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Fibromuscular Dysplasia

By

Koon K. Teo

, MBBCh, PhD, McMaster University, Hamilton, Ontario, Canada

Last full review/revision May 2021| Content last modified May 2021

Fibromuscular dysplasia includes a heterogenous group of nonatherosclerotic, noninflammatory arterial changes, causing some degree of vascular stenosis, occlusion, or aneurysm.

Fibromuscular dysplasia usually occurs in women aged 40 to 60. The cause is unknown. However, there may be a genetic component, and smoking may be a risk factor. Fibromuscular dysplasia is more common among people with certain connective tissue disorders (eg, Ehlers-Danlos syndrome type 4, cystic medial necrosis, hereditary nephritis, neurofibromatosis).

Medial dysplasia, the most common type, is characterized by alternating regions of thick and thin fibromuscular ridges containing collagen along the media. In perimedial dysplasia, extensive collagen deposition occurs in the outer half of the media. Fibromuscular dysplasia may affect the renal arteries (60 to 75%), carotid and intracranial arteries (25 to 30%), intra-abdominal arteries (9%), or external iliac arteries (5%).

Fibromuscular dysplasia is usually asymptomatic regardless of location. Symptoms, when they occur, vary by location:

  • Carotid arteries: Transient ischemic attack or stroke symptoms
  • Intra-abdominal arteries: Mesenteric ischemic symptoms (rare)
  • Intracranial arteries: Symptoms of brain aneurysm
  • Leg arteries: Claudication in the thighs and calves, femoral bruits, and decreased femoral pulses
  • Renal arteries: Secondary hypertension

Ultrasonography may suggest the diagnosis, but definitive diagnosis of fibromuscular dysplasia is made by angiography showing a beaded appearance (in medial or perimedial dysplasia) or a concentric band or long, smooth narrowing (in other forms).

Treatment of fibromuscular dysplasia varies by location. It may involve percutaneous transluminal angioplasty alone, percutaneous stent angioplasty, bypass surgery, or aneurysm repair. Smoking cessation is important. Control of other risk factors for atherosclerosis (hypertension, dyslipidemia, diabetes) helps prevent accelerated development of flow-limiting arterial stenoses.

Key Points

  • Fibromuscular dysplasia is most common in women age 40 to 60 years.
  • Patients who have connective tissue disease, who smoke, or who have a family history are at higher risk.
  • Treatment depends on the location and includes angioplasty, bypass surgery, or aneurysm repair.

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