Atrial fibrillation worsens outcome of mitral valve repair for degenerative mitral regurgitation: Long-term follow-up of 959 patients.

BACKGROUND

The prognostic significance of atrial fibrillation (AF) in patients with degenerative mitral regurgitation (MR) undergoing mitral valve (MV) repair remains controversial. The association between preexisting AF and long-term clinical and echocardiographic outcomes following mitral repair was analyzed.

METHODS

This retrospective study included 959 patients (mean age, 60 ± 12 years) who underwent MV repair for degenerative MR between 2001 and 2022. Patients were stratified by preoperative rhythm: 670 in sinus rhythm and 289 with AF. Serial echocardiographic changes were assessed using linear mixed models. The mean follow-up was 8.6 ± 5.4 years (8219 patient-years).

RESULTS

Compared to patients with sinus rhythm, those with AF were older, more symptomatic, and exhibited greater cardiac remodeling, prompting higher rates of concomitant tricuspid annuloplasty (45% vs 5.7%) and ablation procedures (91% vs 0%) (P < .05 for all). At 10 years, AF patients had lower overall survival (89% vs 96%; P = .003) and freedom from composite adverse events-mitral reintervention, heart failure, stroke, catheter ablation, or pacemaker implantation (56% vs 80%; P < .001). Propensity score matching (n = 239 pairs) for 15 clinical covariates confirmed AF as an independent predictor of adverse events (adjusted hazard ratio, 1.8; 95% confidence interval, 1.3-2.5; P < .001). Additionally, AF patients demonstrated less improvement in left atrial size, tricuspid regurgitation (TR) pressure gradient, and TR severity up to 10 years (group effect P < .001).

CONCLUSIONS

These findings indicate that AF identifies a higher-risk phenotype characterized by advanced atrial disease and persistent hemodynamic burden following MV repair. Future studies are needed to determine whether intervention before the development of advanced atrial remodeling or AF can improve long-term outcomes.