Is intravascular ultrasound the gold standard surrogate for clinically relevant atherosclerosis progression?

Are progressive changes in intravascular ultrasound (IVUS)-derived indexes of plaque size sufficiently predictive of in-trial or future cardiovascular event risk that IVUS can serve as an efficient surrogate for clinical events in coronary disease trials? This question remains unanswered by clinical trials reported to date. Indeed, the answer may well be "yes." Nevertheless, there are enough concerns about the physical limitations, the fundamental assumptions, and the interpretation of the IVUS measurements that the answer cannot be taken for granted. Here, we review the evidence to date, discuss some of the concerns, and compare IVUS results with those of quantitative arteriography.