HomeCirculationVol. 129, No. 9Fibromuscular Dysplasia: State of the Science and Critical Unanswered Questions Free AccessResearch ArticlePDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBFibromuscular Dysplasia: State of the Science and Critical Unanswered QuestionsA Scientific Statement From the American Heart Association Jeffrey W. Olin, DO, FAHA, Heather L. Gornik, MD, MHS, FAHA, J. Michael Bacharach, MD, MPH, Jose Biller, MD, FAHA, Lawrence J. Fine, MD, PhD, FAHA, Bruce H. Gray, DO, William A. Gray, MD, Rishi Gupta, MD, Naomi M. Hamburg, MD, FAHA, Barry T. Katzen, MD, FAHA, Robert A. Lookstein, MD, Alan B. Lumsden, MD, Jane W. Newburger, MD, MPH, FAHA, Tatjana Rundek, MD, PhD, C. John Sperati, MD, MHS and James C. Stanley, MDon behalf of the American Heart Association Council on Peripheral Vascular Disease, Council on Clinical Cardiology, Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation, Council on Cardiovascular Disease in the Young, Council on Cardiovascular Radiology and Intervention, Council on Epidemiology and Prevention, Council on Functional Genomics and Translational Biology, Council for High Blood Pressure Research, Council on the Kidney in Cardiovascular Disease, and Stroke Council Jeffrey W. OlinJeffrey W. Olin Search for more papers by this author , Heather L. GornikHeather L. Gornik Search for more papers by this author , J. Michael BacharachJ. Michael Bacharach Search for more papers by this author , Jose BillerJose Biller Search for more papers by this author , Lawrence J. FineLawrence J. Fine Search for more papers by this author , Bruce H. GrayBruce H. Gray Search for more papers by this author , William A. GrayWilliam A. Gray Search for more papers by this author , Rishi GuptaRishi Gupta Search for more papers by this author , Naomi M. HamburgNaomi M. Hamburg Search for more papers by this author , Barry T. KatzenBarry T. Katzen Search for more papers by this author , Robert A. LooksteinRobert A. Lookstein Search for more papers by this author , Alan B. LumsdenAlan B. Lumsden Search for more papers by this author , Jane W. NewburgerJane W. Newburger Search for more papers by this author , Tatjana RundekTatjana Rundek Search for more papers by this author , C. John SperatiC. John Sperati Search for more papers by this author and James C. StanleyJames C. Stanley Search for more papers by this author and on behalf of the American Heart Association Council on Peripheral Vascular Disease, Council on Clinical Cardiology, Council on Cardiopulmonary, Critical Care, Perioperative and Resuscitation, Council on Cardiovascular Disease in the Young, Council on Cardiovascular Radiology and Intervention, Council on Epidemiology and Prevention, Council on Functional Genomics and Translational Biology, Council for High Blood Pressure Research, Council on the Kidney in Cardiovascular Disease, and Stroke Council Originally published18 Feb 2014https://doi.org/10.1161/01.cir.0000442577.96802.8cCirculation. 2014;129:1048–1078Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: January 1, 2014: Previous Version 1 IntroductionFibromuscular dysplasia (FMD) is nonatherosclerotic, noninflammatory vascular disease that may result in arterial stenosis, occlusion, aneurysm, or dissection.1–3 The cause of FMD and its prevalence in the general population are not known.4 FMD has been reported in virtually every arterial bed but most commonly affects the renal and extracranial carotid and vertebral arteries (in ≈65% of cases).5 The clinical manifestations of FMD are determined primarily by the vessels that are involved. When the renal artery is involved, the most frequent finding is hypertension, whereas carotid or vertebral artery FMD may lead to dizziness, pulsatile tinnitus, transient ischemic attack (TIA), or stroke. There is an average delay from the time of the first symptom or sign to diagnosis of FMD of 4 to 9 years.5,6 This is likely because of a multitude of factors: the perception that this is a rare disease and thus FMD is not considered in the differential diagnosis, the reality that FMD is poorly understood by many healthcare providers, and the fact that many of the signs and symptoms of FMD are nonspecific, thus leading the clinician down the wrong diagnostic pathway. A delay in diagnosis can lead to impaired quality of life and poor outcomes such as poorly controlled hypertension and its sequelae, TIA, stroke, dissection, or aneurysm rupture. It should also be noted that FMD may be discovered incidentally while imaging is performed for other reasons or when a bruit is heard in the neck or abdomen in an asymptomatic patient without the classic risk factors for atherosclerosis.Historical PerspectiveThe first description of FMD is attributed to Leadbetter and Burkland7 in a 5½-year-old boy with severe hypertension and a renal artery partially occluded by an intra-arterial mass of smooth muscle. He underwent a unilateral nephrectomy of an ectopic pelvic kidney, and his hypertension was cured. The authors stated, “It seems quite obvious that by chance we have stumbled on a peculiar anomaly of development affecting a renal artery.”7 The term fibromuscular hyperplasia was introduced in 1958 by McCormack and associates8 after their observation of 3 patients with arterial hypertension and renal artery stenosis. However, it was not until Palubinskas and Wylie,9 Hunt,10 and Kincaid and Davis11 described in 1961 the arteriographic and clinical manifestations of what was then called fibromuscular hyperplasia that this systemic arteriopathy of obscure origin became widely recognized. McCormack and associates12 published a detailed pathological-arteriographic correlation of the different types of FMD and how they compared with atherosclerosis, a more common cause of renal artery stenosis. In 1971, Harrison and McCormack13 proposed a detailed pathological classification (with angiographic correlates) of FMD of the renal artery into 3 distinct types based on the arterial layer most affected: medial, intimal, and adventitial/periarterial.Extracranial cerebrovascular FMD was first identified angiographically by Palubinskas and Ripley14 in 1964 as a nonatherosclerotic cause of internal carotid artery stenosis. One year later, Connett and Lansche15 published the first histologically proven case of FMD of the internal carotid arteries in a 34-year-old woman that resulted in cerebral thrombosis causing right hemiparesis and aphasia. Several years later, a woman with bilateral FMD of the cervical internal carotid arteries was treated with resection of the artery with relief of transient ischemic symptoms.16 Cerebrovascular FMD has been noted not only in the internal carotid arteries but also in the vertebral arteries and less commonly in the middle cerebral arteries and external carotid arteries and its branches.17In 1974 and 1975, Stanley and colleagues18–20 published 3 landmark articles on extracranial internal carotid and vertebral artery FMD and the cause, classification, and surgical treatment of patients with renal artery FMD.In 2011, an expert French/Belgian consensus panel was convened to review the topic of FMD and to make recommendations on diagnosis and management.2 Data from the first 447 patients enrolled in the United States Registry for Fibromuscular Dysplasia (US Registry) were reported several months after the European Consensus document.5 These recent publications have added new information about FMD and dispelled some of the myths about this disease that continue to be taught in medical schools and during postgraduate education.EpidemiologyThe prevalence of FMD in the general population is not known. In one of the largest series of >1000 patients with FMD, 58% of cases involved the renal artery, 32% involved the carotid/vertebral artery, and 10% involved other arteries such as the iliac artery or intracranial vessels.3,21 Others have suggested that the proportion of renal artery involvement in FMD is as high as 75% of all cases.22 The prevalence of renal artery FMD has been estimated to be as high as 4 per 100 adults.22–24 One source of the prevalence data is the renal angiograms of potential renal donors. In a series of 716 potential renal donors for whom 80% of the angiograms were available for retrospective review, 6.6% had FMD.25 In another series of 1862 patients, 3.8% had angiographic evidence of FMD.22 A smaller but more recent study confirmed these results.24 Plouin and associates3 summarized the results of 4 separate angiographic studies involving 3181 asymptomatic potential kidney donors and found that 139 subjects (4.4%) had angiographic evidence of FMD. Over the course of 2.5 to 7.5 years of follow-up, 26% to 29% of nondonating individuals developed hypertension.3,22,26 The Cardiovascular Outcomes in Renal Atherosclerotic Lesions (CORAL) trial was a randomized trial of maximal medical therapy alone versus maximal medical therapy and renal artery stenting for patients with atherosclerotic renal artery stenosis and hypertension. Data from the angiographic core laboratory showed that among 1014 patients, 58 patients (5.7%; mean age, 71.8 years) were incidentally found to have FMD, again illustrating that FMD is more common than previously suggested.27 One large autopsy study by Heffelfinger and colleagues28 with 819 consecutive autopsies found that only 1% of the cases had FMD. Of note, this study was published only in abstract form, and complete details of this report cannot be ascertained. In addition, it is not known whether the angiogram is a more sensitive way of detecting renal FMD than autopsy, nor is it known how carefully the renal arteries were examined. As a result, the prevalence of renal artery FMD in the general population is not known, nor is it known whether it varies by ethnic or racial groups. It is clear that FMD is more common in women than in men by a ratio of 9:1.5 If FMD is as common as suggested by the studies of potential kidney donors, as many as 5 million Americans may have FMD, most undetected. However, it is important to recognize that this estimate is derived from a population of potential kidney donors, most of whom have a family member affected by chronic kidney disease, and may not be reflective of the general population.There is limited information on the prevalence of carotid, vertebral, and intracranial FMD. This may be because of the misconception that carotid or vertebral artery FMD is not as common as renal artery FMD, the nonspecific nature of symptoms of cerebrovascular FMD (ie, headache, dizziness), or the potential for asymptomatic presentation.1,5,29 FMD affects the middle and distal portion of the internal carotid and vertebral arteries and less commonly the intracranial arteries.5,29 The prevalence of carotid and vertebral artery FMD, as assessed from studies that examined consecutive angiograms, ranges from 0.3% to 3.2%.29 Because angiograms were likely performed for specific clinical indications, these percentages may be higher than would occur in the general population. The prevalence of cerebrovascular FMD from autopsy data is far lower than that obtained from series in which angiograms were analyzed. Among 20 244 consecutive autopsy cases, only 4 had cervical (vertebral) or intracranial FMD.30 Spontaneous cervical artery dissections are a common cause of stroke in young adults and are associated with FMD of the cervical artery in ≈15% to 20% of cases.31,32The cause of FMD is unknown. Hormonal factors such as estrogen have been proposed, but there is little supporting epidemiological evidence for the role of female hormones beyond the sex and age distribution of FMD. In the US Registry, 91% of registrants were female.5 FMD has not been associated with the number of pregnancies or the use of oral contraceptives or other hormones.33 Sang and colleagues33 reported a case-control study of 33 FMD patients with renal FMD and 61 control subjects and noted a dose-dependent relationship between cigarette smoking and risk of FMD, although this has not been verified by larger or more recent studies.5,29,33 In the US Registry, only 37% of patients had a history of ever smoking tobacco.5 However, Savard and colleagues33a reported that the proportion of current smokers was higher among patients with FMD compared with a control group matched for age, sex, systolic blood pressure, number of antihypertensive, and year of visit (30% versus 18%; P<0.001; odds ratio [OR], 2.5; 95% confidence interval [CI], 1.6–3.9).Genetic ConsiderationsGenetic and genomic studies have the potential to advance our understanding of FMD. Identification of genes associated with FMD may elucidate disease mechanisms and facilitate detection, prevention, and therapeutic strategies.34 To date, both family-based and association methods have been used in small samples of FMD patients. However, no etiologic genes for FMD have been identified. Studies using contemporary genetic approaches with detailed patient phenotyping in larger cohorts are necessary to discover genes linked to FMD.Several lines of evidence indicate that inherited factors contribute to FMD. A number of individual case reports describe the occurrence of FMD in first-degree relatives of affected individuals.35–37 In a study of 20 families, Rushton38 and Gladstien and colleagues39 classified 60% of cases as familial and found the inheritance pattern to be autosomal dominant with variable penetrance. However, affected family members were identified on the basis of a clinical history of cardiovascular disease or hypertension at an early age without confirmation of FMD diagnosis. Recent studies using renal angiographic definitions estimate familial cases to represent 7% to 11% of all FMD patients.23,40,41 Of 447 patients entered in the US Registry, only 7.3% of patients reported a confirmed diagnosis of FMD among a family member.5 In the US Registry, a family history of aneurysm was reported in 23.5% of patients.5 The phenotypic expression of FMD varies across family members, suggesting a common vascular wall abnormality with variable penetrance in specific vascular beds.42 Distinct disease patterns have been observed in familial cases, including higher rates of bilateral and multivessel involvement, suggesting that inherited disease may have a more severe phenotype.40 Larger family studies are ongoing that will provide more precise heritability estimates for FMD.In general, gene polymorphism associations have not been robust or replicated for FMD. A genetic variant in the angiotensin-converting enzyme (ACE) was associated with FMD in a small case-control study of 43 renal FMD patients and 89 normotensive control subjects but has not been replicated.43 Case reports described individuals with α-1 antitrypsin deficiency and FMD, but a large case-control study reported no such association.44–47 Additional studies have evaluated common variants in ACTA2, the gene for smooth muscle cell α-actin, and elastin genes and found no relation with FMD.41,48 Blood samples have been collected and stored in a biorepository from among a group of FMD patients enrolled at participating US referral centers. When funding becomes available, genetic analyses will be performed.Poloskey and colleagues49 demonstrated that the prevalence of genetic mutations associated with connective tissue disorders, including the COL31A gene, transforming growth factor (TGF)-β1 and β2 genes, and the ACTA2 gene, was negligible in an FMD cohort. In their case series, however, they report 2 patients with distinct novel point mutations in the TGF-β receptor type 1 gene, mutations of which have been associated with inherited aneurysmal disease.49,50 Both patients with these TGF-β receptor type 1 mutations had multifocal disease (medial fibroplasia), had suffered carotid or vertebral artery dissection, had ascending aortic dilatation, and had a family history of sudden death.49In summary, evidence supports a genetic basis for susceptibility to FMD. Multiple barriers have impeded the identification and characterization of genes that may contribute to FMD. Disease rarity hinders the establishment of large cohorts required for robust genetic studies. The disease phenotype in FMD is variable, and it remains possible that genetic abnormalities are confined to specific subsets of FMD patients. Gene-environment interactions may influence the predisposition for FMD and are difficult to detect in small study samples. We anticipate that the application of molecular genetics in future studies will yield novel information on the pathogenesis of FMD. Ideally, complementary genetic approaches, including family-based studies, candidate gene evaluation, and genome-wide association studies, would be pursued to identify potential causative pathways for this disease.Histopathological Classification Systems for FMDIn 1971, Harrison and McCormack13 codified the histological classification system for FMD from a consensus conference between investigators from the Cleveland Clinic and the Mayo Clinic.12,51 This effort provided a framework for a more organized and reproducible classification of FMD that heretofore had been plagued by erratic and inconsistent description and terminology. This classification system categorized FMD according to the arterial layer involved, namely intimal, medial, and adventitial disease (Table 1). Angiographic correlations have been derived largely from the work of Kincaid and colleagues (Figures 1–3).53Table 1. Classification of Fibromuscular DysplasiaHistologicalAngiographicHarrison and McCormack (1971)13French/Belgian Consensus (2012)2American Heart Association(2014)Medial Medial fibroplasia (60%–70%) Perimedial fibroplasia (15%–25%) Medial hyperplasia (5%–15%)MultifocalMultifocalIntimal fibroplasia (1%–2%)Unifocal (<1 cm)Tubular (≥1 cm)Focal*Adventitial (<1%)*There may be multiple areas of focal disease (eg, renal artery and carotid artery in the same patient). Focal and multifocal disease can occur in the same patient.Download figureDownload PowerPointFigure 1. Typical arteriographic findings of multifocal fibromuscular dysplasia in the carotid (A) and renal (B) arteries according to the American Heart Association classification system. This angiographic pattern is indicative of medial fibroplasia. There are multiple areas of alternating stenosis and dilatation (string of beads). Note that the disease is located in the mid to distal portion of the internal carotid and renal arteries. C, In medial fibroplasia, there are alternating areas of thinned media and thickened fibromuscular ridges in which the arterial muscle is replaced by fibroplasia with loose collagen. Shown here is a high-magnification photomicrograph demonstrating a gap in the arterial media. Reprinted from Virmani et al52 with permission from Elsevier. Copyright © 2013, Elsevier, Inc. Photomicrograph courtesy of Renu Virmani, MD, CV Path Institute, Gaithersburg, MD.Download figureDownload PowerPointFigure 2. Arteriographic findings of focal fibromuscular dysplasia in the renal and internal carotid arteries according to the American Heart Association classification system. This angiographic pattern is most consistent with intimal fibroplasia. This can present with a concentric band (focal constriction) as shown in the right internal carotid artery (A) or the right renal artery (B). C, Histopathological findings. There is concentric thickening of the intima. The media and adventitia are relatively normal. Panel C reprinted from Virmani et al52 with permission from Elsevier. Copyright © 2013, Elsevier, Inc. Photomicrograph courtesy of Renu Virmani, MD, CV Path Institute, Gaithersburg, MD.Download figureDownload PowerPointFigure 3. Perimedial fibroplasia of the renal artery. The beads (arrow) are smaller and less numerous than in medial fibroplasia (A). Note the nearly normal appearance of the renal artery after percutaneous balloon angioplasty (B). Reprinted from Slovut and Olin.4 Copyright © 2004, Massachusetts Medical Society. Reprinted with permission from Massachusetts Medical Society. Images courtesy of Anthony W. Stanson, MD, Mayo Clinic, Rochester, MN.Intimal disease is notable for the nonatherosclerotic, noninflammatory accumulation of fibrous tissue in the intima with a moderately cellular component. The internal elastic membrane is preserved and often reduplicated, and intimal disease was believed to account for 1% to 2% of FMD in the early reports. Today, it is likely the second most commonly encountered type of FMD as represented by focal angiographic stenoses (Figure 2).5Medial FMD, the most common histological variant, was originally subdivided into a complex system of 4 subcategories. Medial fibroplasia, characterized by deposition in the media of loose collagen in zones of degenerating elastic fibrils, accounted for 60% to 70% of FMD in initial reports and >90% today.5 It generates fibromuscular ridges, with resultant arterial stenoses alternating with areas of smooth muscle loss with consequent arterial dilatation. The alternating stenoses and dilatation produce the classic “string of beads” appearance on angiography, typically within the distal two thirds of the main renal artery and its branches and in the mid and distal cervical portions of the internal carotid and vertebral arteries (Figure 1). The internal elastic lamina is deficient in the dilated segments.Perimedial fibroplasia, previously thought to account for 15% to 25%, now represents approximately <1% of FMD in adults.5 Perimedial fibroplasia appears to be predominantly a disease of female children. Marked fibroplasia in the outer half of the media results in irregular luminal narrowing. The “beads” (dilated segments) are smaller and less numerous than those seen in medial fibroplasia (Figure 3). The external elastic lamina is generally obliterated by the fibroplasia.Medial hyperplasia is the least common variant of medial FMD (<1% today) and is notable for medial smooth muscle hyperplasia without significant collagen deposition. The arterial walls are otherwise well preserved, including the elastic laminae.The third major histological subtype, adventitial or periarterial disease, accounted for <1% of lesions. This is notable for collagen deposition surrounding the adventitia and extending into the periarterial tissue, with focal infiltration of lymphocytes being common.A host of other classifications of FMD have been proposed, but none have been uniformly accepted because of obtuse terminology and uncertainty of the relationship of the histological variants, given that the pathogenesis is fundamentally unknown.19,20,54–57Further limiting the utility of all histopathological classifications is the realization that FMD today is a disease almost exclusively diagnosed radiographically. With the introduction of percutaneous revascularization, the use of surgical bypass and the obtaining of histological specimens have become quite rare. Indeed, in the US Registry, histopathological confirmation of FMD was available for only 14 of 447 patients enrolled (3.3%).5 The most common arteriographic findings are multiple areas of stenosis and dilatation (string of beads) and tubular and focal stenoses.53 Medial fibroplasia most commonly presents with a string of beads appearance. Although tubular and focal stenoses are common in intimal fibroplasia, these radiographic appearances have been described with all histological subtypes and are rather nonspecific. Adventitial disease often produces tubular stenoses, but the number of reported adventitial cases has been small.4,5,12,13 Intraluminal fibrous webs have also been documented histologically, but they may not be visible angiographically. Intravascular ultrasound (IVUS) may reveal their presence, and their subtlety contributes to the difficulty in diagnosing the presence and hemodynamic significance of FMD lesions.58The 2012 French and Belgian consensus statement supported shifting from histological classification to simple radiographic classification, with multifocal, unifocal (<1 cm stenosis), and tubular (≥1 cm) classifications (Table 1).2 It was further proposed that the latter 2 be combined into 1 definition of unifocal.2 Unifocal implies a solitary lesion and may not accurately describe patients with multiple focal lesions.Savard and colleagues6 have demonstrated that by using a binary angiographic classification, they could discriminate between 2 distinct clinical phenotypes. Of the 337 patients with established renal artery FMD, 276 (82%) were classified as multifocal (ie, string of beads appearance; Figure 1). They demonstrated that patients with unifocal FMD (Figure 2) were younger at diagnosis (30 versus 49 years of age), had onset of hypertension at a younger age (26 versus 40 years of age), were more likely to be male (female-to-male ratio, 2:1 versus 5:1), were more likely to undergo revascularization (90% versus 35%), and had a higher rate of cure of hypertension among those revascularized (54% versus 26%).6 Because all patients in this series presented with hypertension and renal artery FMD, it is not clear whether this phenotypic difference will also be present in those with FMD in other arterial locations.59Acknowledging the practicality and appropriateness of an angiographic classification, we propose an American Heart Association classification that is a minor modification in the classification proposed by the European Consensus (Tables 1 and 2).2 Multifocal disease is the classic string of beads appearance represented by medial fibroplasia in virtually all adults. Focal disease is without regard to lesion length, is usually caused by intimal fibroplasia, but may also be caused by medial hyperplasia or adventitial FMD. Patients may have simultaneous multifocal and focal disease in different vascular territories. Aneurysms and dissections of medium-sized arteries may occur in patients with imaging features of FMD but are not angiographic subtypes of disease. Arterial tortuosity with coils, kinks, loops, and bends is another angiographic finding in FMD that is common but not specific to the disease. Convincing data on the association of radiographic appearance with outcome do not exist. The intent of this updated classification system is to allow further standardization of clinical classification of patients with FMD and to optimize future efforts to study clinical outcomes according to disease category. Multifocal and focal FMD may in fact not be the same disease.59Table 2. 2014 American Heart Association Classification of Fibromuscular DysplasiaMultifocalFocalAngiographic appearanceAlternating dilatation and constriction of the vessel (string of beads)Areas of dilatation are larger than the normal caliber of the arteryOccurs in the mid and distal portion of the renal, internal carotid, and vertebral arteriesMay occur in any other artery in the body†Focal concentric or tubular stenosis*Typical histologyMedial fibroplasia (most common)Intimal fibroplasia (most common)Perimedial fibroplasia (rare)‡Adventitial (periarterial) fibroplasia (rare)Medial hyperplasia (rare)Associated featuresAneurysm, dissection, and vessel tortuosity of medium-sized arteries may be present; multifocal and focal lesions may coexist in the same patient*Lesions are not necessarily confined to the mid or distal portion of the artery (ie, can occur in any arterial segment).†There are no cases of aortic fibromuscular dysplasia that are well documented pathologically.‡This rare form of fibromuscular dysplasia typically occurs in young girls (eg, those 5 to 15 years of age). Although there is a beaded appearance to the renal arteries, the beads are smaller than the normal renal artery and less numerous. There is often collateralization around the area of stenosis (Figure 3).Clinical ManifestationsThe clinical manifestations of FMD are variable and depend on a number of factors; most important among them are the distribution of vascular bed involvement and the type and severity of the vascular lesions (ie, stenoses of various degrees, arterial dissection, arterial aneurysm). In the US Registry, the majority of patients presented with at least 1 clinical symptom or sign, and only 5.6% of patients were truly asymptomatic, although this high prevalence of symptoms reflects the referral nature of the registry cohort.5 The frequency of initial presenting signs and symptoms of FMD among patients in the US Registry is shown in Table 3.Table 3. Presenting Signs and Symptoms Among Patients in the United States Registry for Fibromuscular Dysplasia5Symptoms/Signsn (%) Divided by 447Hypertension285 (63.8)Headache234 (52.4)Current headache135 (30.2)History of headache173 (38.7)Pulsatile tinnitus123 (27.5)Dizziness116 (26)Cervical bruit99 (22.2)Neck pain99 (22.2)Tinnitus84 (18.8)Chest pain or shortness of breath72 (16.1)Flank/abdominal pain70 (15.7)Aneurysm63 (14.1)Cervical dissection54 (12.1)Epigastric bruit42 (9.4)Hemispheric transient ischemic attack39 (8.7)Postprandial abdominal pain35 (7.8)Stroke31 (6.9)Claudication23 (5.2)Amaurosis fugax23 (5.2)Weight loss23 (5.2)Horner syndrome21 (4.7)Renal artery dissection14 (3.1)Azotemia9 (2)Myocardial infarction8 (1.8)Mesenteric ischemia6 (1.3)No symptoms/signs25 (5.6)Reproduced with permission from Olin et al.5 Copyright © 2012, American Heart Association, Inc.Renal Artery FMDThe most common manifestation of renal artery FMD is hypertension, the severity and onset of which are variable. Although FMD should be suspected as a potential diagnosis in the patient with early-onset hypertension (eg, before 35 years of age) or drug-resistant hypertension, it shoul
