Po-02-071 quantifying procedural advantages of a novel variable size cryoballoon to optimize pulmonary vein isolation

Cryoballoon ablation is well-established for the treatment of atrial fibrillation (AF). Fixed-size cryoballoon is often mismatched with variable geometries of pulmonary vein (PV) antrum, resulting in incomplete PV isolation (PVI) and segmental ablation. Novel variable size cryoballoon capable of selecting between 28mm and 31mm may improve these technical challenges. However, the improvement to occlusion for single-shot PVI and calculated incremental ablation area has not been characterized. To evaluate and quantify the potential benefit of a novel cryoballoon (Boston Scientific, Minneapolis, MN), with variable size between 28mm and 31mm in terms of occlusion and create a model to quantify ablation area differences. 8 patients with symptomatic paroxysmal AF underwent de-novo cryoablations. During PVs engagement, the cryoballoon was initially inflated to 28mm, then increased to 31mm while tracking geometrical engagement changes by continuous contrast injection. Assessment of the grade of occlusion, characterization of the physical difference in engagement, and level of isolation were performed with venogram and intracardiac echocardiography. Occlusion score and ability for single-shot PVI were assessed. Offline cine image analysis and modeling were then performed to assess the differences of ablation area attributable to the more proximal engagement of 31mm vs. 28 mm cryoballoon. 26 PVs with PV venogram during 28 to 31mm continuous contrast injection were analyzed: 8 PVs had grade 4 (complete) occlusion with both sizes of balloons (3 LSPVs, 1 LIPV, 2 RSPVs and 2 RIPVs), 14 PVs had grade 4 occlusion by either size of balloon, and incomplete occlusion was found in 4 PVs (1 LSPV, 2 LIPVs and 1 RIPVs) despite manipulations. The availability of 28 and 31mm cryoballoon options improved grade 4 occlusion from 57.6 to 84.5 %, and such an improvement was more pronounced in inferior PVs by 30.7%(from 46.2 to 76.9%). The more proximal PV engagement from 28 to 31mm was calculated with modeling, and was found to increase ablation area by 1.81 ± 1.09 cm2 (figure 1) without compromising PV occlusion. Novel variable size cryoballoon is associated with a higher rate of PV occlusion for single-shot isolation, a more proximal antrum engagement, and increased ablation area. This improvement may translate to higher procedural efficiency. Longer term follow up and clinical correlation will be needed to assess the improved procedural characteristic to translatable clinical benefit.Tabled 1Table 1. Demographics of patients(N=8) & Characteristics of index procedureN(%)Mean ± SDFemale5(62.5)Age(year)67.4 ± 7.7BMI(kg/m2)30.1 ± 6.8Diagnosis to ablation(month)11.6 ± 14.3Diabetes mellitus2(25)Hypertension5(62.5)Congestive heart failure0(0)Ischemic heart & Other vascular disease2(25)CHA2DS2VASc2(median)3Anticoagulation8(100)Anti-arrhythmic drugs7(87.5)Echocardiography(N=7)LV ejection fraction62.1 ± 3.7LV end diastolic diameter(cm)4.4 ± 0.6LA volume index(ml/m2)24.4 ± 6.2E/e10.6 ± 2.7Total cryoablation applications49Single shot PVI21(65.6)LSPV4LIPV7RSPV4RIPV6Time to isolation(s)43.0 ± 11.3Nadir temperature(°C)-58.9 ± 4.5PV occlusion on fluoroscopic image(N=26)28mm and 31mm8(30.7)Neither 28mm nor 31mm4(15.4)31mm but not 28mm7(26.9)28mm but not 31mm7(26.9) Open table in a new tab