Ex vivo donor heart preservation in heart transplantation

To the Editor, Heart transplantation (HT) remains the gold standard to treat advanced cardiac failure but the donors shortage has forced the use of various systems of circulatory mechanical support. Preservation of the donor heart, in case of long‐distance procurement, could be a problem since cold storage (CS) may determine time‐ dependent ischemic‐reperfusion damage. The normothermic ex vivo perfusion using the Organ Care System (OCS; TransMedics Inc.) is becoming an appealing alternative to CS, particularly for long‐distance graft procurement. Since this technique is currently used in our center, we read with great interest the article by Medressova et al., published in the Journal of Cardiac Surgery, and reporting a successful HT in an LVAD patient of a donor's heart preserved for 17h by OCS. We have recently reported our experience with HT in patients with mechanical circulatory support, comparing the results obtained either with CS or OCS for donor heart preservation. Our results, in a series of 38 patients during a 5‐year period, indicate that OCS is superior to CS since it reduces significantly the graft ischemic times and accordingly improving post‐HT outcomes. Therefore, our experience supports the use of ex vivo graft perfusion in patients on mechanical circulatory support as a bridge to an HTx. The longest successful “out of body” time in our experience was of 9 h even if capillary hemorrhage and cardiomyocyte degeneration are soon evident after 6 h of support as showed by myocardial biopsies performed before implantation. For this reason, we do not recommend OCS perfusion longer than 8 h. Nevertheless, the article by Medressova et al., reporting the possibility of maintaining a viable graft for an extraordinarily long period, confirms our belief that ex vivo preservation of donor's heart may significantly contribute to increasing the donors' pool and the number of HT.