Angiotensin II stimulates left ventricular hypertrophy in hypertensive patients independently of blood pressure

Abstract

Angiotensin II (AII) is known to be a growth stimulating factor for myocardial cells. We examined whether an exaggerated responsiveness to AII might aggravate left ventricular (LV) hypertrophy in human essential hypertension. To determine the responsiveness to AII in humans, we examined changes in mean arterial pressure (MAP), renal blood flow (RBF), and glomerular filtration rate (GFR) (steady state input clearance technique with para-aminohippurate and inulin, respectively) and aldosterone secretion to AII infusions (0.5 and 3.0 ng/kg/min) in 71 normotensive male and 48 hypertensive male subjects (age: 26 +/- 3 years; 24-h ambulatory blood pressure: 121 +/- 5/71 +/- 4 mmHg v 138 +/- 7/82 +/- 7 mmHg, P < .001). In addition, each patient underwent two-dimensional guided M-mode echocardiography at rest to assess cardiac structure and function. When given AII 3.0, a greater increase of MAP (13 +/- 7 v 17 +/- 8 mm Hg, P < .022) and a more marked decrease of RBF (-203 +/- 123 mL/min v -270 +/- 137 mL/min, P < .007) were found in hypertensives than in normotensives, whereas changes in GFR and aldosterone concentration were similar in both groups. Most important, changes in GFR to AII correlated with echocardiographically determined LV mass (normotensives: AII 0.5: r = 0.33, P < .006, AII 3.0: r = 0.28, P < .05; hypertensives: AII 0.5: r = 0.41, P < .006, AII 3.0: r = 0.32, P < .05). After taking baseline MAP and body mass index into account, the increase in GFR to AII 0.5 in hypertensives still correlated with LV mass (partial r = 0.37, P < .01). Inasmuch as the increase of GFR is a marker of the responsiveness to AII (related to vasoconstriction at the postglomerular site), our data suggest that increased sensitivity to AII is linked to LV hypertrophy in early essential hypertension, independently of the level of blood pressure.