ROLE OF INTRAVASCULAR ULTRASOUND IN THE EVALUATION OF MECHANISMS OF CORONARY INTERVENTIONS AND RESTENOSIS

Intravascular ultrasound (IVUS) has emerged from being a research tool to becoming an intrinsic part of modern invasive cardiology. The main reason is its ability to obtain ''in vivo'' microanatomy. For the fir st time it is possible to base decisions not only on lumenograms but a lso on vessel wall assessment. The intervention-associated potential o f IVUS includes the ability to allow optimal device selection, i.e., r otablators in calcified lesions or atherectomy devices in large plaque burden. The effects of percutaneous transluminal coronary angioplasty (PTCA) on vessel-wall morphology can be studied in great detail and t he effect on luminal gain can be assessed almost on-line. Several grou ps have showed that the residual plaque area, even after angiographica lly successful PICA, still lies in the range of 60%. A significant red uction of this percentage may influence long-term outcome after PICA. Minimal luminal areas and residual plaque area after PICA seem to be a n indicator of restenosis, whereas the presence or absence of dissecti ons seem to be less predictive. The main mechanism of restenosis after PTCA is vessel shrinkage, not intimal hyperplasia. intravascular moni toring of stent expansion led to high-pressure stent deployment with a significant increase in postprocedural luminal diameters and finally the ability to withhold anticoagulation in patients with optimal stent deployment. (C) 1998 by Excerpta Medica, Inc.