Outcomes and residual gap analysis after the modified cryomaze procedure performed via right minithoracotomy versus sternotomy

OBJECTIVES: Developments in both technique and technology have enabled surgeons to perform the maze procedure via right minithoracotomy (RMT) to treat atrial fibrillation (AF). This study aimed to clarify the outcomes of the modified cryomaze procedure via the RMT approach compared with the sternotomy approach. METHODS: The study cohort comprised 803 consecutive patients who underwent a modified cryomaze procedure (130 via RMT and 673 via sternotomy) for paroxysmal AF and persistent AF from January 2001 to March 2022. The Gray test was applied to compare the incidence of recurrent atrial tachyarrhythmias. Additionally, residual electrical gaps were investigated in the patients who underwent additional catheter ablation for recurrent atrial tachyarrhythmias. RESULTS: The respective 1-, 2-, and 3-year cumulative incidences of recurrent atrial tachyarrhythmias were 13.1%, 19.5%, and 23.1% in the RMT group, and 9.3%, 10.9%, and 12.8% in the sternotomy group (Gray test P = .036). All 31 patients with recurrent atrial tachyarrhythmias underwent additional catheter ablation, comprising 14 (10.8%) in the RMT group and 17 (2.5%) in the sternotomy group. There was a significant intergroup difference in the site of residual electrical gaps; the RMT group more frequently had residual gaps in the tricuspid annulus than the sternotomy group (6.2% vs 0.4%; P < .001). CONCLUSIONS: In the modified cryomaze procedure via the RMT approach, ablation failure is more likely to occur at the tricuspid annulus, where the surgical field of view is relatively poor compared with the sternotomy approach. Therefore, surgical ablation should be performed with caution when the RMT approach is used.