Methods
A prospective cohort of 137 patients aged 70 or more undergoing cardiac surgery with the use of cardiopulmonary bypass were recruited at three university-affiliated hospitals in Spain. Frailty status was assessed preoperatively and six months after surgery using two different validated frailty measurements: The Fried frailty scale and the Clinical Frailty Scale. We analyzed the changes in these frailty scores and the transitions between frailty status after surgery.