Low skeletal muscle mass is associated with low aerobic capacity and increased mortality risk in patients with coronary heart disease - A CARE CR Study

Background: In patients with chronic heart failure, there is a positive linear relationship between skeletal muscle mass (SMM) and peak oxygen consumption (V̇O2peak); an independent predictor of all-cause mortality. We investigated the association between SMM and V̇O2peak in patients with coronary heart disease (CHD) without a diagnosis of heart failure. Methods: Male patients with CHD underwent maximal cardiopulmonary exercise testing and dual X-ray absorptiometry assessment. V̇O2peak, the ventilatory anaerobic threshold and peak oxygen pulse (peak V̇O2/HR) were calculated. SMM was expressed as appendicular lean mass (lean mass in both arms and legs) and reported as skeletal muscle index (SMI; kg/m2), and as a proportion of total body mass (appendicular skeletal mass [ASM%]). Low SMM was defined as a SMI<7.26 kg/m2, or ASM% <25.72%). 5-year all-cause mortality risk was calculated using the Caliber 5-year all-cause mortality risk score. Results: Sixty patients were assessed. Thirteen (21.7%) had low SMM. SMI and ASM% correlated positively with V̇O2peak (r=0.431 and 0.473, respectively; P<0.001 for both). SMI and ASM% predicted 16.3% and 12.9% of the variance in V̇O2peak, respectively. SMI correlated most closely with peak V̇O2/HR (r=0.58; p