What is the most common cause of renovascular hypertension?

The Most Common Cause of Renovascular Hypertension

Atherosclerosis is the most common cause of renovascular hypertension, accounting for approximately 90% of all renovascular stenotic lesions. 1

Etiology of Renovascular Hypertension

• Atherosclerotic disease (90% of cases) typically affects the aorto-ostial segment and proximal 1 cm of the main renal artery 1, 2
• Fibromuscular dysplasia (FMD) is the second most common cause (10% of cases), typically affecting the middle and distal two-thirds of the renal artery 1, 2
• Less common causes include:
  • Renal artery aneurysms 1, 2
  • Takayasu's arteritis 1
  • Atheroemboli and thromboemboli 1
  • Spontaneous renal artery dissection 1, 3
  • Arteriovenous malformations or fistulas 1, 3
  • Trauma (e.g., lithotripsy, direct injury, surgery) 1
  • Prior abdominal radiation therapy 1
  • Retroperitoneal fibrosis causing external compression 1

Demographic and Clinical Patterns

• Atherosclerotic renovascular disease:

  • More common in older individuals 1, 4
  • Often associated with systemic atherosclerosis involving the aorta, coronary, cerebral, and peripheral arteries 1
  • Typically affects the origin and proximal portion of the renal arteries 1

• Fibromuscular dysplasia:

  • Most commonly affects young to middle-aged women (25-50 years old) 1
  • Can occur in both genders at any age 1
  • Often involves both renal arteries 1
  • Has a characteristic angiographic "string of beads" appearance 1

Clinical Significance and Diagnosis

• Renovascular hypertension accounts for 0.5-5% of all hypertension cases in the general population, but its prevalence increases to approximately 25% in elderly patients with end-stage renal disease 2
• Screening tests for diagnosis include:
  • Duplex ultrasonography (recommended first-line screening test) 1, 2
  • Computed tomographic angiography (in individuals with normal renal function) 1
  • Magnetic resonance angiography 2

Management Considerations

• Medical therapy is the preferred initial approach for renovascular hypertension 5
• Revascularization should be considered when medical therapy is ineffective or causes severe impairment of renal function 6
• Caution should be used with ACE inhibitors or ARBs in patients with bilateral renal artery stenosis due to risk of acute renal function deterioration 5
• Angioplasty alone is the preferred treatment for fibromuscular dysplasia, while angioplasty with stenting is typically performed for atherosclerotic disease 5

Clinical Pitfalls

• Atherosclerotic renal artery stenosis can develop in patients with a history of fibromuscular dysplasia as they age 7
• Bilateral renal artery disease presents a diagnostic challenge as it is difficult to quantify the effect on blood pressure of one side versus the other 2
• 10-20% of patients may develop an unacceptable rise in serum creatinine with ACE inhibitors or ARBs, particularly with volume depletion 5

Therefore, the answer to the question "What is the most common cause of renovascular hypertension?" is D. Renal artery atheroma.