Captopril challenge test

In medicine, the captopril challenge test, also CCT, is a non-invasive test used to help diagnose renal artery stenosis. It should not be confused with the "captopril suppression test".

The CCT, in adults, has a high sensitivity, but a low specificity. [Bales A. Hypertensive crisis. How to tell if it's an emergency or an urgency. Postgrad Med. 1999 May 1;105(5):119-26, 130. PMID 10335324. [http://www.postgradmed.com/issues/1999/05_01_99/bales.htm Free Full Text] .] A better test for diagnosing renal artery stenosis is renal subtraction angiography. [Svetkey LP, Himmelstein SI, Dunnick NR, Wilkinson RH Jr, Bollinger RR, McCann RL, Beytas EM, Klotman PE. Prospective analysis of strategies for diagnosing renovascular hypertension. Hypertension. 1989 Sep;14(3):247-57. PMID 2670763.]

How it is done

The CCT is performed by measuring the (plasma) renin prior to and following the administration of captopril, an angiotensin converting enzyme inhibitor. A CCT is considered positive if the renin levels increase substantially or the baseline renin level is abnormally high. [Muller FB, Sealey JE, Case DB, Atlas SA, Pickering TG, Pecker MS, Preibisz JJ, Laragh JH. The captopril test for identifying renovascular disease in hypertensive patients. Am J Med. 1986 Apr;80(4):633-44. PMID 3515933.]

Use of the CCT in children

The CCT has not been found to be very useful in children. [Gauthier B, Trachtman H, Frank R, Pillari G. Inadequacy of captopril challenge test for diagnosing renovascular hypertension in children and adolescents. Pediatr Nephrol. 1991 Jan;5(1):42-4. PMID 2025535.]

Relation to "captopril suppression test"

The CCT should not be confused with the "captopril suppression test", [cite journal |author=Racine MC, Douville P, Lebel M |title=Functional tests for primary aldosteronism: value of captopril suppression |journal=Curr. Hypertens. Rep. |volume=4 |issue=3 |pages=245–9 |year=2002 |month=June |pmid=12003708 |doi= |url=] cite journal |author=Agharazii M, Douville P, Grose JH, Lebel M |title=Captopril suppression versus salt loading in confirming primary aldosteronism |journal=Hypertension |volume=37 |issue=6 |pages=1440–3 |year=2001 |month=June |pmid=11408392 |doi= |url=http://hyper.ahajournals.org/cgi/pmidlookup?view=long&pmid=11408392] a test used to diagnose primary aldosteronism ("Conn syndrome").

The "challenge" test looks for a problem with the renal artery (stenosis). The "suppression" test looks for a problem related to the adrenal gland (over production of a mineralocorticoids).

References