Effects of Angiotensin-Converting Enzyme Inhibition Versus β-Adrenergic Blockade on Aortic Stiffness in Essential Hypertension

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Abstract
We assessed the effects of 6 months of treatment with an angiotensin-converting enzyme (ACE) inhibitor (cilazapril) or a beta 1-adrenergic blocker (atenolol) on aortic stiffness in essential hypertension. Forty patients (16 women) aged 47 +/- 9 years (mean +/- SD) with baseline systolic and diastolic blood pressures of 162 +/- 15 and 105 +/- 5 mm Hg, respectively, were entered into a double-blind, parallel-group study with cilazapril, 5 mg once daily, or atenolol, 100 mg once daily. The treatment period was preceded by a 4-week placebo washout phase. Aortic elastic modulus (Ep) was determined by cine magnetic resonance imaging (MRI) and indirect brachial artery blood pressure measurements prior to and after 3 weeks and 6 months of therapy. The reductions in systolic and diastolic blood pressures from baseline to 6 months averaged -17 +/- 13 and -10 +/- 6 mm Hg, respectively, with cilazapril and -23 +/- 16 and -14 +/- 6 mm Hg with atenolol. Concomitantly, Ep of the ascending aorta decreased with cilazapril from a median of 2,234 10(3)dyn/cm2 (interquartile range, 866-3,740) to 868 10(3)dyn/cm2 (515-1,486) and with atenolol from a median of 1,611 10(3)dyn/cm2 (895-2,790) to 1,054 10(3)dyn/cm2 (616-1,860). In repeated-measurements analysis of variance, the change in Ep with time was statistically significant (p < 0.001) but the group x time interaction was not. We conclude that 6 months of treatment with either cilazapril or atenolol reduces the stiffness of the ascending aorta in essential hypertension. No statistically significant differences between the effects of the two drugs were observed. The mechanisms and clinical significance of improved aortic distensibility with antihypertensive therapy deserve further study.