Pectoralis Muscle Area Predicts Frailty and Risk-Adjusted Mortality After Surgical Aortic Valve Replacement

Background: Psoas muscle cross-sectional area predicts morbidity and mortality as a surrogate for frailty in cardiac surgery patients, but routine preoperative abdominal imaging is uncommon. We hypothesized that pectoralis and psoas muscle cross-sectional area correlate, and pectoralis area may predict morbidity and mortality for patients undergoing surgical aortic valve replacement (SAVR). Methods: A psoas muscle area validation cohort of moderate to high-risk patients undergoing SAVR (1/2009–12/2016) were identified from the University of Virginia. Pectoralis muscle area identified on preoperative computed tomography (CT) was indexed to body surface area to define pectoralis index. Sarcopenia was defined as pectoralis index below sex-specific 25th percentile. Patients were stratified by sarcopenic status, and regression analysis identified risk-adjusted associations utilizing Society of Thoracic Surgeons (STS) predicted risk scores. Results: Preoperative chest imaging was available for 228 patients. Sarcopenic patients were significantly older (median 82 vs 80 years, p = 0.041) and had greater mean society of thoracic surgeons predicted risk of mortality (STS PROM) (7.0% vs 5.7%, p = 0.047). There was no difference by sarcopenic status for operative mortality (8.8% vs 4.1%, p = 0.171) or major morbidity (21.1% vs 19.9%, p = 0.849). Risk-adjusted pectoralis index was associated with greater STS major morbidity (OR 0.998, p = 0.021), likelihood of discharge to a facility (OR 0.998, p = 0.014), and one-year mortality (OR 0.997, p = 0.025). Conclusion: Lower pectoralis index may be associated with worse risk-adjusted outcomes after SAVR. Pectoralis defined sarcopenia may serve as a useful measure of frailty in cardiac surgery patients.