Patient population and study design
Between April 2015 and December 2016, a cohort of patients aged 70 or more undergoing elective cardiac surgery with cardiopulmonary bypass were recruited at three university-affiliated hospital of three different regions of Spain (Madrid, Asturias, and Canary Islands).
Using this cohort of patients, we analyzed the changes in the level of frailty after cardiac surgery with respect to the preoperative ones.
The Institutional Research Ethics Committees at each of the participating hospitals approved the implementation of this study, and every patient provided signed informed consent.
Exclusion criteria were urgent or emergent surgery, off-pump operations, and the absence of the necessary capacity to understand and collaborate in the study. Patients with neurological or physical impairment that could bias the results of the frailty assessment were also excluded.
Frailty was assessed at the time of the hospital admission before the operation, and six months after surgery, using the same frailty assessment tools.
Medical records were used to extract demographic, clinical and surgically related variables.