摘要OBJECTIVES To investigate whether negative remodeling(NR)detected by intravascular ultrasound(IVUS)of the side branch ostium(SBO)would affect in-stent neointimal hyperplasia(NIH)at the one-year follow-up and the clinical outcome of target lesion failure(TLF)at the long-term follow-up for patients with left main bifurcation(LMb)lesions treated with a two-stent strategy.METHODS A total of 328 patients with de novo true complex LMb lesions who underwent a 2-stent strategy of percutaneous coronary intervention(PCI)treatment guided by IVUS were enrolled in this study.We divided the study into two phases.Of all the patients,48 patients who had complete IVUS detection pre-and post-PCI and at the 1-year follow-up were enrolled in phase Ⅰanalysis,which aimed to analyze the correlation between NR and in-stent NIH at SBO at the 1-year follow-up.If the correlation was confirmed,the cutoff value of the remodeling index(RI)for predicting NIH ≥ 50％was analyzed next.The phase Ⅱ analysis focused on the incidence of TLF as the primary endpoint at the 1-to 5-year follow-up for all 328 patients by grouping based on the cutoff value of RI.RESULTS In phase Ⅰ:according to the results of a binary logistic regression analysis and receiver operating characteristic(ROC)analysis,the RI cutoff value predicting percent NIH ≥ 50％was 0.85 based on the ROC curve analysis,with a sensitivity of 85.7％,a specificity of 88.3％,and an AUC of 0.893(0.778,1.000),P=0.002.In phase Ⅱ:the TLR rate(35.8％vs.5.3％,P＜0.0001)was significantly higher in the several NR(sNR,defined as RI ≤ 0.85)group than in the non-sNR group.CONCLUSION The NR of LCxO is associated with more in-stent NIH post-PCI for distal LMb lesions with a 2-stent strategy,and NR with RI ≤ 0.85 is linked to percent NIH area ≥ 50％at the 1-year follow-up and more TLF at the 5-year follow-up.