What is the management and evaluation approach for suspected fibromuscular dysplasia?

Management and Evaluation of Suspected Fibromuscular Dysplasia (FMD)

For patients with suspected fibromuscular dysplasia, comprehensive evaluation with appropriate imaging studies and targeted management based on vascular territory involvement is essential to reduce morbidity and mortality. 1

Diagnostic Approach

Initial Screening and Diagnosis

• Duplex ultrasonography is recommended as an initial screening test for FMD (Class I recommendation) 1, 2
• Computed tomographic angiography (in patients with normal renal function) and magnetic resonance angiography are recommended as screening tests for FMD (Class I recommendation) 1, 2
• When clinical suspicion is high and noninvasive tests are inconclusive, catheter angiography is recommended as the gold standard diagnostic test for FMD 1, 2
• Captopril renal scintigraphy, selective renal vein renin measurements, and plasma renin activity are not recommended as screening tests for FMD (Class III recommendation) 2

Clinical Presentations to Consider FMD

• Young and middle-aged women with hypertension, particularly if difficult to control 2
• Patients with cervical bruits, pulsatile tinnitus ("swishing" sound in ears), or headaches 3
• Patients with transient ischemic attack, stroke, or arterial dissection, especially at young age 3
• Patients with unexplained renal dysfunction or renal artery stenosis 2
• Incidental finding of the classic "string of beads" appearance on imaging performed for other reasons 4

Imaging Findings

• Classic "string of beads" appearance is the most common presentation 4
• Less common presentations include vascular loops, fusiform vascular ectasia, arterial dissection, aneurysm formation, and arterial occlusion 4
• FMD most frequently affects renal, carotid, and vertebral arteries but can theoretically affect any artery 4

Management Approach

General Management Principles

• FMD should be recognized as a systemic disease requiring evaluation of multiple vascular beds, particularly renal, carotid, and vertebral arteries 1
• Annual noninvasive imaging of the carotid arteries is reasonable initially to detect changes in disease extent or severity (Class IIa recommendation) 2
• Administration of antiplatelet medication is beneficial in patients with FMD to prevent thromboembolism (Class IIa recommendation) 2

Management of Renal Artery FMD

• Initial management should focus on appropriate medical therapy to control blood pressure 1
• RAS blockers (ACEIs/ARBs) are the drugs of choice when percutaneous intervention is not feasible, but require careful monitoring of renal function 1
• Percutaneous transluminal renal angioplasty (PTRA) without stenting is the first-line revascularization technique for symptomatic renal FMD (Class IIa recommendation) 1
• Stenting should be considered only for management of dissection or balloon angioplasty failure 1
• Open surgical revascularization should be reserved for complex aneurysms, complex lesions involving arterial bifurcation or branches, or failed endovascular therapy 1

Management of Cerebrovascular FMD

• Carotid angioplasty with or without stenting is reasonable for patients with retinal or hemispheric cerebral ischemic symptoms related to FMD of the ipsilateral carotid artery (Class IIa recommendation) 2
• Revascularization is not recommended for patients with asymptomatic FMD of a carotid artery, regardless of stenosis severity (Class III recommendation) 2

Management of Complications

• Aneurysm formation is a potential complication requiring monitoring and possible intervention 1
• For patients with FMD and aneurysms, treatment with covered stent or open surgical repair is recommended 3, 5
• For arterial dissection associated with FMD, antiplatelet therapy is the initial treatment of choice 5

Special Considerations

Monitoring and Follow-up

• Studies may be repeated less frequently once stability has been confirmed 2
• Regular blood pressure monitoring and renal function assessment in patients with renal artery FMD 1
• Patients with FMD should be referred to specialized centers for dedicated management 1

Treatment Pitfalls to Avoid

• Failure to recognize FMD as a systemic disease affecting multiple vascular beds 1
• Using stents as first-line therapy for renal FMD instead of angioplasty alone 1
• Treating asymptomatic carotid FMD with revascularization 2
• Overlooking less common presentations of FMD beyond the classic "string of beads" appearance 4