Abstract-Brachial-ankle elasticity index (baEI; also known as brachial-ankle pulse wave velocity) has been proposed as a surrogate end point for cardiovascular disease. We performed a meta-analysis of longitudinal cohort studies for determining the ability of baEI to predict risk of cardiovascular events and all-cause mortality and dissecting factors influencing this predictive ability. Multiple online databases, reference lists from retrieved articles, and abstracts from international cardiovascular conventions were searched until April 2012. Longitudinal cohort studies that reported associations of baEI with clinical risk were included. Of the 18 studies included (8169 participants; mean follow-up, 3.6 years), 15 reported results on total cardiovascular events (5544 individuals), 7 on cardiovascular mortality (2274 individuals), and 9 on all-cause mortality (5097 individuals). The pooled relative risks for total cardiovascular events, cardiovascular mortality, and all-cause mortality were 2.95 (95% CI, 1.63-5.33), 5.36 (95% CI, 2.17-13.27), and 2.45 (95% CI, 1.56 -3.86), respectively, for subjects with high versus low baEI (all PϽ0.001). An increase in baEI by 1 m/s corresponded with an increase of 12%, 13%, and 6% in total cardiovascular events, cardiovascular mortality, and all-cause mortality, respectively. We conclude that baEI is associated with increased risk of total cardiovascular events and all-cause mortality. Issues such as expansion of data to non-Asian populations, validation of path length estimation, determination of reference values, and prospective comparison with carotid-femoral pulse wave velocity remain to be resolved. (Hypertension. 2012;60:556-562.) • Online Data Supplement Key Words: brachial-ankle pulse wave velocity Ⅲ cardiovascular risk Ⅲ cardiovascular disease Ⅲ mortality Ⅲ prediction Ⅲ meta-analysis Ⅲ arterial stiffness A rterial stiffness is increasingly recognized as a surrogate end point for cardiovascular (CV) disease and is associated with presence of CV risk factors and atherosclerotic disease.1 Arterial stiffness can be measured with noninvasive, reproducible, and relatively inexpensive techniques, and, thus, it is suitable for large-scale studies. Carotid-femoral pulse wave velocity (PWV; cfPWV) is considered the goldstandard method for assessing aortic stiffness 2 and predicts future CV events and all-cause mortality in a strong and independent manner. Brachial-ankle PWV, calculated as the ratio of the distance between the brachial and the tibial artery divided by the transit time between these 2 arteries, has been proposed as an additional arterial biomarker of CV risk. PWV is classically referred to "segmental stiffness." Because of the complexity of the anatomic course of the brachial-ankle arterial system, it is unclear whether the term brachial-ankle PWV is appropriate to define any particular segmental stiffness or whether it is just the ratio of a virtual brachial-ankle distance and the measurement of the brachial-ankle transit time. For this reason, this index will ...
