A Decade of Experience With Continuous-Flow Left Ventricular Assist Devices

Abstract

The use of continuous-flow left ventricular assist devices (CF-LVADs) has revolutionized the landscape of mechanical circulatory support for patients with heart failure. Clinical trials are already testing the next generation of CF-LVADs. In this study, our objective was to review our long-term experience with the current generation of CF-LVADs, specifically, the HeartMate (HM) II (Thoratec Corp, Pleasanton, CA). In this single-center retrospective analysis, we evaluated the records of 278 consecutive patients who underwent a total of 302 HM II placements from June 2005 through June 2014. We excluded 11 patients from our final study group, who had previously undergone placement of a HM XVE that failed. We divided the remaining 267 patients into 3 equal groups of 89 patients each, by time period: group 1, June 2005 through May 2009; group 2, June 2009 through January 2012; and group 3, February 2012 through June 2014. To examine differences in survival between our 3 groups, we used time-to-event analysis, including the Kaplan-Meier method. To examine secondary outcomes (including stroke, hemolysis, gastrointestinal bleeding, pump thrombus, and transplant), we used one-way analysis of variance. For our final study group of 267 patients, the total follow-up time was 479.01 patient-years (median, 469 days). The mean age of patients was 57 years; 81.4% were male. In all, 209 (78.9%) patients underwent HM II placement as a bridge to transplant; 58 (21.1%), as destination therapy (DT). The overall survival rate was 94% at 30 days, 77% at 1 year, 65% at 2 years, 60% at 3 years, 50% at 4 years, and 48% at 5 years. In bridge to transplant patients, the survival rate was 78% at 1 year and 66% at 2 years; in DT patients, 70% and 60%. In group 1 patients, the survival rate was 94% at 30 days, 64% at 1 year, and 48% at 2 years; in group 2, 93%, 88%, and 76%; and in group 3, 94%, 77%, and 73% (P = 0.003). In the later years of our study period, from June 2009 onwards (ie, in groups 2 and 3), we noted a statistically significant increase in HM II placement as DT, a reduction of driveline infections, increasing pump exchange, increasing hemolysis, a reduced frequency of transplants, and an improved survival rate (as compared with the earlier group 1). The HM II has favorably influenced the outcomes of patients with end-stage heart failure, yet major complications still limit their survival. Improving compatibility between the pump and the individual host patient, enhancing anticoagulation strategies, and developing a totally implantable pump might further reduce complications thereby improving survival times and allowing CF-LVAD placement to be a true long-term alternative to a heart transplant.