Impact of postoperative acute kidney failure in long-term survival after heart valve surgery.

OBJECTIVES: We investigated the impact of acute kidney failure after a heart valve procedure among patients with or without chronic kidney disease (CKD).

METHODS: All patients who had undergone a surgical valve procedure between 2005 and 2017 at our institution were divided into 2 groups depending on whether they had previous history of CKD (estimated glomerular filtration rate <60 ml/min/1.73 m2) or not. Homogeneous groups were obtained by propensity score matching. Long-term mortality was compared between the 2 groups and according to the occurrence of postoperative acute kidney failure. Level of significance was set at P-value <0.008 for multiple comparison tests.

RESULTS: From the 3907 patients included to this study, 1476 (37.78%) had previous history of CKD. After adjusting for propensity score 1:1, patients with preoperative impaired renal function were at a higher risk of acute kidney failure (26.83% vs 10.16%, P < 0.001) and postoperative mortality (8.48% vs 5.17%, P = 0.001). In the follow-up, they had a poorer survival at 1, 5 and 10 years as compared to patients with normal renal function (88% vs 91.95%, 78.29% vs 81.11% and 56.13% vs 66.29%, respectively; P < 0.001). Patients without postoperative kidney failure had similar survival whether they had preoperative CKD or not [hazard ratio (HR) 1.16, 99.2% confidence interval (CI) 0.87-2.52; P = 0.142]. As compared to patients with postoperative preserved renal function, those with postoperative kidney failure had a higher long-term mortality either if they had previous kidney disease or not [(HR 2.18, 99.2% CI 1.75-2.72; P < 0.001) and (HR 1.48, 99.2% CI 1.33-1.65; P < 0.001), respectively]. Preoperative CKD was the strongest predictor of acute kidney failure (odds ratio 4.45; 95% CI 3.59-5.53; P < 0.001).

CONCLUSIONS: Patients with CKD are at higher risk of postoperative adverse events and have poorer long-term outcomes. Postoperative acute kidney failure increases long-term mortality.