What is the initial management and treatment approach for patients with fibromuscular dysplasia (FMD)?

Management and Treatment of Fibromuscular Dysplasia (FMD)

For patients with fibromuscular dysplasia, initial management should include antiplatelet therapy, blood pressure control, and lifestyle modifications, with percutaneous transluminal renal angioplasty without stenting as the treatment of choice for renovascular hypertension due to FMD.

Understanding Fibromuscular Dysplasia

Fibromuscular dysplasia (FMD) is a nonatherosclerotic, noninflammatory vascular disease that affects small to medium-sized arteries, most commonly the renal and carotid arteries. Key characteristics include:

• Predominantly affects women aged 30-50 years
• Can involve multiple vascular beds (systemic arterial disease)
• Classic "string of beads" appearance on angiography in >80% of cases
• Can cause arterial stenosis, occlusion, aneurysm, or dissection

Diagnostic Workup

1. Imaging studies:

   • Duplex ultrasonography (initial screening)
   • CT angiography or MR angiography (higher accuracy)
   • Catheter angiography (gold standard, reserved for when revascularization is planned)

2. Comprehensive vascular assessment:

   • Evaluate for involvement of renal, carotid, vertebral, and other arteries
   • Screen for aneurysms and dissections
   • Annual noninvasive imaging initially to detect changes in disease extent/severity 1

Treatment Approach Based on Vascular Bed Involvement

1. Renal Artery FMD (Renovascular Hypertension)

Medical Management:

• First-line approach for all patients with renovascular hypertension 1
• Antihypertensive medications (RAS blockers are drugs of choice when revascularization not feasible) 1
• Careful monitoring of renal function required with RAS blockers 1

Interventional Management:

• Percutaneous transluminal renal angioplasty (PTRA) without stenting is the treatment of choice for hemodynamically significant renal artery stenosis due to FMD 1
• Indications for PTRA:
  • Refractory hypertension despite adequate medical therapy 1
  • Progressive decline in renal function 1
  • Young patients with milder hypertension of shorter duration (better chance of cure) 2

2. Cerebrovascular FMD (Carotid/Vertebral Arteries)

Medical Management:

• Antiplatelet therapy (e.g., aspirin) to prevent thromboembolism 1
• Blood pressure control to reduce risk of dissection 1
• Lifestyle modifications 1

Interventional Management:

• Carotid angioplasty with or without stenting is reasonable for patients with:
  • Retinal or hemispheric cerebral ischemic symptoms related to ipsilateral carotid FMD 1
  • Recurrent ischemic stroke despite optimal medical management 1
• Not recommended for asymptomatic FMD regardless of stenosis severity 1

Monitoring and Follow-up

• Annual noninvasive imaging initially to detect changes in disease extent/severity 1
• Studies may be repeated less frequently once stability is confirmed
• Monitor for potential complications:
  • Dissection (headache, Horner's syndrome, stroke)
  • Aneurysm formation
  • Progressive stenosis

Important Considerations and Caveats

1. FMD is a systemic disease affecting multiple vascular beds - comprehensive evaluation is essential 1

2. Predictors of successful hypertension cure after renal angioplasty 2:

   • Younger age
   • Lower pre-intervention systolic blood pressure
   • Shorter duration of hypertension

3. Differential diagnosis must include:

   • Atherosclerotic stenosis
   • Vasculitis
   • Vascular Ehlers-Danlos syndrome
   • Williams syndrome
   • Type 1 neurofibromatosis

4. Avoid revascularization in asymptomatic patients with carotid FMD regardless of stenosis severity 1

5. Disease progression is generally slow and rarely leads to ischemic renal failure 3

By following this structured approach to diagnosis and management, clinicians can effectively treat patients with FMD and reduce the risk of serious complications such as stroke, dissection, and uncontrolled hypertension.