Are continuous-flow left ventricular assist devices (CF-LVAD) better than the waiting list? A propensity-score matched analysis of CF-LVAD versus waiting list for adult patients in united network for organ sharing status II (UNOS-II)

Introduction: The improved outcomes of third-generation continuous-flow left ventricular assist devices (CF-LVAD) in bridge-to-transplant and the high attrition rate among patients awaiting an allograft have raised the question whether CF-LVADs are better than the waiting list for transplant eligible patients. Hypothesis: we assessed the hypothesis that survival after LVAD is improved compared to waiting list in adult patients listed in UNOS status II. Methods: We identified all patients >18 years of age in the Organ Procurement and Transplantation Network (OPTN) database listed for their first heart transplant in the US in UNOS status II with no mechanical circulatory support at time of listing and not candidates to multi-organ transplant between January 2011 and March 2014. Of 2468 patients listed during the study period, 208 patients received a third-generation CF-LVAD. CF-LVAD and NO-LVAD patients were then matched 1:2 by mean of the closest-neighbor Propensity Score and survival of the matched groups was estimated with the Kaplan-Meier method. Results: One hundred and ninety CF-LVAD patients were PS-matched with 380 NO-LVAD patients. The matched groups were similar for several baseline characteristics (p=ns). In the CF-LVAD subgroup, 158 patients (83.2%) were transplanted, 21 (11.1%) were still on support and on the list, and 11 patients (5.8%) died or were delisted. In the NO-LVAD group, 314 patients (82.6%) were transplanted, 48 (12.6%) were still on the list and 18 patients (4.7%) died or were delisted. Freedom from death or delisting with CF-LVAD was 80.5% versus 85.5% of NO-LVAD patients at 18 months postoperatively (p=0.4). Cumulative survival considering also the post-transplant period was similar in the two groups at 24 months since listing (80.4% CF-LVAD versus 79.4% NO-LVAD, p=0.3). Conclusions: In conclusion, heart transplant candidates listed in status II and supported with CF-LVAD have shown a similar survival on the waiting list compared to candidates without LVAD. Overall survival of patients who received CF-LVAD was similar to survival of patients who did not receive mechanical support. Further studies are needed to clarify whether the allocation advantage given to the LVAD patients on the waiting list is still justified