Aldosterone escape with diuretic or angiotensin-converting enzyme inhibitor/angiotensin II receptor blocker combination therapy in patients with mild to moderate hypertension.

Renin-angiotensin-aldosterone system (RAAS) hyperactivity is implicated in the development of hypertension and progressive damage in target organs. Chronic inhibition of the RAAS or use of thiazide-type diuretics may trigger an aldoster-one escape. The aim of this study was to assess this phenomenon in hypertensive patients treated with thiazide-type diuretics (hydrochlorothiazide [HCTZ]) or single or double blockade of the RAAS (irbesartan [IRBE], quinapril [QUIN], and IRBE+QUIN). Blood pressure levels were obtained by 24-hour ambulatory blood pressure monitoring. Plasma renin activity and aldosterone levels were determined by immunoradiometric assay. Blood pressure level was normalized in the 4 treatment groups; the HCTZ and IRBE+QUIN groups showed an increased plasma aldosterone level after 12 weeks (9.1+/-2.2 to 14.1+/-1.4 and 6.9+/-1.9 to 12.9+/-2.3 ng/dL, respectively; P<.05), whereas plasma renin activity was increased only in the HCTZ group (0.9+/-0.2-1.7+/-0.2 ng/mL/h; P<.05). The increase in plasma aldosterone level after 12 weeks of HCTZ and IRBE+QUIN therapy suggests early aldosterone escape.