Brown BG.

A direct comparison of intravascular ultrasound and quantitative coronary arteriography: implications for measures of atherosclerosis as clinical surrogates

INTRODUCTION
Several established methods for the imaging of atherosclerosis (quantitative coronary arteriography [QCA], carotid intima-medial thickness, magnetic resonance imaging, and intravascular ultrasound [IVUS]) have been used in clinical trials to determine whether defined therapeutic interventions slow the rate of progression of plaque size or composition, or reduce severity of luminal obstruction, and whether change in these measures predicts in-trial or future cardiovascular (CV) events. The report by Berry et al8 in this issue of Circulation, which compares simultaneously-obtained QCA measures of luminal obstruction with IVUS measures of plaque and luminal volume or percent plaque volume and their in-trial changes is a timely comparison between IVUS and QCA. The present editorial comment addresses the emerging evidence on the relative utility of measurements by these 2 techniques for use as surrogates for efficacy in clinical trials. [...]