Is renal artery stenting effective in an older adult patient with an atrophic kidney and a history of hypertension, atherosclerosis, or other vascular diseases?

Renal Artery Stenting in Atrophic Kidneys: Not Effective

Renal artery stenting should not be performed in patients with atrophic kidneys, as revascularization does not improve kidney function in this setting and the kidney has reached the "point of no return" with irreparable parenchymal damage. 1

Defining an Atrophic Kidney

An atrophic kidney is defined by specific anatomic criteria that indicate nonviable parenchyma 1:

• Renal length <7 cm (pole-to-pole measurement)
• Loss of corticomedullary differentiation or absent cortex on imaging
• Thin cortical thickness (cortex not distinct or <0.5 cm)

Additional markers of poor outcome that indicate severely damaged parenchyma 1:

• Proteinuria (albumin-creatinine ratio >300 mg/g or protein-creatinine ratio >500 mg/g)
• High Doppler ultrasound resistive index (>0.8)

Why Stenting Fails in Atrophic Kidneys

The pathophysiology explains why revascularization cannot salvage atrophic kidneys 1:

• Chronic ischemia leads to vascular rarefaction, RAAS-induced inflammation, oxidative stress, and eventual loss of functioning nephrons with fibrotic replacement
• At some point, the systemic inflammatory response takes precedence over reduced blood flow as the driver of dysfunction
• The kidney has reached irreparable damage beyond which restoring blood flow cannot recover function

When Stenting May Be Appropriate (But NOT in Atrophic Kidneys)

The KDIGO consensus identifies specific high-risk clinical scenarios where stenting may benefit patients with viable kidneys (>8 cm length, distinct cortex >0.5 cm, resistive index <0.8) 1:

Definite indications for revascularization:

• Flash pulmonary edema or acute decompensated heart failure
• Progressive CKD in high-grade bilateral stenosis or stenosis affecting a solitary kidney (with viable parenchyma)
• Acute kidney injury from acute renal artery occlusion or high-grade stenosis
• Intolerance of ACE inhibitors/ARBs when such therapy is necessary

Possible indications requiring further evaluation:

• Chronic heart failure
• Coexistence of progressive CKD and uncontrolled hypertension
• High-grade stenosis in a solitary kidney with viable parenchyma to prevent atrophy

Clinical Pitfalls to Avoid

Do not stent based solely on anatomic stenosis severity 1, 2:

• Incidentally discovered renal artery stenosis without clinical manifestations is considered Rarely Appropriate for intervention
• The ACC/AHA guidelines explicitly state that improving perfusion of an atrophic kidney (<7 cm) is unlikely to improve renal function

Do not assume all stenosis requires intervention 1:

• Many patients in the ASTRAL and CORAL trials had lower-risk phenotypes and physiologically insignificant stenosis
• These landmark trials showed no benefit of stenting over medical therapy alone for most patients 3, 4

Recognize the procedural risks 3:

• Serious complications include procedure-related death (3%), cholesterol embolism requiring dialysis, and infected hematomas
• These risks are not justified when the kidney is already atrophic and non-salvageable

Optimal Management for Patients with Atrophic Kidneys

Focus on comprehensive medical therapy rather than revascularization 1:

• High-dose statin therapy (e.g., atorvastatin 80 mg daily)
• Antiplatelet therapy (aspirin)
• Blood pressure control to target systolic BP <120 mmHg when tolerated
• RAAS blockers should be introduced in all patients with atherosclerotic renovascular disease, though use caution in bilateral disease or solitary kidney 1

The goal shifts from kidney salvage to prevention of cardiovascular events and mortality, as annual mortality from vascular events far exceeds the risk of kidney failure requiring dialysis in these patients 1.