Meta-analysis of clinical outcomes of maze-related surgical procedures for medically refractory atrial fibrillation

Objective: Although maze-related surgical procedures have shown success at eliminating atria[ fibrillation, published controlled studies have generally been too small to detect clinically significant differences in morbidity and mortality. We pooled available studies to determine whether a simultaneous maze procedure reduces the risk of stroke or death in patients with chronic or paroxysmal atria[ fibrillation who receive mitral valve surgery. Secondary outcomes included post-operative bleeding and need for pacemaker. Methods: Our systematic review identified four randomized controlled trials and six retrospective comparative studies that met minimum quality criteria. We conducted meta-analyses of clinical outcomes using Cohen's h, a statistic appropriate for analysis of infrequent events. Results: The findings suggest that maze may reduce stroke risk but also increase the need for pacemaker implantation, as well as increase the risk of post-operative bleeding unless radiofrequency ablation is used. However, the statistically significant findings for stroke, need for pacemaker, and post-operative bleeding were overturned by sensitivity analysis, indicating that the findings are not robust. Conclusion: The literature evaluating maze clinical outcomes suffers from several shortcomings, particularly small sample sizes and selection bias. However, weak evidence supports a reduction in stroke rates and an increase in need for pacemakers among patients receiving the maze procedure. Radiofrequency maze may avoid an excess risk of post-operative bleeding associated with maze incisions. Larger, well-designed RCTs are needed to confirm these findings and evaluate outcomes such as survival and quality of Life. (c) 2005 Elsevier B.V. All rights reserved.