Assessment of Effect of Angiotensin Ⅱ Receptor Antagonist Losartan on Aortic Distensibility in Patients With Essential Hypertension by Echocardiography

摘要

Summary: The effects of angiotensin Ⅱ receptor antagonist losartan on elastic properties of aorta in patients with mild to moderate essential hypertension were assessed. The ascending aortic distensibility in 26 patients (48±3 years) with mild to moderate essential hypertension before and after 12 weeks of treatment with losartan (50 mg/day) was evaluated by using two-dimensional echocardiography. M-mode measurements of aortic systolic (D s) and diastolic diameter (D d) were taken at a level approximately 3 cm above the aortic valve. Simultaneously, cuff brachial artery systolic (SBP) and diastolic(DBP) pressures were measured. Aortic pressure-strain elastic modulus (E p) was calculated as D d×(SBP-DBP)/(D s-D d)×1333 and stiffness index beta (β) was defined as D d×Ln (SBP/DBP)/(D s-D d). Blood pressure significantly decreased from 148±13/95±9 mmHg to 138±12/88±8 mmHg (systolic blood pressure, P=0.001; diastolic blood pressure, P=0.003). There was no significant difference in pulse pressure before and after treatment with losartan (53±10 mmHg vs 50±7 mmHg). The distensibility of ascending aorta increased significantly as showed by the significant decrease in pressure-strain elastic modulus from 4.42±5.79×10 6 dynes/cm 2 to 1.99±1.49×10 6 dynes/cm 2 (P=0.02) and stiffness index beta from 27.4±32.9 to 13.3±9.9 (P=0.02). Although there was a weak correlation between the percent changes in pressure-strain elastic modulus and stiffness index beta and that in diastolic blood pressure after losartan treatment(r=0.40, P=0.04 and r=0.55, P=0.004, respectively), no correlation was found between the percent changes in pressure-strain elastic modulus and stiffness index beta and that in systolic blood pressure (r=0.04, P=0.8 and r=0.24, P=0.2, respectively). Our study demonstrated that angiotensin Ⅱ receptor antagonist losartan has a beneficial effect on aortic distensibility in patients with mild to moderate essential hypertension and this effect is partly independent of blood pressure reduction.