[Usefulness of angiotensin converting enzyme inhibitors in the diagnosis of renovascular hypertension. II. Comparison of the effect of angiotensin converting enzyme inhibition on reno-scintigraphic curves with DTPA in patients with essential and renovascular hypertension].

The aim of the study was to evaluate the effect of angiotensin converting enzyme inhibition on renoscintigraphic curves using DTPA as a tracer in patients with essential (EH) and renovascular (RVH) hypertension. Twenty four patients with EH and sixteen with RVH were studied. Protocol consisted of control renoscintigraphy with DTPA and the second one after captopril administration in dose 25 mg performed after three days. Relative DTPA uptake of the single kidney was calculated from the curve time-activity between 120 and 180 second after tracer administration. Results were expressed as a quotient of the relative DTPA uptake of ischemic or "weaker" kidney to the DTPA uptake of both kidneys (coefficient A) or contralateral one (coefficient B). Coefficient A in basic renoscintigraphy did not differ in patients with EH and RVH and was 45.81 +/- 3.02% and 44.66 +/- 6.17% respectively. In renoscintigraphy with captopril coefficient A decreased significantly (P < 0.001) in patients with RVH and was significantly lower (p < 0.05) than in patients with EH. Change (delta) of coefficient B after captopril was significantly higher in patients with RVH (p < 0.001). Significant correlations were found between delta coefficient A and delta diastolic (DAP) and mean (MAP) arterial pressure as well as delta plasma renin activity (PRA) after captopril in patients with RVH. Similarly, relationships were shown between percentage change (% delta) of coefficient B and % delta of systolic (SAP), DAP and MAP as well as delta PRA after captopril in patients with RVH.