bridged to heart transplantation. One patient is intended for destination therapy and is ongoing since November 2006. In these severely ill patients, this technique offers a good chance surviving until heart transplantation. In selected cases the technique also offers the possibility of a permanent support and longevity.