Prognostic impact of mild renal dysfunction in patients undergoing valve surgery

To analyse the impact of mild renal dysfunction on the prognosis of patients undergoing valve surgery.

A total of 6210 consecutive patients (3238 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 estimated glomerular filtration rate and clinical outcomes, which was validated using inverse probability of treatment weighting-adjusted analysis.

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 estimated glomerular filtration rate on clinical outcomes were diminished in cases of mild renal dysfunction. This finding was corroborated by inverse probability of treatment weighting-adjusted analysis, and subgroup analyses did not show significant differences in clinical outcomes according to the presence of mild renal dysfunction (all-cause mortality, hazard ratio: 1.08; 95% confidence interval 0.90-1.28; P = 0.413; composite outcome, hazard ratio: 1.06; 95% confidence interval 0.92-1.21; P = 0.421).

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.