Figure 2.

Representative cases of angiography-guided and online 3-dimensional (3D)-optical frequency domain imaging (OFDI)-guided percutaneous coronary intervention. Sixty-nine-y-old female with Medina 0, 1, 0 left main (LM) bifurcation lesion (diameter stenosis by quantitative coronary angiography: 58% in left anterior descending artery [LAD]) was randomized to the angiography arm (A). A 3.0×15 mm Ultimaster stent (B: yellow dotted line) was implanted in the LM toward proximal LAD, followed by proximal optimization technique (POT) with a 4.0 mm balloon and subsequent wire recrossing to the left circumflex artery. After final kissing balloon dilatation (KBD), 3D-OFDI was performed for documentation purpose, which revealed presence of metallic struts in front of the side branch ostium (C). The frequency of malapposed struts (D: yellow arrow) was 33.9% by cross-sectional OFDI image. Fifty-eight-y-old male with Medina 1, 1, 1, LAD bifurcation lesion was randomized to the 3D-OFDI arm (E). A 3.0×28 mm Ultimaster stent (F: yellow dotted line) was implanted in the LAD followed by POT. After the first attempt of rewiring to the diagonal branch, 3D-OFDI revealed suboptimal position of the wire (A2-S) according to the specific classification (G). According to the protocol, crossing of the wire to the diagonal branch was repeated to achieve optimal wiring through the distal cell. A subsequent OFDI pullback confirmed the optimal position of the recrossing wire (H: A1-L). After KBD, the final OFDI image demonstrated wide opening of the sidebranch ostium without overhanging metallic structure (I and J: yellow arrow indicates malapposed strut).