Comparison of Intraaortic Balloon Pump and Impella 5.5 as Heart Transplant Bridging Strategies

Background Temporary mechanical circulatory support is increasingly utilized as a bridge to heart transplantation. The Impella 5.5 (Abiomed) has achieved anecdotal success as a bridge since receiving US Food and Drug Administration approval. The purpose of the current study was to compare waitlist and posttransplant outcomes of patients bridged with intraaortic balloon pumps (IABPs) to those receiving Impella 5.5 therapy. Methods Patients listed for heart transplantation between October 2018 and December 2021 who received IABP or Impella 5.5 at any time during waitlist course were identified from the United Network for Organ Sharing database. Propensity-matched groups of recipients with each device were created. Competing-risks regression for mortality, transplantation, and removal from waitlist for illness was performed according to the method of Fine and Gray. Posttransplant survival was censored at 2 years. Results Overall, 2936 patients were identified, of whom 2484 (85%) were supported with IABP and 452 (15%) received Impella 5.5. Patients with Impella 5.5 support had more functional impairment, higher wedge pressures, higher rates of preoperative diabetes and dialysis, and more ventilator support (all P < .05). Waitlist mortality was significantly worsened in the Impella group and transplantation was less frequent (P < .001). However, survival at 2 years after transplant was similar in both complete (90% vs 90%, P = .693) and propensity-matched cohorts (88% vs 83%, P = .874). Conclusions Patients bridged with Impella 5.5 were sicker than IABP-bridged patients and less frequently transplanted; however, posttransplant outcomes were similar in propensity-matched cohorts. The role of these bridging strategies in patients listed for heart transplantation should be continually assessed with future allocation system changes.