What is the management of fibromuscular dysplasia?

Management of Fibromuscular Dysplasia (FMD)

For patients with fibromuscular dysplasia, management should focus on antiplatelet therapy for all patients, annual imaging surveillance, and reserving revascularization only for symptomatic patients with cerebral ischemic symptoms related to the affected artery. 1, 2

Overview and Diagnosis

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that primarily affects medium-sized arteries, most commonly the renal and carotid arteries. It is characterized by abnormal cell development in the arterial wall leading to stenosis, aneurysms, or dissections.

Diagnostic Approach:

• Initial screening: Duplex ultrasonography (Class I recommendation, Level of Evidence B) 2
• Advanced imaging: CTA (highest sensitivity at 84.2%) or MRA (sensitivity 62.5%) 2
• Gold standard: Catheter angiography when noninvasive tests are inconclusive or intervention is planned 2

Management Algorithm

1. Medical Management

• Antiplatelet therapy: Recommended for all patients with FMD to prevent thromboembolism 1, 2

  • Aspirin (75-325 mg daily) is commonly used
  • Optimal drug and dosing regimen have not been definitively established

• Blood pressure control: Essential for hypertensive patients 2

  • For renovascular hypertension due to FMD, medical therapy should be the first-line approach 1

2. Surveillance

• Annual noninvasive imaging is reasonable initially to detect changes in disease extent or severity 1, 2
• Studies may be repeated less frequently once stability has been confirmed
• Comprehensive evaluation should consider multiple vascular beds, as FMD can affect multiple arterial territories 2

3. Revascularization

• For symptomatic carotid FMD:

  • Carotid angioplasty with or without stenting is reasonable for patients with retinal or hemispheric cerebral ischemic symptoms related to FMD of the ipsilateral carotid artery (Class IIa, Level of Evidence C) 1

• For renovascular FMD:

  • Percutaneous transluminal renal angioplasty (PTRA) without stenting should be considered for patients with hypertension and hemodynamically significant renal artery stenosis due to FMD (Class IIa, Level of Evidence C) 1
  • PTRA can restore renal perfusion pressure and lower blood pressure

• For asymptomatic FMD:

  • Revascularization is NOT recommended for patients with asymptomatic FMD of a carotid artery, regardless of the severity of stenosis (Class III: No Benefit, Level of Evidence C) 1

Special Considerations

Complications to Monitor

• Arterial dissection: Affects approximately 12% of FMD patients 2
• Stroke: Affects approximately 9.8% of FMD patients 2
• Aneurysm formation: Common complication requiring surveillance 2

Multivascular Involvement

• FMD should be considered a systemic disease affecting multiple vascular beds 1
• Evaluate for involvement of carotid, coronary, and other major arteries, as this may lead to dissection if blood pressure is not controlled 1

Pitfalls and Caveats

1. Don't miss multivascular involvement: FMD often affects multiple arterial beds simultaneously, requiring comprehensive vascular evaluation beyond the initially identified site 2

2. Avoid unnecessary revascularization: Intervention is not beneficial for asymptomatic patients, regardless of stenosis severity 1

3. Recognize atypical presentations: FMD can present with headache, pulsatile tinnitus ("swishing" sound in ears), or be discovered incidentally 3

4. Consider FMD in young hypertensive patients: FMD should be in the differential diagnosis for patients aged ≤35 years with new-onset hypertension 3

5. Distinguish from atherosclerosis: FMD has distinct angiographic patterns (string of beads in medial fibroplasia or focal stenosis in intimal fibroplasia) that differ from atherosclerotic disease 1, 3

By following this evidence-based approach to FMD management, clinicians can optimize outcomes while avoiding unnecessary interventions in asymptomatic patients.