Comparison of luminal enlargement by direct coronary stenting versus predilation coronary stenting by three-dimensional volumetric intravascular ultrasound analysis

Abstract

S tudies using planar intravascular ultrasound (IVUS) have shown that during intracoronary stent implantation, the mechanisms of lumen enlargement are similar to those of balloon angioplasty, with significant plaque redistribution and extrusion, vessel expansion, and plaque reduction. However, these assessments were performed with stents implanted after predilation by balloon. New stents, crimped onto their low-profile flexible delivery systems, with more rapid tapering of the balloon outside of the conical markers, are suitable for direct stenting (DS). DS has become routine in some laboratories. This new therapeutic approach of DS without predilation provides a way to rationalize stent implantation with the potential of less ischemic complications, less use of balloons, and less x-ray exposure. Although DS has become widespread, the mechanism by which it causes lumen enlargement is still unknown. Furthermore, there remains concern about the risk of microplaque embolization with DS. The present 3-dimensional volumetric IVUS study compares the mechanisms of lumen enlargement with DS versus predilation stenting (PDS) using the same contemporary stent design and the same stent length. • • • We retrospectively studied 30 patients with DS and 30 patients with PDS of nonostial, noncalcified, native coronary lesions treated with the same stent design and dimensions (ACS Multilink DUET or TRISTAR stent, Guidant Corporation, Santa Clara, California) and the same stent length (13 mm). The decision to predilate or not to predilate was partly based on general operator attitude. All lesions in both groups had met the inclusion criterion of the physical feasability of preintervention IVUS examination. Consequently, the DS success rate was 100%. For each procedure, the number of inflations, the maximum balloon inflation pressure, and the diameter of the stent used were recorded. Stent-to-artery ratio was defined as the diameter of the stent (according to the linear compliance curve of the balloon and the maximum balloon inflation pressure) divided by the reference luminal diam-