Association between sarcopenia and exercise capacity in patients with pulmonary hypertension without left heart disease

Background: Pulmonary hypertension (PH) has recently been described as a complex clinical syndrome affecting multiple organ systems, including the heart, lungs, and skeletal muscle, each of which plays an important role in exercise capacity. However, the relationship between exercise capacity and skeletal muscle abnormalities in patients with PH has not been fully elucidated. Methods: We retrospectively analysed the exercise capacity and measures of skeletal muscle of 107 patients with PH without left heart disease (mean age 63 +/- 15 years, 32.7% males, n = 30/6/66/5 in the clinical classification Group 1/3/4/5). Results: Sarcopenia, low appendicular skeletal muscle mass index, low grip strength, and slow gait speed, determined by international criteria, were found in 15 (14.0%), 16 (15.0%), 62 (57.9%), and 41 (38.3%) patients, respectively. The mean 6-min walk distance of all patients was 436 +/- 134 m and was independently associated with sarcopenia (standardised beta = 0.292, p < 0.001). All patients with sarcopenia showed reduced exercise capacity defined as 6-min walk distance < 440 m. Multivariable logistic regression analysis showed that each of the components of sarcopenia was associated with reduced exercise capacity (adjusted odds ratio and 95% confidence interval of appendicular skeletal muscle mass index: 0.39 [0.24-0.63] per 1 kg/m(2), p = 0.006, grip strength: 0.83 [0.74-0.94] per 1 kg, p = 0.003, and gait speed: 0.31 [0.18-0.51] per 0.1 m/s, p < 0.001). Conclusions: Sarcopenia and its components are associated with reduced exercise capacity in patients with PH. A multifaceted evaluation may be important in the management of reduced exercise capacity in patients with PH.