Comparison of dilatation mechanism and long-term vessel remodeling between directional coronary atherectomy and balloon angioplasty assessed by volumetric intravascular ultrasound

Although acute and late outcomes of coronary interventions have been determined by coronary angiography, this method cannot determine changes in vessel and plaque volume. Volumetric intravascular analysis has the potential to evaluate the morphology and redistribution of plaque after coronary intervention as well as longitudinal vessel remodeling. We used 3-dimensional intravascular ultrasound (3-D IVUS) to delineate the mechanism of coronary dilatation and long-term (> 1 year) remodeling in 25 patients. Ten patients underwent directional coronary atherectomy (DCA), and 15 underwent balloon angioplasty (POBA). No patients exhibited restenosis at 6-month angiographic follow-up. Validated Netra 3-D IVUS was performed pre- and post-intervention, at 6-months and at > 1-year. There were some differences in mechanism of dilatation and time course of change in vessel size between DCA and POBA patients. The principal mechanism was vessel stretching and longitudinal plaque redistribution in the POBA group and plaque debulking in the DCA group. In the POBA group, vessel volume increased just after the procedure; this increase was maintained at 6 months and at > 1-year. However, in the DCA group, vessel volume increased initially 6 months after the procedure. 3-D IVUS revealed a difference in mechanism of dilatation between POBA and DCA; this difference might affect late-term vessel remodeling even in patients without restenosis.