Management of Bilateral Renovascular Resistance
Medical therapy is the cornerstone of management for bilateral renovascular hypertension, with calcium channel blockers and alpha-blockers as preferred agents, while avoiding ACE inhibitors and ARBs due to their risk of acute kidney injury in bilateral disease. 1
Diagnosis and Assessment
Bilateral arm BP measurement is recommended for all patients with suspected renovascular disease 2
Diagnostic evaluation should include:
- Laboratory tests to examine renal function
- Office and out-of-office BP recordings
- Duplex ultrasonography (DUS) of renal arteries 2
- A renal-aortic peak flow velocity ratio >3.5 has high sensitivity and specificity for ≥60% stenosis
- Side-to-side difference of intrarenal resistance index ≥0.5 indicates hemodynamically relevant stenosis
Consider advanced imaging if DUS suggests stenosis or is inconclusive:
- MRA (sensitivity 88%, specificity 100%)
- CTA (sensitivity 64-100%, specificity 92-98%) 2
Medical Management
First-line Antihypertensive Therapy
Medications to Avoid or Use with Caution
- ACE inhibitors and ARBs are contraindicated in bilateral renal artery stenosis due to risk of acute kidney injury 1, 4
- These medications can cause acute renal failure in patients with tight bilateral stenoses or a stenosed solitary functioning kidney 2
Cardiovascular Risk Reduction
- High-intensity statin therapy
- Low-dose aspirin
- Smoking cessation
- Diabetes management 1
Revascularization Considerations
Revascularization should be considered in patients with:
- Recurrent heart failure, unstable angina, or flash pulmonary edema despite maximally tolerated medical therapy 2
- Resistant hypertension 2
- Hypertension with unexplained unilaterally small kidney 2
- 70% stenosis with high-risk clinical features and signs of kidney viability 1
Revascularization Options
- For fibromuscular dysplasia: Percutaneous transluminal renal angioplasty (PTRA) without stenting is the treatment of choice 2
- For atherosclerotic stenosis: PTRA with stenting performed in experienced centers 2, 5
Assessment of Kidney Viability for Revascularization
| Parameter | Nonviable | Likely to be viable |
|---|---|---|
| Renal length | <7 cm | >8 cm |
| Cortical thickness | Loss of corticomedullary differentiation | Cortex distinct (>0.5 cm) |
| Albumin-creatinine ratio | >300 mg/g | <200 mg/g |
| Renal resistive index | >0.8 | <0.8 |
Post-Revascularization Management
- Continue antihypertensive medications as needed
- Maintain statin therapy
- Dual antiplatelet therapy for at least 1 month after stent implantation 1
- ACE inhibitors may be safely introduced after successful bilateral renal artery stenting 4
Follow-up Protocol
- Initial follow-up at 1 month
- Subsequent follow-up every 12 months or when new symptoms arise
- Monitoring should include:
- Blood pressure control
- Renal function
- Duplex ultrasound to assess for restenosis 1
Pitfalls to Avoid
- Unnecessary revascularization in patients who can be managed medically
- Inappropriate use of ACE inhibitors/ARBs in bilateral disease
- Failure to recognize bilateral disease
- Not confirming hemodynamic significance of moderate stenosis before intervention 1
Remember that patients with bilateral renovascular disease are at very high risk of cardiovascular disease and renal events, requiring careful monitoring and aggressive risk factor management alongside specific treatment for the renovascular disease 2.