Impact of cryoballoon size on pulmonary vein occlusion in pulmonary vein isolation: a comparative study of 28mm and 31mm cryoballoon modes

Abstract Background/Introduction Cryoballoon ablation has become an established treatment for atrial fibrillation (AF). Conventional cryoballoon systems have a fixed diameter of 28mm. However, novel cryoballoon systems with variable sizing options, such as 28mm and 31mm diameters, have been developed to potentially improve pulmonary vein (PV) occlusion and ablation outcomes. Purpose This study aimed to evaluate the impact of cryoballoon size on PV occlusion and to determine the anatomical parameters for optimal balloon size selection in patients undergoing pulmonary vein isolation (PVI). Methods A total of 108 patients with paroxysmal or persistent AF underwent PVI using a cryoballoon system with 28mm and 31mm diameter options. PV occlusion was graded during ablation with both the 28mm and 31mm modes. Baseline CT and echocardiography data were analyzed to identify predictors of successful occlusion. Results The rates of complete occlusion (grade 4) across all PVs were 58.33% and 68.52% for the 28mm and 31mm modes, respectively (p=0.158). The 31mm mode achieved significantly higher occlusion rates in the left superior PV (96.30% vs. 87.04%, p=0.027) and right superior PV (91.67% vs. 75.00%, p=0.002) compared to the 28mm mode. Cut-off values for recommending the 31mm balloon were identified for each PV: left superior PV (diameter >19.3mm, ovality index >0.321) and right superior PV (diameter >21.1mm, ovality index >0.205). Conclusion The 31mm sized cryoballoon improves PV occlusion in superior PVs compared to the 28mm sized cryoballoon during PVI. PV-specific diameter and ovality index cut-off values can guide optimal cryoballoon size selection, potentially enhancing procedural efficacy and patient outcomes.