Vessel wall changes in the proximal non-treated segment after PTCA. An in vivo intracoronary ultrasound study.

Intimal disruption is known to induce prolonged intimal functional disturbance and is thought to be one of the mechanisms contributing to restenosis after PTCA. Although such damage can be induced by minimal trauma, the inevitable far greater disruption caused by passage of the PTCA apparatus through the stenosis does not appear to induce significant angiographically documented intimal proliferation. Pathological studies, however, have suggested that such a process might occur. Intravascular ultrasound allows in vivo study of vessel wall shape and constitution and is a far more sensitive detector of coronary atheroma than angiography. In this study we sought to determine the frequency of such functional disturbances and to assess their significance with respect to restenosis. The study group comprised 18 patients who underwent IVUS examination immediately after PTCA and at 6-months follow-up. They were analysed for luminal dimensions and vessel wall changes at the site of PTCA and at the level of the proximal non-treated segment. Seven patients (38%) had restenosed at follow-up IVUS examination; two patients had angiographically demonstrated luminal narrowing proximal to the PTCA site whereas seven had new intimal thickening in the proximal non-treated segment demonstrated by IVUS. Six patients had no intimal changes in either PTCA treated or untreated segments. Proximal intimal thickening was seen more frequently in those in whom increased intimal thickening at the PTCA site was noted. A trend (P < 0.1) was found towards an increased rate of new proximal vessel disease in those patients who had angiographically restenosed. IVUS demonstrates new intimal thickening in proximal non-treated segments in a considerable number of or patients undergoing PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)