Prediction of primary graft dysfunction and survival in heart transplantation using normothermic ex-vivo perfusion of the donor heart

IntroductionEx vivo perfusion (EVP) in heart transplantation (HTX) enables transportation of explanted organs over longer distances as well as monitoring of cardiac metabolism under unloaded coronary perfusion, thereby expanding the possible pool of suitable donors for HTX. We aimed at identifying possibly modifiable risk factors predicting impaired outcome after HTX through analysis of perfusion parameters, donor and recipient characteristics.MethodsWe included 64 patients after HTX using EVP (TransMedics Organ Care System) between February 2010 and October 2022 in this retrospective, single-center analysis. Blood gas analyses were taken during EVP in a standardized manner.ResultsHTX recipients were 44.8 ± 16.2 years old, six patients being younger than 18 years at the time of transplantation. High urgency listing status was present in 79.7%, and 67.2% had previous cardiac surgery. Lower base excess during EVP predicted severe primary graft dysfunction (PGD) (-5.55 ± 1.95 vs -3.94 ± 2.38 mmol/L, <i>p</i> = 0.043). With every additional minute of warm ischemia, the risk of PGD was 3.7% higher (OR 1.037, 95% CI [1.004; 1.072], <i>p</i> = 0.028). Low donor serum potassium (3.4 ± 0.76 mmol/L vs 4.2 ± 0.60, <i>p</i> = 0.008), high glucose after EVP priming (207.63 ± 99.05 mg/dL vs 146.45 ± 51.99, <i>p</i> = 0.045), and resuscitation of the donor (55.6% vs 18.2%, <i>p</i> = 0.027) were associated with impaired survival after HTX.ConclusionsEVP provides a unique method to assess graft function during the retrieval of hearts for cardiac transplantation. Low base excess, priming glucose, warm ischemia and donor hypokalaemia influence the frequency of adverse outcomes after HTX. Future studies may address possible strategies to safely modify these risk factors.