Aim: Value the utility of studies with 99mTc-DMSA with captopril (scintigraphy imaging and unilateral renal function) in identifying renovascular disease or renal disease in hypertension patients with high probability of renovascular hypertension.
Methods: We studied 27 hypertension patients (12 males, 15 females) mean age 49 years, SD: 9.46, with high probability of renovascular disease. General analysis and radiology was made to all of them including renal arteriography as gold standard. Two renal scintigraphies with 99mTc-DMSA were made to all of them, baseline study and one hour after administration of 50 mg of captopril, a week between both studies. Renal scintigraphy (anterior and posterior images) was obtained 4 hours after the administration of 111 MBq (3 mCi) of 99mTc-DMSA and results were evaluated quantitatively and qualitatively calculating unilateral renal function. We considered positive for renovascular hypertension studies with decrease of more than five percentual points in unilateral renal function or a new defect absent in baseline study. Scintigraphic results were compared with arteriography to determine sensitivity, specificity and predictive values.
Results: Arteriography demonstrated significant renal artery stenosis in 18.5% of patients. Renal scintigraphy with captopril using 99mTc-DMSA demonstrated sensitivity of 60%, specificity of 91%, positive predictive value of 60% and negative predictive value of 91%. We identified 3 patients with segmental defects of uptake consistent with chronic pyelonephritis scarring.
Conclusions: Studies with 99mTc-DMSA using captopril present high specificity and are useful in patients with high probability for renovascular hypertension, identifying high number of patients with significant renal artery stenosis. The utility of DMSA in identify renal abnormalities, as specially pyelonephritis scarring, add value to renal studies with captopril using others tracers. DMSA could identify renal etiologies of renovascular hypertension different to renal artery stenosis.