Ex vivo Heart Perfusion for Heart Transplantation: A Single-Center Update after 5 Years

Objectives: Ex vivo heart perfusion is an advanced preservation technique that permits graft assessment and extended out-of-body intervals. In times of high-risk recipients and donors with extended donation criteria, we hypothesized that its properties for prolonged heart preservation might be especially beneficial.

Methods: We reviewed the outcome of 97 end-stage heart failure patients that underwent heart transplantation in our institution between January 2015 and September 2019. Data were collected from prospective institutional databases. Patients were divided into two groups: group A (OCS) versus group B (conventional). Ex vivo organ perfusion was performed using Organ Care System (OCS Heart, Transmedics, United States). All recipients were potentially considered eligible, but an effort was made to apply the OCS Heart particularly in challenging cases with previous cardiac surgery.

Results: A total of 49 patients were transplanted using the OCS. Baseline characteristics in both groups: age (y; A: 46.2 ± 16.7 vs. B: 39.8 ± 21.4; p = 0.17), male gender (%; A: 69.4 vs. B: 66.7, p = 0.77), time on waiting list (min; A: 5.8 ± 9.8 vs. B: 14.5 ± 22.8, p < 0.05), HU status (%; A: 90.0 vs. B: 85.0, p = 0.51), previous VAD (%; A: 75.5 vs. B: 62.5, p = 0.16). Operative results: ex situ time (min; total preservation time group A, ischemia for group B; A: 407 ± 64 vs. B: 239 ± 37, p < 0.001), Total OCS time (min): 280 ± 57, clamping time (min; A: 107 ± 23 vs. B: 91 ± 31, p < 0.01), ventilation time (d; A: 2.3 ± 4.1 vs. B: 13.8 ± 25.1, p < 0.05), ICU stay (d; A: 17.6 ± 26.2 vs. B: 25.7 ± 40.5, p = 0.84), postoperative ECMO (%; (A: 24.5 vs. B: 22.9, p = 0.85), bleeding requiring redo surgery (%; A: 12.5 vs. B: 18.8, p = 0.13), and early graft rejection (%; A: 10.4 vs. B: 22.9, p = 0.10). 30-day survival (%; A: 94 vs. B: 94), 1-year survival (%; A: 84 vs. B: 76), and 2-year survival (A: 77 vs. B: 73; p = 0.42).

Conclusion: OCS Heart allowed safe transplantation of surgically complex recipients with excellent 2-year outcomes, despite mean preservation times of almost 7 hours. Furthermore, we observed trends to decreased ventilation times and shorter ICU stays in the OCS group. In times of reduced organ availability and increasing recipient complexity, OCS heart is a strong instrument that enables otherwise infeasible allocations and contributes to increase surgical safety.