Treatment of Renal Artery Stenosis from Fibromuscular Dysplasia
For renal FMD, perform balloon angioplasty alone as first-line treatment, reserving stent placement only for bailout situations such as dissection or inadequate balloon result. 1
Primary Treatment Strategy
Balloon angioplasty without stenting is the definitive treatment of choice for symptomatic renal artery stenosis caused by fibromuscular dysplasia. 1 This represents a Class I recommendation with Level B evidence from both ACC/AHA and ESC guidelines. 1
Why Balloon-Only for FMD
The pathophysiology of FMD differs fundamentally from atherosclerotic disease—FMD lesions are non-inflammatory, non-atherosclerotic arterial abnormalities that respond well to mechanical dilation alone. 1 Unlike atherosclerotic ostial lesions that are prone to elastic recoil and require stenting, FMD lesions typically maintain patency after balloon angioplasty. 1
When to Use Bailout Stenting
Stent placement should be considered only in two specific scenarios: 1, 2
- Arterial dissection occurring during balloon angioplasty
- Suboptimal angioplasty result with persistent hemodynamically significant stenosis despite adequate balloon inflation
This bailout stenting strategy is explicitly recommended by both ACC/AHA and ESC guidelines. 1
Technical Considerations
Balloon Technique
FMD lesions often demonstrate considerable resistance to dilation, frequently requiring maximum balloon inflation pressures (up to 10 atmospheres). 3 Some focal FMD stenoses may show persistent waisting of the balloon even at maximum inflation. 3
Procedural Success Rates
Meta-analysis data shows that balloon angioplasty for FMD achieves: 4
- Hypertension cure in 46% of patients (using study-specific definitions)
- Hypertension cure in 36% using current strict definitions (BP <140/90 mmHg off medications)
- Major complication rate of only 6.3%
- Mortality rate of 0.9%
These outcomes are substantially better than the complication profile of surgical revascularization (15.4% major complications, 1.2% mortality). 1, 4
Critical Distinction from Atherosclerotic Disease
This recommendation applies specifically to FMD—do not confuse with atherosclerotic renal artery stenosis, which requires a completely different approach. 1
For atherosclerotic ostial lesions, primary stenting is indicated because: 1
- Balloon angioplasty alone has only 63% procedural success versus 90% with stenting
- Restenosis occurs in 48% with balloon alone versus 14% with stenting
- Aorto-ostial atherosclerotic plaques are prone to elastic recoil
Common Pitfalls to Avoid
Never use primary stenting for FMD lesions—this adds unnecessary hardware, cost, and potential long-term complications without improving outcomes. 1, 2 The single case report suggesting primary stenting 5 contradicts all major guideline recommendations and should not influence practice.
Do not assume all "beaded" renal arteries require intervention—only treat symptomatic FMD with signs of organ ischemia (uncontrolled hypertension, declining renal function). 1, 2
Ensure procedures are performed in experienced centers due to technical complexity and the need for appropriate bailout strategies. 1, 2
Surgical Revascularization
Reserve open surgical reconstruction only for: 1, 2
- Complex aneurysms associated with FMD
- Lesions involving arterial bifurcations or multiple segmental vessels
- Failed endovascular therapy
- Ex vivo reconstruction for complex disease
In patients under 21 years, prefer internal iliac artery grafts over vein grafts to avoid late aneurysmal degeneration. 1
Adjunctive Medical Therapy
All patients with renal FMD require: 6, 2
- Antiplatelet therapy (aspirin or clopidogrel)
- Antihypertensive medications (calcium channel blockers, thiazide diuretics)
- ACE inhibitors/ARBs can be used in unilateral stenosis with careful monitoring
- Statin therapy for cardiovascular protection