Fibromuscular dysplasia

Background

• Non-inflammatory, non-atherosclerotic fibroplastic disorder
• Far more common in women (90% of cases)

Clinical Manifestations

• Arteries involved:
  • Renal 58%
  • Carotid or vertebral 32%
  • Other arteries including iliac and intracranial 10%

Renal Artery FMD

• Hypertension, especialy early-onset <35 years or drug-resistant
  • Average age of onset 43 years
• Epigastric or flank bruit
• Flank pain if dissection or aneurysm
• Progression to end-stage renal disease is rare

Cerebrovascular FMD

• Headache is most common complaint, usually migrainous
• Pulsatile tinnitus
• Dizziness or lightheadedness
• Cervical bruit
• Neck pain
• TIA or stroke
• Carotid and vertebral artery dissections, presenting with headache and neck pain, cranial nerve deficits, or Horner syndrome
• Can cause cerebral aneurysms

Mesenteric FMD

• Rare, often incidental finding
• Can cause mesenteric ischemia

FMD of the extremities

• Most commonly the external iliac arteries, though can involved brachial arteries as well
• Often asymptomatic, or claudication; rarely, acute ischemia
• May have a lower abdominal or inguinal bruit

FMD of the Coronary Arteries

• Can present as an acute coronary syndrome, though rare

Differential Diagnosis

• Standing waves caused by contrast-induced spasm
• Atherosclerosis
• Vasculitis
• Segmental arterial mediolysis

Diagnosis

• CT or MR angiography (or Duplex ultrasound, if CT unavailable)
  • Measures a gradient
• Previously would use captopril renal scan

Management

Renal Artery Revascularization

• Recurs in 50-60%

Indications

• Resistant hypertension despite 3-drug regimen including diuretic
• Recent-onset hypertension, with the goal of curing it
• Renal artery dissection (needs stenting)
• Renal artery aneurysm
• Branch renal artery disease and hypertension
• Preservation of renal function if severe stenosis

Chronic

• Low-dose ASA recommended for all patients

Screening

• All patients with FMD anywhere are recommended to be screened for intracranial aneurysms with CTA or MRA
• Carotid, coronary, vertebral aneurysms all possible, so likely useful to do whole-body CTA

Hypertension

• First-line is ACEi/ARB
• Can consider percutaneous transluminal angioplasty

Dissection

• LMWH or wardarin for 3 to 6 months, or antiplatelet therapy

Follow-up

• Monitor blood pressure and creatinine every three months, then annually if stable
• Duplex ultrasound or other noninvasive imaging of the involved arteries every 6 to 12 months

Further Reading

• Olin et al. Fibromuscular Dysplasia: State of the Science and Critical Unanswered Questions. Circulation 2014;129:1048-1078.