Aldosterone-to-renin ratio, arterial stiffness, and the response to aldosterone antagonism in essential hypertension

Background: Some 10% to 15% of hypertensive patients have hyperaldosteronism, an increased ambulant aldosterone-to-renin ratio. As aldosterone reduces arterial compliance, we examined the relationship between aldosterone-to-renin ratio, aortic blood pressure (BP), arterial stiffness, and the effect of spironolactone in a hypertensive population. Methods: In 24 untreated patients (mean age 51 +/- 2 years, 10 women), we assessed arterial stiffness by augmentation index-height of the late systolic peak in the aorta, pulse pressure (Sphygmocor), and aortic pulse wave velocity (Complior). Results: There were significant positive correlations between the aldosterone-to-renin ratio and aortic systolic pressure, aortic pulse pressure, and augmentation index and negative correlations with pulse pressure amplification, but none with brachial BP or pulse wave velocity. After randomization in a cross-over design to 50 mg of spironolactone or 2.5 mg of bendroflumetazide for 4 weeks with washout period of 1 month, both drugs significantly reduced brachial BP, but only spironolactone reduced (P < .001) pulse wave velocity and augmentation index, which remained significant when corrected for its greater reduction in mean BP. There were significant (P < .001) positive correlations between the ratio and decrease in aortic systolic (r = 0.78), mean (r = 0.75), diastolic BP (r = 0.66), aortic pulse pressure (r = 0.69, augmentation index (r = 0.64) and with, brachial systolic pressure (r = 0.66), brachial pulse pressure (r = 0.44, P < .05) and pulse pressure amplification (r = 0.46, P < .05). Such relationships were not found with pulse wave velocity. Conclusions: The aldosterone-to-renin ratio may have an important role in determining arterial stiffness, particularly wave reflection and aortic systolic pressure and is of predictive value for the responsiveness to spironolactone. Aldosterone antagonism has BP-independent effects on arterial stiffness. (C) 2005 American Journal of Hypertension, Ltd.