Liu, Michael

Background: Pulsed field ablation (PFA) has become a cornerstone for atrial fibrillation ablation. Multiple platforms have been developed and approved worldwide, and routine screening for asymptomatic brain injury (ABI) has been included in several trials as part of the safety assessment of this technology. The incidence by catheter/platform, predictors of occurrence, and clinical impact remain incompletely understood. Research Question: In patients with atrial fibrillation undergoing pulmonary vein isolation, does the incidence of ABI vary between different PFA platforms? Methods: We searched the MEDLINE/PubMed, Embase, and Cochrane Central Register of Controlled Trials databases for studies reporting on patients who underwent PFA and post-procedure brain MRI to screen for ABI. The review was conducted in accordance with PRISMA guidelines. A random-effects proportion meta-analysis was performed, with subgroup analysis based on the PFA platform used. For studies including a thermal ablation control group, risk ratio (RR) was used to compare outcomes. Finally, a meta-regression was conducted to identify potential predictors of ABI incidence. Results: A total of 19 studies reporting data from 742 patients who underwent post-ablation brain MRI were included in this review. The pooled incidence of silent cerebral events (new findings visible only on DWI sequences) and silent cerebral lesions (new findings on both DWI and FLAIR sequences) was 5% each (95% CI, 3%–8%). The pooled incidence of any ABI was 10% (95% CI, 8%–13%). A platform-level subgroup analysis demonstrated comparable outcomes across the platforms with available data (Figure 1). The meta-regression included age, sex, CHA2DS2-VASc score, and incidence of symptomatic stroke/TIA, but no statistically significant associations were identified. In the four studies that included a thermal ablation control group, there was no significant difference in ABI incidence between PFA and thermal ablation (RR: 1.37; 95% CI, 0.68–2.74; P = 0.38; I2 = 16%) (Figure 2). Seven studies reported follow-up MRI in patients who presented with an ABI. Among 20 patients with ABI after ablation, radiologic lesions persisted in 2 patients. Conclusion: ABI is a relatively frequent finding following PFA; however, current evidence does not reveal significant differences between available platforms. Radiologic findings tend to be transient, suggesting a limited long-term clinical impact.

Introduction: Embolic stroke of undetermined source (ESUS) is a clinical paradigm that helps to classify and lead investigations into cryptogenic stroke. Diagnostic evaluation of ESUS involves investigating several potential etiologies of stroke. One such etiology includes antiphospholipid syndrome (APLS), a syndrome known to cause hypercoagulability. Clinical characteristics of primary APLS in ESUS have not been described. Methods: This is an IRB approved, retrospective study including patients from 2015-2020 who were seen at Mayo Clinic, were diagnosed with ESUS, and had APLS testing (anti-cardiolipin, beta-2 glycoprotein, or lupus anticoagulant). Baseline characteristics and radiographic features were collected and compared between patients who were and were not diagnosed with APLS, as well as between patients who were and were not APLS antibody positive. Results: Our study included 206 patients. Positive APLS antibody testing was seen in 21 (10%) patients. Of those patients, 8 (4%) received a formal diagnosis of APLS. Compared to controls, patients with positive APLS antibodies as well as those diagnosed with APLS were more likely to have a history of cancer (20 [11%] APLS antibody negative vs 7 [33%] APLS antibody positive p=0.004) (23 [12%] APLS diagnosis negative vs 4 [50%] APLS diagnosis p=0.002). Mean age in primary APLS was greater, 57 years old APLS antibody negative vs 69 years old APLS antibody positive (p<0.001) and 58 years old APLS diagnosis negative vs 75 years old APLS diagnosis (p=0.001) (Table 1). Regressions analyses examining infarct topography and rate of hemorrhagic transformation were non-significant between groups (p>0.1) Conclusion: APLS presenting as ESUS is associated with older age and history of malignancy. We speculate this finding may underscore the need to consider hypercoagulable conditions more broadly in stroke evaluations of older populations. Larger cohorts and longer follow up will be required to validate this observation.