Survival after biventricular assist device implantation: an analysis of the Interagency Registry for Mechanically Assisted Circulatory Support database

Background: Patients requiring biventricular assist device (BiVAD) for mechanical circulatory support (MCS) have substantially worse outcomes than patients requiring left VAD (LVAD) support only. Patient-specific risk factors have yet to be consistently identified in a large, multicenter registry, which may underlie the poorer outcomes for BiVAD patients. The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) is a registry of U.S. Food and Drug Administration-approved durable MCS devices used for bridge-to-transplantation, destination therapy, or recovery. The purposes of this study were to 1) identify the underlying pre-implant characteristics of the population requiring BiVAD support that contribute to reduced survival, and 2) identify differences in postoperative outcomes with respect to adverse events compared with patients supported with LVAD alone.

Methods: From June 2006 to September 2009, 1,646 patients were entered into the INTERMACS database in which adverse events and outcomes were recorded for primary implants with LVAD or BiVAD. Competing outcomes methodology was used to estimate the time-related probability of death, transplant, or recovery. Overall survival for all groups was analyzed with Kaplan-Meier methods and Cox proportional regression analysis.

Results: The distribution of primary device implants included 1,440 LVADs and 206 BiVADs. BiVAD patients presented with a lower INTERMACS profile 93% in INTERMACS 1 or 2, compared with 73% for LVAD patients (p < 0.001). Survival at 6 months was 86% for LVADs and 56% for BiVADs (p < .0001). Adverse event rates, expressed as episodes/100 patient-months for the BiVAD group compared with LVAD, were significantly higher for infection (33.2 vs 14.3), bleeding (71.6 vs 15.5), neurologic events (7.9 vs 2.6), and for device failure (4.9 vs 2.0).

Conclusions: Patients requiring BiVAD support at the time of durable MCS implant are more critically ill at the time of MCS implant. BiVAD patients experience worse survival than patients supported with LVAD alone and higher rates of serious adverse events. Characteristics of the population present at the time of BiVAD implant likely influence post-implant MCS outcomes.