Clinical Value of Optical Coherence Tomography in Guiding Bifurcation Percutaneous Coronary Intervention
論文ID: CJ-23-0689
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論文ID: CJ-23-0689
Revascularization of bifurcation lesions remains an important challenge in percutaneous coronary intervention (PCI), and various stenting techniques using guidance have been proposed. However, angiography is limited for guiding complex procedures, whereas intravascular optical coherence tomography (OCT) gives more detail of complex lesion morphology and stent structures at the bifurcation. Therefore, guidance with OCT is helpful in determining the PCI strategy, optimal stents, and predicting procedural complications.1
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In this issue of the Journal, Akase et al2 report a detailed analysis of the risk factors for side branch occlusion after main vessel stenting using data from a prospective, multicenter, 3-dimensional (3D)-OCT bifurcation registry. The OCT score, which included the pre-PCI side branch diameter, length from proximal branching point to carina tip, distance of the polygon of confluence, and 3D bifurcation type (parallel or perpendicular type), was useful for risk stratification of side branch occlusion after main vessel stenting.
It is well known that at the bifurcation, smaller bifurcation angles and longer carina increase the risk of side branch occlusion after main vessel stenting. Previous studies have used long-axis 2D-OCT images of the main vessel to predict side branch occlusion. A retrospective 2D-OCT study3 showed that a bifurcation angle <50° and a side branch ostium diameter <1.70 mm were the best cutoff values to predict side branch occlusion after main vessel stenting. Expanding on those findings, Akase et al suggest that 3D-OCT can more easily and quickly assess the risk of side branch occlusion.
Main vessel calcification at the bifurcation is also associated with an increased risk of side branch occlusion after main vessel stenting.4 The stent does not expand toward the hard calcification, but rather toward the soft side branch ostium. This non-uniform stent expansion induces a carina shift, resulting in side branch occlusion. OCT can clearly identify calcifications within the vessel wall.5 In addition, the latest OCT software can automatically identify calcification using artificial intelligence technology. Understanding the extent of calcification with OCT prior to intervention can greatly influence the PCI strategy. In highly calcified bifurcation lesions, adequate lesion preparation prior to stenting is critical for successful PCI. Removal of the main vessel calcification using rotablator atherectomy, orbital atherectomy system, directional coronary atherectomy or intravascular lithotripsy may reduce the risk of side branch occlusion after main vessel stenting.6
OCT plays an important role in stent optimization in bifurcation PCI. 3D-OCT can clearly delineate the stent struts over the side branch ostium and the guidewire that crosses the stent to the side branch. The use of 3D-OCT facilitates optimal guidewire crossing for kissing balloon inflation (KBI). For KBI, the guidewire to the side branch should ideally pass through the stent cell without links. Guidewire crossing with 3D-OCT guidance and subsequent KBI reduces stent deformation in the main vessel and provides adequate apposition of the stent struts to the vessel wall at the bifurcation. The OCT software can automatically detect stent struts with significant malapposition that need to be corrected. Co-registration of OCT and angiography can project the location of stent malapposition onto the angiogram.7 These features of OCT help to accurately identify the target for post-dilatation and thus reduce stent malapposition.8 The OPTIMUM (Online 3-Dimensional Optical Frequency Domain Imaging to Optimize Bifurcation Stenting Using UltiMaster Stent) trial9 compared 3D-OCT-guided PCI and angiography-guided PCI for post-procedural stent findings in bifurcation lesions. The frequency of post-procedural stent malapposition at the bifurcation was significantly lower in 3D-OCT-guided PCI than in angiography-guided PCI.
Recently, the OCTOBER (Optical Coherence Tomography Optimized Bifurcation Event Reduction) trial10 showed that OCT-guided PCI improves long-term clinical outcomes in patients with complex bifurcation lesions compared with angiography-guided PCI. The primary endpoint was a composite of major adverse cardiac events (MACE), defined as cardiac death, target-lesion myocardial infarction, or ischemia-driven target-lesion revascularization. The incidence of MACE at a median follow-up of 2 years was significantly lower in OCT-guided PCI than in angiography-guided PCI (10.1% vs. 14.1%; hazard ratio, 0.70; 95% confidence interval, 0.50 to 0.98; P=0.035). The incidence of procedure-related complications was 6.8% for OCT-guided PCI and 5.7% for angiography-guided PCI, with no statistically significant difference between groups. The results of the OCTOBER trial might influence future guideline recommendations for the use of OCT to guide PCI for bifurcation lesions.
Unlike therapeutic devices, OCT, a diagnostic device, does not affect the outcome of PCI as long as the OCT catheter is inserted into the coronary artery for observation only. The OCT information should be utilized in PCI procedures (Figure). Therefore, it is important to develop OCT criteria that help guide optimal PCI outcomes.11,12 The results of this study by Akase et al will contribute to standardizing OCT guidance and improving outcomes in bifurcation PCI.
OCT guidance in bifurcation PCI using a single stent. Ca, calcification; GW, guidewire; KBI, kissing balloon inflation; MV, main vessel; OCT, optical coherence tomography; PCI, percutaneous coronary intervention; POT, proximal optimization technique; SB, side branch.
None.
None of the authors are members of the Circulation Journal’s Editorial Team, nor do they have relationships relevant to the contents of this paper to disclose.
R.T. and T.K. equally wrote and approved the manuscript.
Name of the ethics committee: N/A. Reference number: N/A.
