INTRAVASCULAR ULTRASOUND - A GUIDE FOR MANAGEMENT OF COMPLICATIONS DURING INTERVENTION

Within a few years, intravascular ultrasound (NUS) has emerged from a research tool into an intrinsic part of modern invasive cardiology, ma inly because histology can be obtained 'in-vivo'. For the first time i n invasive cardiology it is possible to base decisions not only on lum enograms but also on vessel wall assessment. IVUS can be used as both a diagnostic tool and for intervention purposes. Its diagnostic streng th lies in its ability to monitor compensatory coronary artery enlarge ment as a response to arteriosclerosis, to reveal occult left main ste rn disease, and angiographically 'silent' arteriosclerosis. As regards intervention, IVUS aids in optimal device selection, i.e. whether to use rotablators in calcified lesions or atherectomy devices in large p laques. The effects of PTCA on vessel wall morphology can be studied i n great detail and the effect on luminal gain assessed almost on-line. Several groups have shown that the residual plaque area, even after a ngiographically successful PTCA, is about 60%. A significant reduction in this percentage may influence long-term outcome after PTCA. Lumina l areas that are minimal after PTCA seem to indicate restenosis, while morphological appearance on its own seems to be less predictive. One answer to the shortcomings of standard PTCA are coronary artery stents . Intravascular monitoring of stent expansion led to the deployment of high-pressure stents with a significant increase in post-procedural l uminal diameters, and finally the ability to withhold anticoagulation in patients with optimal stent deployment. Furthermore, integrated dev ices such as balloons on IVUS catheters, steerable catheters, integrat ed flow measurements, pressure transducers, and hopefully,tissue chara cterization, will further enhance the usefulness of IVUS.