Is Temporary Here to Stay? Excellent Outcomes and Shorter Wait Times with Increased Use of Temporary Mechanical Support Since the 2018 Revision to Heart Transplant Allocation Policy

Abstract

<h3>Purpose</h3> A 2018 revision to United States (US) heart transplant (HT) allocation policy grants higher priority to those treated with intra-aortic balloon pump (IABP), extracorporeal membrane oxygenation (ECMO), or other temporary mechanical support (tMCS). Use of each has since increased, likely to a varying extent across HT centers with a varying impact on outcomes. We assessed the impact at one high-volume center. <h3>Methods</h3> We included adult HT recipients in the year before ("pre"; n = 71) and after ("post"; n = 72) the allocation change on October 18, 2018. Recipient characteristics, clinical management, and outcomes were compared. <h3>Results</h3> Recipients after (vs. before) the allocation change were younger (mean age 52 vs. 55 years; p = 0.11) with higher rates of Hispanic ethnicity (21% vs. 7%; p = 0.017). More had non-ischemic dilated cardiomyopathy (67% vs. 45%; p = 0.009) and fewer had restrictive/infiltrative cardiomyopathy in the "post" (vs. pre) cohort (13% vs. 4%; p = 0.07). Pre-HT ECMO and IABP use increased from 0% of patients in the "pre" cohort to 11% and 32% in the "post" cohort, respectively (p < 0.005 for both changes). Concurrently, there was a trend towards lower durable ventricular assist device (VAD) use (27% to 19%; p = 0.30) and significantly lower median wait time (25 to 13 days; p = 0.049). One-year death or graft failure decreased (non-significantly) by almost half (pre: 8.5% post: 4.4%; p = 0.32) with no significant change in other post-HT outcomes. <h3>Conclusion</h3> The 2018 revision to US HT allocation policy prompted increased tMCS use at a high-volume center, to an even greater extent than seen nationwide. A concurrent drop in durable VAD use and waitlist time - with their attendant complications - could be offsetting the tMCS trend from a cost standpoint and driving a favorable trend in post-HT survival. The latter contrasts with nationwide trends, suggesting that the revised policy's impact could vary across institutions.