Three-dimensional modeling of double-stent techniques at the left main coronary artery bifurcation using micro-focus X-ray computed tomography.

BACKGROUND: Various double-stent techniques using drug-eluting stents have been proposed to treat the left main coronary artery (LMCA) bifurcation. However, use of these techniques is frequently associated with focal restenosis at the ostium of the left circumflex coronary artery (LCX).

OBJECTIVES: To examine the results of double-stent techniques, using a silicon model of the LMCA bifurcation and three-dimensional (3D) reconstruction images created with micro-focus X-ray computed tomography (MFCT).

METHODS: Crush, kissing, and modified T stentings were performed with bare metal stents in a LMCA bifurcation model. The stents were then inspected using MFCT at a minimal resolution of 0.06 mm.

RESULTS: Gaps in stent apposition to the vessel were observed at the site of stent overlap in the distal LMCA with all stenting techniques. In crush stenting, when the left anterior descending artery stent overlapped the LCX stent, the latter was crushed on the myocardial side of the vessel, and a gap was observed on the nonmyocardial side, at the LCX ostium. When the overlap was reversed, the LCX stent was crushed on the nonmyocardial side and a gap was observed on the myocardial side. In the case of kissing stents, stent overlap created a gap beneath the overlapped portion of the stents. In modified T-stenting, correct positioning of the LCX stent was difficult and MFCT imaging revealed a nonmyocardial gap.

CONCLUSIONS: Close apposition of the stent to the vessel at the ostium of the LCX is difficult to achieve at the LMCA bifurcation, regardless of which double-stent technique is employed, due to the site's wide bifurcation angle and complex 3D structure. The distribution of plaque and the bifurcation angle should be considered before double-stent deployment, to avoid leaving a gap over significant plaques.