PH has no effect on mortality in heart transplant: Study

New finding contradicts earlier studies that suggested higher risk for recipients

Steve Bryson, PhD avatar

by Steve Bryson, PhD |

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The presence of pulmonary hypertension (PH) didn’t increase mortality after a heart transplant, according to a new study.

The findings oppose earlier studies that suggested an increased mortality rate among transplant recipients with PH, which was considered a contraindication.

A secondary analysis of a large transplant registry with 24 years of data supported the study’s main findings that PH didn’t increase the mortality risk in patients undergoing heart transplants in the modern era, data showed.

“Wider acceptance of [heart transplantation] candidates with preexisting high-risk PH should be considered with advent of advances in medical treatment,” wrote researchers in “High-Risk Pulmonary Hypertension Does Not Worsen Outcomes in Heart Transplantation,” published in The American Journal of Cardiology.

Due to a potentially high mortality rate, a heart transplant to treat heart failure hasn’t been recommended for people with PH, a progressive condition marked by high blood pressure in the blood vessels that supply the lungs.

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Heart transplants with, without PH

Early mortality in heart transplant recipients with PH has been attributed to the inability of the new heart’s right ventricle, which pumps blood through the pulmonary arteries, to adapt to high blood pressure immediately after surgery.

Investigators at New York Medical College/Westchester Medical Center surmised that, given new medications and improvements in critical care, “the right ventricle (RV) can be supported after surgery, allowing time for RV adaptation, and leading to better early and long-term outcomes in patients with PH who underwent [heart transplant].”

After reviewing the medical records of 120 patients who had a heart transplant at their clinic between 2014 and 2018, the researchers identified 98 with complete data, of whom 31 had PH (32%). The pre-transplant characteristics between those with and without PH were similar, except PH patients were significantly younger (mean, 55 vs. 60) and more often women (42% vs. 12%).

Survival rates were similar between heart transplant recipients with and without PH after 30 days (100% in both), one year (87% vs. 93%), and three years (81% vs. 81%). Survival was the same in those with more severe PH and the causes of death after a transplant were similar in both groups.

Graft rejection at one year was similar between transplant patients with and without PH (43% vs. 55%), as was new dialysis before hospital discharge (5% vs. 7%), and length of hospital stay (23 vs. 22 days). The use of extracorporeal membrane oxygenation (ECMO) to pump and oxygenate blood outside the body was also similar (48% vs. 42%), but with a trend toward longer ECMO time in the PH group.

In both groups, measures of pulmonary arterial blood pressure decreased immediately after heart transplant and at one month. By six months, blood flow readings were similar.

Comparing past, present outcomes

The researchers also examined national trends of heart transplant recipients with PH between 1994 and 2018 from the United Network for Organ Sharing (UNOS) registry. Among the 58,317 patients who had a heart transplant, 12,421 (21%) had preexisting high-risk PH.

Here, those with PH were older than those without PH (54 vs. 52) and were more often women (34% vs. 31%). The three-year survival rate was slightly higher in the non-PH group (83% vs. 82%), however.

Between 1994-1999 (early transplant era), transplant survival was similar in those with and without PH (77% vs. 78%), and was the same at 85% between 2014-2018 (modern transplant era). The three-year survival rate significantly improved over the decades. While the number of heart transplants increased from 1994 to 2018, the number of recipients with PH decreased from 25% to 19% over the same period.

“Recipients of [heart transplantation] with and without PH had similar early and late mortality in the modern era,” the researchers said. “Large, prospective studies are needed to confirm the hypothesis raised in this analysis that in the modern era, pre-transplant PH may no longer need to be a relative contraindication to [heart transplantation].”

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