Interest of renal scintigraphy with captopril in the diagnosis of renovascular arterial hypertension

Introduction: Renal scintigraphy with captopril test of the kidney is a simple, non-invasive functional imaging technique that can be used to demonstrate the role of stenosis in the development of renovascular hypertension (RVH). It also makes it possible to distinguish renal artery stenosis responsible for RVH from stenosis associated with primary arterial hypertension. Objective: To illustrate the benefits of renal scintigraphy with captopril test in the diagnosis of RVH. Material and method: This was a prospective and descriptive study over a period of 12 months, from 1 March 2016 to 4 March 2017, carried out in the nuclear medicine department of the Institut des Radio Isotopes (IRI) in Niamey. The parameters studied were age, frequency, creatinemia, tracer used, relative perfusion, relative renal function and maximum uptake time. Results: We collected 6 cases presenting with either hypertension refractory to well-administered two- or three- therapy, or severe hypertension at the complication stage, or hypertension associated with hypokalaemia or unexplained renal failure or reversible renal failure induced by a conversion enzyme inhibitor. The mean age was 35 years. The age of diagnosis of hypertension ranged from 20 to 28 years. Four patients underwent echodoppler of the renal arteries: unilateral stenosis in patients A, C and F, and bilateral stenosis in patient D. The captopril test was positive in 3 cases, patients A, B and C. Conclusion: Dynamic renal scintigraphy with captopril testing is a non-invasive, low-radiation diagnostic method for the investigation of renovascular hypertension. It has a triple benefit, including the detection of the most severe arterial stenoses, the prediction of the curability of the stenosis by a revascularisation procedure and, finally, post-treatment follow-up.