Poor Heart Function Raises Risk of Early Death After Lung Transplant for IPAH Patients, Study Suggests

Certain parameters of poor heart function are risk factors for early death among idiopathic pulmonary arterial hypertension (IPAH) patients who undergo lung transplant, a small Chinese study suggests.

The study, “Risk Analysis of Perioperative Death in Lung Transplant Patients With Severe Idiopathic Pulmonary Hypertension,” was published in the journal Transplantation Proceedings.

Lung transplant remains the most effective treatment to improve an IPAH patient’s survival. However, the death rate associated with the procedure is high: 2015 estimates from the International Society for Heart and Lung Transplantation Registry show that 23% of patients with IPAH die within three months of their lung transplants.

Researchers in the study decided to investigate the risk factors associated with an early death among IPAH patients undergoing lung transplants.

The study enrolled 22 critically ill IPAH patients who underwent lung transplants at the Affiliated Wuxi People’s Hospital of Nanjing Medical University, between November 2007 and October 2016.

The mortality rate for these patients was 22.99% three months after their transplants. The researchers then divided patients into two groups: an early death group that included five patients who died within three months following transplant, and a control group with the 17 remaining patients.

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When comparing potential risk factors between both groups, the researchers saw that patients who died within three months of the transplant had a significantly higher frequency of syncope — a sudden transient loss of consciousness (fainting) — and lower salt (sodium) concentration of 116.80 mmol/L in their blood (a condition called hyponatremia), when compared with the control group, which had a sodium concentration of 129.88 mmol/L.

Syncope frequency is a symptom that can arise from several underlying causes, including cardiac problems.

The researchers then analyzed patients’ cardiac characteristics before surgery. The cardiac index, which measures the amount of blood pumped from the left side of the heart to the whole body and is proportional to heart performance, was lower in the early death group (1.30 L/min/m2) compared with the control group (1.58 L/min/m2).

Also, an echocardiogram of the heart showed that the right ventricle (the heart’s right chamber) was enlarged in the early death group, which indicates a lower ability of the heart to pump out blood, often leading to blood supply complications. The heart’s left ventricle was also smaller in the early death group.

The results suggest that “lung transplant patients with severe idiopathic pulmonary hypertension are at higher risk of perioperative mortality,” and that “high frequencies of syncope, hyponatremia, lower CI [cardiac index], inner diameter of the LV [left ventricle], and upward RV/LV [right ventricle/LV]” are risk factors for an early death in this patient population, the researchers wrote.

According to the team, the data “support the need for a careful assessment of cardiovascular risks before lung transplant to improve IPAH patients’ outcomes,” they concluded.