What are the findings and management of fibromuscular dysplasia in the chest?

Fibromuscular Dysplasia in the Chest: Findings and Management

Fibromuscular dysplasia (FMD) affecting the chest vasculature requires comprehensive cross-sectional imaging from head to pelvis, with antiplatelet therapy recommended for all patients regardless of symptoms to prevent thromboembolic complications. 1

Clinical Presentation and Prevalence in Chest Vasculature

FMD is a non-atherosclerotic, non-inflammatory arterial disease that primarily affects medium-sized arteries. While most commonly affecting renal and cervical arteries, thoracic manifestations are less common but clinically significant:

• Thoracic aortic involvement is relatively rare (3% of FMD patients) 2
• Manifestations in the chest may include:
  • Arterial beading (the classic "string-of-beads" appearance)
  • Aneurysms (particularly in subclavian arteries)
  • Dissections (can affect descending thoracic aorta)
  • Arterial tortuosity
  • Stenosis of subclavian or brachiocephalic arteries 1, 3

Diagnostic Imaging

For suspected FMD with chest involvement, a systematic imaging approach is essential:

1. Initial screening: Computed Tomographic Angiography (CTA) from head to pelvis is recommended as the first-line comprehensive imaging modality (highest sensitivity at 84.2%) 1, 4

   • Crucial for detecting all affected vascular territories
   • Particularly important as 41.7% of FMD patients have aneurysm and/or dissection by the time of diagnosis 4

2. Alternative imaging:

   • Magnetic Resonance Angiography (MRA) if radiation exposure is a concern
   • Catheter angiography as the gold standard when noninvasive tests are inconclusive or intervention is planned 1

3. Important technical considerations:

   • Reformatted images are crucial and can affect final assessment in 36-56% of cases 2
   • Electrocardiogram-triggered acquisition improves image quality

Management Approach

Management depends on the specific vascular manifestations and symptoms:

1. Antiplatelet therapy:

   • Recommended for all FMD patients regardless of symptoms (typically aspirin 75-325mg daily) 1
   • Essential for preventing thromboembolic complications

2. For stenotic lesions:

   • Symptomatic subclavian artery stenosis should be considered for revascularization 5
   • Options include:
     • Endovascular approach: Balloon angioplasty with or without stenting
     • Surgical approach: Extra-anatomic bypass (carotid-subclavian, axilloaxillary) or subclavian-carotid arterial transposition 5
   • Surgical repair shows better long-term patency (96% at 5 years vs 70% for endovascular) 5

3. For aneurysms:

   • One-third of FMD patients with aneurysms require therapeutic intervention 4
   • Intervention decisions based on aneurysm size, location, and growth rate

4. For dissections:

   • Typically managed with antiplatelet or anticoagulant therapy
   • Intervention reserved for cases with end-organ ischemia or progressive dissection

5. Asymptomatic FMD:

   • Revascularization is NOT recommended for asymptomatic FMD regardless of stenosis severity 1

Surveillance

• Annual noninvasive imaging initially recommended to detect disease progression 1
• More frequent imaging may be needed in the first few years after diagnosis
• Imaging frequency can be reduced once stability is confirmed
• Consider alternating between CTA and MRA to reduce radiation exposure in younger patients 1

Important Caveats

• FMD should be considered a systemic disease affecting multiple vascular beds
• Patients with FMD-related dissection tend to be younger at presentation (48.4 vs 53.5 years) and experience more neurological symptoms 4
• The differential diagnosis is extensive and includes imaging artifacts and other arterial diseases 6
• Men with FMD may have more progressive disease, especially when smoking 6
• FMD patients require referral to specialized centers for dedicated management 1