ASAIO journal : a peer-reviewed journal of the American Society for Artificial Internal Organs
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Comparative Study
Comparative analysis of von Willebrand factor profiles in pulsatile and continuous left ventricular assist device recipients.
A higher rate of nonsurgical bleeding has been observed in nonpulsatile left ventricular assist device (LVAD) recipients. von Willebrand factor (vWF) profiles were compared for nonpulsatile and pulsatile LVAD recipients to explore mechanisms that may contribute to the development of postimplant nonsurgical bleeding. The nonpulsatile mechanism may impair vWF function by creating a deficiency in vWF high molecular weight multimers (HMWMs), essential for hemostasis. High molecular weight multimer deficiency should result in low ristocetin cofactor (RCo) to vWF antigen ratios (vWF:RCo/vWF:Ag) because of impaired platelet (plt)-binding ability. von Willebrand factor profiles and HMWM were measured pre- and post-LVAD placement in 11 nonpulsatile (HeartMate II [HM II[) and 3 pulsatile (HeartMate XVE [HM XVE]) recipients. ⋯ Similar results were not observed in our small series of pulsatile HM XVE recipients. This finding could suggest a contributing factor to the increase in nonsurgical bleeding observed in nonpulsatile LVAD patients. Further investigation is ongoing to identify specific causes of vWF impairment.
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Meta Analysis Comparative Study
How minimalized extracorporeal circulation compares with the off-pump technique in coronary artery bypass grafting.
Recognition of the adverse effects of conventional extracorporeal circulation (CECC) led to the development of alternative technologies and techniques to minimize their impact while maintaining circulation during coronary artery bypass grafting (CABG). Off-pump coronary artery bypass (OPCAB) grafting has become established as one such alternative and more recently minimalized extracorporeal circulation (MECC) circuits have been developed with the aim of providing circulatory support while minimizing the interface between blood and the foreign surfaces of the circuit that initiates the associated adverse effects of CECC. Recently, some authors have suggested that MECC may be an alternative to OPCAB in patients undergoing CABG; the aim of this article is to systematically analyze and compare the impact of CABG with MECC with that of OPCAB, studying the adverse outcomes related to CECC. ⋯ We found no statistically significant difference in hospital or intensive care unit (ICU) LOS, blood loss, mean number of patients transfused, neurocognitive disturbance, or 30-day mortality between the two groups but a trend toward an increased number of cerebrovascular events in the MECC group was observed. The number of studies comparing these alternative techniques for coronary revascularization is small, and there is a lack of high-quality data. Currently, there seems little difference between MECC and OPCAB but larger randomized controlled trials focusing on high-risk patients are required.
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Debate exists regarding the merits and limitations of continuous versus pulsatile flow mechanical circulatory support. To characterize the hemodynamic differences between each mode of support, we investigated the acute effects of continuous versus pulsatile unloading of the failing left ventricle in a bovine model. Heart failure was induced in male calves (n = 14). ⋯ However, a normal range of left ventricular pressures was preserved. Continuous unloading deranged the physiologic profile of myocardial and vascular hemodynamic energy utilization, whereas pulsatile unloading preserved more normal physiologic values. These findings may have important implications for chronic LVAD therapy.