Newer cryoballoon scores on efficacy but with higher complication rate

A newer generation cryoballoon allowed for shorter ablation procedures with a high success rate in patients with paroxysmal atrial fibrillation compared with the first-generation device but it also had a higher rate of phrenic nerve palsy, a serious complication, in a study published in the March issue of HeartRhythm.

Raphael P. Martins, MD, of the Centre Hospitalier Universitaire de Rennes in Rennes, France, and colleagues compared the first-generation Arctic Front cryoballoon with the newer Arctic Front Advance cryoballoon in a nonrandomized study. Medtronic manufactures both devices. Their goal was to evaluate the safety and efficacy of the newer cryoballoon in patients with paroxysmal atrial fibrillation.

They enrolled 66 patients between August 2011 and September 2012 in the Arctic Front arm and 81 patients between August 2012 and June 2013 in the Advance arm. They studied 252 and 310 pulmonary veins, respectively.

Pulmonary veins were completely isolated in both groups, with a single cryoapplication isolating 81 percent in the group with the first-generation device vs. 90.3 percent in the newer generation device group. Mean procedural time in the first-generation group was 120.1 minutes vs. 107.4 minutes with the newer cryoballoon, and duration of exposure to fluoroscopy was 28.7 minutes vs. 25 minutes, respectively. Mean time to pulmonary vein isolation was 12 seconds shorter with the newer device.

But the incidence of phrenic nerve palsy was higher in the newer generation group, with phrenic nerve palsy occurring in 13.6 percent of procedures with the newer cryoballoon vs. 5.6 percent with the older device. “[T]he rate of right-sided PNP [phrenic nerve palsy] was significantly higher with the ARC-Adv-CB [Arctic Front Advance cryoballoon] and strongly correlates with the estimates of the procedural CB-PN [cryoballoon-phrenic nerve] proximity by using the SVC [superior vena cava] pacing catheter.”

The results may help in identifying predictors of phrenic nerve palsy, they wrote, adding that further studies are needed.