The Effect Of Renin-angiotensin System Blockade On Arterial Stiffness: A Meta-Analysis

BackgroundArterial stiffness is associated with cardiovascular morbidity and mortality, and is well accepted as an independent cardiovascular risk factor. Pulse wave velocity (PWV) is now widely used in the clinical assessment of patients as an effective index of arterial stiffness. The rennin-angiotensin system (RAS) may play an important role in cardiovascular remodeling and atherosclerosis processing. RAS blockade therapy can improve vascular compliance and endothelial function. Many publications have reported the beneficial effects of renin-angiotensin system blockade in modulating arterial stiffness. However, results of the comparative effect of RAS blockade and other antihypertensive agents are inconsistent. Also, the role of treatment duration and baseline PWV in affecting the benefits is still unclear.ObjectivesTo assess the effect of RAS blockade administration on arterial stiffness as estimated by PWV measurements.MethodsA systematic literature search up to October 2010 was conducted. All randomized drug controlled or placebo controlled trials using angiotensin-converting enzyme inhibitors (ACEI) or angiotensinⅡreceptor blockers (ARB) and reported aortic and/or brachial-ankle PWV (baPWV) measurements were selected. The comparative changes in PWV for RAS blockade with placebo and control therapy were calculated. Results were expressed as weighted mean differences (WMD) with 95% confidence intervals (CI). P<0.05 was considered statistically significant. ResultsA total of 23 randomized controlled trials (RCT) with 1178 participants were included. Among them,10 studies used placebo as control, and 13 studies used other antihypertensive agents as control.1. Compare with placebo(1) RAS blockade significantly reduced aortic PWV (WMD-0.92m/s,95%CI-1.25,-0.59; P<0.0001).(2) Subgroup analyses:Both ACEI and ARB significantly reduced aortic PWV (WMDs of-1.05m/s and-0.66m/s, respectively); Significant reductions in aortic PWV were both found in studies that had baseline aortic PWV≤12m/s (WMD-0.89m/s, 95%CI-1.31,-0.47; P<0.0001) and> 12m/s(WMD-1.11m/s,95%CI-2.06,-0.15; P=0.02); Similar benefits were found in studies that had follow-up≤4w and> 4w (WMDs of-1.11m/s and-0.90m/s, respectively).2. Compare with control therapy(1) When compared with CCB, a significant reduction in aortic PWV was found (WMD-0.58m/s,95%CI-1.05,-0.11; P=0.02). RAS blockade also significantly reduced brachial-ankle PWV (baPWV) in comparison to CCB (WMD-1.27m/s, 95%CI-2.48,-0.07; P=0.04).(2) No significant reduction was found in studies that compared withβ-blockers (WMD 0.04m/s,95%CI-0.28,0.35; P=0.82) or diuretics(WMD-0.22m/s,95%CI-1.17,0.73; P=0.65).Conclusions1. ACEI/ARB provides a beneficial effect in improving arterial stiffness, and the effect of ACEI appears superior to ARB.2. The beneficial effects of RAS blockade in improving arterial stiffness may increase as baseline level of aortic PWV increase.3. The effect of ACEI/ARB in improving arterial stiffness is superior to CCB. More studies are still needed to assess the comparative effects of RAS blockade with (3-blockers and diuretics.