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https://doi.org/10.47803/rjc.2020.30.3.363

Abdullah Al Saiedi1,2, Pierluigi Demola1, Carlo Di Mario1

1 Structural Interventional Cardiology, University Hospital, Florence, Italy
2 King Faisal Cardiac Canter, Jeddah, Saudi Arabia

This editorial refers to ‘Four-year outcomes of unprotected left main lesion treated with one-stent versus two-stent technique’, by L. Predescu et al., on page 399.

A countless number of registries, randomized trials and metanalyses have shown a reduced event rate in patients receiving a provisional stent instead of a two stent strategy for bifurcational stenting1,2,3,4,5. The difference in registries was obviously driven by the greater complexity of patients requiring two stents. In randomized trials true bifurcations in clear need of a two-stent strategy were excluded from the start and cross-over to a second stent concealed cases of possible acute failure. Metanalyses have added the power of numbers, with small trials of few hundred patients with borderline significant results suddenly becoming unquestionable when thousand patients are included. The consequence of these registries and trials has been universal blame for the few balanced interventionalists that cared more of an optimal procedural outcome than of passive acquiescence to dogmatic recommendations and Guidelines6.
The tide started to change when it became clear that the most efficient two-stent technique for almost all bifurcation anatomies including left main bifurcation is DKCrush7,8,9, a technique not amenable like T-stenting or culotte to a provisional application. Only recently a randomized trial and network meta-analyses10,11,12 challenged the old dogmas and concluded that a two stent technique has better clinical outcome in terms of MACE and revascularisation than provisional single stent, maintaining a low risk of stent thrombosis (Figure 1).
This large consecutive registry of left main bifurcation comes to similar conclusions, highlighting the pitfalls of registries in terms of selection bias. Here, however, the main bias is the more frequent adoption of a single stent technique in the emergency situations of a left main critical lesion in STEMI or NSTEMI when established or impending cardiogenic shock develop due to the large area jeopardised. This selection bias outweighs the traditional more favourable characteristics of the single stent population and translates into a large difference in 1 to 4-year mortality. The registry is a real world all-comers study with a realistic percentage (>30% rather than the 10-20% of other studies) of patients requiring a two- stent technique for left main bifurcation. When a large artery such as the circumflex is involved, often beyond 1-2 mm from the ostium, leaving a severe residual lesion with a dissecti-on cannot be conceptually better than optimal lesion expansion secured by a second generation drug eluting stent. This trial shows just this. You may argue that a more liberal use of post treatment physiology, limited to only few cases in this registry, might have led to a better selection of true residual critical lesions14,15. The logic of using physiologic thresholds coming from validation studies performed before treatment is questionable since recoil and restenosis may modify the severity much more quickly than in de novo untreated lesions. A more valid criticism is the low usage of intravascular imaging (less than 25% in this trial), despite growing evidence of improved outcome due to better strategy selection and optimal stent expansion and apposition16. New treatment modalities such as intravascular lithotripsy for calcific lesions particularly suitable for large arteries such as ostial LAD or LCx have shown promising results in a recent registry17.
In conclusion this registry should be commended to stand against outdated concepts that remained unchallenged for too long. It is obvious that a single stent provisional strategy remains the preferred option in bifurcations with small side-branches and in the 50-70% of non-left main bifurcations with purely ostial side-branch disease. In LM bifurcations, operators should identify before lesions unlikely to achieve an optimal result with a single stent, as doable with experience from angiography or, better, assessing plaque burden and distribution with two-vessel IVUS. In those cases, an immediate adoption of the most efficient two-stent strategy, often IVUS guided DK Crush, is the most logical option.

Figure 1. Primary efficacy and secondary safety endpoints of the DEFINITION II trial at 1 year. TLF, target lesion failure.
Conflict of interest: none declared.

References
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