Prospective study of simultaneous orthoiodohippurate and diethylenetriaminepentaacetic acid captopril renography. The Einstein/Cornell Collaborative Hypertension Group.
Captopril renography (CR) has been established in the past 10 yr as a useful diagnostic test for renovascular hypertension. However, direct comparison of tubular and glomerular tracers, quantitative criteria, comparison of quantitative and qualitative results and the reliability of the results in renal failure have not been described in a systematic, prospective fashion.


METHODS
Same-day baseline and CR using 99mTc-labeled diethylenetriaminepentaacetic acid (DTPA) and [131I]orthoiodohippurate (OIH) were simultaneously performed in two groups of hypertensive subjects, one with demographically defined essential hypertension (n = 43) and the other (n = 60) with a high prevalence of renovascular disease, defined with angiograms. Quantitative criteria for abnormal CR were derived from results among the subjects with essential hypertension. Qualitative analysis was performed using widely established criteria.


RESULTS
There were no statistically significant differences between quantitative and qualitative accuracy, between OIH and DTPA or among quantitative parameters. The best accuracies for quantitative CR were 56% with DTPA (n = 57) and 60% with OIH (n = 60), in both cases using the relative renal uptake parameter. Qualitative CR (n = 60) had accuracies of 43% (DTPA) and 50% (OIH), both hindered by 29 (DTPA) and 25 (OIH) abnormal but nondiagnostic studies. Two false-positive studies were detected. Twenty-seven of 29 nondiagnostic studies were associated with a glomerular filtration rate of <50 ml/min (n = 17), one small kidney (n = 17) and/or bilateral renal artery stenosis (n = 16). Supplemental measurement of in vitro stimulated plasma renin activity insignificantly (p > 0.10) and improved accuracies to 63% (DTPA) and 70% (OIH), without introducing additional false-positive tests.


CONCLUSIONS
Orthoiodohippurate and DTPA have comparable accuracy in prospective simultaneous evaluation of CR. False-positive studies are fewer than 5%. The accuracies of quantitative and qualitative criteria do not differ significantly but may be improved by supplemental use of the in vitro stimulated plasma renin activity. In individuals with renal insufficiency, small kidneys and/or bilateral renal artery disease, up to 48% of CR studies are abnormal but nondiagnostic.
Blaufox
M D
MD
Department of Nuclear Medicine, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, New York, USA.
Fine
E J
EJ
Heller
S
S
Hurley
J
J
Jagust
M
M
Li
Y
Y
Mann
S J
SJ
Pickering
T G
TG
Zanzonico
P
P
Zhang
C G
CG
D000959:Antihypertensive Agents; D002216:Captopril; D005260:Female; D006801:Humans; D006978:Hypertension, Renovascular / Q000000981:diagnostic imaging* / Q000453:epidemiology; D007457:Iodine Radioisotopes; D007465:Iodohippuric Acid; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D011866:Radioisotope Renography / Q000379:methods*; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D016284:Technetium Tc 99m Pentetate
D000959:Antihypertensive Agents; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D007465:Iodohippuric Acid; D002216:Captopril; D016284:Technetium Tc 99m Pentetate