Types of In-Stent Restenosis and Predictive Factors for Diffuse Type In-Stent Restenosis

ABSTRACT

BACKGROUND AND OBJECTIVES: oronary stents have been used increasingly in the field of coronary intervention. However, in-stent restenosis (ISR) remains a therapeutic challenge. The subsequent response to repeat intervention in the restenotic lesion may be predicted by the angiographic pattern of ISR. In particular, the restenosis rate following re-intervention in this lesion is higher. This study evaluated the incidence of restenosis types and the predictors for diffuse type ISR. SUBJECTS AND METHODS: he study population included 66 patients with in-stent restenotic lesions after stent implantation. Angiographic restenosis was defined as a diameter stenosis of > or = 50% at follow-up coronary angiography. Patterns of ISR were defined as focal type ( or = 10 mm in length). The patients were divided into two groups according to the angiographic patterns of ISR. Clinical characteristics, pre-stenting angiographic features, and stenting procedure related factors were analyzed. A multivariate logistic regression analysis was performed in order to identify the independent predictors for diffuse-type ISR. RESULTS: ngiographic analysis of 66 restenotic lesions showed diffuse type in 29 lesions (44%) and focal type in 37 (56%). Most of the focal in-stent restenoses occured in the proximal and mid portions of the stents. The reference diameter (3.02+/-0.37 mm vs 3.25+/-0.46 mm, p=0.046) and post-stenting minimal luminal diameter (2.89+/-0.36 vs 3.19+/-0.39 mm, p=0.002) were significantly smaller in the diffuse type as compared to the focal type, whereas other parameters were significantly different. Using multivariate logistic regression analysis, the only predictive factor for diffuse type ISR was post-stenting MLD (OR=4.74, p=0.025). CONCLUSION: mall post-stenting MLD (<3 mm) has a high risk for diffuse type INR. Therefore, new therapeutic strategies are required for these lesions.