The 15th meeting of the European Bifurcation Club was held October 18-19, 2019, in Barcelona. The key topics discussed included intracoronary imaging, real-world bifurcation registries, drug-coated balloons (DCB), and bench and computational simulation. Multiple case studies were reviewed, strategies were analyzed in depth, and consensus opinions were formulated.

Intracoronary Imaging

In addition to the recognized role of intracoronary imaging on lesion evaluation, vessel sizing, and assessment of optimal stent deployment, there was an emphasis on the growing role of three-dimensional optical coherence tomography (OCT) guidance for side branch rewiring in provisional stent strategies. Furthermore, the role of three-dimensional OCT in evaluating ostial left circumflex artery angiographic in-stent restenosis after left main intervention (classical restenosis vs. endothelialization of overlying struts covering the side branch ostium) and the complementary role of instantaneous wave-free ratio assessment of these lesions were highlighted using multiple case studies. The potential role of new hybrid catheters that combine imaging and physiology was discussed and showed initial promising data. In addition to wire re-crossing, the advantage of OCT over intravascular ultrasound in detecting the depth of calcification to achieve appropriate stent expansion was demonstrated through case series. The minimum number of OCT runs that were recommended were three: pre-procedure for plaque assessment, after wire re-crossing, and after the final result.

Real-World Bifurcation Registries

Real-world bifurcation registries were also presented, most notably the e-Ultimaster (Prospective, Single-arm, Multi Centre Observations Ultimaster Des Registry) and the COBIS (Korean Coronary Bifurcation Stenting) I, II and II registries.¹ The e-Ultimaster registry included over 37,000 patients treated in over 376 centers in 50 countries in 4 continents. It demonstrated that provisional stenting remains the dominant strategy worldwide in the treatment of bifurcational disease with an excellent midterm outcome when using the latest generation Ultimaster (Terumo Corporation; Tokyo, Japan) drug-eluting stent (DES). The two-stent strategy was noted in only 21% of the total cohort. This registry also demonstrated that proximal optimization is associated with a significant benefit in terms of major adverse cardiovascular events (MACE)—target vessel myocardial infarction, clinically driven target lesion revascularization (TLR), target lesion failure, and stent thrombosis—irrespective of the stent strategy used. It also clearly demonstrated that two-stent techniques are no longer associated with a worse outcome using the newer-generation DES platforms compared with first-generation DES. It also indicated that kissing balloon therapy is associated with better outcomes than side branch ballooning, especially with regard to target vessel myocardial infarction. The COBIS I, II, and III registries1 were similar to the e-Ultimaster registry, and the pooled data from this ongoing registry also confirmed that a provisional strategy is the predominant technique used. In addition, the two-stent strategy performed using second-generation DES no longer carries the adverse outcomes of two-stent strategies performed with first-generation DES. The COBIS investigators recommend starting with the more severe lesion in an upfront two-stent strategy. They demonstrated a reduction in TLR when using a final kissing balloon in a provisional strategy. The conclusion from the COBIS III registry was that there was no significant difference in target lesion failure among the different two-stent strategies (double kissing crush [DK Crush], T and small protrusion, and culotte), although numerically the lowest target lesion failure was with DK Crush.

DCBs

DCBs were suggested as an option to preserve a provisional strategy particularly when the anatomy is suitable as in the Medina 0,0,1 classification. This remains an understudied area, with limited data from the BASKET SMALL2 (Basel Stent Kosten Effektivitäts Trial Drug Eluting Balloons vs. Drug Eluting Stents in Small Vessel Interventions) study that showed no difference in MACE at 12 months when comparing DCB in de novo lesions in vessels <3.0 mm to second-generation DES.² Unlike BASKET SMALL 2, the PICCOLETO (Drug Eluting Balloon Efficacy for Small Coronary Vessel Disease Treatment) study used a cut-off of 2.75 mm to define a small vessel.³ In this small randomized trial, the DCB group did not meet the non-inferiority mark with regard to angiographic stenosis at 6 months when compared with the TAXUS stent (Boston Scientific; Marlborough, MA) group. Generally, questions revolve around the lack of a class effect of DCB, late lumen loss as a poor endpoint, defining appropriate side branch selection, and defining adequate technique: DCB with final kissing ballooning or DCB with re-proximal optimization, or DCB with re-proximal optimization with distal optimization technique. Results from the International Drug Coated Balloon Registry for the Treatment of Bifurcations were presented.⁴ This observational study from Japan enrolled 130 patients in which 54% had DCB-only strategy, 34.6% had at least one stent in the main branch, 8.5% had at least one stent in the side branch, and 3.1% at least one stent in the main branch and side branch. Follow up was 9.8 months. The TLR rate was 4.5%, MACE was 6.1%, and no stent thrombosis was detected. This registry suggested that the DCB-only strategy was safe and effective in select bifurcations, possibly allowing for an abbreviated antiplatelet regimen.

Bench and Computational Simulation

Bench testing and flow simulation using ultra computed tomography allowed for a better understanding of the different two-stent strategies. Firstly, underexpansion and malapposition lead to higher shear stress, which was dose dependent; that is, the worse the malapposition, the higher the shear stress rate. In vitro, higher platelet aggregation and clot formation occurred when large segments of malapposition were simulated. Interestingly, with proximal optimization and imaging confirming appropriate apposition, the computed model revealed less platelet aggregation and better flow dynamics. These models emphasized the importance of optimization and image guidance. Engineers explained that with appropriate post-dilatation (expansion to manufacturer limits) the radial force is increased, and the recoil is reduced in the newer-generation ultrathin strut stents.

Consensus Opinions

A majority vote of the attendees led to the following opinions:

• Isolated ostial left anterior descending or left circumflex artery lesions cannot be stented precisely and lead to restenosis at that site, the ostium of the other side branch, or distal left main. Stenting should therefore extend from the vessel with ostial stenosis into the left main with final proximal optimization in the left main.
• In provisional stenting with a crossover stent jailing the ostium of a major side branch without significant stenosis, balloon dilation of the side branch struts leads to increased frequency of side branch ostial stenosis and should not be performed. Proximal optimization is adequate in main vessel stent. There was an emphasis on final kissing inflations in a provisional strategy.
• For a complex bifurcation stenosis where a two-stent strategy is used, a Crush technique such as DK Crush is preferred.
• Irrespective of the strategy (DCB or not, provisional or two-stent) or left main and non-left main percutaneous coronary intervention, the ideal duration of dual antiplatelet regimen for bifurcations remains unknown at this time.

References

1. Park TK, Park YH, Song YB, et al. Long-Term Clinical Outcomes of True and Non-True Bifurcation Lesions According to Medina Classification- Results From the COBIS (COronary BIfurcation Stent) II Registry. Circ J 2015;79:1954-62.
2. Jeger RV, Farah A, Ohlow MA, et al. Drug-coated balloons for small coronary artery disease (BASKET-SMALL 2): an open-label randomised non-inferiority trial. Lancet 2018;392:849-56.
3. Cortese B, Micheli A, Picchi A, et al. Paclitaxel-coated balloon versus drug-eluting stent during PCI of small coronary vessels, a prospective randomised clinical trial. The PICCOLETO study. Heart 2010;96:1291-6.
4. Bruch L, Zadura M, Waliszewski M, et al. Results From the International Drug Coated Balloon Registry for the Treatment of Bifurcations. Can a Bifurcation Be Treated Without Stents? J Interv Cardiol 2016;29:348-56.

Keywords: Drug-Eluting Stents, Tomography, Optical Coherence, Coronary Vessels, Dilatation, Taxus, Platelet Aggregation, Constriction, Pathologic, Prospective Studies, Follow-Up Studies, Stents, Myocardial Infarction, Percutaneous Coronary Intervention, Angiography, Coronary Angiography, Registries, Thrombosis

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