Guideline sources The following summarized guidelines for the evaluation and management of fibromuscular dysplasia are prepared by our editorial team based on guidelines from the American Heart Association (AHA/ASA 2021), the Hypertension Canada Guidelines (Hypertension Canada 2020), the Society for Vascular Surgery (SVS 2020), the American College of Radiology (ACR 2019), the Society for Vascular Medicine (SVM/ESH 2019), the European Society of Cardiology (ESC/ESVS 2018), the Kidney Disease: Improving Global Outcomes Foundation (KDIGO 2017), and the Society for Cardiovascular Angiography and Interventions (SCAI/SNIS/SVM/AANS/ASNR/CNS/AANN/SVS/AHA/ACR/SAIP/ACC/ASA/SIR 2011). 1 2 3 4 5 6 7 8 9 9 9 10 Definition FMD is a noninflammatory, nonatherosclerotic arterial disease of medium-sized arteries characterized by arterial stenosis, occlusion, aneurysm, and dissection. 9 Epidemiology The exact cause of FMD is unknown. 9 Disease course https://web.pathway.md/diseases/rec0uu1MUwNH7NOwo 1/7 6/29/23, 4:05 AM Fibromuscular dysplasia Pathway Clinical manifestations of FMD depend on the artery involved (commonly carotid, renal, vertebral) resulting in stenosis, occlusion, aneurysm, and dissection. Renal involvement presented with renovascular hypertension; carotid artery involvement symptoms included headache, pulsatile tinnitus, and dizziness; and mesenteric (celiac and mesenteric) artery involvement presented with abdominal pain, hypertension, diarrhea, nausea, vomiting, headache, hemoperitoneum, and shock. 9 Prognosis and risk of recurrence The in-hospital mortality associated with FMD is 0.74%. 10 Guidelines 1. Screening and diagnosis Indications for testing (symptomatic patients): Evaluate for FMD-related renal artery stenosis in patients with hypertension presenting with 1 of the following clinical clues: significant (> 1.5 cm), unexplained asymmetry in kidney sizes abdominal bruit without apparent atherosclerosis FMD in another vascular territory family history of FMD. B Indications for testing (patients with RAA): consider screening female patients of childbearing age with renal artery aneurysm for FMD with a focused history and one-time axial imaging study (CT angiography or MRA) to assess for cerebrovascular, mesenteric, and iliac artery dysplasia. C Indications for testing (family relatives): Do not obtain genetic testing in asymptomatic relatives of patients with FMD as there are currently no genetic tests that are specific to FMD. D Perform clinical examination and obtain imaging-based evaluation of potentially affected arterial beds in relatives of patients with FMD upon presentation with suggestive symptoms or signs of FMD: Situation Guidance < 30 years old patients with hypertension, especially females Clinical signs of renal artery FMD Accelerated, malignant, or grade 3 (> 180/110 mmHg) hypertension Drug-resistant hypertension (BP target not achieved despite 3 drug-therapy at optimal doses including a diuretic) Unilateral small kidney without a causative urological abnormality Abdominal bruit in the absence of atherosclerotic disease or risk factors for https://web.pathway.md/diseases/rec0uu1MUwNH7NOwo 2/7 6/29/23, 4:05 AM Fibromuscular dysplasia Pathway atherosclerosis Suspected renal artery dissection/infarction Presence of FMD in at least one other vascular territory Severe and/or chronic migraine headaches, especially in the presence of other suggestive symptoms or signs Cardinal symptoms or signs of cerebrovascular FMD Pulsatile tinnitus ('whooshing' or 'swooshing' sound in the ears timed to heart beat) Cervical bruit on exam Stroke, TIA, or amaurosis fugax Unilateral head/neck pain or focal neurologic findings (such as partial Horner's syndrome with ipsilateral ptosis and miosis) suggestive of a cervical artery dissection Headaches (not chronic migraine or not migraine-type) Possible symptoms of cerebrovascular FMD Tinnitus (not pulsatile) Dizziness/lightheadedness. E Diagnosis: Establish the diagnosis of FMD in the presence of at least one focal or multifocal arterial lesion. Do not make the diagnosis solely in the presence of aneurysm, dissection, or tortuosity. E View the presence of aneurysm, dissection, or tortuosity in another/other vascular beds as multivessel involvement of all affected vascular beds if the patient has a focal or multifocal lesion in one vascular bed to establish the diagnosis of FMD. E 2. Classification and risk stratification Classification: classify arterial lesions of FMD according to angiographic appearance as focal or multifocal FMD. E 3. Diagnostic investigations Renal artery imaging: As per CHEP 2020 guidelines, obtain MRA or CT angiography to evaluate for FMD of the renal arteries. B https://web.pathway.md/diseases/rec0uu1MUwNH7NOwo 3/7 6/29/23, 4:05 AM Fibromuscular dysplasia Pathway As per SVM 2019 guidelines, consider obtaining imaging-based evaluation for renal artery FMD in the presence of suggestive symptoms and signs. E Show 2 more Cervicocephalic vascular imaging: As per CHEP 2020 guidelines, screen for cervicocephalic lesions and intracranial aneurysm in patients with confirmed FMD of the renal arteries. B As per SVM 2019 guidelines, consider obtaining imaging-based evaluation for cerebrovascular FMD in the presence of suggestive symptoms and signs. E Show 5 more Peripheral artery imaging: obtain contrast-enhanced CT angiography, contrast-enhanced MRA, or arteriography of lower extremities for the initial imaging in patients with suspected or known FMD. B Imaging of other arteries: screen for FMD in other vascular beds in the presence of suggestive symptoms in patients with confirmed FMD of the renal arteries. B 4. Medical management Thromboprophylaxis: As per SVM 2019 guidelines, consider initiating antiplatelet therapy (aspirin 75-100 mg daily) in patients with FMD, in the absence of contraindication, to prevent thrombotic and thromboembolic complications. E As per ASA 2011 guidelines, consider platelet-inhibitor medication in patients with FMD of the carotid arteries to prevent thromboembolism. Optimal drug and dosing regimens have not been established. C 5. Therapeutic procedures Renal artery revascularization: As per CHEP 2020 guidelines, perform renal artery angioplasty without stenting for the treatment of patients with FMD-related renal artery stenosis. Do not perform stenting unless required because of a periprocedural dissection. B As per ESC 2018 guidelines, consider performing balloon angioplasty with bailout stenting in patients with hypertension and/or signs of renal impairment related to renal arterial FMD. C Carotid artery revascularization: consider carotid angioplasty with or without stenting for patients with retinal or hemispheric cerebral ischemic symptoms related to FMD of the ipsilateral carotid artery, but comparative data addressing these methods of revascularization are not available. C 6. Surgical interventions Surgical revascularization: consider performing surgical revascularization in patients with complex lesions of FMD in the renal arteries less amendable to angioplasty, stenosis https://web.pathway.md/diseases/rec0uu1MUwNH7NOwo 4/7 6/29/23, 4:05 AM Fibromuscular dysplasia Pathway associated with complex aneurysm, and restenosis despite two unsuccessful attempts of angioplasty. C 7. Specific circumstances Patients with ischemic stroke: initiate antiplatelet therapy, control BP control, and offer lifestyle modifications for the prevention of future ischemic events in patients with a history of ischemic stroke or TIA and FMD without other attributable causes. B Show 2 more Kidney donation: regard donor candidates with FMD involving the orifices of both renal arteries as ineligible for kidney donation. 8. Follow-up and surveillance Indications for referral: refer patients with confirmed renal FMD to a hypertension specialist. B Follow-up: As per ESH 2019 guidelines: Follow-up patients with FMD at least annually, including clinical assessment, assessment of renal function, and imaging. E Insufficient evidence to recommend specific algorithms for modality and frequency of imaging studies in the follow-up. Customize the timing of follow-up imaging to each patient's pattern and severity of disease, including the need for monitoring of aneurysms or dissections and local imaging resources and experience. I As per ASA 2011 guidelines, consider annual noninvasive imaging of the carotid arteries in patients with FMD, to detect changes in the extent or severity of disease, although the effect on outcomes is unclear. C Clinical findings Symptoms Past medical history Abdominal pain worsening after eating Acute coronary syndrome CKD Chest pain Carotid-cavernous fistula Claudication Cervical artery dissection Cold fingers or toes Ehlers-danlos syndrome Difficulty speaking Intracranial aneurysm Dizziness Marfan syndrome Facial weakness Mesenteric ischemia Headache Migraine Nausea Renal artery aneurysm Neck pain Renal artery dissection Numbness Stroke https://web.pathway.md/diseases/rec0uu1MUwNH7NOwo 5/7 6/29/23, 4:05 AM Fibromuscular dysplasia Pathway Sweating TIA Temporary loss of vision Vertebral arteriovenous fistula Tinnitus Visceral artery aneurysm Weakness Social history Weakness in the legs Weight loss Cigarette smoking Family history Vascular exam Early-onset hypertension Abdominal bruit Cervical bruit Vital signs Cold limb Hypertension Femoral bruit Pulse differences between arms Respiratory exam Integument exam Dyspnea Digital ischemia Imaging findings Arterial aneurysm Arterial dissection Arterial tortuosity Renal atrophy String of beads sign References 1. 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