The ABSORB BVS is currently being used in daily clinical practice around the world. Unfortunately, very limited data are available about the use of the BVS in coronary bifurcation lesions. Several case reports have shown that treatment of bifurcation lesions and fenestration of the scaffold towards the side branch is feasible, which is supported by in vitro testing. However, all recommendations made in the treatment of coronary bifurcation lesions are not supported by any long-term clinical or in vivo data and are solely based on either expert opinion or limited in vitro data.
D┼¥avík and Colombo are the first to publish in vitro benchmark testing. The tests performed are extensive; however, only one or two experiments were performed in each bifurcation stenting procedure. For example, a double-crush procedure could be successful once or twice but what if the experiment is repeated multiple times, will these results still hold? Although silicone models provide us with valuable insights into BVS geometry, in vitro models almost always have their limitations, which makes it difficult to deduce these results in terms of in vivo use. Silicone models are in general more rigid compared with coronary arteries, which makes it harder to overstretch and fracture the ABSORB BVS. Furthermore, the radial force of these models differ from coronary arteries, which makes assessment of non-apposed struts less reliable.
Okamura et al. provided a detailed description of how the ABSORB BVS obstructs SB orifices at baseline and the patterns of compartmentalisation and the number of compartments obstructing the SB. These observations are intellectually interesting; however, it is uncertain what implications it has for everyday clinical practice. Furthermore, the clinical outcome in relation with the pattern of compartmentalisation and number of compartments is still unknown and needs further investigation.
Moreover, the effect of different bifurcation stenting procedures at follow up is unknown. Different stenting procedures could alter the endothelial shear stress patterns and coronary blood flow in different ways, hypothetically leading to different neointimal formation patterns at 1-year follow up.28 The effect of all these factors could alter the neo-intimal bridge formation in front of the side branch in two ways. At follow-up this could potentially lead to increased neo-intimal formation with obstruction of the SB, although also non-covered NASB struts can persist.
Due to the lack of data, we believe that there is an urgent need for prospective randomised clinical data with OCT imaging for different bifurcation stenting techniques using the ABSORB BVS. In the absence of these data we recommend the use of the single scaffold provisional stenting strategy in coronary artery bifurcation lesions as is recommended by the European bifurcation club for metallic stents.