The largest study to date exploring the mid-term efficacy of cryoablation with the second generation device has shown favourable outcomes in patients with persistent atrial fibrillation. At a median follow-up of 10 months, 67% of patients were in sinus rhythm.
Buelent Koektuerk (Department of Cardiology & Electrophysiology, Witten/Herdecke University, Krankenhaus Porz am Rhein, Cologne, Germany) and others reported the results of this observational study ahead-of-print in Circulation Arrhythmia and Electrophysiology.
According to the authors, the use of the cryoballoon technique has increased in recent years and reports have shown success rates of pulmonary vein isolation as high as 80% treating patients with paroxysmal atrial fibrillation with second generation cryoballoon. They note that the technique is also being increasingly performed in patients with persistent atrial fibrillation; however, they write “long term success is not well known.”
In order to assess the medium-term efficacy of the second generation cryoballoon (Arctic Front Advance, Medtronic) for treatment of patients with persistent atrial fibrillation, Koektuerk et al undertook this study, which has the largest patient group reported to date in this setting.
The study enrolled 100 patients (63±10 years, 80% male) with symptomatic persistent atrial fibrillation (94% persistent, 6% long standing persistent) despite one or more than one antiarrhythmic drug. All patients underwent pulmonary vein isolation using a 28mm second generation cryoballoon. The authors note that when documenting atrial fibrillation recurrences a blanking period of three months was considered.
In total, 393 pulmonary veins were successfully isolated with a 100% acute procedural success rate. Total procedural time was 96.2±21.3 minutes and total fluoroscopy time was 19.7±6.7 minutes, the authors report.
At a mean follow-up of 10.6±6.3 months, 67% of the patients were free from symptomatic atrial fibrillation recurrence. The authors comment that previous studies evaluating first generation cryoballoon demonstrated lower success rates in persistent atrial fibrillation treatment, such as the report from Aytemir K et al (J Interv Card Electrophysiol 2013;38:187-195), which showed 50% success rate at a median of 18 months follow-up.
The authors also found that recurrence at blanking period was the only predictor of long-term atrial fibrillation recurrence.
Regarding complication rate, Koektuerk et al reported that it was low without any pericardial tamponade or cerebrovascular events and only one femoral pseudoaneurysm surgery. Phrenic nerve palsy developed in 3% of patients; the authors note that in two of those it was transient and resolved completely during the intervention.
Koektuerk et al conclude that “using second generation cryoballoon in patients with persistent atrial fibrillation as an index procedure is associated with improved outcomes.” However, they acknowledge that large scale randomised studies are needed to confirm and expand these data and that long-term monitoring with loop recorders “might give more accurate data regarding recurrence rates in this patient population.”