By Maciej Lesiak
Provisional stenting has remained the preferred technique for bifurcation lesions, and controversies still exists regarding the use of complex two-stent strategies. However with the advent of second-generation drug-eluting stents and the associated improved safety and efficacy, the risks of using two stents for bifurcation lesions has significantly decreased. Maciej Lesiak explores when a two-stent strategy should be used.
Three factors seem to play a critical role in deciding whether or not two stents are needed and all involve a side branch: the importance of a side branch, the extent of atherosclerotic disease in the side branch, and the easiness of side-branch access. The loss of a vessel supplying substantial amount of myocardium will lead to a large periprocedural myocardial infarction, which may worsen patients’ prognosis. Three studies—NORDIC-Baltic Bifurcation IV, Tryton investigational device exemption, and European Bifurcation Club II—recently showed a trend towards improved clinical or angiographic outcome with a two-stent strategy when used in bifurcations with large side branches. They also revealed that at follow-up, side-branch diameter stenosis was higher and restenosis was more frequent with provisional stenting.
Diffuse side-branch disease is another indication for using a two-stent strategy. In such lesions, balloon angioplasty alone is usually not sufficient to ensure the adequate lumen gain, prevent vessel abrupt closure or to prevent restenosis. The choice of technique depends mainly on operator preference and the anatomy.
The T-technique is the simplest one, but may be applied only in rare cases in which the bifurcations angle is wide (>70 degrees). Currently, the mini-crush technique is the most widely used, since it may be applied to any bifurcation anatomy. When performed accurately, it provides an optimal coverage of the lesion, including the side branch ostium.
The double-kiss crush technique (DK crush) is probably its most efficient variant. In fact, this is the only technique that demonstrated clinical superiority over provisional stenting. In the DKCRUSH-II randomised trial, target lesion and target vessel revascularisation were significantly reduced, with a strong trend towards reduction of major adverse cardiac events (MACE) in patients treated with DK crush as compared with those treated with provisional stenting. This technique also proved to be superior to culotte stenting in the DKCRUSH-III study—after one year of follow-up, both target vessel revascularisation and MACE were significantly reduced in patients with unprotected left main distal stenosis.
Numerous bifurcation dedicated stents have been investigated in recent years, but very few have been evaluated in a randomised trial. The largest multicentre randomised study (of more than 700 patients with true bifurcation lesions) to date did not show that the two-stent technique with the Tryton side-branch stent (Tryton) was clinically non-inferior to provisional main vessel stenting with drug-eluting stents. This was mainly due to a small excess of a study-defined periprocedural myocardial infarctions in the Tryton arm, which in turn may be explained by the inclusion of relatively small side branches in the trial (60% did not meet the inclusion criterion of side branch diameter >2.5mm). A post-hoc analysis identified a strong interaction in the occurrence of the primary clinical endpoint (target vessel failure) with side-branch diameter, showing lack of benefit with the complex strategy in smaller side branches and a potential benefit in larger ones (≥2.25mm in diameter). A complementary study with the same device, targeting large side branches is ongoing and the results of this study should be available later this year.
While provisional technique is still recommended as the treatment of choice for bifurcation lesions, recent data show that the use of complex two-stent strategy may be a better option in selected cases—especially in cases in which a side branch is large, diffusely diseased or if the access to this vessel is difficult. An appropriate technique must be selected and a great attention should be paid to every stage of the procedure to ensure an optimal long-term result.
Maciej Lesiak, Department of Cardiology, Poznan University of Medical Sciences, Poznan, Poland