Wave Reflection Predicts Cardiovascular Events in Hypertensive Individuals Independent of Blood Pressure and Other Cardiovascular Risk Factors An ASCOT (Anglo-Scandinavian Cardiac Outcome Trial) Substudy

Objectives This study investigated whether wave reflection measured by wave intensity analysis predicts future cardiovascular events in individuals with hypertension and sought to establish whether this relationship is independent of other cardiovascular risk factors and is associated with evidence of increased load on the left ventricle. Background Wave reflection may impose an additional load on the left ventricle, and augmentation index, a surrogate of wave reflection, has been reported to predict cardiovascular events in some, but not all studies. Methods Measurements of brachial and carotid blood pressure (BP) measurement, carotid ultrasound, echocardiography, and blood chemistry analyses were performed on 259 ASCOT (Anglo Scandinavian Cardiac Outcomes Trial) participants approximately 1 year after randomization, and wave intensity analysis was used to calculate wave reflection index (WRI), the ratio of peak forward to peak backward pressure (P-b/P-f), and carotid augmentation index (cAI(x)). All participants were followed up for a median period of 5.9 years, accruing 33 cardiovascular events. Results WRI, P-b/P-f, and to a lesser extent, cAI(x), were correlated. WRI predicted cardiovascular events (hazard ratio: 2.10; 95% confidence interval: 1.10 to 3.99; p = 0.02) in an unadjusted model. Multivariate analysis showed that this association was independent of BP. P-b/P-f and cAI(x) did not significantly predict cardiovascular events. WRI was also positively associated with increased left ventricular mass index and elevated B-type natriuretic peptide adjusted for age and sex, and these associations were independent of BP or other cardiovascular risk factors. Conclusions Higher wave reflection predicts future cardiovascular events independent of conventional risk factors in people with treated hypertension. (J Am Coll Cardiol 2010; 56: 24-30) (C) 2010 by the American College of Cardiology Foundation