Bilateral Lung vs Heart-Lung Transplant in Patients With PAH

VIENNA — Survival rates at 1 and 5 years for patients with pulmonary arterial hypertension (PAH) who receive bilateral lung and heart-lung transplants are similar, said researchers presenting at the European Respiratory Society (ERS) 2024 International Congress.

Transplant for end-stage PAH remains an important treatment option. Heart-lung transplantation plummeted from 91.7% to 21.4% between 1991 and 2014. Yet in the United States and Europe, PAH is the second most common reason to perform a heart-lung transplant, Baharan Zarrabian, DO, a pulmonologist at the Mayo Clinic in Rochester, Minnesota, told Medscape Medical News.

Over the past decades, physicians have debated whether to opt for a bilateral lung or a heart-lung transplant. However, there is currently a lack of definitive cardiac indicators to guide the decision between the two procedures in patients with PAH.

While the lung condition has cardiac ramifications, some experts suggest that the heart can repair itself over time after a bilateral lung transplant.

No Survival Difference Between Bilateral Lung and Heart-Lung Transplants

Researchers compared the outcomes of bilateral lung transplantation with those of combined heart-lung transplantation in patients with PAH. They used data from the Organ Procurement and Transplantation Network, focusing on adult patients with PAH without congenital or structural cardiac abnormalities who underwent transplantation between June 2004 and September 2022.

The study included 918 patients, with the majority (84.6%) receiving bilateral lung transplants and 15.4% receiving heart-lung transplants. Pretransplant mean pulmonary arterial pressure and pulmonary vascular resistance were similar between the two groups. However, those who received bilateral lung transplants had higher cardiac output and lower pulmonary capillary wedge pressure than those who received heart-lung transplants. A higher percentage of heart-lung transplant recipients required extracorporeal membrane oxygenation (ECMO) before transplantation, while bilateral lung transplant recipients had longer median ischemic times.

Despite these differences in pretransplant characteristics and surgical factors, researchers found no significant difference in survival outcomes between the two groups at the 1-year and 5-year marks. Similarly, graft survival rates at 1 and 5 years posttransplant did not differ significantly between the two groups.

A higher proportion of patients who received bilateral lung transplant were on ECMO and remained intubated at 72 hours. “That did not translate into a worse outcome later on,” Zarrabian said.

Cardiac Recovery Post-Bilateral Lung Transplant

Saskia Bos, MD, PhD, a respiratory consultant, lung transplant physician, and transplant pulmonologist at University Hospitals Leuven, Leuven, Belgium, who was not involved in the study, told Medscape Medical News that doctors have historically preferred combined heart-lung transplantation. The decision was motivated by a lack of understanding regarding whether the heart could remodel on its own. “Now we know that the right ventricle, which is the most affected part of the heart in pulmonary hypertension, has a huge ability to readapt to the new situation after just bilateral lung transplantation,” she said.

Bos suggested that in cases where a patient has pulmonary hypertension without any structural heart defects and where the left side of the heart is functioning normally, doctors can opt for a bilateral lung transplant rather than a combined heart-lung transplant. The right ventricle, typically the only part of the heart affected by the condition, can recover once the pulmonary hypertension is addressed through lung transplantation, she explained.

The advantage of bilateral lung transplantation over a heart-lung transplant is that the donor’s heart remains available for someone else.

“The recommendation is that physicians opt for a bilateral lung transplant,” Zarrabian concluded. “But we need to make that decision on a case-by-case basis because we still don’t know what are the cardiac parameters that we need to look for before the transplant to decide whether or not they should receive a bilateral lung or a heart-lung.”

Zarrabian and Bos reported no relevant financial relationships.

Manuela Callari is a freelance science journalist specializing in human and planetary health. Her words have been published in The Medical Republic, Rare Disease Advisor, The Guardian, MIT Technology Review, and others.