Ablation improves rhythm control in mitral valve surgery

Issue: May 2015

SAN DIEGO — Mitral valve surgery plus ablation yielded significant improvement in freedom from atrial fibrillation compared with mitral valve surgery alone, according to late-breaking findings presented at the American College of Cardiology Scientific Sessions.

Perspective from David Wilber, MD

Marc Gillinov, MD, of the department of thoracic and cardiovascular surgery at the Heart & Vascular Institute at the Cleveland Clinic, presented findings on behalf of the Cardiothoracic Surgical Trials Network investigators.

Marc Gillinov

The analysis included 260 patients with persistent or long-standing persistent AF undergoing mitral valve surgery. Gillinov reported findings for 127 patients assigned mitral valve surgery alone and 133 patients assigned mitral valve surgery and ablation.

Freedom from AF at 6 and 12 months was the primary endpoint. Major adverse cardiovascular/cerebrovascular events, mortality, adverse events, anti-arrhythmic interventions, quality of life and readmissions comprised the secondary endpoints.

Forty-five percent of patients had persistent AF before surgery, whereas 55% had long-standing persistent AF with a median duration of 69 months (interquartile range, 37-132), according to Gillinov. Baseline data indicated that 15% of the cohort was being treated with class III anti-arrhythmic medications.

Patients remained free from AF at 6 and 12 months in 29.4% of the group that received surgery alone, compared with 63.2% of those in the surgery plus ablation group (Risk difference of success = 0.34; 95% CI, 0.21-0.47). Among patients with biatrial lesions, the freedom from AF rate was 66%, compared with 61% for those with pulmonary vein isolation (Risk difference of success = 0.05; 95% CI, –0.13 to –0.23).

Mortality rates were comparable but slightly favored ablation (HR = 0.76; 95% CI, 0.32-1.84), whereas incidence of major adverse cardiovascular/cerebrovascular events was similar between groups but slightly favored surgery alone (HR = 1.12; 95% CI, 0.67-1.89).

Quality-of-life parameters also were comparable between the two groups. “However, people having surgery alone were more likely to have daily episodes of AF than those having surgery plus ablation,” Gillinov said.

Serious adverse events were reported at a rate of 120 per 100 patient-years in the mitral valve surgery alone group, compared with 143 per 100 patient-years in the ablation arm (incidence rate ratio = 1.2; 95% CI, 0.95-1.51).

“Patients in the mitral valve surgery plus ablation group were 2.6 times more likely to have a pacemaker inserted,” Gillinov said. Most pacemakers were inserted during index hospitalization.

“Surgical ablation improves rhythm control in mitral valve patients with persistent and long-standing persistent AF,” Gillinov said. “Establishing the impact of ablation on long-term survival, freedom from stroke and need for anticoagulation will require further investigation.”– by Rob Volansky

References:

Gillinov A, et al. Late Breaker IV Session. Presented at: American College of Cardiology Scientific Sessions: March 14-16, 2015; San Diego.

Gillinov A, et al. N Engl J Med. 2015;doi:10.1056/NEJMoa1500528.

Disclosure: Gillinov reports associations with AtriCure, Clear Catheter, Edwards, Medtronic, On-X, St. Jude Medical and Tendyne.

Perspective

David Wilber, MD

This is one of the first formal comparisons showing that adding ablation of AF to surgical repair of the mitral valve substantially improves the freedom from AF in long-term follow-up. In fact, it doubled the number of patients who remained in sinus after a year. So, in that sense, it is important to get that quantification and confirmation. What is even more exciting, and perhaps surprising, is that a relatively less technically demanding and extensive ablation procedure worked equally well compared with a decades-old Cox-Maze procedure that previously had been the standard for surgical ablation of AF. One might expect that because of that, this is not only a more attractive surgery, but that it will be likely applied far more often than it is now.

Past information suggested that the pulmonary vein isolation procedure, while easier, had much more inferior results. One thing to consider is that, unlike what we see in the ablation lab by electrophysiologists, surgeons don’t always routinely check that when they perform ablation, they have actually isolated the vein and confirmed it electrically. This study required that. That may account for why the pulmonary vein isolation looked much more effective than had been reported previously.

David Wilber, MD

Editor-in-Chief, JACC: Clinical Electrophysiology

Director of Clinical Electrophysiology

Director of the Division of Cardiology and the Cardiovascular Institute

Loyola University Medical Center

Disclosures: Wilber reports associations with Biosense Webster, Medtronic and St. Jude.