Intravascular ultrasonography in the evaluation of results of coronary angioplasty and stenting

The main advantage of intravascular ultrasonography (IVUS) over angiography in assessing the effect of coronary interventions is the ability of IVUS t o directly visualize the vessel walt. IVUS often reveals a high residual pl aque burden after angiographically successful angioplasty, and this can mot ivate the operator to use additional, more aggressive measures in an attemp t to increase lumen dimensions. Studies using IVUS imaging before and after balloon angioplasty have shown that luminal gain after percutaneous transl uminal coronary angioplasty (PTCA) results from a combination of plaque red uction and Vessel wall stretch. Minimal luminal area and residual area sten osis after PTCA and stent deployment, as measured by IVUS, have been shown to be predictors of restenosis. IVUS studies have pointed to vessel shrinka ge, not intimal hyperplasia, as the main mechanism of restenosis after PTCA . IVUS guidance of stent deployment has often revealed inadequate stent exp ansion despite optimal results on angiography, leading to high-pressure ste nt deployment with significant additional luminal gain. Restenosis rates ma y be lower with IVUS-guided stent deployment. (C) 1999 Lippincott Williams & Wilkins, Inc.