What is the best course of treatment for a young to middle-aged woman with suspected fibromuscular dysplasia, potentially presenting with hypertension and impaired renal function?

Management of Fibromuscular Dysplasia in Young to Middle-Aged Women with Hypertension and Renal Impairment

Immediate Medical Therapy (Required for All Patients)

All patients with fibromuscular dysplasia must receive antiplatelet therapy and blood pressure control as the foundation of treatment, regardless of whether revascularization is performed. 1

Antiplatelet Therapy

• Start aspirin or clopidogrel immediately to prevent thromboembolic complications in all patients with FMD 1
• Continue antiplatelet therapy indefinitely, even in asymptomatic patients 2

Blood Pressure Management

• ACE inhibitors or ARBs are the first-line antihypertensive agents when percutaneous intervention is not immediately feasible 2, 1, 3
• Critical caveat: Monitor renal function closely when using ACE inhibitors/ARBs, particularly in bilateral renal artery stenosis or solitary functioning kidney, as acute renal failure can occur 2, 4
• The FDA label warns that in hypertensive patients with bilateral renal artery stenosis, increases in blood urea nitrogen and serum creatinine may occur with ACE inhibitors 4
• Alternative agents if ACE inhibitors/ARBs are contraindicated: calcium channel blockers (dihydropyridine or non-dihydropyridine) or alpha-receptor antagonists 1

Indications for Revascularization

Percutaneous transluminal renal angioplasty (PTRA) without stenting should be considered for patients with hypertension and hemodynamically significant renal artery stenosis due to FMD (Class IIa recommendation). 2, 1

Specific Clinical Scenarios Warranting Intervention:

• Symptomatic FMD with signs of organ ischemia 2
• Refractory hypertension despite medical management 1
• Worsening renal function 1
• Recent onset hypertension in young patients 1
• Flash pulmonary edema or congestive heart failure with preserved left ventricular function 2

Revascularization Technique

First-Line: Balloon Angioplasty Alone

• PTRA without stenting is the treatment of choice for renal artery FMD 2, 1, 5
• Balloon angioplasty alone yields cure rates of approximately 46% and improvement in blood pressure control in the majority of patients 6
• Never use stents as first-line therapy—stenting should be reserved only for dissection or balloon angioplasty failure 2, 1
• Perform procedures in experienced centers due to technical complexity 1
• Major complication rates are lower with endovascular therapy compared to surgery (6.3% vs 15.4%) 2

Second-Line: Surgical Revascularization

• Reserve open surgery for complex aneurysms, complex lesions involving arterial bifurcations or branches, or failed endovascular therapy 2, 1, 3
• Surgery yields higher cure rates (58%) but with greater periprocedural complications (17% vs 12% for angioplasty) 6

Systemic Disease Evaluation (Critical—FMD is Not Isolated)

FMD is a systemic arterial disease requiring comprehensive vascular evaluation at diagnosis. 1

Initial Screening

• Perform CT or MRI angiography from head to pelvis at diagnosis to identify involvement in multiple vascular beds, particularly carotid, vertebral, renal, and iliac arteries 1, 3
• The iliac arteries are commonly affected and require evaluation beyond the initially symptomatic site 3
• Screen for aneurysms as they represent a potential complication requiring surveillance or intervention 1

Ongoing Surveillance

• Annual non-invasive imaging of carotid arteries initially to detect disease progression or new lesions (Class IIa recommendation) 1, 3
• Reduce imaging frequency once stability has been confirmed over time 1, 3

Cerebrovascular FMD Management

• Do not revascularize asymptomatic carotid FMD, regardless of stenosis severity (Class III recommendation) 1
• For symptomatic patients with stroke or TIA attributable to FMD, antiplatelet therapy is the primary treatment 1
• Carotid angioplasty with or without stenting may be considered for recurrent ischemic events despite optimal medical management 2, 1

Diagnostic Workup

First-Line Tests

• Duplex ultrasonography as initial screening (Class I recommendation) 1, 3
• CT angiography or MR angiography for comprehensive screening (Class I recommendation) 1, 3
• Renal artery Doppler ultrasound with bilateral assessment of renal arterial resistive index 3

Gold Standard

• Catheter angiography (digital subtraction angiography) is the gold standard when clinical suspicion is high and noninvasive tests are inconclusive 1, 3, 5
• The classic "string of beads" appearance on angiography is pathognomonic of medial FMD, which accounts for 70-95% of cases 7

Tests to Avoid

• Do not use captopril renal scintigraphy, selective renal vein renin measurements, or plasma renin activity for screening (Class III recommendation) 1, 3

Critical Pitfalls to Avoid

• Never assume isolated disease—always evaluate multiple vascular beds as FMD is systemic 1
• Never use stents as first-line therapy for renal FMD—balloon angioplasty alone is superior 2, 1
• Never revascularize asymptomatic carotid lesions—medical management is appropriate 1
• Monitor renal function closely when using ACE inhibitors/ARBs in bilateral disease to prevent acute kidney injury 2, 1, 4
• Control blood pressure aggressively to prevent arterial dissection, which can occur in multiple vascular territories 1

Long-Term Management

• Regular blood pressure monitoring and renal function assessment in all patients with renal artery FMD 1
• Refer to specialized centers for dedicated multidisciplinary FMD management 1
• Age is a negative predictor of cure—younger patients have better outcomes with revascularization 6