BackgroundIn the last year there has been an increasing interest for using frailty scales for risk stratification of elderly patients undergoing major surgery. We planned to compare two frailty scales with risk scales already used in cardiac surgery, to study which of these scores have better prognostic value predicting postoperative outcome in open heart surgery.MethodsWe conducted a prospective clinical trial, including 57 patients over 65 years. We calculated Cardiac Anesthesia Risk Evaluation score, EuroScore II, Clinical Frailty Scale, Edmonton Frail Scale for each patient and followed the postoperative complications, length of mechanical ventilation, length of stay in the intensive care unit and hospital, and in-hospital death related to these risk and frailty scores.ResultsPostoperative complications occurred in 25 patients (43.9%), while four patients (7%) died with multiple organ failure. All scales had low predictability for postoperative complications, but for length of mechanical ventilation we obtained positive correlations with EuroScore II, Edmonton Frail Scale and Clinical Frailty Scale. EuroScore II can also predict the length of stay in the intensive care unit. For postoperative deaths, the highest sensitivity had EuroScore II, followed by Clinical Frailty Scale and Edmonton Frail Scale.ConclusionsEuroScore II and the frailty scales have an increased prognostic value regarding the postoperative outcome of patients (length of mechanical ventilation and in-hospital mortality), the EuroScore II can predict the length of stay in the intensive care unit as well.