Angiographic patterns of in-stent restenosis - Classification and implications for long-term outcome

Background-The angiographic presentation of in-stent restenosis (ISR) may c onvey prognostic information on subsequent target vessel revascularizations (TLR). Methods and Results-We developed an angiographic classification of ISR acco rding to the geographic distribution of intimal hyperplasia in reference to the implanted stent. Pattern I includes focal (less than or equal to 10 mm in length) lesions, pattern II is ISR>10 mm within the stent, pattern III includes ISR>10 mm extending outside the stent, and pattern IV is totally o ccluded ISR. We classified a total of 288 ISR lesions in 245 patients and v erified the angiographic accuracy of the classification by intravascular ul trasound. Pattern I was found in 42% of patients, pattern II in 21%, patter n III in 30%, and pattern IV in 7%. Previously recurrent ISR was more frequ ent with increasing grades of classification (9%, 20%, 34%, and 50% for cla sses I to IV, respectively; P = 0.0001), as was diabetes (28%, 32%, 39%, an d 48% in classes I to IV, respectively; P < 0.01), Angioplasty and stenting were used predominantly in classes I and II, whereas classes III and IV we re treated with atheroablation. Final diameter stenosis ranged between 21% and 28% (P = NS among ISR patterns). TLR increased with increasing ISR clas s; it was 19%, 35%, 50%, and 83% in classes I to IV, respectively (P < 0.00 1). Multivariate analysis showed that diabetes (odds ratio, 2.8), previousl y recurrent ISR (odds ratio, 2.7), and ISR class (odds ratio, 1.7) were ind ependent predictors of TLR. Conclusions-The introduced angiographic classification is prognostically im portant, and it may be used for appropriate and early patient triage for cl inical and investigational purposes.