Impact of acute kidney injury on clinical and functional outcomes in patients undergoing coronary artery bypass grafting: a prospective cohort study

Abstract Introduction: Acute kidney injury (AKI) is a common complication after coronary artery bypass grafting (CABG), associated with worse clinical outcomes. However, its impact on functional outcomes remains uncertain. Objective: To evaluate the clinical and functional outcomes of patients undergoing cardiac surgery who developed AKI during hospitalization. Methods: A prospective cohort study was conducted with 60 patients evaluated preoperatively, at ICU discharge and at hospital discharge. Clinical and functional variables were collected, including the six-minute walk test (6MWT), sit-to-stand test (STS), Timed Up and Go (TUG), peripheral muscle strength, and the functional independence measure (FIM). Patients were divided into two groups: those with and those without AKI. Results: Fifteen patients (25%) developed AKI. There was no significant difference in ICU length of stay between groups; however, hospital stay was longer in the AKI group (14 ± 5 vs. 9 ± 3 days), and mortality was higher. Patients with AKI showed a 33.53% reduction in the 6MWT distance at ICU discharge, with partial recovery by the time of hospital discharge. In the STS test, patients without AKI performed better at hospital discharge. In the TUG test, AKI patients showed better performance at discharge compared to those without AKI. FIM scores were lower in the AKI group, indicating reduced functional independence. Conclusion: Patients with AKI presented worse clinical outcomes and lower functional independence, although they demonstrated potential for functional recovery by the time of hospital discharge, highlighting the importance of postoperative rehabilitation.