Pulmonary Vein Stenosis After Second-Generation Cryoballoon Ablation.

BACKGROUND Pulmonary vein stenosis (PVST) can occur after first-generation cryoballoon ablation. This study aimed to evaluate the incidence, severity, and characteristics of PVST after second-generation cryoballoon ablation. METHODS In total, 103 patients underwent PV isolation of paroxysmal atrial fibrillation using second-generation cryoballoons with a single big-balloon 3-minute freeze technique. Cardiac enhanced multidetector computed tomography (MDCT) was performed both before and a median of 6.0 (4.0-8.0) months after the procedure in all. PVST was classified as follows: minimal (<25%), mild (25-50%), moderate (50-70%), or severe (>70%). RESULTS In total, 406 PVs were analyzed. MDCT demonstrated PV stenosis in 10(2.5%) PVs among 8(7.8%) patients. In detail, minimal and mild PVSTs were observed in 6 and 4 PVs, respectively. PVST occurred in the left superior (LSPV), left inferior, and right superior PVs in 6, 1, and 3 PVs, respectively. No stenosis was observed in 15 PVs with active balloon deflations during freezing. All PVSTs had concentric patterns except for 2 PVs with minimal stenosis. Balloon deformities were observed during freezing of 2 PVs with mild stenosis. When the PVST was defined as a >25% decreased diameter, the incidence was 0.98% (4/406; including 3 LSPVs). PVST did not progress further during the follow-up period. CONCLUSIONS Although the incidence of PVST was low, it could occur even if a single big-balloon short freeze technique was applied. The risk of PV stenosis significantly differed among the 4 PVs, and reaching balloon temperatures of -60 °C and active balloon deflations during freezing were not associated with any PV stenosis.