Prognostic impact of mild renal dysfunction in patients undergoing valve surgery

Abstract OBJECTIVES To analyze the impact of mild renal dysfunction on the prognosis of patients undergoing valve surgery. METHODS A total of 6,210 consecutive patients(3,238 women; mean age, 59.2 ± 12.7 years) who underwent left-sided heart valve surgery between 2000 and 2022 were included in the study cohort. The primary outcome was all-cause death, and the secondary outcome was a composite of death, reoperation, stroke, and heart failure. The restricted cubic spline function was utilized to investigate the association between eGFR and clinical outcomes, which was validated using inverse probability treatment weighting(IPTW)-adjusted analysis. RESULTS Severities of baseline renal dysfunction were none in 1520(24.5%), mild in 3557(57.3%), moderate in 977(15.7%), severe in 59(1.0%), and end-stage in 97(1.6%). Clinical outcomes varied significantly according to the degree of baseline renal dysfunction. The restricted cubic spline function curve showed a non-linear association, indicating that the significantly adverse effects of low eGFR on clinical outcomes were diminished in cases of mild renal dysfunction. This finding was corroborated by IPTW-adjusted analysis and subgroup analyses did not show significant differences in clinical outcomes according to the presence of mild renal dysfunction(all-cause mortality, HR: 1.08; 95% CI: 0.90–1.28; P = 0.413; composite outcome, HR: 1.06; 95% CI: 0.92–1.21; P = 0.421). CONCLUSIONS In patients undergoing valve surgery, long-term clinical outcomes were significantly associated with the degree of baseline renal function impairment, but not with the presence of mild renal dysfunction, demonstrating a non-linear association between baseline renal function and postoperative outcomes.