When should prophylactic maze procedure be considered in patients undergoing mitral valve surgery?

BACKGROUND: Some patients are at high risk for late atrial fibrillation (AF) after mitral valve surgery, even without a prior history of arrhythmias. We examined the incidence and predictors of late AF in patients with functional tricuspid regurgitation (TR) undergoing mitral valve repair.

METHODS: From March 1995 to December 2005, 573 patients (375 men) with severe mitral regurgitation owing to leaflet prolapse and functional TR underwent mitral valve repair; 75 patients (13%) had greater than mild TR preoperatively. We excluded patients with preoperative AF or other cardiac disease. We assessed late rhythm status, and results were expressed as a time-related event. A separate cohort of patients undergoing tricuspid valve repair was compared.

RESULTS: Cumulative risk of late AF was 11% at 5 years and 23% at 10 years (>mild preoperative TR, 23% versus <mild TR, 9%; p = 0.0007). In a multivariable model, the risk of late AF was independently associated with advanced age (hazard ratio [HR], 1.05), left atrial size greater than 50 mm (HR, 1.06), greater than mild preoperative TR (HR, 2.3), and diabetes (HR, 4.8). Patients undergoing tricuspid valve repair (n = 25) had a similar risk of late AF at 5 years (tricuspid valve surgery, 18% versus no tricuspid valve surgery, 23%; p = 0.439). When analyzed as a time-dependent risk factor, patients with late AF had decreased late survival (HR, 4.01; p = 0.001).

CONCLUSIONS: New, late-onset AF after mitral valve repair for leaflet prolapse is significantly increased in patients with greater degrees of preoperative TR, and late survival is subsequently decreased. To avoid the adverse consequences of late AF, the addition of surgical AF ablation may be warranted.