The impact of mitral valve surgery combined with maze procedure

Objective: Recent studies indicated that successful maze procedure for atrial fibrillation (AF) adjunct to mitral valve surgery provided a lower incidence of stroke and recurrence of AF. The purpose of this study is to review the 13-year experience of these combined procedures and to identify the risk factors and late outcomes of successful maze procedures compared to failed maze procedures. Methods: At a single institution, 521 consecutive patients underwent combined maze procedures with mitral valve replacements or valvuloplasties. Three kinds of maze techniques were primarily used: Cox-maze III, Kosakai maze, and cryo-maze procedure. Three months after the operation, 394 patients were in sinus rhythm (Group S) while the remaining 116 patients were in continuous or intermittent AF (Group F), excluding 11 early death patients. Risk factors for Group F were determined by the analysis of all patient demographics. Survival, freedom from stroke, cardiac events, and AF recurrence were analyzed. Results: The proportion of the patients without any other simultaneous procedures was greater in Group S (41% vs 29%, P = 0.02). The distributions of mitral valve surgery and maze procedure techniques were similar in these two groups. A left atrium larger than 70 mm [hazard ratio (HR) = 2.6; 95% confidence interval range 1.04-6.3, P = 0.043], preoperative AF history longer than 10 years (HR = 8.2; 4.5-15.1, P < 0.001) and f-wave voltage in V1 smaller than 0.1 mV (HR = 6.2; 5.0-15.2, P < 0.001) were determined to be risk factors for unsuccessful maze procedures. All the results of Cox proportional hazards models showed superiority in Group S; actuarial survival rates (HR = 2.7; 1.04-7.0, P = 0.035), freedoms from stroke (HR = 3.0; 1.1-8.1, P = 0.003) and cardiac events (HR = 4.3; 2.9-6.1, P < 0.001). Freedom from AF recurrence rate was 98.4% at 5 years and 81.0% at 12 years in Group S, and 73.0% and 60.1% in overall patients. Conclusions: Patients with successful maze procedures resulted in higher survival rate, greater freedom from stroke and cardiac events. The large left atrium, small f-wave, and long AF duration were significant risk factors for failed maze procedures, suggesting that earlier surgical interventions would result in superior results in mitral valve surgery combined with maze procedure.