Optimal surgical timing for atrial functional mitral regurgitation based on preoperative diuretic requirement: a...

Atrial functional mitral regurgitation (AFMR) is increasingly prevalent worldwide and is associated with poor clinical outcomes, yet the optimal timing of surgical intervention remains unclear. Although preoperative diuretic dosage may reflect heart failure severity, its prognostic significance after surgery for AFMR has not been fully established. This study investigated the association between preoperative diuretic dosage and postoperative outcomes in patients undergoing surgery for AFMR.

Among 915 patients who underwent mitral valve surgery (MVS) between 2008 and 2023, 85 patients with AFMR were identified and categorized into high-dose (≥40 mg furosemide-equivalent, n=35) and low-dose (<40 mg, n=50) groups based on preoperative diuretic dosage. Ten-year cumulative incidences of all-cause mortality, cardiac mortality, and heart failure readmission were evaluated.

Baseline characteristics were comparable between groups in terms of age (78 vs. 75 years, P=0.09), male sex (46% vs. 62%, P=0.19), total bilirubin (1.0 vs. 0.9 mg/dL, P=0.23), ejection fraction (EF; 61% vs. 65%, P=0.20), and Society of Thoracic Surgeons Predicted Risk of Mortality (STS-PROM) (5.3% vs. 4.5%, P=0.94). Estimated glomerular filtration rate (eGFR) was lower in the high-dose group (48.3 vs. 58.9 mL/min/1.73 m², P=0.006). All-cause mortality (51.7% vs. 22.9%, P=0.02), cardiac mortality (47.8% vs. 13.1%, P=0.007), and heart failure readmission (71.1% vs. 52.4%, P=0.005) were significantly higher in the high-dose group over the 10-year follow-up. High-dose diuretic use remained an independent risk factor in multivariable analysis [adjusted hazard ratio (HR) 2.89; 95% confidence interval (CI): 1.01-8.25; P=0.048]. Mortality was particularly higher among patients with renal dysfunction, regardless of dosage, and those with liver dysfunction receiving high-dose diuretics.

In AFMR surgery patients, especially with concomitant renal or liver dysfunction, high-dose diuretic use was associated with increased mortality and heart failure readmission.