What is the workup and management for renovascular hypertension (renovascular HTN)?

Workup and Management of Renovascular Hypertension

The workup for renovascular hypertension should include imaging studies such as renal artery Doppler ultrasound, CT angiography, or MR angiography based on renal function, followed by medical therapy with calcium channel blockers and diuretics as first-line treatment, with revascularization reserved for specific indications including refractory hypertension and progressive renal dysfunction. 1

Clinical Suspicion and Diagnosis

When to Suspect Renovascular Hypertension

• Sudden onset or worsening of hypertension, especially in patients <30 years (fibromuscular dysplasia) or >55 years (atherosclerosis)
• Resistant hypertension (requiring ≥3 antihypertensive medications)
• Recurrent flash pulmonary edema (Pickering syndrome)
• Unexplained renal dysfunction
• Asymmetric kidney sizes
• Abdominal bruit
• Very elevated renin levels (though not highly sensitive) 1

Diagnostic Imaging Based on Renal Function

Normal Renal Function:

1. MR angiography without and with IV contrast (Rating: 8/9) 1
2. CT angiography with IV contrast (Rating: 8/9) 1
3. Renal artery Doppler ultrasound (Rating: 7/9) 1

Impaired Renal Function (eGFR <30 mL/min/1.73 m²):

1. Renal artery Doppler ultrasound (Rating: 9/9) - first choice 1
2. MR angiography without IV contrast (Rating: 7/9) 1
3. CT angiography with IV contrast (Rating: 5/9) - use with caution 1

Doppler Ultrasound Criteria for Renal Artery Stenosis

• Peak systolic velocity (PSV) >180-200 cm/s
• Renal-to-aortic ratio (RAR) >3.5
• Parvus-tardus waveform in intrarenal arteries (acceleration time >70 ms)
• Loss of early systolic peak 1

Management Approach

Medical Management

1. First-line medications:

   • Calcium channel blockers (dihydropyridines) - safe and effective 1, 2
   • Diuretics (thiazides or loop diuretics based on renal function) 2

2. Second-line medications:

   • Beta-blockers 2

3. Medications to use with caution:

   • ACE inhibitors and ARBs - can cause acute renal failure in bilateral stenosis or stenosis to a solitary kidney 1, 2, 3
   • Should be monitored closely with renal function tests if used 3

Revascularization Indications

Revascularization should be considered for:

1. Refractory hypertension despite optimal medical therapy
2. Progressive deterioration of renal function
3. Recurrent flash pulmonary edema
4. Significant hemodynamic stenosis with clinical correlation 1, 2

Revascularization Methods

1. For fibromuscular dysplasia: Percutaneous transluminal renal angioplasty (PTRA) without stenting (Class IIa recommendation) 1
2. For atherosclerotic stenosis: PTRA with stenting may be considered for hemodynamically significant stenosis (Class IIb recommendation) 1

Follow-up and Monitoring

• Monitor renal function 1-2 weeks after medication changes 2
• Check blood pressure control regularly
• For patients on ACE inhibitors or ARBs, monitor for acute deterioration in renal function
• Consider follow-up imaging in patients with high-risk features or inadequate response to therapy

Special Considerations

Fibromuscular Dysplasia

• More common in children and younger women
• Consider CT or MRI angiography from head to pelvis as fibromuscular dysplasia is a systemic disease affecting multiple vascular beds 1
• PTRA without stenting is the treatment of choice 1

Atherosclerotic Renal Artery Stenosis

• More common in older patients with cardiovascular risk factors
• Patients are at very high risk for cardiovascular and renal events
• Medical therapy should include intensive risk factor management (statins, antiplatelet therapy) 2
• Consider PTRA with stenting in experienced centers for appropriate candidates 1

Pitfalls to Avoid

1. Failing to recognize "bystander" renal artery stenosis that may be present without causing renovascular hypertension 1
2. Using ACE inhibitors or ARBs without monitoring in patients with bilateral renal artery stenosis or stenosis to a solitary kidney 3
3. Overreliance on single diagnostic tests - correlation of clinical, laboratory, and imaging findings is essential
4. Performing revascularization in patients unlikely to benefit (e.g., long-standing hypertension >10 years with irreversible kidney damage) 2