Examination of Stent Deformation and Gap Formation after Complex Stenting of Left Main Coronary Artery Bifurcations Using Microfocus Computed Tomography

Background: Fluoroscopy and intravascular ultrasound (IVUS) lack sufficient resolution for assessing the results of complex stenting in true bifurcation lesions. Objectives: After diverse bifurcation stenting at the left main coronary artery (LM) bifurcation model, the results were examined using microfocus computed tomography (MFCT). Methods: The strut distribution of three kinds of stents deployed on a straight vessel segment was investigated. Classical crush, double kissing (DK)-double crush, and culotte stenting were performed on a three-dimensional (3D) LM model. The results were assessed using cross-sectional, longitudinal, and 3D reconstruction views of MFCT. Results: Nonuniform strut distribution was observed in a corrugated stent design deployed on a straight vessel segment. Following classical crush stenting, a relatively large gap at the nonmyocardial site was observed in the corrugated stents. When the guidewire recrossed outside the ostium of the crushed side branch stent, kissing balloon inflation caused further crushing of the stent at the more distal segment. The dilated strut rose up from the main vessel bed after the first kissing balloon inflation in DK crush stenting; the advantage of DK would be cancelled after main vessel stenting due to recrushing the raised strut. The culotte stenting with closed-cell stents showed the restriction of the expansion at the branch ostium when it was dilated with a 3.5-mm balloon. The culotte stenting with open-cell-based stents showed a good stent apposition except for a tiny gap and small metallic carina at the distal bifurcation. Conclusion: MFCT analysis in the 3D phantom model is useful to assess the structural deformation of the stents and gap on vessel wall coverage after complex stenting at the LM bifurcation. (J Interven Cardiol 2009;22:135-144).