HEARTMATE IMPLANTABLE LEFT-VENTRICULAR ASSIST DEVICE - BRIDGE TO TRANSPLANTATION AND FUTURE APPLICATIONS

The HeartMate implantable left ventricular assist device (LVAD) is approaching the time when it will be implanted permanently. Experience with the HeartMate 1000 IP LVAD at the Cleveland Clinic as a bridge to heart transplantation in 21 patients has shown (1) excellent hemodynamic function [improving cardiac index from a mean +/- standard deviation of 1.6 +/- 0.26 L.min(-1).m(-2) to 3.0 +/- 0.42 L.min(-1).m(-2)]; (2) 81% survival before transplantation with a mean duration of 64 +/- 34 days of LVAD support; (3) 100% survival after transplantation; (4) New York Heart Association class IV and moribund patients were returned to class I or II status while on the LVAD; and (5) a remarkably low risk of thromboemboli during 1,583 patient-days of support. The multicenter experience (173 patients) confirms the low risk of embolic events (2%, including septic emboli). A ''target population'' for initial use of the permanent device was outlined from a retrospective review of 570 patients. A subgroup of 74 patients (13%) were between 18 and 75 years of age, had isolated cardiac failure (without multiple comorbidities), and required inotropic medications, intraaortic balloon pump support, or both. Survival for this patient group (mean age, 57 +/- 13 years; 68% male) was poor: median survival was 7 months, 21.6% died during the hospitalization, and 47.3% died after discharge. Of the survivors, only 4 patients (5% of the initial 74 patients) were in New York Heart Association class I. From the bridge-to-transplantation experience we extrapolate that survival and quality of life should improve for patients in the target population treated with the portable LVAD. A randomized, clinical trial (medical therapy versus portable LVAD) is therefore appropriate and is necessary to evaluate long term effectiveness of the LVAD.