Renal Artery Stenosis

Renal Artery Stenosis (RAS) is the narrowing of one or both renal arteries, which supply blood to the kidneys. This can lead to hypertension (high blood pressure) and progressive kidney dysfunction.

🩺 Causes of RAS

1. Atherosclerosis (most common, ~90%)

• Occurs in older adults
• Often associated with other cardiovascular disease
• Usually affects the proximal part of the renal artery

2. Fibromuscular Dysplasia (FMD)

• Seen in younger women
• Non-atherosclerotic, non-inflammatory
• Typically affects the mid-to-distal artery
• “String of beads” appearance on imaging

🚨 Why It Matters

• Can cause secondary hypertension, especially in:
• Young patients (<30) or those with sudden-onset high BP
• Resistant hypertension (not responding to 3+ meds)
• Can lead to ischemic nephropathy → progressive renal failure
• Flash pulmonary edema due to volume overload (in bilateral RAS)
• Unstable Angina

🔍 Signs & Clues to Suspect RAS

• Sudden-onset or worsening hypertension
• Abdominal bruit (whooshing sound over renal arteries)
• Worsening renal function after starting ACE inhibitors/ARBs
• Asymmetric kidney sizes on imaging
• Recurrent flash pulmonary edema

🧪 Diagnosis

1. Renal Doppler Ultrasound – good screening tool
2. CT Angiography (CTA) or MR Angiography (MRA)
• High-resolution, detailed view of vessels
3. Digital Subtraction Angiography (DSA)
• Gold standard, often done before intervention

🛠️ Treatment

🩹 Medical Management (first-line for most)

• Antihypertensives: especially ACE inhibitors/ARBs (caution in bilateral RAS!)
• Statins and antiplatelets if atherosclerotic
• Lifestyle changes: smoking cessation, diet, exercise
• Close monitoring of kidney function

🛠️ Revascularization (angioplasty ± stent)

Consider in:

• Refractory hypertension
• Progressive kidney dysfunction
• Recurrent flash pulmonary edema
• FMD with significant stenosis (especially in younger patients)

🧠 Summary Chart