PubMed · 6752902
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S J Hopkins. 1982-10-13. Captopril.. https://pubmed.ncbi.nlm.nih.gov/6752902/
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The finding from a normal-appearing angiotensin converting enzyme (ACE)-inhibitor renal scan is generally reassuring to the physician screening for renovascular hypertension. In fact, the false-negative rate for captopril scintigraphy is very low. Possible reasons for false-negative scans have not been well documented. A fifty-two-year-old man was evaluated and found to have renovascular hypertension on two occasions, at initial presentation and again eight months later (restenosis had occurred). Renovascular hypertension was present on both occasions as judged by decline of blood pressure following angioplasty of right renal artery stenosis (approximately 80% and approximately 70% stenosis on the two occasions, respectively). However, ACE-inhibitor renal scanning with 99mTc MAG-3 gave disparate results on the two occasions. The first study using oral captopril (25 mg) indicated a low probability of renal artery stenosis, whereas the second study done with the patient regularly taking lisinopril (10 mg daily) was markedly positive. Possible reasons for the initial negative study include poor absorption of oral captopril or inadequate inhibition of the renin-angiotensin system by the 25 mg dose.
We wished to provide comparative information regarding the direct effects of flosequinan, a novel quinolone under development for treating heart failure, on isolated human arterial, venous, and cardiac muscle. A similar assessment was made for four other agents--milrinone, ouabain, captopril and diltiazem--that have been used to treat heart failure patients, as well as for flosequinoxan, which is the primary metabolite of flosequinan. Flosequinan produced a potent and balanced relaxant effect on norepinephrine (NE)-contracted human arterial and venous smooth muscle, with IC25 values of 0.32 and 0.50 microM, respectively. At higher concentrations, flosequinan also produced a positive inotropic effect on human cardiac muscle (EC25 = 32 microM). A similar pattern of responses was observed with flosequinoxan. The pharmacologic profile obtained for the other agents examined differed from that observed with flosequinan and flosequinoxan in the following ways: Milrinone produced both vascular relaxant and positive inotropic effects, but at comparable concentrations; ouabain produced both vasoconstrictor and positive inotropic effects; diltiazem exerted a vascular relaxant effect at low concentrations and a negative inotropic effect at higher concentrations; and captopril had slight arterial relaxant and negative inotropic effects. These results demonstrate that the pharmacologic profile of flosequinan and flosequinoxan is unique as compared with that of other agents that have been used to treat patients with heart failure.
OBJECTIVE: To evaluate published reports of diagnostic methods for renovascular hypertension, including Doppler ultrasonography, magnetic resonance imaging, the captopril test, and captopril scanning. DATA SOURCES: MEDLINE and selected references from appropriate published articles. STUDY SELECTION: Studies included those that calculated sensitivities and specificities; studies that derived diagnostic criteria without application to another population of patients were excluded. Consensus of both authors was necessary for inclusion. DATA EXTRACTION: Articles were critically assessed independently by the authors and a consensus critique was developed. DATA SYNTHESIS: Major sources of variability exist in the investigations of recently developed tests for renovascular hypertension. These include variability in patient populations, performance of tests, and determination of outcome measures. CONCLUSIONS: Among the newer diagnostic tests, both magnetic resonance imaging and Doppler ultrasonography hold promise for the anatomic detection of renal artery stenosis, but clear diagnostic criteria have not been universally accepted. There is more information concerning the captopril test, which has a sufficiently high sensitivity to be useful in the screening of high-risk patients for renovascular hypertension. Scans after captopril administration, which appear to be more specific, may enable the prediction of a blood pressure response to angioplasty or surgery.