Chronic progression of cardiac surgery associated acute kidney injury: Intermediary role of acute kidney disease

Objective: The association between acute kidney injury (AKI) and chronic kidney disease (CKD) remains elusive in cardiac surgery. We investigated the association between postoperative AKI and CKD development, emphasizing the intermediary role of acute kidney disease (AKD), in patients undergoing valvular heart surgery. Methods: We assessed the occurrence of postoperative AKI (7 days postsurgery), AKD (3 months postsurgery), and CKD (12 months postsurgery) in 1386 patients. The primary outcome was the development of AKD and CKD according to AKI occurrence. Relevant risk factors of AKI, AKD, and CKD were identified through multivariable regression analysis. Results: AKI occurred in 23.9% of patients with normal preoperative renal function. Even with early recovery of renal function within 3 days, AKI increased the risk of AKD (odds ratio [OR], 3.21; 95% confidence interval [CI], 1.98-5.20, P < .001) and CKD (OR, 2.86; 95% CI, 1.68-4.86, P < .001), whereas persistent AKI further increased the risk of AKD (OR, 12.07; 95% CI, 5.56–26.21, P < .001) and CKD (OR, 10.54; 95% CI, 4.01-27.76, P < .001). We also found these relationships in patients with pre-existing renal dysfunction. Multivariable analysis identified 3-month postoperative heart failure and high right ventricular systolic pressure as independent risk factors for CKD. Conclusions: Even after early recovery, postvalvular heart surgery AKI was associated with increased risk of CKD via AKD in a graded manner related to AKI severity and persistence. Postoperative cardiac dysfunction assessed 3 months postsurgery also significantly influenced CKD development, indicating a need for close follow-up of cardiac and renal function to improve patient outcomes.