How is fibromuscular dysplasia (FMD) treated?

Updated: Jul 27, 2018
  • Author: James A Wilson, MD, MSc, FRCPC; Chief Editor: Helmi L Lutsep, MD  more...
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Answer

Partly because of the unknown etiology of FMD, no curative therapy exists. Fortunately, FMD is often benign when asymptomatic, and medical treatment is not indicated. Patients presenting with hypertension should be evaluated by a nephrologist and possibly considered for vascular intervention.

When FMD manifests as a transient ischemic attack or as an ischemic stroke, then initial management depends on many factors. If the patient presents in the emergency department with symptoms of stroke within 4.5 hours of onset, then they may be considered for intravenous (IV) tissue plasminogen activator (tPA) treatment (see Acute Stroke Management). Intra-arterial mechanical embolectomy may be considered to extend the acute treatment window to 24 hours. If TPA treatment is employed, then anticoagulants and antiplatelet agents are generally avoided for at least the ensuing 24 hours.

The diagnosis of FMD should be considered in any young individual presenting with a stroke or subarachnoid hemorrhage. Fortunately, cerebral angiography is the investigation of choice to detect not only FMD but also arterial dissection, vasculitis, and aneurysms, which are other major etiologies of stroke in this population. Thus, cerebral angiography should be performed if another cause for the stroke is not clear. The treatment options are influenced by the findings on angiography.

If only FMD is identified on angiography, medical treatment usually incorporates antiplatelet agents, similar to the treatment of atherosclerotic disease. Often, daily aspirin is considered first-line therapy, and another antiplatelet agent is substituted or added if another ischemic event occurs (such as clopidogrel or combination acetylsalicylic acid and extended-release dipyridamole).

If arterial dissection with FMD is identified with cerebral angiography, then initial treatment primarily addresses the dissection (see Dissection Syndromes). Although evidence from randomized trials is lacking, anticoagulation is often used after cerebral hemorrhage has been ruled out. Anticoagulation is with heparin initially, then Coumadin is administered on an outpatient basis for 3-6 months. Some neurologists advocate reassessment of the arteries for dissection before discontinuation of anticoagulation and initiation of an antiplatelet agent for life. Often, if the dissection could be observed with MRA or CTA, these modalities are used in follow-up because of its less invasive nature.

If the presentation is that of subarachnoid hemorrhage, then acute treatment is primarily focused on preventing rebleeding, and preventing arterial vasospasm and further ischemic cerebral injury. Aneurysms may be closed by endovascular coiling or surgical clipping. Nimodipine, a calcium channel blocker, is generally used to reduce vasospasm-mediated brain injury. See Cerebral Aneurysms for a more in-depth discussion of aneurysm management.

After the aneurysms have been dealt with, either surgically or through an endovascular approach, then unless further history is consistent with thromboembolic phenomena, management may be conservative. Antiplatelets are unnecessary if the FMD lesions themselves are asymptomatic and not causing emboli.

Some authors have suggested that FMD could be caused by arterial wall injury fragility followed by hemodynamic stress. Hence, treating FMD by reducing hemodynamic stress (ie, aggressive blood pressure control) may be reasonable. [31]


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