Cardiac Comorbidity and Exercise Intolerance in Bilateral Lung Transplant Recipients Followed at a Pediatric Center.

Abstract

Reduced exercise capacity is common in young bilateral lung transplantation (Bi-LTx) recipients, but longer-term data on cardiac comorbidities are limited. We evaluate potential cardiac contributions to long-term exercise intolerance in this population. All Bi-LTx recipients at a single pediatric center, who completed routine clinical post-transplant cardiac assessment, including echocardiogram, cardiac exam, and cardiopulmonary exercise testing (CPET), were included. Cardiac risk factors (CRFs) were assessed by history and laboratory tests. CPET-derived peak and percent-predicted peak myocardial oxygen consumption (VO₂ peak, ppVO₂ peak) were used to quantitate exercise capacity. Percent-predicted peak oxygen pulse (pp peak O₂ pulse) assessed stroke volume. 15 patients (67% M; median age 21.6 years, median follow-up from Bi-LTx 7.0 years) were included. Almost all patients (14, 93%) had multiple CRFs; hypertension and hyperlipidemia/dyslipidemia were the most common. On CPET, 93% (n = 14) had abnormal (≤ 85%) ppVO₂ peak (median 59%). 73% (n = 11) had abnormal pp peak O₂ pulse (median 74%). Ten had blunted heart rate response to exercise. Nine had left ventricular diastolic dysfunction (LV-DD) on echocardiogram. Median percent-predicted forced expiratory volume in one second was 70%. One had severe chronic lung allograft dysfunction. Cardiac risk factors and exercise intolerance are common among young Bi-LTx recipients years post-transplant, even among those without significant pulmonary dysfunction. High prevalence of multiple CRFs, LV-DD, chronotropic dysfunction, and abnormal stroke volume suggest cardiac comorbidities may contribute to intolerance. Medical management of CRFs and tailored exercise may decrease cardiac risk and improve functional capacity for Bi-LTx survivors.