Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD), formerly called fibromuscular fibroplasia, is a group of nonatherosclerotic, noninflammatory arterial diseases that most commonly involve the renal and carotid arteries. The prevalence of symptomatic renal artery FMD is about 4/1000 and the prevalence of cervicocranial FMD is probably half that. Histological classification discriminates three main subtypes, intimal, medial and perimedial, which may be associated in a single patient. Angiographic classification includes the multifocal type, with multiple stenoses and the 'string-of-beads' appearance that is related to medial FMD, and tubular and focal types, which are not clearly related to specific histological lesions. Renovascular hypertension is the most common manifestation of renal artery FMD. Multifocal stenoses with the 'string-of-beads' appearance are observed at angiography in more than 80% of cases, mostly in women aged between 30 and 50 years; they generally involve the middle and distal two-thirds of the main renal artery and in some case also renal artery branches. Cervicocranial FMD can be complicated by dissection with headache, Horner's syndrome or stroke, or can be associated with intracerebral aneurysms with a risk of subarachnoid or intracerebral hemorrhage. The etiology of FMD is unknown, although various hormonal and mechanical factors have been suggested. Subclinical lesions are found at arterial sites distant from the stenotic arteries, and this suggests that FMD is a systemic arterial disease. It appears to be familial in 10% of cases. Noninvasive diagnostic tests include, in increasing order of accuracy, ultrasonography, magnetic resonance angiography and computed tomography angiography. The gold standard for diagnosing FMD is catheter angiography, but this invasive procedure is only used for patients in whom it is clinically pertinent to proceed with revascularization during the same procedure. Differential diagnosis include atherosclerotic stenoses and stenoses associated with vascular Ehlers-Danlos and Williams' syndromes, and type 1 neurofibromatosis. Management of cases with renovascular hypertension includes antihypertensive therapy, percutaneous angioplasty of severe stenoses, and reconstructive surgery in cases with complex FMD that extends to segmental arteries. The therapeutic options for securing ruptured intracerebral aneurysms are microvascular neurosurgical clipping and endovascular coiling. Stenosis progression in renal artery FMD is slow and rarely leads to ischemic renal failure.

Fibromuscular dysplasia (FMD) is an arteriopathy associated with hypertension, stroke and myocardial infarction, affecting mostly women. We report results from the first genome-wide association meta-analysis of six studies including 1556 FMD cases and 7100 controls. We find an estimate of SNP-based heritability compatible with FMD having a polygenic basis, and report four robustly associated loci (PHACTR1, LRP1, ATP2B1, and LIMA1). Transcriptome-wide association analysis in arteries identifies one additional locus (SLC24A3). We characterize open chromatin in arterial primary cells and find that FMD associated variants are located in arterial-specific regulatory elements. Target genes are broadly involved in mechanisms related to actin cytoskeleton and intracellular calcium homeostasis, central to vascular contraction. We find significant genetic overlap between FMD and more common cardiovascular diseases and traits including blood pressure, migraine, intracranial aneurysm, and coronary artery disease.

AimsSpontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and in rare cases sudden cardiac death (SCD). Connective tissue abnormalities, coronary inflammation, increased coronary vasa vasorum (VV) density, and coronary fibromuscular dysplasia have all been implicated in the pathophysiology of SCAD but have not previously been systematically assessed. We designed a study to investigate the coronary histological and dermal collagen ultrastructural findings in SCAD.Methods and resultsThirty-six autopsy SCAD cases were compared with 359 SCAD survivors. Coronary and myocardial histology and immunohistochemistry were undertaken. Transmission electron microscopy (TEM) of dermal extracellular matrix (ECM) components of n = 31 SCAD survivors and n = 16 healthy volunteers were compared. Autopsy cases were more likely male (19% vs. 5%; P = 0.0004) with greater proximal left coronary involvement (56% vs. 18%; P ConclusionsAssessment of SCD requires careful exclusion of SCAD, particularly in cases without myocardial necrosis. Peri-coronary inflammation in SCAD is distinct from vasculitides and likely a reaction to, rather than a cause for SCAD. Coronary fibromuscular dysplasia or increased VV density does not appear pathophysiologically important. Dermal connective tissue changes are not common in SCAD survivors.

ObjectiveTo investigate the clinical characteristics, imaging features, relationship with ischemic stroke, treatment strategies, and follow-up outcomes of patients with carotid web (CaW) diagnosed by digital subtraction angiography (DSA), in order to improve the understanding and clinical management of CaW.MethodsA retrospective analysis was conducted on the clinical data of 48 patients diagnosed with CaW by DSA in the Department of Cerebrovascular Diseases, Zhuhai People's Hospital from December 2021 to June 2025. Data included baseline characteristics, imaging findings, treatment methods, and follow-up results. All clinical outcomes (ischemic stroke, transient ischemic attack, recurrent ipsilateral ischemic event) were defined a priori according to the American Heart Association/American Stroke Association 2013 (stroke) and 2009 (tissue-based TIA) criteria, and follow-up imaging (carotid Doppler at 6 and 12 months, with brain MRI ± MRA/CTA when clinically indicated) was standardized across all patients.ResultsThe 48 patients aged from 28 to 83 years, with a mean age of (60.81 ± 11.58). There were 26 males (54.17%) and 22 females (45.83%). All lesions were located at the carotid bifurcation or the origin of the internal carotid artery. The typical DSA manifestation was a thin, linear or membranous filling defect originating from the vessel wall. Among the 48 patients, 13 had a history of smoking, 12 of alcohol consumption, 17 had hypertension, 18 had hyperlipidemia, 7 had diabetes mellitus, 2 had hyperhomocysteinemia, and 4 had hyperuricemia. There were 24 cases of left-sided CaW, 21 cases of right-sided CaW, and 3 cases of bilateral CaW. Subweb thrombus was present in 22 cases (45.83%). Acute ischemic stroke events occurred in 9 cases (18.75%). Treatment modalities included antiplatelet or anticoagulant therapy alone, endovascular interventional therapy, and surgical resection. Specifically, 34 patients received medication alone, 1 underwent emergency endovascular thrombectomy, 1 underwent carotid endarterectomy, 4 underwent carotid artery stenting, and 8 received no treatment. Patients were followed up for 3 to 12 months. One patient in the medication group experienced recurrence of ipsilateral cerebral infarction, while no ischemic events occurred in the remaining patients. "Recurrence" was defined as a new ipsilateral ischemic event occurring ≥24 h after the index event and meeting the AHA/ASA 2013 criteria. All patients completed the 12 month clinical follow-up; loss-to-follow-up was 0%.ConclusionIn this retrospective, non-randomized cohort, the observed rate of recurrent ipsilateral ischemic events was numerically lower among patients who received active endovascular treatment (0/6) than among those who received medical therapy alone (1/34). However, given the very small number of patients who received active intervention, the short follow-up (3-12 months), and the non-randomized, indication-based treatment allocation, no causal inference can be drawn from these data regarding the efficacy of endovascular treatment in preventing stroke recurrence. The observed difference should be interpreted as hypothesis-generating only and requires confirmation in adequately powered prospective randomized controlled trials. Carotid web is an important risk factor for cryptogenic stroke across all age groups. DSA remains the diagnostic gold standard. For patients who have already experienced ischemic events or who have subweb thrombus, active endovascular treatment represents a potentially useful therapeutic option that warrants further evaluation.