Predictors and implications of residual plaque burden after coronary stenting:: An intravascular ultrasound study

Background Residual plaque burden after coronary stenting may be visualized by use of intravascular ultrasound. Determinants and implications of residual atherosclerotic plaque burden after coronary stenting are not well established. In particular, the implications of residual plaque burden, after adjusting for confounding factors, are still unknown. Methods Sixty-two consecutive patients (age 56 +/- 9 years) undergoing coronary stenting-under intravascular ultrasound imaging guidance were prospectively studied. A total of 616 slices were analyzed (every 2 mm of stent length) from motorized pull-back recordings. Residual plaque burden was calculated as residual plaque/vessel area X 100. Results In 565 slices (89%), both residual plaque area and stent area could be measured. Mean residual plaque burden was 46.5% +/- 6%. By use of multiple regression analysis, lesion plaque area and reference segment plaque burden were identified as independent predictors of residual plaque burden after stenting. In addition, a significant correlation was found between residual plaque burden and most relevant angiographic parameters at follow-up (including minimal lumen diameter, percent diameter stenosis, and loss index), which persisted after adjustment. Furthermore, stents with a residual plaque burden greater than or equal to46% had higher a restenosis rate (relative risk [RR] 4.4, 95% Cl 1.09-18.2, P = .03). On logistic regression analysis, residual plaque burden (RR 4.8, 95% Cl 4.1-5.6, P = .01) and diabetes (RR 4.3, 95% Cl 3.6-5.1, P = .03) emerged as the only independent predictors of restenosis. Conclusions The amount of residual plaque burden after coronary stenting plays an independent role on the late angiographic outcome of these patients.