Background: Even after successful single-lung transplantation (SLTx) or bilateral lung transplantation (BLTx), patients continue to have peripheral muscle weakness and exercise impairment. After SLTx, exercise limitation is also attributed to persistent or recurrent pulmonary vascular abnormalities with elevated pulmonary arterial pressures at rest or during exercise. Therefore, the aim of this study was to evaluate systolic pulmonary artery pressures (PASPs) at rest and during supine bicycle exercise, exercise capacity and cardiopulmonary function in post-BLTx patients.
Methods: Nine patients underwent BLTx due to end-stage pulmonary arterial hypertension (PAH) and 37 age- and gender-matched control subjects underwent a physical examination, electrocardiographic (ECG) test, a 6-minute walk test, a lung function test, a cardiopulmonary exercise test and echocardiographic assessment at rest and during exercise.
Results: Exercise capacity was significantly reduced in the BLTx group, with an impaired 6-minute walk test and maximal oxygen uptake and workload. Ventilatory factors did not appear to limit exercise capacity. Right and left ventricular size and pump function and PASP values at rest were normal in both groups, but exceeded 40 mm Hg in 3 of 9 BLTx recipients and in 1 of 37 controls during exercise at low workloads. Mean PASP during exercise was only slightly higher in the BLTx group (40 +/- 5 vs 36 +/- 4 mm Hg, p = not statistically significant).
Conclusions: Reduced exercise capacity of patients after BLTx due to end-stage pulmonary hypertension is not attributed to persistent or recurrent manifest pulmonary hypertension or cardiopulmonary dysfunction. Nevertheless, latent pulmonary hypertension with exaggerated pulmonary artery pressures during exercise may occur in some patients.