In vitro evaluation of hemolysis and sublethal blood trauma in a novel subcutaneous vascular access system for hemodialysis.

Abstract

Hemodialysis requires reliable frequent access to the patients' vasculature, with blood flow rates of > 300 ml/min. Currently in the U.S. market, there are three types of hemodialysis access systems: the native arteriovenous fistula, generally using 15G needles; the synthetic arteriovenous (AV) graft, also generally using 15G needles; and the percutaneous catheter. Some of the problems with current vascular access technologies include insufficient blood flow, blood trauma, thrombosis, infection, cardiac load, and venous stenosis. The LifeSite System (Vasca, Inc.) represents an alternative for vascular access, and consists of a subcutaneous valve and 12F cannula accessed by a standard 14G needle. The LifeSite valve is implanted in the upper torso with the cannula generally entering the right internal jugular vein. The purpose of this study was to compare the LifeSite System with two known vascular access systems: the 10F dialysis catheter (Tesio-Cath, MedComp) and the 15G A.V. Fistula Needle Set (JMS Co., Ltd.) with regard to blood damage produced by these devices in use. Mechanical hemolysis and sublethal blood trauma were evaluated by means of in vitro blood pumping through a circulating loop incorporating a hemodialysis vascular access system. Sublethal blood damage was examined by using a hemorheologic assay that included parameters such as erythrocyte mechanical fragility, plasma total protein and fibrinogen concentrations, and blood viscosity. The tests demonstrated that, at both studied flow rates of 300 ml/min and 450 ml/min, the LifeSite produced lower hemolysis and less sublethal damage to blood than either the Tesio-Cath catheter or the A.V. Fistula Needle Set.