Time course of exercise capacity, skeletal and respiratory muscle performance after heart-lung transplantation

Recipients of heart-lung transplantation (HLT) show reduced exercise capacity due to several pre- and postsurgical factors. The aim of this study was to evaluate the time course of exercise capacity, and skeletal and respiratory muscle performance in 11 patients (5 females and 6 males; age (mean ± SD) 38 ± 13 yrs) undergoing HLT. All of the patients were admitted to our institution for a rehabilitation programme after surgery, and were followed-up for 18 months. On admission, at discharge after an in-patient rehabilitation programme, and every 6 months, patients underwent evaluation of: lung function values; incremental treadmill exercise, 6 min walking distance (6-MWD); maximal inspiratory and expiratory pressures (MIP and MEP, respectively); and peak torque of isokinetic contraction of leg flexor and extensor muscles (IFX and IEX, respectively). On admission, patients had: reduced lung volumes as assessed by vital capacity (VC) (60 ± 15% of predicted); reduced exercise capacity as assessed by peak oxygen consumption (V'O₂,peak) (40 ± 12% pred); reduced skeletal and respiratory muscle performance as assessed by IEX, IFX (48 ± 16 and 28 ± 12 Newton-metres (Nxm), respectively) and by MIP and MEP (54 ± 21 and 58 ± 19 cmH₂O, respectively). Ten patients completed the rehabilitation programme. At discharge, no significant change in dynamic and static lung volumes was observed. However, nonsignificant increases in MIP, MEP, IEX, IFX, 6-MWD and V'O₂,peak were recorded. After 6 and 12 months, indices of skeletal and respiratory muscle function and V'O₂,peak improved further, but still remained lower than normal values. We conclude that in patients with heart-lung transplantation, skeletal and respiratory muscle function and exercise performance are reduced after surgery, that they may improve with time but are still less than normal after 18 months.