Low exercise tolerance correlates with reduced inspiratory capacity and respiratory muscle function in recipients with advanced chronic lung allograft dysfunction.

Background: Advanced chronic lung allograft dysfunction limits survival after lung transplantation. We hypothesize that patients with chronic lung allograft dysfunction can be subdivided by exercise tolerance in two groups, and quality of life (QOL) and survival differ between the groups.
Methods: A single-center, cross-sectional, partly prospective, study was performed in our outpatient clinic between July and November 2011, including all patients with a forced expiratory volume in 1 s <50% baseline. Respiratory parameters, 6-min walk test, and QOL were measured. Patients with low exercise capacity were defined as 6-min walk test <50% predicted or use of rollator or wheelchair.
Results: Fifty-two patients consented to participating in the study and 22 demonstrated low exercise capacity. These patients had pathologic respiratory muscle function (P=0.005) and decreased inspiratory capacity (IC; P=0.001). QOL was significantly reduced. Multivariate analysis proved that low IC (hazard ratio, 17.9; 95% confidence interval, 2.8-111; P=0.002) and increased P0.1/Pimax (hazard ratio, 7.1; 95% confidence interval, 1.4-35.8; P=0.016) were independently associated with decrease exercise capacity.
Conclusion: Heterogeneity of patients with advanced lung allograft dysfunction regarding exercise tolerance might result from altered IC and impaired respiratory muscle function.