Near-normal aerobic capacity in long-term survivors after lung transplantation

Abstract

The clinical course of lung transplantation (LT) is diverse: some patients present chronic lung allograft dysfunction (CLAD) and progressive decline in pulmonary function, but others maintain normal spirometric values and active lives. Objectives: The aim of this study was to elucidate whether long-term LT survivors with normal spirometry achieve normal exercise capacity, and to identify predictive factors of exercise capacity. Methods: This was a cross-sectional multicentre study, where bilateral LT recipients who survived at least 10 years after LT, with normal spirometry, no diagnosis of CLAD and modified Medical Research Council dyspnoea degree ⩽2 underwent cardiopulmonary exercise testing (CPET). Results: 28 LT recipients were included with a mean±SD age of 48.7±13.6 years. Oxygen uptake (V′O2) had a mean±SD value of 21.49±6.68 mL·kg−1·min−1 (75.24±15.6%) and the anaerobic threshold was reached at 48.6±10.1% of the V′O2max predicted. The mean±SD heart rate reserve at peak exercise was 17.56±13.6%. The oxygen pulse increased during exercise and was within normal values at 90.5±19.4%. The respiratory exchange ratio exceeded 1.19 at maximum exercise. The median (25–75th percentile) EuroQol-5D score was 1 (0.95–1), indicating a good quality of life. The median (25–75th percentile) International Physical Activity Questionnaire score was 5497 (4007–9832) MET-min·week−1 with 89% of patients reporting more than 1500 MET-min·week−1. In the multivariate regression models, age, sex and diffusing capacity of the lung for carbon monoxide remained significantly associated with V′O2max (mL·kg−1·min−1); haemoglobin and forced expiratory volume in 1 s were significantly associated with maximum work rate (watts), after adjusting for confounders. Conclusion: We report for the first time near-normal peak V′O2 values during CPET and normal exercise capacity in long-term LT recipients without CLAD.