Utility of captopril renal scans for detecting renal artery stenosis.
BACKGROUND
Captopril renal scanning (CRS) is commonly recommended as a noninvasive method for detecting renal artery stenosis (RAS), based on performance characteristics determined in research settings. Scant data are available, however, regarding the utility of CRS in clinical practice.


METHODS
We evaluated the performance characteristics (sensitivity, specificity, and predictive values) of CRS in a consecutive series of 90 patients who underwent both CRS and renal arteriography within a 6-month period (January 1, 1991, through December 31, 1995) at a university hospital.


RESULTS
Among 86 eligible patients (and 169 kidneys), the prevalence of RAS was 43%. The sensitivity of CRS was 74% (95% confidence interval [CI], 62%-83%); the specificity was 59% (95% CI, 49%-69%); the positive predictive value was 58% (95% CI, 47%-68%); and the negative predictive value was 75% (95% CI, 64%-84%). Also, there was evidence of spectrum bias, because the sensitivity and specificity (as well as the positive and negative predictive values) were different for groups with and without vascular disease.


CONCLUSIONS
The results of CRS were substantially worse in a clinical practice setting than previously reported in research settings, despite a similar prevalence of RAS. Captopril renal scanning should not be used as an initial screening test for diagnosing RAS, even among patients with high clinical likelihood of disease.
Huot
Stephen J
SJ
Department of Internal Medicine, West Haven Veterans Affairs Medical Center, Conn., USA. stephen.huot@yale.edu
Hansson
Joni H
JH
Dey
Holly
H
Concato
John
J
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril; D003237:Connecticut / Q000453:epidemiology; D005188:False Negative Reactions; D005500:Follow-Up Studies; D006801:Humans; D018810:Magnetic Resonance Angiography; D011237:Predictive Value of Tests; D015995:Prevalence; D011859:Radiography; D012077:Renal Artery / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D012078:Renal Artery Obstruction / Q000175:diagnosis* / Q000453:epidemiology / Q000601:surgery; D012680:Sensitivity and Specificity
D000806:Angiotensin-Converting Enzyme Inhibitors; D002216:Captopril