Predictors of Side Branch Occlusion Immediately after Coronary Stenting: an Intravascular Ultrasound Study

ABSTRACT

BACKGROUND AND OBJECTIVES: Previous studies have indicated that side branch occlusion (SBO) remains a significant problem in coronary bifurcation lesions during percutaneous intervention. SUBJECTS AND METHODS: To evaluate the predictors of SBO by intravascular ultrasound (IVUS), 35 patients (28 males, mean age 56+/-11 years) were studied at their left anterior descending artery (LAD)-diagonal branch (DB) bifurcation lesions, prior to coronary intervention for the measurement of the following plaque characteristics: total plaque area (PA), PA of the branch-side semicircle, % area stenosis (%AS) of the LAD, the presence of bull's eye in the DB, the diameter of the vessel and the ostial lumen of the DB, and the LAD-DB angle. SBO was defined as a persistant reduction in the TIMI flow to < OR = 1 by the end of the procedure. RESULTS: The PA of the branch-side semicircle, the vessel diameter and the ostial lumen diameter of the DB all significantly affected the SBO. The total PA and the %AS of the LAD were not related to the SBO. Multivariate analysis identified that the PA of the branch-side semicircle was the only predictor of SBO (odds ratio 3.2, 95% confidence interval 1.3 to 8.6, p=0.015). CONCLUSION: It appears that the plaque distribution of LAD is a major determinant of SBO. These findings support the theory that the plaque shift ("snow plow effect") may be the mechanism of the SBO following stenting.