HOUSTON (FRONTLINE MEDICAL NEWS) – At the time of mitral valve repair or replacement operations, the addition of surgical ablation to treat atrial fibrillation (AF) can be performed without increased risk of mortality, results from a large cohort study has demonstrated.

“Surgical ablation for atrial fibrillation performed concomitant to mitral valve repair or replacement is accepted to reduce long-term AF rates and improve quality of life, and has recently attained a class I, level of evidence A recommendation in the recent Society of Thoracic Surgeons Guidelines,” Vinay Badhwar, MD, said in an interview. Dr. Badhwar is the lead author of the STS Guidelines and senior author of the current study on mortality following surgical ablation of AF. “Nevertheless, the direct impact of surgical ablation on operative mortality has not been studied on a large scale using robust registry data.”

In an effort to examine the impact of performing or not performing surgical ablation (SA) on mortality of contemporary mitral valve repair or replacement (MVRR) operations, Dr. Badhwar, Gordon F. Murray Professor and Chair, department of cardiovascular and thoracic surgery at West Virginia University, Morgantown, W.Va., and his associates at eight other leading centers nationwide evaluated the medical records of 88,765 MVRR patients in the STS Adult Cardiac Surgery Database between July 2011 and June 2014.

The research, presented as the Richard E. Clark award winning paper in adult cardiac surgery by study leader J. Scott Rankin, MD, professor of surgery in the department of cardiovascular and thoracic surgery at West Virginia University, included cases of tricuspid repair and coronary artery bypass grafting and assessed all STS comorbid risk variables and mitral etiology for predictors of mortality. After performing multivariable logistic regression, the researchers compared risk-adjusted odds ratios for mortality by AF type at operation and SA performance: group 1 (no AF plus no SA), group 2 (no AF plus SA), group 3 (AF plus no SA), group 4 (AF plus SA), group 5 (persistent AF plus no SA), and group 6 (persistent AF plus SA).

The median age of patients ranged from 63 to 72 years. Compared with their counterparts in other groups, patients in groups 3 and 5 were older (median age of 71 and 72 years, respectively), had worse symptoms (50% in each group had NYHA class III or IV disease), had more reoperations (30% vs. 32%), and had higher unadjusted mortalities (6.7% vs. 6.6%).

Following multivariable risk adjustment, groups 2-6 with AF history plus or minus SA were referenced to group 1 patients without AF or SA. Groups 2-4 represented the overall population, and groups 5 and 6 were patients with persistent AF. Patients with AF at the time of operation not receiving SA (groups 3 and 5) had odds ratios of 1.16 and 1.17, respectively, or an increase of 16% and 17% in relative risk of mortality (P = .004 and P = .01, respectively). In groups 4 and 6, concomitant SA reduced the AF-related mortality to a level that was statistically comparable to reference baseline group 1 without a history of AF (P = .13 and P = .21, respectively).

“The present study appears to clearly illustrate the adverse effects of AF on operative mortality following MVRR,” Dr. Badhwar said. “After thorough risk adjustment, we were impressed to learn that the relative mortality risk of mitral procedures increased by nearly 15% for either paroxysmal or persistent AF, and results were similar for the two AF types. A remote history of AF with preoperative sinus rhythm immediately prior to surgery had little effect on prognosis, and these patients appeared to have outcomes more like those without AF. In patients with active AF at the time of mitral operation, SA reduced the AF-related mortality and decreased operative mortality to levels not statistically different from patients without AF.” He added that the findings of this study support the recent STS Guidelines on Surgical Ablation published in the January 2017 edition of Annals of Thoracic Surgery ( Ann Thorac Surg. 2017 Jan;103[1]:329-41 ). “However, the ultimate decision on whether or not to add surgical ablation must always remain between the surgeon and the patient,” he said.

Dr. Badhwar acknowledged that the study is limited by the information available in version 2.73 of the STS Adult Cardiac Surgery Database. “This does highlight the ongoing need for participants in the database to provide as much complete information as possible for all patients undergoing cardiac operations, especially those involving surgical ablation,” he said.

Dr. Badhwar reported having no financial disclosures. Dr. Rankin disclosed ties with Admedus, AtriCure, and BioStable Science and Engineering.