Comparison of acute vessel wall injury after self-expanding stent and conventional balloon-expandable stent implantation: a study with optical coherence tomography.

The acute impact in vivo from a selfexpanding stent on the vessel wall has not been sufficiently evaluated.We sought to compare acute in vivo injury on the vessel wall and the clinical impact between a self-expanding coronary stent and conventional balloon-expandable stents immediately after stent implantation.We included 40 patients (45 vessels) with stable or unstable angina who were assigned to either the self-expanding stent (vProtect Luminal Shield) group (n = 9; Group 1) or the conventional balloon-expandable stent group (n = 36; Group 2). Optical coherence tomography (OCT) was performed after stent deployment, as were qualitative and quantitative assessments of tissue prolapse, intrastent dissection, edge dissection and incomplete stent apposition.Tissue prolapse was visible in all vessels in both groups. The corrected tissue prolapse area by stent length was larger in Group 2 than in Group 1 (0.06 +/- 0.06 vs. 0.02 +/- 0.01 mm(2); p < 0.001). Intrastent dissection was more frequently seen in Group 2 (33/36 vs. 4/9 vessels; p = 0.004) and the mean length of the dissection flap was greater in Group 2 than in Group 1 (277.6 +/- 110.0 vs. 76.9 +/- 103.7 microm; p < 0.001). Although edge dissection was not detected in Group 1, it was visible in 19/36 vessels (52.8%) in Group 2. The frequency of incomplete stent apposition was not significantly different between Group 2 and Group 1 (23/36 vs. 7/9 vessels, p = 0.7), but the mean depth of incomplete stent apposition was greater in Group 2 than in Group 1 (268.2 +/- 72.1 vs. 178.2 +/- 156.7 microm, p = 0.03).A selfexpanding stent was associated with less intrastent dissection and edge dissection than conventional balloon-expandable stents with OCT.