Real World Experience with Transmedics Organ Care System in Cardiac Transplantation with Donor Organs Associated with Marginal Risk Factors

Abstract

<h3>Purpose</h3> Donor organ acceptance is limited by preservation method using cold storage. We sought to evaluate the efficacy of normothermic TransMedics OCS Heart to preserve BD donor organ associated with pre-donation criteria that may increase risk of primary graft dysfunction (expanded criteria). <h3>Methods</h3> All cardiac transplantations between 2017-19 were evaluated in this single-centre, observational analysis. Expanded criteria was defined as: (I) cold ischaemic time between 4-8 hours, (ii) donor age >55 year-old with normal coronary angiography, (iii) reported circulatory down-time > 20mins, (iv) LVEF <50% where impairment is thought to be reversible, and (v) LV hypertrophy (wall thickness 12-16mm). Final transcoronary lactate level < 5 mmol/L at the end of the ex-vivo perfusion period was required for final organ acceptance. Clinical outcomes of interest include: total cold ischaemic time, index hospitalisation length of stay, and all-cause mortality at 90-day. <h3>Results</h3> Between July 2017 and December 2019, the OCS Heart Retrieval team was dispatched on 9 occasions, with 8 cases of ex-vivo organ retrievals. Of the 8 cases, 6 were successfully transplanted. With a total of 43 heart transplants were undertaken, availability of OCS Heart effectively allowed 14% increase in successful transplantation (6/43). Donor organ retrieval using TransMedics OCS Heart was associated with significant reduction in the total cold ischaemic time compared to cold storage (192.4mins vs 80.33mins, p=0.0005). Despite the expanded criteria, donor hearts that were successfully preserved were associated with comparable clinical outcomes: index hospitalization length of stay (P=0.97) and excellent post-transplant survival (Figure). <h3>Conclusion</h3> Normothermic donor heart preservation, with TransMedics OCS, allows comparatively safe transplantation with expanded criteria BD donor organ compared to conventional cold storage method with conservation donor characteristics.