Circulation Journal Official Journal of the Japanese Circulation Society http://www. j-circ.or.jp benefit of routine FKI after single stenting of bifurcation lesions. 6 In addition, inadequate side-branch dilatation may result in stent deformation or incomplete stent apposition. 7 In contrast, quantitative coronary angiography (QCA) conducted in the Nordic-Baltic Bifurcation Study III showed better expansion of the side-branch orifice in the FKI group. 6 Because delayed arterial healing characterized by exposed stent struts is considered a possible risk factor for stent thrombosis, 8 struts floating at the side-branch orifice (jailing strut) could affect thrombus formation after DES implantation. Despite these controversies, the relationship between stenting strategies and local findings, such as stent apposition, thrombus formation, and neointimal coverage, which may be associated with long-term clinical outcome, has not been well evaluated to date.Several studies have shown that the high resolution of optical coherence tomography (OCT) enables visualization of coronary arteries at the micron level for evaluation of strut coverercutaneous coronary intervention (PCI) using drugeluting stents (DES) reduces restenosis and major adverse cardiac events (MACE) compared to PCI with bare metal stents. 1 Even in the DES era, however, the procedures for bifurcation remain complex and challenging. 2,3 The single-stent strategy is currently considered preferable because the 2-stent strategy has higher rates of periprocedural myocardial infarction and long-term MACE, 4,5 which is probably associated with the increased use of contrast and prolonged procedure time. Therefore, a 1-stent strategy with a provisional approach to the side branch with final kissing inflation (FKI) might be the most acceptable strategy in clinical practice.Recently, the Nordic-Baltic Bifurcation Study III, a randomized comparison of clinical outcomes in patients with coronary bifurcation lesions treated with FKI vs. without FKI after main vessel (MV) stenting, found a similar 6-month clinical outcome between the 2 groups, raising questions regarding the Background: Treatment of coronary bifurcation lesions using a single stenting strategy is preferable over that using a 2-stent technique. The benefit of final kissing inflation (FKI), however, has not been established.