Does Surgical Ablation Energy Source Affect Long-Term Success of the Concomitant Cox Maze Procedure?

Background The Cox maze (CM) procedure is routinely performed using surgical ablation technology. Reports are scarce on long-term outcomes of CM, especially for a large series of patients. This study examined the potential impact of surgical ablation energy source on safety and long-term efficacy of concomitant CM procedures. Methods The study sample consisted of 709 concomitant CM-treated patients operated on with cryothermal energy only (group 1; n = 386) or combination of cryothermal and bipolar radiofrequency (group 2; n = 323). Data were collected prospectively on perioperative outcomes, rhythm status, survival, and clinical events. Propensity score matching conducted by energy source resulted in 298 patients per group. Results Perioperative outcomes included stroke (n = 4), reoperation for bleeding (n = 23), renal failure requiring temporary dialysis (n = 18), readmissions before 30 days (n = 86), and operative death before 30 days (n = 16; ratio of observed to expected mortality [O/E ratio], 0.50). Independent predictors for 1-year and 5-year rhythm success were a shorter history of atrial fibrillation (1-year odds ratio [OR], 0.93, p = 0.001; 5-year OR, 0.93, p = 0.042) and cryothermia alone (1-year OR=1.77, p = 0.020; 5-year OR = 2.29, p = 0.009). After matching, group 1 had significantly higher sinus rhythm without antiarrhythmic drugs at 6 months (79% vs 70%; p = 0.016), 36 months (81% vs 69%; p = 0.010), and 60 months (75% vs 57%; p = 0.008). Stroke incidence was lower for group 1 (0.7% vs 3%; p = 0.033), with no difference in major bleeding (10% vs 11%; p = 0.597). Groups had similar survival rates (log rank, 0.6; p = 0.452). Conclusions Concomitant CM procedures performed with cryothermal energy alone or combined with bipolar radiofrequency ablation are safe and exceedingly effective. The association of cryothermal energy alone with higher rates of sinus rhythm and stroke reduction should be investigated further.