A 38-year-old woman with hypertension refractory to three antihypertensive drugs (including a diuretic) is found to have a right renal artery stenosis >70% on CT angiography. Plasma renin activity is markedly elevated. Which investigation should be performed BEFORE considering renal artery revascularisation?
- A 24-hour ambulatory blood pressure monitoring to confirm hypertension
- B Captopril renography (captopril scintigraphy) or selective renal vein renin sampling to confirm functional significance of the stenosis ✓
- C Urine catecholamines to rule out pheochromocytoma
- D Genetic testing for fibromuscular dysplasia (FMD) mutations
Explanation
Anatomical stenosis on imaging alone does not confirm that the stenosis is the functional cause of hypertension. Captopril-enhanced renal scintigraphy (demonstrating captopril-augmented asymmetry of renal function) or selective renal vein renin sampling (lateralisation ratio ≥1.5 from the affected side) confirms that the stenosis is haemodynamically and functionally significant before invasive revascularisation (angioplasty ± stenting). Fibromuscular dysplasia, the most common cause of RAS in young women, is a clinical/angiographic diagnosis; no specific genetic test exists.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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