Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System

Abstract

Background: The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak).

Methods: From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed.

Results: Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival.

Conclusions: In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool.

FIGURE 1.

Standardized mean difference plots of patient demographics and comorbidities before (×) and after (+) matching. Variable balances were improved after matching. Shaded area represents an absolute standardized mean difference of ≤0.25. ALT, alanine aminotransferase; BMI, body mass index; ECMO, extracorporeal membrane oxygenation; IABP, intra-aortic balloon pump; ICD, implantable cardioverter-defibrillator; VAD, ventricular assist device.

FIGURE 2.

KM survival curves of heart transplantation using organs preserved and transported in SherpaPak (blue) and non-SherpaPak (red) or conventional static cold storage method before (A) and after matching (B). Both before and after matching, there was no difference in survival after heart transplantation using organs preserved and transported in SherpaPak vs static cold storage (P = 0.29 vs 0.34, respectively). Shaded area indicates 95% confidence interval. KM, Kaplan-Meier.