Furosemide-131I-hippuran renography after angiotensin-converting enzyme inhibition for the diagnosis of renovascular hypertension.
OBJECTIVE
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.


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).


CONCLUSIONS
Furosemide-131I-hippuran renography with ACE inhibition is highly predictive in identifying patients with RVH.
Erbslöh-Möller
B
B
Division of Nephrology, University of Miami/Jackson Memorial Medical Center, Florida 33101.
Dumas
A
A
Roth
D
D
Sfakianakis
G N
GN
Bourgoignie
J J
JJ
D000328:Adult; D000368:Aged; D000465:Algorithms; D000792:Angiography; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D004285:Dogs; D005260:Female; D005665:Furosemide; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D007668:Kidney / Q000000981:diagnostic imaging* / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D011866:Radioisotope Renography; D012680:Sensitivity and Specificity
D000806:Angiotensin-Converting Enzyme Inhibitors; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D005665:Furosemide