Cardiopulmonary exercise testing following allogeneic lung transplantation for different underlying disease states

Objectives: To assess the exercise response to single lung transplantation in chronic airflow obstruction (CAO), idiopathic pulmonary fibrosis (IPF), and pulmonary vascular disease (PVD) vs double lung transplantation at well- defined time points after transplantation, and to define the change in exercise response in SLT and DLT over the first year after transplantation. Design: Prospective study. Setting: Tertiary referral hospital. Patients: Fourteen stable SLT recipients (6 with CAO, 4 with IPF, 4 with PVD) and 11 stable DLT recipients. Measurements: Spirometry, lung volumes, diffusion lung capacity for carbon monoxide (DL(CO)) and MVV measured prior to exercise at 3 months (n=25) then at 3-month intervals up to a maximum of 12 months post- transplantation (n=18 [12 SLT and 6 DLT]). Symptom-limited cardiopulmonary exercise tests at same time points (n=25 at 3 months, n=18 [12 SLT and 6 DLT] at 3-month intervals up to 12 months). Breathlessness was estimated by visual analogue scale prior to exercise and at peak exercise. Results: At 3 months, FEV(I) percent predicted was lower for SLT-CAO and SLT-IPF vs DLT (p≤0.05). Mean FEV(I)/FVC was lower for SLT-CAO vs all other groups (p≤0.05). The FVC, MVV, and DLCO/VA were similar for all groups. The TLC and RV were higher for the SLT-CAO group compared with all others. The TLC was lower for SLT-PVD compared with DLT. Exercise responses were similar in all groups studied without a statistically significant difference in achieved V̇O₂, work rate, O₂ pulse, anaerobic threshold, heart rate response, respiratory rate, VE/MVV, and VT/VC. The change in O₂ saturation during exercise was the least in recipients of DLT. Maximal achieved V̇O₂ rose from 3 to 6 months after SLT but dropped by 9 to 12 months after transplantation. Maximal achieved V̇O₂ trended up from 3 to 6 months after DLT but dropped by 9 to 12 months after transplantation. Maximal achieved work rate rose in both SLT and DLT from 3 to 9 to 12 months after transplantation. There was no significant difference in breathlessness at rest and peak exercise measured between recipients of SLT or DLT. Conclusions: Minor differences in pulmonary function and change in O₂ saturation occur between recipients of SLT and DLT during the first posttransplant year. These differences are most pronounced when comparing SLT-CAO with DLT. However, there is no significant difference in exercise capacity between SLT for CAO, IPF, PVD, and DLT. The rise in maximum achieved V̇O₂ over the first 6 months after transplantation may reflect the effects of exercise training and should be taken into account when examining aerobic response after transplantation.