Association of Smoking With Phenotype at Diagnosis and Vascular Interventions in Patients With Renal Artery Fibromuscular Dysplasia

Cerebrovascular Fibromuscular Dysplasia - A Practical Review

Fibromuscular dysplasia (FMD) is a rare idiopathic, segmental, noninflammatory and nonatherosclerotic arteriopathy of medium-sized arteries. It is classically considered to be a disease of young and middle adulthood, with females more commonly affected than males. FMD is a systemic disease. Although historically considered to be rare, cerebrovascular FMD (C-FMD) has now been recognized to be as common as the renovascular counterpart. Extracranial carotid and vertebral arteries are the most commonly involved vascular territories in C-FMD with the clinical presentation determined by vessels affected. Common symptoms include headaches and pulsatile tinnitus, with transient ischemic attacks, ischemic stroke and subarachnoid or intracerebral hemorrhage constituting the more severe clinical manifestations. Cervical artery dissection involving carotids more often than vertebral arteries and intracranial aneurysms account for the cerebrovascular pathologies detected in C-FMD. Our understanding regarding C-FMD has been augmented in the recent past on account of dedicated C-FMD data from North American, European and other international FMD cohorts. In this review article, we provide an updated and comprehensive overview on epidemiology, clinical presentation, etiology, diagnosis and management of C-FMD.

Spontaneous Coronary Artery Dissection: Review of Possible Pathophysiological Risk Factors

Spontaneous coronary artery dissection (SCAD) is a rare cause of acute coronary syndrome (ACS) that typically affects the younger and healthier female population without the typical ACS risk factors such as hypertension, diabetes, or hyperlipidemia. The clinical presentation of SCAD can be diverse and the diagnosis is typically by coronary angiography but also can require advanced imaging such as intravascular ultrasound or optical coherence tomography. Past studies have shown the atypical patient characteristics of SCAD patients among ACS patients. The main challenge is that the exact pathophysiology of SCAD is unknown. Potential pathophysiological risk factors are discussed including fibromuscular dysplasia, other arteriopathies, pregnancy and female sex hormone changes, migraines, inflammatory conditions, and stress. The current understanding of these risk factors along with potential pathophysiological mechanisms are discussed. There still remain many areas of additional investigation in understanding this rare cause of ACS.

Mesenteric Artery Dissection and Wall-Thickening, Case Study and General Review

Mesenteric artery dissection (D) and wall-thickening (WT) are rare vasculopathies that can lead to serious complications. This is a single center analysis of all patients evaluated for mesenteric arterial (celiac, superior (SMA) and/or inferior mesenteric (IMA)) D and/or WT from January 1, 2000, to January 31, 2020 at our hospital. Among the 101 included patients, the average age was 55.6 ± 13.6 years, mostly affecting men (62%). There were 20 celiac artery D, 8 WT, 15 D with WT, 15 SMA D, 7 WT, 8 D with WT, one IMA D, two WT, and 25 with multiple arterial involvement. Primary etiologies included segmental arterial mediolysis (SAM) (n = 17), isolated D (n = 17), localized vasculitis of the gastrointestinal tract (LVGT) (n = 16), fibromuscular dysplasia (FMD) (n = 13), extension of thoracoabdominal aortic D (n = 12), and trauma (n = 12). Most (71%) patients presented with abdominal pain. Hypertension (55%), hyperlipidemia (33%) and tobacco use (31%) were prevalent. Management included conservative (22%), medical (47%), endovascular (19%), and/or open repair (12%) with high in-hospital survival (98%) and symptom relief (73%). Our paper complements the scarce literature addressing the diagnosis and management of rare mesenteric vasculopathies. Most patients improved with conservative management, reserving endovascular or surgical interventions for symptomatic patients with more complicated presentations.

Clinical characteristics and long-term outcomes of endovascular treatment of renal artery fibromuscular dysplasia with branch lesions

BACKGROUND

Renal artery fibromuscular dysplasia (FMD) can cause arterial stenosis, dissection, and aneurysm of renal arteries. This study aimed to analyze the clinical characteristics and evaluate the long-term outcomes of renal branch artery FMD in children and adults.

METHODS

Sixty-one patients with renal artery FMD underwent endovascular treatment, including 23 children and 38 adults. They were divided into two groups, the main artery FMD group (n = 40, with severe stenosis located in the main renal artery) and the branch artery FMD group (n = 21, with only the branch lesions in unilateral or bilateral branch artery). The clinical characteristics and long-term outcomes of these pediatric and adult patients were evaluated.

RESULTS

The incidence of branch FMD was higher in children than in adults (P = 0.005). Thirteen children showed one or more branch artery involvements. Hypertension and headache were the most common symptoms. The branch aneurysm with coexisting stenosis was more common in patients with branch artery FMD. During the follow-up, blood pressure was normal in 8 patients and lowered in 11 patients in the branch FMD group. The patient's glomerular filtration was increased in 61 patients (P < 0.001). Four-year freedom from reintervention in 21 branch artery FMD patients was lower than that in 40 main artery FMD patients (P < 0.05).

CONCLUSIONS

A higher incidence of renal branch artery FMD was observed in children than in adults. Endovascular treatment with balloon angioplasty can be used for treating renal branch artery FMD.

Casper stent in the treatment of pulsatile tinnitus in fibromuscular dysplasia: Therapeutic review and case report

Fibromuscular dysplasia (FMD) is a known cause of pulsatile tinnitus that can, on rare occasion, evolve into an incapacitating condition. It is a noninflammatory and nonatherosclerotic arteriopathy of unknown cause that affects medium-sized vessels, such as the carotid and renal arteries, occurring mainly in women. We describe a 72-year-old woman suffering from pulsatile tinnitus refractory to medical treatment who was successfully treated with Casper stent in the carotid artery. The different treatment strategies published in the literature were reviewed.

Current progress in clinical, molecular, and genetic aspects of adult fibromuscular dysplasia

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 which has led to improved understandings 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.

[Fibromuscular dysplasia and its neurological manifestations]

The authors present the current data on the classification, epidemiology, etiology, neurological manifestations, prognosis, diagnosis, and treatment of patients with fibromuscular dysplasia (FMD). The review is based on the selection of publications by searching PubMed for keywords from the first sources until March 2019. FMD is a segmental non-atherosclerotic and non-inflammatory disease of large- and medium-caliber arteries leading to their stenosis. The disease occurs mostly in women (90%), and manifests itself in the 5th decade of life. In the cerebrovascular form of FMD, the extracranial internal carotid artery and the vertebral artery are usually affected. Diagnosis is based on the identification of alternation of narrowing and dilation of arteries using angiography (the string of beads sign (multifocal form)). Neurological manifestations include headache, tinnitus, and ischemic stroke, usually due to the dissection or stenosis, rarely, intracerebral or subarachnoid hemorrhages. The prognosis in most cases is favorable, relapses of strokes are rare. Treatment includes antiplatelet agents, if they are ineffective to prevent recurrence of ischemic stroke, endovascular treatment is carried out. Approaches to the treatment of intracranial aneurysms do not differ from those in patients without FMD.

First international consensus on the diagnosis and management of fibromuscular dysplasia

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD) which was commissioned by the Working Group 'Hypertension and the Kidney' of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.

Systematic and Multidisciplinary Evaluation of Fibromuscular Dysplasia Patients Reveals High Prevalence of Previously Undetected Fibromuscular Dysplasia Lesions and Affects Clinical Decisions: The ARCADIA-POL Study

Fibromuscular dysplasia (FMD), regarded as a generalized vascular disease, may affect all vascular beds and may result in arterial stenosis, occlusion, aneurysm, or dissection. It has been proposed to systematically evaluate all vascular beds in patients with FMD, regardless of initial FMD involvement. However, the impact of this approach on clinical decisions and on management is unknown. Within the prospective ARCADIA-POL study (Assessment of Renal and Cervical Artery Dysplasia-Poland), we evaluated 232 patients with FMD lesions confirmed in at least one vascular bed, out of 343 patients included in the registry. All patients underwent a detailed clinical evaluation including computed tomography angiography of intracranial and cervical arteries, as well as computed tomography angiography of the abdominal aorta, its branches, and upper and lower extremity arteries. In the study group, FMD lesions were most frequently found in renal arteries (87.5%). FMD was also found in cerebrovascular (24.6%), mesenteric (13.8%), and upper (3.0%) and lower extremity (9.9 %) arteries. Newly diagnosed FMD lesions were found in 34.1% of the patients, and previously undetected vascular complications were found in 25% of the patients. Among all FMD patients included in the study, one out of every 4 evaluated patients qualified for interventional treatment due to newly diagnosed FMD lesions or vascular complications. The ARCADIA-POL study shows for the first time that the systematic and multidisciplinary evaluation of patients with FMD based on a whole-body computed tomography angiography scan has an impact on their clinical management. This proved the necessity of the systematic evaluation of all vascular beds in patients with FMD, regardless of initial FMD involvement.

Prevalence, Presentation, and Associated Conditions of Patients With Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is defined by focal narrowing of small and medium-sized arteries due to an idiopathic, noninflammatory, nonatherosclerotic vascular disease. The population-based prevalence of FMD remains unknown. Using the National Inpatient Sample database, we evaluated the prevalence, clinical presentation, mortality, and associated conditions of FMD from January 1, 2004, to September 30, 2015. Among 2,420 patients who presented with FMD, 2,086 (86.20%) of patients were female. The mean age was 55.18 ± 18.99 years in men and 63.37 ± 17.10 years in women. FMD patients most commonly presented with hypertension (67.3%), transient ischemic attack (3.7%), headache (2.1%), dizziness (1.1%), abdominal pain (0.6%), or hematuria (0.3%). In-hospital mortality of FMD patients was 0.74%. In conclusion, FMD is a rare condition with low in-hospital mortality that may be considered among female patients presenting with hypertension.

First International Consensus on the diagnosis and management of fibromuscular dysplasia

This article is a comprehensive document on the diagnosis and management of fibromuscular dysplasia (FMD), which was commissioned by the working group ‘Hypertension and the Kidney’ of the European Society of Hypertension (ESH) and the Society for Vascular Medicine (SVM). This document updates previous consensus documents/scientific statements on FMD published in 2014 with full harmonization of the position of European and US experts. In addition to practical consensus-based clinical recommendations, including a consensus protocol for catheter-based angiography and percutaneous angioplasty for renal FMD, the document also includes the first analysis of the European/International FMD Registry and provides updated data from the US Registry for FMD. Finally, it provides insights on ongoing research programs and proposes future research directions for understanding this multifaceted arterial disease.

Prevalence of smoking and clinical characteristics in fibromuscular dysplasia. The ARCADIA-POL study

PURPOSE

Smoking was identified as a potential factor contributing to fibromuscular dysplasia (FMD). To evaluate the prevalence of smoking and clinical characteristics in FMD subjects.

MATERIAL AND METHODS

We analysed 190 patients with confirmed FMD in at least one vascular bed. The rate of smokers in FMD patients was compared to that in two control groups selected from a nationwide survey.

RESULTS

The rate of smokers in FMD patients was 42.6%. There were no differences in frequency of smokers between FMD patients and: a group of 994 matched control subjects from general population and a group of matched hypertensive subjects. There were no differences in the characteristics of FMD (including rates of multisite FMD and significant renal artery stenosis) and its complications (including rates of dissections and aneurysms) between smokers and non-smokers. Smokers as compared with non-smokers were characterized by higher left ventricle mass index.

CONCLUSIONS

There is no difference in the rate of smokers between FMD patients and subjects from the general population. Moreover, we did not find any association between smoking and clinical characteristics of FMD patients nor its extent and vascular complications. Our results do not support the hypothesis that smoking is involved in the pathophysiology of FMD.

Spontaneous coronary artery dissection: contemporary aspects of diagnosis and patient management

Spontaneous coronary artery dissection is an increasingly recognised cause of acute coronary syndromes, especially in young and middle-age women. Recognising its particularities and differences with atherosclerotic disease is central for appropriately identifying and approaching these patients. The authors review the current state of knowledge on spontaneous coronary artery dissection and provide practical recommendations for the diagnosis and management of this condition, both in the acute and convalescence phases.

Visceral Fibromuscular Dysplasia: From asymptomatic disorder to emergency

Fibromuscular dysplasia (FMD) is an idiopathic, segmental, non-atherosclerotic and non-inflammatory disease of the musculature of arterial walls, leading to stenosis of small and medium-sized arteries, mostly involving renal and cervical arteries. As a result of better and more systematic screening, it appears that involvement of the splanchnic vascular bed is more frequent than originally assumed. We review epidemiology, pathogenesis, clinical picture as well as diagnosis and treatment of visceral artery (VA) FMD. The clinical picture is very diverse, and diagnosis is based on CT-, MR- or conventional catheter-based angiography. Involvement of VAs generally occurs among patients with multi-vessel FMD. Therefore, screening for VA FMD is advised especially in renal artery (RA) FMD and in case of aneurysms and/or dissections. Treatment depends on the clinical picture. However, the level of evidence is low, and much of the common practice is extrapolated from visceral atherosclerotic disease.

Genomics of Fibromuscular Dysplasia

Fibromuscular Dysplasia (FMD) is &ldquo;an idiopathic, segmental, non-atherosclerotic and non-inflammatory disease of the musculature of arterial walls, leading to stenosis of small and medium-sized arteries&rdquo; (Persu, et al; 2014). FMD can lead to hypertension, arterial dissections, subarachnoid haemorrhage, stroke or mesenteric ischemia. The pathophysiology of the disease remains elusive. While familial cases are rare (<5%) in contemporary FMD registries, there is evidence in favour of the existence of multiple genetic factors involved in this vascular disease. Recent collaborative efforts allowed the identification of a first genetic locus associated with FMD. This intronic variant located in the phosphatase and actin regulator 1 gene (PHACTR1) may influence the transcription activity of the endothelin-1 gene (EDN1) located nearby on chromosome 6. Interestingly, the PHACTR1 locus has also been involved in vascular hypertrophy in normal subjects, carotid dissection, migraine and coronary artery disease. National and international registries of FMD patients, with deep and harmonised phenotypic and genetic characterisation, are expected to be instrumental to improve our understanding of the genetic basis and pathophysiology of this intriguing vascular disease.

Prevalence of Intracranial Aneurysm in Women With Fibromuscular Dysplasia: A Report From the US Registry for Fibromuscular Dysplasia

Importance

The prevalence of intracranial aneurysm in patients with fibromuscular dysplasia (FMD) is uncertain.

Objective

To examine the prevalence of intracranial aneurysm in women diagnosed with FMD.

Design, Setting, and Participants

This cross-sectional study included 669 women with intracranial imaging registered in the US Registry for Fibromuscular Dysplasia, an observational disease-based registry of patients with FMD confirmed by vascular imaging and currently enrolling at 14 participating US academic centers. Registry enrollment began in 2008, and data were abstracted in September 2015. Patients younger than 18 years at the time of FMD diagnosis were excluded. Imaging reports of all patients with reported internal carotid, vertebral, or suspected intracranial artery aneurysms were reviewed. Only saccular or broad-based aneurysms 2 mm or larger in greatest dimension were included. Extradural aneurysms in the internal carotid artery were included; fusiform aneurysms, infundibulae, and vascular segments with uncertainty were excluded.

Main Outcomes and Measures

Percentage of women with FMD with intracranial imaging who had an intracranial aneurysm.

Results

Of 1112 female patients in the registry, 669 (60.2%) had undergone intracranial imaging at the time of enrollment (mean [SD] age at enrollment, 55.6 [10.9] years). Of the 669 patients included in the analysis, 86 (12.9%; 95% CI, 10.3%-15.9%) had at least 1 intracranial aneurysm. Of these 86 patients, 25 (53.8%) had more than 1 intracranial aneurysm. Intracranial aneurysms 5 mm or larger occurred in 32 of 74 patients (43.2%), and 24 of 128 intracranial aneurysms (18.8%) were in the posterior communicating or posterior arteries. The presence of intracranial aneurysm did not vary with location of extracranial FMD involvement. A history of smoking was significantly associated with intracranial aneurysm: 42 of 78 patients with intracranial aneurysm (53.8%) had a smoking history vs 163 of 564 patients without intracranial aneurysm (28.9%; P < .001).

Conclusions and Relevance

The prevalence of intracranial aneurysm in women diagnosed with FMD is significantly higher than reported in the general population. Although the clinical benefit of screening for intracranial aneurysm in patients with FMD has yet to be proven, these data lend support to the recommendation that all patients with FMD undergo intracranial imaging if not already performed.

Non-Atherosclerotic Vascular Disease in Women

OPINION STATEMENT

Takayasu arteritis, fibromuscular dysplasia (FMD), spontaneous arterial dissection, Raynaud's phenomenon, and chilblains are vascular conditions that are associated with an increased predisposition in women and are often underdiagnosed. Takayasu arteritis has an incidence rate of 2.6 cases per million individuals per year in the USA and predominantly affects women of childbearing age. HLA-B5 genetic locus is linked with Takayasu arteritis susceptibility. Methods to determine active disease are limiting; currently utilized clinical and imaging findings and laboratory tests are of limited value for this purpose. Pregnancy poses risks for maternal and fetal complications, and these patients need additional monitoring and care before and after conception. Controlling hypertension and immunosuppression using steroids, biological and non-biological immunosuppressants, are key components of managing patients with this arteritis. FMD commonly affects middle-aged, white females. Its true prevalence is unknown. Renal and cerebrovascular beds are the most frequently involved vascular beds. Its clinical presentation varies from no symptoms to catastrophic events. Controlling vascular risk factors, periodic surveillance, and revascularization when indicated are important factors in FMD management. Spontaneous arterial dissections are less common, but are an important cause of morbidity and mortality in specific populations. Cervicocephalic dissection causes 10-20% of the strokes in young adults, and coronary artery dissection is the culprit in almost one fourth of young women presenting with acute myocardial infarction. Early diagnosis is key to improving prognosis in these patients, as the majority of patients have spontaneous resolution of the dissection with conservative management alone. Increased clinician awareness of the presentation features and angiographic findings are imperative for early diagnosis. Raynaud's phenomenon and chilblains are cold- or stress-induced cutaneous lesions, commonly involving distal extremities. Secondary causes such as connective tissue diseases and malignancies must be thoroughly excluded during evaluation of these conditions. Cold avoidance, systemic and local warming, and oral vasodilator therapy are the mainstays of therapy.

Dissection and Aneurysm in Patients With Fibromuscular Dysplasia: Findings From the U.S. Registry for FMD

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.

Multimodality imaging of fibromuscular dysplasia

OBJECTIVE

Fibromuscular dysplasia (FMD) is an uncommon non-inflammatory and non-atherosclerotic cause of arterial disease that may result in stenosis, tortuosity, aneurysm, or dissection. The clinical presentation depends on the vascular bed involved and ranges from asymptomatic to multisystem disease and end organ ischemia. The purpose of this article is to review the role of imaging in patients with FMD with an emphasis on renal FMD. The relevant epidemiology, histopathology, imaging techniques, and interpretation of images will be discussed.

CONCLUSION

Renal artery FMD requires a high index of suspicion for accurate and prompt diagnosis and implementation of appropriate therapy. The treatment will vary based on clinical presentation and distribution of involvement. Noninvasive imaging with duplex ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI) are reasonable alternatives for the depiction of FMD in comparison to catheter-directed angiography (CA). Patients with FMD are often treated by multispecialty practice including the interventional radiologist.

Clinical characteristics and treatment of renal artery fibromuscular dysplasia with percutaneous transluminal angioplasty: a long-term follow-up study

BACKGROUND

Renal artery fibromuscular dysplasia (RAFMD) is a non-atherosclerotic cause of renal artery stenosis often affecting the young. Percutaneous transluminal renal angioplasty (PTRA) is the treatment of choice but there are few studies of the outcome of the procedure.

METHODS

This retrospective analysis included 64 patients (56.2 % female; mean age at diagnosis, 28.0 years) with RAFMD who underwent PTRA between November 2003 and August 2015. Technical and clinical success rates and restenosis rates were evaluated.

RESULTS

Seventy-six procedures were performed on 64 RAFMD patients. Technical success was 96.9 %, as defined by <30 % residual stenosis, with stent placement required in 11 patients (17.2 %). In the short term (1 month), the majority (79.7 %) had an immediate clinical benefit, with cure of hypertension in 35.9 %, and improvement in hypertension and a lower requirement for antihypertensive medications in 43.8 %. In the long term (mean, 47.5 months; range, 5-141 months), the survival rate was 96.9 %, freedom from restenosis was 84.4 %, and 76.6 % of patients showed a sustained clinical benefit (cure rate 40.6 %, improvement rate 35.9 %). Eight patients were treated with a second procedure and two had a third procedure, with half of these patients showing an improvement in hypertension.

CONCLUSION

PTRA for symptomatic RAFMD is safe and clinically successful. More than half of patients experience an immediate clinical benefit with sustained long-term effects. For patients with restenosis, there was a good response to a second PTRA.

Epidemiology of fibromuscular dysplasia: A review of the literature

Fibromuscular dysplasia (FMD) is a non-atherosclerotic, non-inflammatory disease of medium sized arteries that has been described in multiple anatomic territories with a wide variety of manifestations (e.g. beading, stenosis, occlusion, aneurysm, or dissection). While the first case of FMD is thought to have been described over 75 years ago, the causes, natural history, and epidemiology of FMD in the general population remain incompletely understood. This article reviews important historical and contemporary contributions to the FMD literature that inform our current understanding of the prevalence and epidemiology of this important disorder. A particular focus is given to studies which form the basis for FMD prevalence estimates. Prevalence estimates for renal FMD are derived from renal transplant donor studies and sub-studies of clinical trials of renal artery stenting; however, it is unclear how well these estimates generalize to the overall population as a whole. Newer data are emerging examining the genetic associations and environmental interactions with FMD. Significant contributions to the understanding of FMD have come from the United States Registry for Fibromuscular Dysplasia; however, many unanswered questions remain, and future studies are required to further characterize FMD epidemiology in general populations and advance our understanding of this important disorder.

Differences between the pediatric and adult presentation of fibromuscular dysplasia: results from the US Registry

BACKGROUND

Fibromuscular dysplasia (FMD) is a non-inflammatory arteriopathy that causes significant morbidity in children.

METHODS

The clinical features, presenting symptoms, and vascular beds involved are reviewed in the first 33 patients aged <18 years who are enrolled in the United States Registry for FMD from five registry sites and compared with 999 adult patients from 12 registry sites.

RESULTS

Mean age at diagnosis was 8.4 ± 4.8 years (16 days to 17 years). Compared with adults, pediatric FMD occurs in more males (42.4 vs 6 %, p < 0.001). Children with FMD have a stronger previous history of hypertension (93.9 vs 69.9 %, p = 0.002). Hypertension (100 %), headache (55 %), and abdominal bruits (10.7 %) were the most common presenting signs and symptoms. FMD affects renal vasculature in almost all children (97 vs 69.7 %, p = 0.003). The extra-cranial carotid vessels are less commonly involved in children (23.1 vs 73.3 %, p < 0.001). The mesenteric arteries (38.9 vs 16.2 %, p = 0.02) and aorta (26.3 vs 2.4 %, p < 0.001) are more commonly involved in children.

CONCLUSIONS

In the United States Registry for FMD, pediatric FMD affects children from infancy throughout childhood. All children presented with hypertension and many presented with headache and abdominal bruits. In children, FMD most commonly affects the renal vasculature, but also frequently involves the mesenteric arteries and abdominal aorta; the carotid vessels are less frequently involved.

[Fibromuscular dysplasia of renal arteries]

Fibromuscular dysplasia is non-atherosclerotic, non-inflammatory disease of the medium caliber arteries causing segmental stenosis, and sometimes aneurysm and/or dissection. Renal involvement is either asymptomatic or revealed by hypertension, rarely acute complications (renal infarction/hemorrhage). Cross-sectional imaging or angiography differentiates multifocal fibromuscular dysplasia (pearl necklace appearance) and focal fibromuscular dysplasia (tubular stenosis). Several differential diagnoses are to be mentioned. Carotid and vertebral involvement are possible. Smoking cessation must be encouraged. Selected patients benefit from renal revascularization. The best indications are recent or resistant hypertension, and progressive renal atrophy. Angioplasty without stent revascularization is the technique of choice in purely stenotic forms.

Fibromuscular Dysplasia in a Normotensive Patient Presented With Renal Infarct: Case Report and Endovascular Technique

Fibromuscular dysplasia (FMD) is a well-known disease, but its diagnosis can be challenging. Typically, the symptomatic FMD are reported by young and middle aged people with high blood pressure refractory to medical treatment. We present a rare case of a young, healthy, and normotensive patient who presented with pain secondary to renal infarction, without any prior signs or symptoms or history of hypertension. This presentation of FMD has not been previously described. The typical but subtle angiographic findings of the macro-aneurysmal FMD as well as the successful endovascular treatment are discussed herein. The macro-aneurysmal form of FMD should be considered in the differential diagnosis of acute renal infarction in young and middle aged patients even if they do not have a history of hypertension.

European consensus on the diagnosis and management of fibromuscular dysplasia

The main objectives of this expert consensus are to raise awareness about fibromuscular dysplasia, which is more frequent and more often systemic than previously thought and can sometimes have devastating consequences; to provide up-to-date recommendations for the diagnosis, evaluation, and management of the disease; and to identify research priorities. The emphasis has been put on recommendations for daily practice. The main topics covered include definition, classification, diagnosis, and management of fibromuscular dysplasia in adult patients with symptomatic involvement of the renal arteries, supra-aortic trunks, and digestive and peripheral arteries.

Renal artery stenosis-when to screen, what to stent?

Renal artery stensosis (RAS) continues to be a problem for clinicians, with no clear consensus on how to investigate and assess the clinical significance of stenotic lesions and manage the findings. RAS caused by fibromuscular dysplasia is probably commoner than previously appreciated, should be actively looked for in younger hypertensive patients and can be managed successfully with angioplasty. Atheromatous RAS is associated with increased incidence of cardiovascular events and increased cardiovascular mortality, and is likely to be seen with increasing frequency. Evidence from large clinical trials has led clinicians away from recommending interventional revascularisation towards aggressive medical management. There is now interest in looking more closely at patient selection for intervention, with focus on intervening only in patients with the highest-risk presentations such as flash pulmonary oedema, rapidly declining renal function and severe resistant hypertension. The potential benefits in terms of improving hard cardiovascular outcomes may outweigh the risks of intervention in this group, and further research is needed.

Optimal management of renal artery fibromuscular dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory angiopathy of unknown cause affecting medium-sized (most commonly renal) arteries and causing renovascular hypertension. The most common medial multifocal type of FMD (with the “string of beads” appearance) is more than four times more prevalent in females than in males. FMD accounts for up to 10% of cases of renovascular hypertension. Compared with patients with atherosclerotic renal artery stenosis, patients with FMD are younger, have fewer risk factors for atherosclerosis, and a lower occurrence of atherosclerosis in other vessels. The etiology is multifactorial, including vessel wall ischemia and smoking, as well as hormonal and genetic factors. Intra-arterial digital subtraction angiography is still the gold standard for exclusion or confirmation of renal artery stenosis caused by FMD, at least in young patients, who more often have lesions in branches of the renal artery. For FMD patients with atherosclerosis and those who are older (>50–55 years), significant renal artery stenosis may be confirmed or excluded with ultrasonography. The FMD lesion is typically truncal or distal, whereas atherosclerotic lesions are more often proximal or ostial. Treatment options are medical, endovascular (percutaneous transluminal renal angioplasty [PTRA]), and surgical. Invasive treatment should be considered when hypertension cannot be controlled with antihypertensive drugs and in patients with impaired renal function or ischemic nephropathy. PTRA has become the treatment of choice and normally yields good results, especially in unifocal disease and young patients. Pressure gradients are normally completely abolished, and there is no indication for stent placement. Surgical revascularization is indicated after PTRA complications; thrombosis, perforation, progressive dissection, repeated PTRA failure or restenosis. Centralization of handling is recommended.

Treatment of hypertension in patients with renal artery stenosis due to fibromuscular dysplasia of the renal arteries

Renal artery stenosis (RAS) from fibromuscular dysplasia (FMD) is an uncommon cause of hypertension that affects mostly women. FMD is a noninflammatory vascular disease that predominantly affects mainly the renal arteries, but can also affect arteries in other vascular territories. The most common type of FMD is the media fibroplasia with the characteristic "string of beads" appearance (80-90%), whereas the two other types, the "intimal" and "adventitial" FMD are much less common accounting for 10% and <5% of cases, respectively. The prevalence of FMD in the general population is not well known. Estimates are derived from screening kidney donors, with a prevalence of about 2.6%. Among patients with renovascular hypertension (RVH), its incidence is about 10%, whereas 80-90% of RVH is due to atherosclerotic renal artery stenosis (ARAS). The treatment of choice of hypertension due to FMD is percutaneous renal angioplasty (PTRA). In contrast, hypertension due to ARAS is not frequently responsive to PTRA. In order to achieve successful control of hypertension in patients with FMD, a combination of PTRA with drugs that block the renin-angiotensin-aldosterone system (RAAS) is often necessary. The purpose of this review was to search the literature for newer diagnostic methods and treatment of FMD. Therefore, a Medline search of the English literature of published papers between 2008 and December 2013 was performed. Of 58 papers reviewed, 19 pertinent papers were selected including, studies, reviews, registries and case reports. The information from these studies together with collateral literature will be discussed in this concise review.