Abstract WP111: Fibromuscular Dysplasia and Cerebrovascular Dissection: Insights from a Multicenter Cohort

Background and aims: Fibromuscular dysplasia (FMD) is a systemic non-inflammatory arteriopathy that can cause arterial stenosis, dissections, aneurysms, and vessel tortuosity. Data remains limited on outcomes among FMD patients with spontaneous cervical arterial dissection (SCeAD). This study aimed to characterize clinical features and outcomes in this population. Methods: We conducted a retrospective multicenter cohort study of patients diagnosed with cervical carotid and/or vertebral artery dissection and FMD at three Southeast U.S. comprehensive stroke centers (2018-2023). Patients were identified via hospital records and vascular registries. Diagnoses were confirmed through imaging and reviewed by vascular neurologists or cardiologists. Outcomes included recurrent dissections, cardiovascular events (ischemic stroke, transient ischemic attack, myocardial infarction, subarachnoid hemorrhage) and mortality. Results: Among 1,632 patients with SCeAD, 97(6%) had FMD diagnosis. The cohort was predominantly female (91%) and median age at FMD diagnosis is 50 years(IQR 42-63). Carotid dissections were more frequent than vertebral dissections (86%vs.27%, p<0.001). Multiple dissections occurred in 32 patients (33%):24 (75%) had bilateral dissections, 4(13%) had recurrent dissections in the same artery, and 7 (22%) had dissections in extracranial vascular beds (renal, iliac, mesenteric, coronary). Younger age [OR 0.945; 95%CI 0.908-0.983;p=0.005] and classical FMD “beading” on imaging [OR 3.06; 95%CI 1.28-7.36;p=0.012] were associated with multiple dissections. Aneurysms were detected in 27% more frequently in patients with multiple dissections [OR 1.66; 95%CI 1.02-2.71;p=0.041]. Most patients were discharged on single (49%) or dual (29%) antiplatelet therapy and 22% received anticoagulation with no significant difference in cardiovascular events rates p=0.18. Over a mean follow-up of 5±2.5 years,13% developed recurrent dissections and 28% experienced cardiovascular events. Recurrent dissections were associated with future cardiovascular events [OR11.56; 95%CI 2.22-60.07;p=0.004]. Conclusion: FMD should be considered in patients presenting with SCeAD, particularly middle-aged women with multifocal dissections and no traditional vascular risk factors. The increased risk of recurrence and cardiovascular events warrants systematic vascular screening, long-term surveillance, and individualized antithrombotic strategies to optimize outcomes in this high-risk population.