Side Branch Interventions After Main Vessel Stent Implantation
Trials conducted in the setting of (selected) bifurcated lesions have used different protocols of the provisional technique (as testified by the highly variable rates of SB ballooning and stenting). The available clinical data suggest that routine kissing balloon inflation is not associated with improved clinical outcome.17,18 However, kissing ballooning in patients undergoing provisional stenting has been recognised to:
Thus SB rewiring and kissing balloon dilation retains a relevant role in bifurcation interventions conducted according to the provisional approach, especially in the subgroup of patients with complex anatomies.
In the recent years, it has been recognised that the SB rewiring site impacts on MV stent distortion after SB dilation. Crossing of the MV stent struts in the most distal cell is associated with better SB ostium scaffolding.21-22 Accordingly, the operators should focus their attention not only on getting into the SB through the stent but also in doing this in the most distal part of the SB ostium. To this aim, the best way is to wire the SB with the pullback technique (see Figure 2),6 and check the rewiring site before performing kissing balloon inflation. To do this, some authors have recently proposed OCT assessment.21 A simple alternative method consists of pulling back the jailed wire until the radiopaque segment is located at the bifurcation level to facilitate visualisation of the distance between jailed wire and rewiring wire, as shown in Figure 2.
Once the wire has re-crossed the stent struts, SB dilation is usually performed with the kissing balloon technique. Such attitude is supported by a series of experimental data documenting that isolated SB balloon dilation, without kissing balloon inflation, induces a stent deformation in the MV resulting in lumen reduction distal to the carina.23-25 The choice of balloons for kissing inflation should consider diameters that match the two branches and have a length sufficiently short to avoid inflating them out of the stent. Recently, the use of non-compliant balloons has been proposed for final kissing inflation to have better opening of the stent struts and to reduce SB dissections.26
Concerning rewiring and kissing balloon procedural features, it must be underlined that the technical characteristics of the DES implanted in the MV may play a pivotal role. Indeed, the size and the shape of the MV stent cells to be re-crossed have major differences among available stents and this may translate into different easiness of SB management.27
How to Rescue a Failed Provisional Approach
The worst scenario in the setting of a bifurcation intervention with provisional technique is represented by comp lete loss of a relevant SB after MV stenting, with failure to rewire it. When SB occlusion is clinically relevant and any attempt to rewire it fails, operators should consider the possibility of a rescue technique28 based on the advancement of a small balloon over the jailed wire with the aim of reaching the SB under the stent struts. Gentle balloon dilation may restore SB flow thus facilitating rewiring. In such circumstances, jailed balloon-induced MV stent distortion should be corrected by the POT and final kissing balloon inflation.