What is the next best investigation for an elderly patient with long-standing hypertension (HTN) and renal artery stenosis, who has undergone multiple lines of drug treatment and has a small left kidney?

Next Investigation for Renal Artery Stenosis in Elderly Patient with Uncontrolled Hypertension

For an elderly patient with long-standing uncontrolled hypertension, small left kidney, and confirmed renal artery stenosis on arteriography, balloon angioplasty (option D) is the next appropriate step rather than additional diagnostic imaging.

Diagnostic Pathway for Renal Artery Stenosis

The patient already has several key findings that establish the diagnosis of renal artery stenosis:

1. Long-standing hypertension resistant to multiple drug treatments
2. Small left kidney on ultrasonography (suggesting chronic ischemia)
3. Confirmed renal artery stenosis on renal arteriography

Why Additional Imaging Is Not Needed

• Renal arteriography is considered the gold standard for diagnosing renal artery stenosis 1
• The patient has already undergone definitive diagnostic testing with arteriography, which has confirmed the presence of renal artery stenosis
• Additional imaging with CTA (option A) or MRA (option B) would be redundant since:
  • These are typically used as confirmatory tests after initial screening with duplex ultrasound 1
  • The patient has already progressed beyond this diagnostic step with arteriography

Why Retrograde Pyelography Is Not Appropriate

• Retrograde pyelography (option C) evaluates the collecting system rather than the vascular supply 1
• It would not provide additional information about the renal artery stenosis already confirmed by arteriography
• It is not indicated in the evaluation of renovascular hypertension

Why Balloon Angioplasty Is the Next Step

Balloon angioplasty (with or without stenting) is indicated in this patient because:

1. The patient has refractory hypertension despite multiple drug treatments 1
2. There is evidence of end-organ damage (small left kidney) 1
3. Arteriography has already confirmed the diagnosis of renal artery stenosis

According to the 2024 ESC guidelines, renal artery revascularization should be considered in patients with:

• Atherosclerotic unilateral >70% renal artery stenosis
• Concomitant high-risk features (resistant hypertension)
• Signs of kidney viability 1

Procedural Considerations

When proceeding with balloon angioplasty:

• For atherosclerotic lesions, stenting is often required in addition to angioplasty 1
• For fibromuscular dysplasia, angioplasty alone may be sufficient 1
• The procedure should be performed in experienced centers due to risk of restenosis 1
• Regular follow-up is essential, including:
  • Renal function monitoring
  • Blood pressure assessment
  • Duplex ultrasound at 1 month and then every 12 months 1

Potential Benefits and Risks

Benefits:

• Improved blood pressure control in 52-68% of patients 2
• Potential stabilization of renal function 3
• Reduced cardiovascular risk

Risks:

• Procedure-related complications (approximately 18%) 2
• Restenosis (occurs in 15-30% of patients) 1, 2
• Acute renal function deterioration

The patient's presentation with uncontrolled hypertension despite multiple medications, small kidney, and confirmed renal artery stenosis represents a classic indication for revascularization rather than additional diagnostic testing.