Significance of Preoperative Body Composition Assessment on the Short-term Outcomes of Elective Cardiac Surgery
Background: Traditionally, surgical risk is determined by a preoperative assessment of age, comorbidities, and performance status. Although it is known that various age associated factors affect postoperative outcomes in the elderly, evidence in the field of cardiac surgery is still insufficient. In patients aged 50+ admitted to our hospital for elective cardiac surgery, body composition was evaluated immediately before surgery and its association with length of Intensive Care Unit (ICU) stay, length of hospital stay, and outcome was examined. Methods: In 101 consecutive patients (52 with valvular disease, 24 with ischemic heart disease, 12 with arrhythmia, 11 with aortic aneurysm, and 2 with cardiac tumor) bioelectrical impedance analysis body composition measurements were taken on the day of surgery, and skeletal muscle mass index (SMI), the ratio of visceral fat area to skeletal muscle mass (VFA/SMM), and Phase Angle (PA) were measured and calculated. Results: The subjects’ age was 72.0 ± 8.8 years, body mass index (BMI) was 22.3 ± 3.9 kg/m2, the length of hospital stay was 35.6 ± 28.0 days, and the ICU stay was 4.1 ± 3.1 days. The outcomes were 81 patients (80.2%) discharged to their home, 16 (15.8%) transferred to other hospitals, and 4 (4.0%) died. A low SMI was associated with a longer hospital stay (p < 0.01), a high VFA/SMM was associated with transfer to another hospital or death (p < 0.05), and a PA <4.5 in men and <4.0 in women was associated with a longer hospital stay (p < 0.05). Conclusion: Low skeletal muscle mass, a high visceral fat area to skeletal muscle mass ratio, and poor muscle quality were all associated with a worse short-term prognosis in patients undergoing elective cardiac surgery.