Smaller rectus femoris size measured by ultrasound is associated with poorer outcomes after cardiac surgery

Abstract

ObjectiveWe sought to evaluate the association of low rectus femoris cross-sectional area (RFCSA) with hospital length of stay and poorer outcomes in patients undergoing cardiac surgery. MethodsA single right-leg RFCSA was measured with ultrasound preoperatively and baseline characteristics, clinical data, and outcomes recorded. Patients were categorized as low rectus femoris muscle size (lowRF) or normal rectus femoris muscle size (normalRF), if they were in the lowest quartile or not, respectively. All analyses were performed on both body surface area (BSA)- and sex-adjusted RFCSA. ResultsOne hundred eight-four patients had a RFCSA measured with a mean of 5.01 cm2 (1.41 cm2), and range of 0.71 to 8.77 cm2. When analyzing the BSA-adjusted RFCSA, we found the lowRF group had a longer hospital stay, 11.0 days [7.0-16.3] versus 8.0 days [6.0-10.0] for the normalRF group (P < .001), and a greater proportion of extended hospital stay (≥18.5 days) of 19.6% compared with 6.2% (P = .010). When the RFCSA was adjusted for sex, the lowRF group had a greater length of hospital stay, 9.0 days [7.0-14.5] versus 8.0 days [6.0-11.0] (P = .049). In both the BSA- and sex-adjusted RFCSA, the lowRF group suffered greater morbidity and were more likely discharged to a destination other than home. In multivariate analyses adjusting for European System for Cardiac Operative Risk Evaluation II, BSA-adjusted lowRF but not sex-adjusted lowRF was independently associated with log-transformed hospital length of stay. LowRF was not independently associated with increased major morbidity and death for both BSA and sex-adjusted RFCSA. ConclusionsLow RFCSA has a significant association with increased hospital length of stay, morbidity, and nonhome discharge in patients undergoing cardiac procedures. Trial Registry NumberACTRN12620000678998.