Quantitative gated intravascular ultrasound largely reduces the population size for atherosclerosis progression-regression trials: A computer simulation study

During imaging of coronary vessels with ultrasound (ICUS), cardiac cycle-dependent motion of the catheter introduces artifacts resulting in possible measurement inaccuracies. Although this problem can be avoided by ECGor image-based gating, still most analyses are performed non-gated in longitudinal studies investigating the effects of new interventional methods on coronary atherosclerosis progression-regression. To investigate the impact of these motion-induced artifacts on the possible outcome of these studies, we developed a computer simulation model. In the model a clinical trial (n = 400) was simulated where 200 patients received a drug (estimated 3%plaque reduction) and 200 a placebo. Using gating the 3% plaque reduction could be detected in 26 patients while for non-gated analyses 254 patients were necessary, indicating that gating can reduce population sizes significantly.