Patient Frailty Can Increase the Risk of Acute Kidney Injury after Cardiac Surgery: Pilot Study

Background: Acute kidney injury (AKI) is a severe common postoperative complication of cardiac surgery (CS). It increases the risk of mortality by up to 80%. Therefore, it is essential to have preoperative risk evaluation tools. Frailty is a marker of deterioration of physiologic systems and may be associated with AKI. Purpose: The study aimed to determine the utility of frailty as a predictor of AKI after CS. Method: We enrolled 91 patients undergoing CS with cardiopulmonary bypass to determine if they had frailty before surgery and were associated with postoperative AKI. The diagnosis of postoperative AKI was based on the serum creatinine criteria of the Acute Kidney Injury Network classification up to 7 days following CS. Results: The incidence of postoperative AKI was 62% in the frail group and 21% in the non-frail group. Frailty was associated with a higher risk of AKI (relative risk [RR] = 3.00, 95% CI 1.56 - 5.77, p = 0.00). In regression models, there were associa-tions between frailty and postoperative AKI. Conclusion: This study demonstrated that frailty could be a predictor for post-CS AKI. Therefore, frailty assessment should become an essential part of the preoperative evaluation to help the anesthesiologist to estimate the surgical risk and develop preoperative and transoperative strategies to preserve the renal function and improve the cardiac surgery outcome.