Efficacy of post-dilatation during carotid artery stenting for unstable plaque using closed-cell design stent evaluated by optical coherence tomography

Background and purpose. - This study aimed to use optical coherence tomography (OCT) to evaluate the efficacy of post-dilatation (PD) after stent placement for unstable plaques during carotid artery stenting (CAS) using closed-cell design stent. Materials and methods. - Twelve unstable carotid plaque lesions diagnosed by magnetic resonance imaging were evaluated by OCT during CAS. Pre-procedural minimum lumen diameter and area were 1.5 +/- 0.6 mm and 2.6 +/- 1.6 mm(2), respectively. The lesion was pre-dilated with balloon catheters (diameter 4.8 +/- 0.3 mm), and closed-cell stent was deployed. PD was performed with balloon catheters of the same size as those used for pre-dilatation. Minimum lumen diameter/area and in-stent tissue prolapse volume after stent placement and after PD were calculated by 2-dimensional cross section images. The number of the stent cells showing tissue prolapse and malapposition after stent-placement and after PD were calculated by 3-dimensional analysis. Results. - Compared to after stent placement, in-stent tissue prolapse volume (0.18 +/- 0.10 to 0.22 +/- 0.07 mm(2)/slice, P < 0.01), number of stent cells with any tissue prolapse (12.7 +/- 8.2 to 21.0 +/- 11.8%, P < 0.001) were significantly increased after PD; stent cells with >= 500-mu m tissue prolapse (1.6 +/- 1.1 to 0.7 +/- 0.8%, P<0.01) and stent malapposition (17.4 +/- 7.2 to 14.0 +/- 6.3%, P<0.01) were significantly decreased. Conclusions. - PD after carotid stent placement caused increase in in-stent tissue prolapse volume and small tissue prolapse, however, the in-stent large tissue prolapse decreased, as the in-stent tissue prolapse may have been crushed into debris. (C) 2019 Elsevier Masson SAS. All rights reserved.