Pulmonary vein isolation by catheter ablation is a standard treatment for atrial fibrillation. Previous studies have found that patients with atrial fibrillation have a low risk of thromboembolism after catheter ablation, which is about 0.5%-1%, but the risk of clinically asymptomatic cerebral embolism (SCEs) is as high as 10%-40%. Cryoballoon (CB) and radiofrequency (RF) are two commonly used ablation modalities, and there are few prospective studies on the incidence of cerebral embolism after CB and RF ablation. Recently, the Embo-Abl trial, which was released at the 2024 ACC Annual Meeting, explored this and showed that CB and RF ablation had similar rates of perioperative SCEs.
Study design
Embo-ABL is a prospective, multicenter, randomized, open-label, non-inferiority-controlled trial to compare the incidence of cerebral embolism after CB and RF ablation in patients with atrial fibrillation. The study was conducted between May 2021 and January 2024 at three centers in Japan. Patients with atrial fibrillation aged 20-85 years who are scheduled to undergo CB and RF ablation and have at least one recorded episode ≥ 30 seconds were included, and patients with a history of previous ablation or cardiac surgery, left atrial diameter greater than >55mm, brain magnetic resonance imaging (MRI) incapacitated, current or planned pregnancy, and participation in other intervention studies were excluded. Enrolled patients were randomly assigned 1:1 to CB or RF ablation (Figure 1).
The primary endpoint of the study was the incidence of SCEs by MRI within 3 days after ablation. Secondary endpoints included asymptomatic brain injury (SCL) by MRI within 3 days after ablation, microemboli signal (MES) on transcarotid ultrasound during ablation, and complications during postoperative follow-up.
Fig.1 Study design
Findings:
A total of 229 patients with atrial fibrillation were included, including 115 in the CB group and 114 in the RF group. Paroxysmal atrial fibrillation occurred in 80 patients in both the CB group and the RF group, and the proportion of patients with hypertension was high, and the baseline characteristics of the patients in the two groups were similar (Table 1).
Table 1 Baseline characteristics of enrolled patients
In terms of primary endpoints, SCE occurred in 16 patients (13.9%) in the CB group and 11 (9.7%) in the RF group within 3 days after ablation, with a risk difference of 4.18% (95% CI: -4.18%-12.5% ;p=0.02). In terms of secondary endpoints, 6 patients (5.2%) developed SCL in the CB group and 3 patients (2.7%) in the RF group within 3 days after ablation, with a risk difference of 2.56% (95%CI: -2.47%-7.59%;p=0.002<; Fig. 2).
Fig.2 Characteristics of head MRI and the incidence of SCE and SCL in the two groups
Fig.3 Comparison of the number of intraoperative MES occurrences between the two groups
In addition, in terms of safety, there was no significant difference in the complication rate between the two groups during the follow-up period, both of which were 2.6%, and the common complications were cardiac tamponade and pericardial effusion. No MRI-detected cerebral embolism after ablation was independently associated with the following risk factors: patient-related risk factors, procedure-related risk factors, or MES risk factors during ablation (Figure 4).
Fig.4 Complications after ablation
Conclusions of the study
The prospective, randomized controlled trial of Embo-Abl showed that the incidence of SCEs (detected by MRI of the head) after CB ablation in patients with atrial fibrillation was similar to that of RF ablation.
bibliography
1.K. Miyamoto, K. Kanaoka, K. Kusano, et al. A Multicenter Prospective Randomized Study Comparing The Incidence Of Periprocedural Cerebral Embolisms Caused By Catheter Ablation Of Atrial Fibrillation Between Cryoballoon And Radiofrequency Ablation. 2024ACC. 6–8 April 2024.
Yimaitong is a professional online doctor platform, and the mission of the platform is to "sense the pulse of the world's medicine and help China's clinical decision-making". Yimaitong has a series of products such as "Clinical Guidelines", "Medication Reference", "Medical Literature King", "Yizhiyuan", "eYantong" and "ePulse", which fully meet the needs of medical workers in clinical decision-making, obtaining new knowledge and improving scientific research efficiency.