Abstract 12390: Association of Plaque Morphology and Tissue Prolapse by OCT with Periprocedural (Type IVa) Myocardial Infarction
Background: Frequency Domain-Optical Coherence Tomography (FD-OCT) is able to define both pre- and post stenting features of the atherosclerotic plaque. We sought to examine whether FD-OCT-defined thin-cap fibroatheroma (TCFA) and post-stenting tissue prolapse had impact on periprocedural (type IVa) Myocardial Infarction (MI).
Methods: FD-OCT was performed before and after coronary stenting in 46 patients undergoing Percutaneous Coronary Intervention (PCI) for either Non-ST segment elevation MI (NSTEMI) or stable angina (SA). All patients underwent single vessel stenting and only drug-eluting stents were implanted. No-one received IIb-IIIa glycoprotein inhibitors. Troponin T was analyzed at admission, before PCI and at 24- and 48-hour after PCI. Periprocedural MI was diagnosed in 19 pts and was defined as a rise of at least 0.03 mg/dl in post-PCI TnT in SA and as a pre-PCI TnT fall followed by post-PCI TnT rise in NSTEMI. The remaining 27 pts were the control group.
Results: Periprocedural MI and control group were not different for NSTEMI frequency (57.9% and 44.4%; p=0.4). Minimum lumen area and imaged stent length were not different between two groups 2.1mm2 (1.5-2.8 IQR) vs 2.1mm2 (1.5-3.2; p=0.7) and 22.4mm (16.2-29.4) vs 20.2mm (18.7-28.2; p=0.7), respectively. FD-OCT showed that TCFA, in-stent thrombus and in-stent dissection were significantly more frequent in periprocedural MI than in control group (78.9% vs 40.7%; p=0.016; 66.7% vs 27.3%; p=0.013 and 66.7% vs 36.4%; p=0.05; respectively). In contrast, tissue prolapse volume, maximal intra-lumen tissue prolapse length and malapposition length were not different between groups, being 4.5mm3(2.5-7.7) vs 4.9mm3 (2.6-8.2) and 327µm (232-466) vs 337µm (254-426) and 339µm (155-857) vs 445µm (256-572).
Conclusions: FD-OCT showed TCFA, in-stent thrombus and in-stent dissection as predictors of periprocedural MI. An underlying vulnerable plaque may represent a complication-prone plaque also after stenting due to its high tendency to rupture, favoring distal embolization. Thrombus attached to the stent struts can be easily dislodged due to its friability. On the contrary, tissue “prolapse” through stent struts might involve more firmly attached material not involved in embolic events.
- © 2011 by American Heart Association, Inc.