Functional tests for primary aldosteronism: value of captopril suppression.
With the introduction of more simple screening tests such as the aldosterone/renin ratio, the detection rate of primary aldosteronism has increased considerably. Until now, no reference values have been available for reporting the aldosterone/renin ratio using plasma aldosterone values expressed in SI units (pmol/L) and plasma active renin (ng/L) measured by immunoradiometric assay. We studied 153 subjects who had either normal blood pressure, essential hypertension, or primary aldosteronism. Essential hypertensive patients usually have aldosterone/renin (pmol/L/ng/L) ratios below 100, whereas ratios for patients with primary aldosteronism are above 140. Results that fall between 100 and 140 suggest a need for repeat testing. Patients with elevated aldosterone/renin ratios require confirmatory testing to demonstrate nonsuppressive autonomous aldosterone production. To this end, salt loading is widely used, but this approach may be contraindicated in patients with severe hypertension. The captopril suppression test appears as effective as salt loading in confirming a diagnosis of primary aldosteronism. In addition, the captopril test is safe, well tolerated, and cost-effective.
Racine
Marie-Claude
MC
CHUQ, L'Hôtel-Dieu de Québec Hospital, 11 Côte du Palais, Québec, (QC), G1R 2J6, Canada.
Douville
Pierre
P
Lebel
Marcel
M
D000450:Aldosterone / Q000097:blood / Q000592:standards; D002216:Captopril; D006801:Humans; D006929:Hyperaldosteronism / Q000097:blood / Q000175:diagnosis*; D015592:Immunoradiometric Assay / Q000592:standards; D012016:Reference Values; D012083:Renin / Q000097:blood / Q000592:standards; D012084:Renin-Angiotensin System / Q000187:drug effects*
D000450:Aldosterone; D002216:Captopril; D012083:Renin