Is aspirin (acetylsalicylic acid) needed for someone with fibromuscular dysplasia (FMD) in the carotid artery?

Aspirin Therapy for Fibromuscular Dysplasia in the Carotid Artery

Administration of platelet-inhibitor medication such as aspirin is beneficial in patients with fibromuscular dysplasia (FMD) of the carotid arteries to prevent thromboembolism, even though the optimal drug and dosing regimen have not been definitively established. 1

Recommendations for Asymptomatic FMD

• Platelet inhibitor therapy (such as aspirin) is recommended for patients with carotid FMD, even when asymptomatic, to prevent thromboembolism 1
• The typical dose range for aspirin in this setting is 81-325 mg daily 1
• Annual non-invasive imaging of the carotid arteries is reasonable initially to detect changes in disease extent or severity, with less frequent imaging once stability is confirmed 1
• Revascularization is NOT recommended for patients with asymptomatic FMD of a carotid artery, regardless of stenosis severity 1

Management Algorithm for Carotid FMD

For Asymptomatic Patients:

• Initiate antiplatelet therapy with aspirin (81-325 mg daily) 1
• Perform baseline imaging with contrast-enhanced CTA, MRA, or catheter-based angiography 1
• Schedule annual follow-up imaging initially, then less frequently once stability is confirmed 1
• Monitor for development of symptoms such as TIA, stroke, or dissection 2

For Symptomatic Patients (with retinal or hemispheric cerebral ischemic symptoms):

• Continue antiplatelet therapy 1
• Consider carotid angioplasty with or without stenting for symptomatic patients who have retinal or hemispheric cerebral ischemic symptoms related to the FMD 1
• For patients with carotid dissection related to FMD:
  • Consider anticoagulation with heparin followed by warfarin for 3-6 months, then transition to antiplatelet therapy 1
  • Consider carotid angioplasty and stenting if ischemic neurological symptoms don't respond to antithrombotic therapy 1

Clinical Considerations and Caveats

• FMD is a non-atherosclerotic, non-inflammatory vascular disease that most commonly affects middle-aged women 1, 2
• FMD can cause stroke, TIA, carotid dissection, Horner syndrome, cranial nerve palsies, and subarachnoid hemorrhage 1
• Symptoms result from reduced blood flow or thromboembolism, making antiplatelet therapy a logical preventive measure 1, 2
• Common pitfall: Misdiagnosing FMD as atherosclerotic disease - FMD typically has a "beaded" appearance on imaging (medial fibroplasia) or focal, concentric stenosis (intimal fibroplasia) 1
• FMD may be more common than previously thought, potentially affecting up to 4% of adult women 2
• The natural history of FMD is relatively benign in most cases, with disease progression occurring in only a minority of patients 3
• Avoid the common mistake of withholding antiplatelet therapy in asymptomatic patients - guidelines clearly support its use in carotid FMD 1

While the optimal antiplatelet regimen hasn't been definitively established, aspirin is the most commonly recommended agent for thromboembolism prevention in patients with carotid FMD 1, 4.