Reflection Magnitude as a Predictor of Mortality
The Multi-Ethnic Study of Atherosclerosis
Arterial wave reflections have been associated with mortality in an ethnically homogenous Asian population. It is unknown whether this association is present in a multiethnic population or whether it is independent of subclinical atherosclerosis. We hypothesized that reflection magnitude (defined as the ratio of the amplitude of the backward wave [Pb] to that of the forward wave [Pf]) is associated with all-cause mortality in a large multiethnic adult community-based sample. We studied 5984 participants enrolled in the Multi-Ethnic Study of Atherosclerosis who had analyzable arterial tonometry waveforms. During 9.8±1.7 years of follow-up, 617 deaths occurred, of which 134 (22%) were adjudicated cardiovascular deaths. In Cox proportional hazards models, each 10% increase in reflection magnitude was associated with a 31% increased risk for all-cause mortality (hazard ratio [HR]=1.31; 95% confidence interval [CI]=1.11–1.55; P=0.001). This relationship persisted after adjustment for various confounders and for markers of subclinical atherosclerosis (HR=1.23; 95% CI=1.01–1.51; P=0.04), including the coronary calcium score, ankle–brachial index, common carotid intima–media thickness, and ascending thoracic aortic Agatston score. Pb was independently associated with all-cause mortality in a similarly adjusted model (HR per 10 mm Hg increase in Pb=2.18; 95% CI=1.21–3.92; P=0.009). Reflection magnitude (HR=1.71; 95% CI=1.06–2.77; P=0.03) and Pb (HR=5.02; 95% CI=1.29–19.42; P=0.02) were mainly associated with cardiovascular mortality. In conclusion, reflection magnitude is independently associated with all-cause mortality in a multiethnic population initially free of clinically evident cardiovascular disease. This relationship persists after adjustment for a comprehensive set of markers of subclinical atherosclerosis.
- Received May 7, 2014.
- Revision received May 23, 2014.
- Accepted June 24, 2014.
- © 2014 American Heart Association, Inc.