Performance characteristics of a disposable ventricle assist device

A disposable ventricle assist device (VAD) including atrium, ventricle and trileaflet valves (all polyurethane) can be driven either a) by its original self adjusting drive unit (ABIOMED BVS 5000) or b) by a standard intra-aortic balloon pump console (DATASCOPE). Maximum flow in vitro was 4.3 l/min with the original drive console versus 9.2 l/min for activation with the intra-aortic balloon pump console. Performance characteristics of the VAD were evaluated in 11 bovine experiments. In vivo left ventricular assist for up to 24 hours with VAD and either original drive console or standard intra-aortic balloon pump console showed superior flow on activation with the intra-aortic balloon pump console (5.3 +/- 1.7 l/min) versus original drive console (3.5 +/- 0.5 l/min). After 6 hours of assist (before any transfusions) there was no significant difference in classic parameters for evaluation of blood trauma such as plasma hemoglobin production, LDH production and platelet depletion. We conclude that VAD is extremely simple to use. Activation by an intra-aortic balloon pump console enables significant increase of VAD-output without detectable increase of blood trauma. Successful weaning of VAD activated with standard intra-aortic balloon pump console was possible in a first clinical application

Performance characteristics of centrifugal pumps with heparin surface coating

Heparin surface coating is one approach to improve the biocompatibility of existing blood pumps used for mechanical circulatory support. Experimental evaluation of centrifugal pumps with heparin surface coating was performed during open chest left heart bypass (3.7 L/min over 6 hours) in two series of bovine experiments. Eight calves (74 +/- 4 kg) were perfused either by heparin surface coated equipment without systemic heparinization or uncoated equipment with systemic heparinization (300 I. U,/kg bodyweight; ACT greater than 400 s). A standard battery of analyses was performed before and at regular intervals after onset of perfusion. At the end of perfusion all pump-heads were gently rinsed. There were no macroscopic clots for both groups whereas macroscopic clots were observed in uncoated tubings introduced for control in the group perfused without systemic heparinization. The hemodynamics were significantly better in the group perfused without systemic heparinization and maintained functional coagulation system. Clinical application of heparin surface coated equipment during resection of thoraco-abdominal aortic aneurysms is showing promising results in 12 patients

CCTTT-repeat polymorphism of the inducible nitric oxide synthase is not associated with HIV pathogenesis

Nitric oxide (NO) produced by the inducible form of nitric oxide synthase (iNOS) has bactericidal and virocidal effects. Although NO synthesis and iNOS expression in macrophages affect several aspects of human immunodeficiency virus (HIV) type-1 pathogenesis, their role in HIV disease remains largely unknown. In humans, the expression of iNOS is influenced by a functional CCTTT-repeat polymorphism in the promoter region of the gene. We investigated the association of this polymorphism with HIV pathogenesis in naive HIV-infected patients before the initiation of antiretroviral therapy. The allele frequencies of the iNOS CCTTT-repeat polymorphism were assessed by PCR in 857 patients from the Swiss HIV Cohort Study, including rapid progressors and long-term nonprogressors, and in 240 healthy volunteers. In HIV-infected patients, the initial viral load and the decline in total CD4 cells was calculated to estimate disease progression. Allele frequencies of the iNOS CCTTT-repeat polymorphism were similar between the HIV-infected and noninfected blood donors. In treatment-naive HIV-positive patients, there was no association of the iNOS polymorphism with viral load or with the course of CD4 cells. Regulation of iNOS expression by the functional CCTTT-polymorphism does not modify HIV pathogenesis