Detection of brain lesions after catheter ablation depends on imaging criteria - Insights from AXAFA-AFNET 5 trial

BACKGROUND AND AIMS: Left atrial catheter ablation is well-established in patients with symptomatic atrial fibrillation (AF) but associated with risk of embolism to the brain. To assess the impact of diffusion-weighted imaging (DWI) slice thickness on the rate of magnetic resonance imaging (MRI) detected ischemic brain lesions after ablation. METHODS: AXAFA-AFNET 5 trial (NCT02227550) participants underwent MRI using high-resolution (hr) DWI (slice thickness: 2.5-3 mm) and standard DWI (slice thickness: 5-6 mm) within 3-48 hours after ablation. RESULTS: In 321 patients with analyzable brain MRI (mean age 64 years, 33% female, median CHA2DS2-VASc 2), hrDWI detected at least one acute brain lesion in 84 (26.2%) patients and standard DWI in 60 (18.7%; p?<?0.01) patients. hrDWI detected more lesions compared to standard DWI (165 vs. 104; p?<?0.01). The degree of agreement for lesion confirmation using hrDWI vs. standard DWI was substantial (?=0769). Comparing the proportion of DWI-detected lesions, lesion distribution and total lesion volume per patient, there was no difference in the cohort of participants undergoing MRI at 1.5 Tesla (n?=?52) vs. 3 Tesla (n?=?269). CONCLUSION: The pre-specified AXAFA-AFNET 5 sub-analysis revealed significantly increased rates of MRI-detected acute brain lesions using hrDWI instead of standard DWI in AF patients undergoing ablation. In comparison to DWI slice thickness, MRI field strength had a no significant impact in the trial. Comparing the varying rate of ablation-related MRI-detected brain lesions across previous studies have to consider these technical parameters. Future studies should use hrDWI, as feasibility was demonstrated in the multicenter AXAFA-AFNET 5 trial.