Pre-operative physical performance as a predictor of in-hospital outcomes in older patients undergoing elective cardiac surgery

Objective: Risk stratification of cardiac surgery patients is usually based on the Society of Thoracic Surgeons (STS) score, that has limited predictive value in older persons. We aimed assessing whether the Short Physical Performance Battery (SPPB) improves, beyond the STS score, assessment of hospital prognosis in older patients undergoing elective cardiac surgery. Methods: All patients aged 75+ years referred for elective cardiac surgery to Careggi University Hospital (Florence, Italy) from April 2013 to March 2017 were evaluated pre-operatively. Participants were classified according to the STS-Predicted Risk Of Mortality (STS-PROM): low (<4%), intermediate (4 to 8%), and high risk (>8%). Primary study outcomes were hospital mortality and STS-defined major morbidity. Length of hospital stay was an additional outcome. Results: Out of 235 participants (females: 46.5%; mean age: 79.6 years), 144 (61.3%) were at low, 67 (28.5%) at intermediate and 24 (10.2%) at high risk, based on the STS-PROM. SPPB (mean +/- SEM) was 8.8 +/- 0.2, 7.0 +/- 0.5, and 6.0 +/- 0.8 in participants at low, intermediate, and high risk, respectively (p<0.001). The primary outcome occurred in 62 participants (26.4%). In low-risk participants, the SPPB score predicted the primary endpoint (adjusted OR 0.77, 95% CI 0.66-0.89 per each point increase; p<0.001) controlling for STS-Major Morbidity or Operative Mortality (STS-MM) score. This result was not observed in the intermediate-high risk group. Conclusions: SPPB predicts mortality and major morbidity in older patients undergoing elective cardiac surgery, classified as low risk with the STS risk score. The SPPB, applied preoperatively, might improve risk stratification in older patients undergoing elective cardiac surgery.