New Storage Systems Could Expand Donor-Organ Availability

By Will Boggs

August 15, 2019

NEW YORK (Reuters Health) - Two new organ preservation systems could improve the availability of donor hearts and lungs, researchers report.

"There is an increased focus on organ preservation in transplantation," Dr. David A. D'Alessandro of Massachusetts General Hospital in Boston told Reuters Health by email. "There has been little attention paid to this on heart transplantation for past 50 years."

The Paragonix SherpaPak Cardiac Transport System (CTS), recently approved for clinical use in the U.S., is a single-use disposable device for static hypothermic donor-heart preservation. According to the manufacturer, it is the only commercially available transport device for donor hearts that's been approved in the U.S. and Europe.

Dr. D'Alessandro and colleagues describe the first clinical use of this system for a long-distance donor-heart procurement in a report online July 10 in The Journal of Thoracic and Cardiovascular Surgery.

The donor was a female in her 30s, and the donor hospital was more than 1,100 miles from the recipient institution, where the recipient was a 65-year-old male with a history of type 2 diabetes, atrial fibrillation, and ischemic cardiomyopathy resulting in end-stage heart failure.

The CTS maintained the donor heart temperature at 5.51°C throughout transportation, which took 205 minutes, with a total ischemic time of 312 minutes.

The recipient operation was uneventful, and the postoperative course was complicated by acute kidney injury that recovered without dialysis. The patient was discharged from the ICU to the step-down floor on postoperative day 6 and was discharged home on postoperative day 17, where he continues to do well.

Transthoracic echocardiography before discharge showed good biventricular function, with a left ventricular ejection fraction (LVEF) of 72%.

Organ temperatures can fall below freezing during transportation with other static systems, and there is growing interest in pulsatile, normothermic ex vivo heart perfusion for marginal-donor allografts.

Dr. D'Alessandro said that the CTS, compared with other storage systems, "adds significant cost, and (it) remains to be seen whether there is a significant benefit."

"Efforts are being made to improve organ preservation and extend the donor pool," he said. "This is an exciting time in organ transplantation."

Dr. Alessandro and colleagues state that they have no conflicts of interest or funding to report.

In a second study, online August 1 in The Lancet Respiratory Medicine, Dr. Gabriel Loor of the University of Minnesota, in Minneapolis, and colleagues in the EXPAND trial evaluated the efficacy of normothermic portable Organ Care System (OCS) lung perfusion and ventilation on donor lung use from extended-criteria donors and donors after circulatory death, which are rarely used.

Of the 93 donor lungs (61 from brain-death donors and 32 from circulatory-death donors), 12 were excluded because they did not meet the prespecified criteria after OCS Lung assessment, and two that were suitable for transplantation were not transplanted solely because of logistical reasons.

Overall, then, 79 transplants were completed in this trial, for a donor-lung use rate of 87%.

The primary effectiveness composite endpoint of patient survival at day 30 posttransplant and the absence of primary graft dysfunction grade 3 (PGD3) within 72 hours after transplantation was achieved in 43 (54%) of the 79 recipient patients.

Patient survival at day 30 was 99% (78/79 patients), but a relatively high proportion of patients (35/79, 44%) had PGD3 within the initial 72 hours.

Patient survival was 94% at six months and 91% at 12 months, which are similar to survival rates for standard-donor-criteria lung transplants.

The primary safety endpoint of 30-day mean lung-graft-related serious adverse events was 0.3 events per patient, which is also similar to that reported for standard-criteria donor lungs.

"Longer follow-up of EXPAND trial patients is underway to assess the long-term survival and prevalence of bronchiolitis obliterans syndrome," the researchers note. "In addition, a prospective OCS Thoracic Organ Perfusion registry has been developed to further expand prospective clinical evidence with the OCS Lung technology in the postmarket setting."

"Advances in portable ex-vivo lung perfusion technology, along with evolving strategies for reducing PGD, could usher in a new era in lung transplantation marked by greater use and improved quality of lung allografts," they conclude.

Dr. Hilary J. Goldberg from Brigham and Women's Hospital in Boston, who wrote an accompanying editorial, told Reuters Health by email, "The procurement rate reported in this study at a minimum doubles the rate currently observed nationally, which would substantially impact the wait times for lung transplantation and the number of candidates who unfortunately die while waiting."

"If we can demonstrate that procurement from higher-risk donors such as those considered in this cohort using this or similar technology leads to acceptable posttransplant outcomes, this could become a turning point for lung transplantation," she said. "However, more studies are needed, preferably controlled studies to better examine posttransplant outcomes, and efficiency and cost must also be factored into the role that this technology could play."

Dr. Goldberg added, "Beyond the need for more study of novel technology in lung transplantation, given the continued unmet need, it would be the value of and the urgency to facilitate multicenter clinical trials to reach more definitive conclusions both in terms of maximizing lung transplantation and improving posttransplant outcomes."

Dr. Loor did not respond to a request for comments.

TransMedics Inc. funded the EXPAND trial and had various relationships with several of the authors.

SOURCE: https://bit.ly/2KvfAlO

J Thoracic Cardiovasc Surg 2019.

https://bit.ly/2GLVVvJ and https://bit.ly/2YH22Ym

Lancet Respir Med 2019.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....