P336Cryoballoon energy pulmonary vein isolation with and without radiopaque contrast agent injection to control the balloon occlusion of the pulmonary veins: a prospective randomized study

Abstract

Background: Despite the increasing role of cryoballoon ablation (CBA) in the treatment of atrial fibrillation only few real‐world data are available on standard clinical cryoablation practice. In a prospective 2:1 randomized study we examined two different ablation strategies: CBA controlled by 1.) assessment of the degree of balloon occlusion at the PV entrance using radiopaque contrast agent injection and additional PVelectrogram recording versus 2.) PV‐electrogram recording only. Methods: 69 patients with paroxysmal (PAF) or persistent (PERAF) Afib underwent CBA with the Arctic Front Advanced ablation system (AFA) with an integrated circular mapping catheter (CMC). In 43 patients (Group 1) the CMC were positioned under fluoroscopy in the target vein. The AFA inflated and a cryoablation therapy were started only after antral PV occlusion of degree 3 or 4 controlled by radiopaque contrast agent injection, than real time PV electrogram recording was used to monitor or assess the PV isolation. In 26 patients (Group 2) the use of contrast fluid was allowed only in line with the transseptal puncture procedure. The therapeutic effectivity control based on real time PV electrogram recording only. Therapeutic‐settings: 180 seconds per cryoshot, after PV isolation a safety cryoshot was applied. Phrenicusstimulation was performed during treatment of the right PV's. The primary endpoints were complete PV isolation (PVI) at the end of the ablation procedure, and early Afib recurrence by assessing 3 month long‐term follow‐up data. Furthermore the study examined procedural variables during ablation for PVI. Results: In group 1 patients mean age was 64 ±18 years, 49% were male, 65% had persistent Afib; in the group 2 the mean age was 68±9 years, 46% were male, 62% had persistent Afib. The two modalities were comparable in efficiencies, including: acute PVI >88%, cryoenergy application (in minutes), time to isolation, temperature drop/nadir and procedural time (119.8±17.6 vs 117.7±22.5 min). However, when compared to group 1, the cryoballoon procedure in group 2 demonstrated a 26% reduction in the dose area product (2528 vs 3419 Gcm2) but significant more cryoapplications to isolate the left superior pulmonary vein (3.3 vs 2.5 cryoshots; p<0.05). Additionally, the complication rate (15% and 9%) was comparable and also the 3 month follow up results: 90% SR for PERAF and 100% for PAF in both groups. Conclusion: CBA without fluoroscopic control of balloon occlusion of the PVentrance using contrast fluid can reduce radiation exposure without prolonging procedure times or affecting the outcome.