Bovine pericardial valves. Nine-year clinical experience with the Novacor left ventricular assist system

The Novacor electrically powered left ventricular assist system (LVAS), currently used in a bridge-to-transplant (BTT) clinical trial, incorporates bovine pericardial (BP) valves (Edwards CVS Division, Baxter Healthcare Corporation). In preclinical evaluation in the adult sheep, BP valves exhibited severe calcific stenosis as early as 8 weeks postimplant (longest implant 158 days, elective termination for calcific deposit). The clinical experience, however, has been in sharp contrast. Eighty-one patients have been supported for a cumulative duration of 9.1 years (two currently on LVAS). Thirty-five (43%) patients were supported for longer than 30 days, and of these, 29 (85%) were transplanted. The longest implant duration was 370 days (alive, 8 months posttransplant). There was no evidence of calcific degeneration of these valves for durations to 370 days. These results are encouraging for ultimate chronic clinical application.