Fibromuscular dysplasia (FMD) represents the most common non-inflammatory and non-atherosclerotic cause of renal artery stenosis (RAS), frequently manifesting as resistant renovascular hypertension (RVH). While anatomical imaging can identify structural abnormalities such as the classic "string-of-beads" pattern, 99mTc-DTPA captopril renal scintigraphy provides essential physiological data by demonstrating a measurable drop in the glomerular filtration rate (GFR) when the compensatory renin-angiotensin-aldosterone system is disrupted. This case report details a 33-year-old male with severe hypertension (190/140 mmHg) and secondary hyperaldosteronism whose diagnosis was supported by baseline and post-captopril scintigraphy, showing a reduction in differential renal function. Subsequent renal angiography confirmed a 50% stenotic lesion. Balloon angioplasty was complicated by distal dissection, necessitating stent placement, and the patient subsequently achieved symptom resolution with discontinuation of antihypertensive therapy. With a reported sensitivity of 83-93% and a specificity of 90%, 99mTc-DTPA scintigraphy serves as a highly effective, non-invasive diagnostic tool that captures the functional significance of renal lesions, potentially avoiding more invasive procedures while guiding early intervention to prevent permanent kidney injury.
Infante et al. (Mon,) studied this question.