Ex Vivo Perfusion and Transplantation of Hearts Donated After Circulatory Death Is Safe and Effective
Key findings
- This study examined hemodynamic profiles of transplanted hearts that were donated after circulatory death (DCD hearts) and compared patient outcomes to those of contemporary historical controls who received hearts donated after brain death
- The median waiting list time after consent to DCD heart transplant was 17 days compared with 70 days on the waiting list for the standard care group (P<0.001)
- 47 of 61 (77%) of DCD hearts accepted for potential transplantation were able to be transplanted
- DCD recipients exhibited post-transplant right heart dysfunction that normalized about three weeks later; the incidence of severe primary graft dysfunction was 10.6% and declined over time with greater clinical experience
- The DCD and standard care groups had similar short-term outcomes, including one-year survival, which was 97% in the DCD group
It's been projected that transplantation of hearts donated after circulatory death (DCD) could expand the availability of donor hearts by over 30%. In 2006, the European Union approved a proprietary system, the TransMedics Organ Care System (OCS), for ex vivo warm perfusion of DCD hearts en route to the transplanting hospital.
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Massachusetts General Hospital is part of pioneering work with the OCS and led the prospective, randomized DCD Heart Trial. Recipients in that trial were offered the standard of care (SOC) with a heart donated after brain death (control arm) or could receive either a DCD heart or the SOC, whichever became available first.
In the Journal of the American College of Cardiology, physicians from the Corrigan Minehan Heart Center at Mass General report on patients who received DCD hearts as part of the DCD Heart Trial, its continued-access protocol, or subsequent off-label use of the OCS.
Gregory D. Lewis, MD, Jeffrey and Mary Ellen Jay chair and section head of Heart Failure, medical director of Heart Transplantation, David A. D'Alessandro, MD, surgical director of the Heart Transplant Program and Ventricular Assist Devices, Stanley B. Wolfe, MD, MPH, general surgery resident, and colleagues present encouraging data on safety and efficacy.
Methods
The researchers compared 47 patients who received DCD hearts between December 2019 and February 2022 with 166 patients who received SOC since April 2016. Outcomes for both groups were tracked through March 4, 2022.
The article details the inclusion and exclusion criteria for donors and recipients and the techniques for procurement, OCS monitoring, and postoperative monitoring. The timing of the recipient operation for DCD hearts is based on when a decreasing lactate trend is identified on the OCS.
Waiting Time
Patients who received DCD hearts had an extra delay attributable to the need to provide informed consent. The median waiting list time after consent to DCD was 17 days compared with 70 days on the waiting list for the standard care group (P<0.001).
Number of Hearts Transplanted
61 planned DCD procurements resulted in 47 DCD hearts transplanted (77%). Reasons for no transplantation included the donor not progressing to circulatory death (n=9), progression to brain death before procurement (n=3), the discovery of contamination of the field on opening caused by unsuspected pre-procurement abdominal visceral rupture (n=1), and increasing lactate during OCS perfusion (n=1).
Right Heart Function
One week after transplantation, all measures of right heart function were significantly impaired in DCD recipients compared with SOC recipients:
- Median right atrial pressure—10 vs. 7 mm Hg (P<0.001)
- Ratio of right atrial pressure to pulmonary capillary wedge pressure ratio—0.64 vs. 0.57 (P=0.016)
- Pulmonary arterial pulsatility index—1.66 vs. 2.52 (P<0.001)
All measures were similar between groups by three weeks after the transplant. Still, centers developing DCD heart transplantation programs should pay careful attention to supporting right ventricular function with inotropes and pulmonary vasodilators during the first weeks after the transplant.
Primary Graft Dysfunction
Five DCD recipients (10.6%), versus 3.6% of SOC recipients, exhibited severe primary graft dysfunction (PGD) 24 hours after transplant (P=0.07). All five DCD recipients, versus nine SOC recipients (5.4%), required venoarterial extracorporeal membrane oxygenation (ECMO) postoperatively for severe PGD (P=0.20). The maximum duration of ECMO for DCD recipients was four days, and graft function normalized in all recipients.
The DCD and SCO groups did not differ significantly concerning inotrope scores from ICU admission to 48 hours following surgery or median peak lactate levels during the first 48 hours after transplant.
Outcomes
Neither of the two groups differed significantly in hospital length of stay after transplant, ICU length of stay, ICU readmission rates, 30-day readmission rates, in-hospital mortality, 30-day mortality, or one-year mortality. The latter rate was 3% for DCD recipients vs. 8% for SOC recipients.
Trends
During the establishment of the DCD program at Mass General, both utilization of DCD and the incidence of severe PGD have declined over time. These trends presumably reflect improved clinical judgment about donor selection and perioperative management.
Toward Broader Adoption of DCD Heart Transplantation
In the DCD Heart Trial, warm ischemia time was limited to 30 minutes. After study enrollment ended, Mass General transplanted three DCD hearts after longer ischemia times, and to date, this practice has not been associated with the need for post-transplant ECMO.
Mass General has also successfully combined DCD heart transplantation with kidney transplants (n=2) or liver transplants (n=2) through off-label use of the OCS, not included in this analysis.
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