Cardiac CTA-based assessment of pulmonary vein and perivascular remodeling after high- and very high-power ablation

Introduction High-power short-duration (HPSD) and very high-power short-duration (vHPSD) ablation are emerging strategies to improve pulmonary vein isolation (PVI) outcomes in atrial fibrillation (AF). The HPSD-Remap trial prospectively compared PVI using 50 W (HPSD) and 90 W (vHPSD). This sub-study aimed to assess pulmonary vein stenosis (PVS) and peri-pulmonary vein adipose tissue (PPVAT) remodeling using pre- and post-procedural cardiac CT angiography (CTA). Methods In this single-center, prospective, randomized study, 40 patients with paroxysmal or persistent AF underwent PVI with either 50 W (n=20) or 90 W (n=20) ablation. Cardiac CTA was performed before and three months after ablation using identical imaging protocols. Pulmonary vein (PV) dimensions (diameter and area) and PPVAT parameters (attenuation, gradient, volume) were analyzed per vein. Results Median age was 67.5 [59.0–70.5] in the HPSD group and 65.0 [61.0–68.0] in the vHPSD group. The BMI was 28.7 [26.0-29.8] in the 50W group and 28.7±4.2 in the 90W group, with 40% and 50% female representation, respectively. A total of 240 PVs were analyzed. The vHPSD group showed a significantly greater reduction in PV area and diameter (p<0.05), though effect sizes were small (r=0.19 and r=0.17, respectively). A similar trend was observed for PV diameter reduction (p<0.005, r=0.17). No significant differences were observed in PPVAT attenuation (p=0.27) or volume (p=0.4). However, PPVAT gradient was significantly higher in the vHPSD group (p<0.001, r=0.89). A trend toward higher gradient was noted in patients with AF recurrence (p=0.06, r=-0.4). Conclusion vHPSD ablation led to greater PV narrowing and significantly increased PPVAT gradient, suggesting deeper thermal effects. Gradient changes may serve as a potential imaging biomarker for tissue response and AF recurrence risk.