Arterial remodeling patterns before intervention predict diffuse in-stent restenosis: an intravascular ultrasound study.

OBJECTIVES The aim of this retrospective study was to determine the predictors of diffuse in-stent restenosis (ISR) among the lesions causing the first ISR by intravascular ultrasound (IVUS) studies. BACKGROUND Although some predictors of diffuse ISR have been reported, parameters on IVUS relating to diffuse ISR are not well characterized. METHODS We classified 52 ISR lesions that had undergone successful stent implantation and led to restenosis into two types--focal and diffuse ISR--using quantitative coronary angiography. Restenosis was defined as > or =50% diameter stenosis, and diffuse ISR as lesion length > or =10 mm at follow-up. The remodeling index (RI) was defined as the vessel area at the target lesion divided by that of averaged reference segments. RESULTS There were no significant differences in patient, angiographic, and procedural characteristics between the focal (n = 25) and diffuse (n = 27) ISR groups. Baseline RI was significantly greater in the diffuse ISR group (1.03 +/- 0.18 vs. 0.88 +/- 0.24, p = 0.0159). Negative remodeling, defined as RI <0.9, was detected in 60% of the focal ISR group and in only 26% of the diffuse ISR group. By logistic regression analysis, baseline RI was the only independent predictor of diffuse ISR (p = 0.0341). Moreover, volumetric analyses revealed that lesions developing into diffuse ISR had less capacity to compensate for further plaque growth. CONCLUSIONS Among the first ISR lesions, baseline positive remodeling was the most powerful predictor of diffuse ISR. Measuring pre-interventional arterial remodeling patterns by IVUS may be helpful to stratify lesions at higher risk.