Abstract 2860: Long Term Efficacy and Side Effects of Antral Isolation of Pulmonary Veins With Cryoballoon Technique in a Large Patient Cohort With Atrial Fibrillation
Background: Circumferential substrate modification of the antrum of pulmonary veins (PV) with radiofrequency energy includes the risk of PV stenoses and esophago-left atrial fistula. This study reports on the success and side effects in antral isolation of PV with the cryoballoon technique.
Methods: PV isolation was performed with 28 or 23 mm balloon (Arctic Front, Medtronic) occluding the venous antrum and freezing for 6 min 2 times per vein with nitrous oxide. Rest potentials were eliminated with additional balloon freezes. Phrenic nerve conduction was monitored continuously with constant pacing at the superior caval vein. Patients (p) were followed 3-monthly with 7-day Holter.
Results: We treated 318 p (104 women, mean age 59±10 years, 296 with paroxysmal, 22 with persistent AF, left atrium 43±5 mm, 154 p with lone AF, 118 with hypertension, 46 with structural heart disease). With a mean number of 2.4±1.1 impulses we isolated all PV with balloon only in 84% (touchup in 17 %). In the last 266 p all pv could be isolated with balloon only, in 44 % combining two balloon sizes. Procedure time decreased to 169±38 min and X-ray burden to 27±8 min. Phrenic nerve palsy in 10 p (3%, 9 with 23 mm balloon) recovered within 3 to 9 months. Due to the pacing technique, a damage of phrenic nerve could be reduced to 1.5% (last 200 p). In 6 p (2%) we observed cough, hemoptysis and hematomas around single PVs in CT scans representing frozen lung tissue. During a mean follow-up of 11.6±6.6 months and 1.1 procedures per p (32 redos) of 212 p analyzed after blanking time of 3 months 82 % (173 p) were free of AF compared to 73% with one procedure. No PV stenoses, no fistulas were observed. Other side effects were one reversible stroke, 2 pericardial effusions, 5 groin hematomas. Comparing the long-term efficacy of single large balloon or use of two balloon sizes showed a significantly lower recurrence of AF (p=0.002) when treated with two sizes, i.e. a higher reliability in the long run.
Conclusion: Antral cryoisolation of the pv with balloon technique is highly efficient. With the pacing technique, persistent phrenic nerve palsy can be minimized. Freezing too far inside the pv may result in frozen lung tissue. Isolation of mismatching veins with two balloon sizes may be associated with a lower recurrence rate of AF.