Furosemide-131I-hippuran renography after angiotensin-converting enzyme inhibition for the diagnosis of renovascular hypertension.
 PURPOSE: We have previously demonstrated the greater sensitivity of 131I-hippuran renography than 99mTC-DTPA scintigraphy to diagnose renovascular hypertension (RVH).
 This study assesses the predictive diagnostic value of furosemide-131I-hippuran renography after angiotensin-converting enzyme (ACE) inhibition in patients with and without RVH.
 PATIENTS AND METHODS: All patients were investigated at the University of Miami/Jackson Memorial Medical Center.
 Twenty-eight patients had RVH and 22 did not.
 Twenty-eight patients had normal or minimally decreased renal function (serum creatinine level 1.5 mg/dL or less) and 22 had renal insufficiency (serum creatinine level 1.8 mg/dL or more).
 Renography was performed 60 minutes after oral administration of 50 mg captopril or 10 minutes after intravenous injection of 40 micrograms/kg enalaprilat.
 Forty milligrams of furosemide were administered intravenously 2 minutes after injection of 131I-hippuran.
 The residual cortical activity (RCA) of 131I-hippuran was measured at 20 minutes.
 RESULTS: RVH was unlikely when RCA after ACE inhibition was less than 30% of peak cortical activity.
 Conversely, RVH was present when 131I-hippuran cortical activity steadily increased throughout the test to reach 100% at 20 minutes.
 In azotemic patients with RCA between 31% and 100%, RVH was differentiated from intrinsic renal disease by obtaining a baseline renogram without ACE inhibition and comparing RCA in that study and RCA after ACE inhibition.
 If RCA increased (indicating worsening renal function) after ACE inhibition, RVH was likely; whereas, intrinsic renal disease was more likely if RCA remained unchanged or decreased (indicating improved renal function) with ACE inhibition.
 The test had a specificity of 95% and a sensitivity of 96% in this population.
 There was a direct correlation between the results of angioplasty or surgery on high blood pressure and the changes in RCA before and after intervention (n = 20).
 CONCLUSION: Furosemide-131I-hippuran renography with ACE inhibition is highly predictive in identifying patients with RVH.
