Lower extremity performance predicts length of hospital stay in older candidates to elective cardiac surgery

Introduction: Prolonged hospital stay must be considered as risk factor for poor outcomes after cardiac surgery; different variables have been advocated as predictors of in-hospital stay. Nevertheless, most patients requiring prolonged hospital stay are frail older subjects; thus, we hypothesized a significant influence of pre-operative physical performance, as a frailty measure, on in-hospital stay after elective cardiac surgery. Methods: In a prospective, single-center, cohort study we enrolled patients aged 75+ years referred to our Division of Cardiac Surgery at Careggi University Hospital, for their first elective cardiac surgery. All participants were preoperatively evaluated by a team composed by a cardiac surgeon, a cardiologist, an anaesthesist, and a geriatrician to assess global cardiac surgery risk; lower extremity performance was measured with the Short Physical Performance Battery-SPPB. Results: A total of 518 patients were included in the study. Mean age was 79.5 +/- 3.3 years; 256 (49.4%) were women. Isolated coronary by pass graft was performed in 37 patients (7.1%), isolated valve surgery in 115 (22.0%), and combined cardiac surgery procedures in 366 (70,9%). In a multivariable model, SPPB score was strongly associated with hospital length of stay both as continuous, categorized and dichotomous variable (p < 0.001; p = 0.002; p = 0.002 respectively) in all study population, and in subgroup of patients candidate to cardiac surgery considered by the Society of Thoracic Surgeons calculator score (p = 0.023; p = 0.056; p = 0.013 respectively). Conclusions: Our findings support the use of pre-operative SPPB evaluation before elective cardiac surgery based on the independent ability to predict length of hospital stay.