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TOPLINE:

Using the Organ Care System (OCS) Heart platform to perfuse, optimize, and assess donor hearts has excellent outcomes, including 87% of extended criteria donor (ECD) hearts being successfully transplanted, potentially significantly increasing the number of life-saving heart transplants, results of a single-arm, multicenter trial suggested.

METHODOLOGY:

• After satisfying inclusion criteria, ECD hearts underwent extracorporeal perfusion using the OCS Heart platform. ECD hearts were defined by an expected cross-clamp time of 4 or more hours, or greater than 2 hours plus one or more risk factors including age 55 years or older, or diabetes.
• The primary outcome of the OCS Heart EXPAND trial was a composite of patient survival at day 30 post-transplant and freedom from International Society for Heart and Lung Transplantation (ISHLT) severe left ventricular (LV) or right ventricular (RV) primary graft dysfunction (PGD).
• Secondary outcomes were rate of donor heart use (number of eligible donor hearts successfully transplanted after OCS Heart assessment divided by number of eligible donor hearts assessed and preserved using OCS Heart), survival at day 30, and ISHLT severe LV or RV PGD in the first 24 hours post-transplant.
• The safety outcome was the mean number of heart graft–related serious adverse events, including moderate or severe LV or RV PGD, within 30 days, with an additional outcome being survival through 2 years benchmarked to concurrent nonrandomized control subjects.
• Of 173 donor hearts placed on OCS Heart, 150 were successfully transplanted, resulting in a donor heart utilization rate of 86.7%.

TAKEAWAY:

• There was a significant reduction of ischemic injury in donor hearts, and incidence of ISHLT severe LV or RV PGD was 6.7%, a rate the authors said is substantially lower than contemporary rates reported for PGD in heart transplants.
• Among the 150 heart transplants, 92.0% (95% CI, 86.4%-95.8%; P < .0001) met the primary effectiveness outcome of patient survival at day 30 post-transplant and freedom from ISHLT severe PGD, which was above the predefined performance goal of 65%.
• The average rate of heart graft–related serious adverse events was 0.17 (95% CI, 0.11-0.23), and the incidence of ISHLT moderate or severe PGD through 30 days post-transplant was 16.0%, with only one patient experiencing primary graft failure requiring re-transplantation.
• Overall survival for transplanted participants was 92.6% at 6 months, 89.3% at 12 months, and 86.0% at 24 months, which are rates comparable with concurrent nonrandomized control patients.

IN PRACTICE:

Expanding the donor pool with OCS Heart addresses limitations of cold storage for donor hearts and being able to safely use ECD hearts for donation after brain death "could substantially increase the number of heart transplants and expand access to patients in need," said the authors.

SOURCE:

The study was carried out by Jacob N. Schroder, MD, Duke University Hospital, Durham, North Carolina, and colleagues. It was published on January 24, 2024, in JACC: Heart Failure.

LIMITATIONS:

The study had a single-arm design. Researchers could not obtain a risk-adjusted comparator from the Scientific Registry for Transplant Recipients database for heart transplant outcomes in the United States. The study used OCS Heart circulating absolute lactate levels and trends, along with stable OCS Heart perfusion parameters, to assess suitability of donor hearts for transplantation, but whether this is the best biomarker for this important clinical decision needs to be studied further.

DISCLOSURES:

The study was funded by TransMedics Inc. Schroder received research funding paid to his institution from TransMedics; see paper for disclosures of other authors.