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Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease that may involve medium-sized muscular arteries throughout the body. The majority of FMD patients are women. Although a variety of genetic, mechanical, and hormonal factors play a role in the pathogenesis of FMD, overall, its cause remains poorly understood. It is probable that the pathogenesis of FMD is linked to a combination of genetic and environmental factors. Extensive studies have correlated the arterial lesions of FMD to histopathological findings of arterial fibrosis, cellular hyperplasia, and distortion of the abnormal architecture of the arterial wall. More recently, the vascular phenotype of lesions associated with FMD has been expanded to include arterial aneurysms, dissections, and tortuosity. However, in the absence of a string-of-beads or focal stenosis, these lesions do not suffice to establish the diagnosis. While FMD most commonly involves renal and cerebrovascular arteries, involvement of most arteries throughout the body has been reported. Increasing evidence highlights that FMD is a systemic arterial disease and that subclinical alterations can be found in non-affected arterial segments. Recent significant progress in FMD-related research has led to improve our understanding of the disease's clinical manifestations, natural history, epidemiology, and genetics. Ongoing work continues to focus on FMD genetics and proteomics, physiological effects of FMD on cardiovascular structure and function, and novel imaging modalities and blood-based biomarkers that can be used to identify subclinical FMD. It is also hoped that the next decade will bring the development of multi-centred and potentially international clinical trials to provide comparative effectiveness data to inform the optimal management of patients with FMD. [ABSTRACT FROM AUTHOR]

Background: Fibromuscular dysplasia (FMD) is a noninflammatory arterial disease that predominantly affects women. The arterial manifestations may include beading, stenosis, aneurysm, dissection, or tortuosity.Objectives: This study compared the frequency, location, and outcomes of FMD patients with aneurysm and/or dissection to those of patients without.Methods: The U.S. Registry for FMD involves 12 clinical centers. This analysis included clinical history, diagnostic, and therapeutic procedure results for 921 FMD patients enrolled in the registry as of October 17, 2014.Results: Aneurysm occurred in 200 patients (21.7%) and dissection in 237 patients (25.7%); in total, 384 patients (41.7%) had an aneurysm and/or a dissection by the time of FMD diagnosis. The extracranial carotid, renal, and intracranial arteries were the most common sites of aneurysm; dissection most often occurred in the extracranial carotid, vertebral, renal, and coronary arteries. FMD patients with dissection were younger at presentation (48.4 vs. 53.5 years of age, respectively; p < 0.0001) and experienced more neurological symptoms and other end-organ ischemic events than those without dissection. One-third of aneurysm patients (63 of 200) underwent therapeutic intervention for aneurysm repair.Conclusions: Patients with FMD have a high prevalence of aneurysm and/or dissection prior to or at the time of FMD diagnosis. Patients with dissection were more likely to experience ischemic events, and a significant number of patients with dissection or aneurysm underwent therapeutic procedures for these vascular events. Because of the high prevalence and associated morbidity in patients with FMD who have an aneurysm and/or dissection, it is recommended that every patient with FMD undergo one-time cross-sectional imaging from head to pelvis with computed tomographic angiography or magnetic resonance angiography. [ABSTRACT FROM AUTHOR]

Background: We previously described a strong association between fibromuscular dysplasia (FMD) and spontaneous coronary artery dissection. Angiographic manifestations of coronary FMD aside from dissection were considered rare. However, we observed several coronary FMD angiographic abnormalities with corresponding optical coherence tomography abnormalities. Methods and Results: Baseline demographics and imaging of patients with suspected coronary FMD at Vancouver General Hospital were reviewed. Presence of multifocal (string-of-beads) extracoronary FMD was confirmed by 2 specialists. In these patients, coronary angiographic findings (excluding dissected segments) were reviewed and classified by 2 experienced angiographers for irregular stenosis, that is, stenosis with irregular borders in a focal or diffuse pattern with/without systolic accentuation; smooth stenosis, diffuse or focal; segmental dilatation/ectasia; and tortuosity. Optical coherence tomography was performed in a subset of patients. Of 32 patients with extracoronary FMD and suspected coronary involvement, 28 were women (88%), and their mean age was 59.4±9.9 years. Nineteen presented with myocardial infarction (13 caused by spontaneous coronary artery dissection), and 13 had stable symptoms. The observed coronary angiographic abnormalities included tortuosity in all cases (91% were moderate to severe), irregular stenosis in 59%, smooth stenosis in 19%, and segmental dilatation/ectasia in 56%. Fifteen patients had optical coherence tomography of the abnormal segments showing abnormalities, including multiple areas of patchy or diffuse intimal, medial or adventitial abnormalities with thickening/accumulation of varied reflectivities, macrophage infiltration, loss/duplication of elastic membranes, and cavitation. Conclusions: This is the first case series describing findings suggestive of angiographic and intracoronary manifestations of coronary FMD. Future studies should prospectively review these features in patients with extracoronary FMD. [ABSTRACT FROM AUTHOR]