Clinical significance of rectus femoris diameter in heart failure patients.

Heart failure (HF) is often accompanied by skeletal muscle weakness and exercise intolerance, which are known as prognostic factors of HF. Comprehensive evaluation of physical function is important, but it is not commonly conducted because of the lack of equipment or appropriate expertise. Measurement of rectus femoris diameter (RFD) by ultrasound is convenient and noninvasive, but it has not been clarified that RFD could represent physical functions in HF patients. This study evaluated 185 consecutive HF patients and underwent assessment including RFD, grip power (GP), knee extension strength (KES), skeletal muscle index (SMI), nutrition status, cardiopulmonary exercise testing, and New York Heart Association (NYHA) functional class. RFD was related with NYHA class and significantly correlated with GP, KES, SMI, body mass index, pre-albumin level, geriatric nutritional risk index, and peak VO2 (r = 0.631, 0.676, 0.510, 0.568, 0.380, 0.539, 0.527, respectively; p < 0.001). Multivariate regression analysis revealed that estimated glomerular filtration rate (β = 0.551) and RFD (β = 0.326) were predictive factors of peak VO2. Gender, age, brain natriuretic peptide level, left ventricular ejection fraction, and hemoglobin level were the other explanatory parameters. The cut off value of RFD for sarcopenia diagnosis was estimated as 15 mm (sensitivity = 0.767 and specificity = 0.808). RFD is a simple and useful marker which reflects skeletal muscle strength/volume, exercise tolerance, nutrition status, and NYHA class. It is also associated with sarcopenia in HF patients.