Effects Of TCFA On Stent Neointimal Coverage At 9 Months After EXCEL Drug-eluting Stent Implantation Assessed By OCT

BACKGROUND:Although drug-eluting stents have reduced rates of restenosis and late lumen loss compared with bare metal stents, late stent thrombosis (LST), a life-threatening complication of this technology, has emerged as a major concern. Researches indicated incomplete neointimal coverage of stent struts as the most important morphometric predictor of LST. Pathological research showed stenting disruption of adjacent vulnerable plaques can precipitate LST, Meanwhile, thin-cap fibroatheromas (TCFA) as the most important predictor of Major Adverse Cardiovascular. Therefore, there is a hypothesis that TCFA may impair intimal healing which are prone to LST in vivo.Optical coherence tomography (OCT) is a high-resolution (<10μm), catheter-based imaging modality capable of investigating detailed coronary plaque morphology in vivo. This study aimed to observe that TCFA will arise what of the effect on intimal healing of stent struts in the artery in 9 months after EXCELTM stent was implanted by OCT (ClinicalTrials.gov number, NCT02384837).Part Ⅰ:OCT Assessment of the distribution of thin-cap fibroattheromas in target coronary arteries for patients with Non ST segment elevated acute cornary syndromeOBJECTIVES:We evaluated the distribution of thin-cap fibroatheromas (TCFAs) in target coronary arteries for patients with Non-ST segment elevated acute cornary syndrome (NSTEACS) by optical coherence tomography (OCT), a high-resolution imaging equipment.METHODS:We did target vessel OCT examinations in 33 patients:24 unstable angina pectoris,9 NSTEMI patients. The criteria for TCFA in an OCT image was a lipid-rich plaque with fibrotic cap thickness 65μm. OCT measured the distance between each TCFA location and the respective coronary artery ostium. The total length of all 3 coronary arteries imaged by OCT pullbacks was 82±22mm in the left anterior descending coronary artery (LAD),75±25 mm in the left circumflex coronary artery (LCx), and 91±27 mm in the right coronary artery (RCA).RESULTS:OCT detected 38 TCFAs in 29 target vessels. The minimum fibrous-cap thickness of TCFAs was56.7±6.4μm in NSTEMI patients, and 55.4±7.5μm in unstable angina pectoris patients (p=0.5).Of the total of 38 TCFAs,18 were detected in the LAD, 9 in the LCx, and 11 in the RCA. Most LAD TCFAs were located between 0 and 40 mm from the LAD ostium (88.9%). However, LCx and RCA TCFAs were evenly distributed throughout the entire coronary length.CONCLUSIONS:OCT imaging indicated that TCFAs tend to cluster in the proximal segment of the LAD, but evenly distributed throughout the entire coronary length of the LCx and RCA arteries in Non-ST segment elevated acute cornary syndrome. imaging equipment.Part II:Effects of TCFA on stent neointimal coverage at 9 months after EXCEL drug-eluting stent implantation assessed by OCT imaging equipment.OBJECTIVES:We observed that TCFA will arise what of the effect on intimal healing of stent struts in the artery in 9 months after EXCELTM stent was implanted by optical coherence tomography (OCT).METHODS:A total of 33 patients (17 TCFAs and 16 Non-TCFAs) were involved in this study. Among these patient,28 patients were finally evaluated by optical coherence tomography 9 months after EXCELTM implantation. Strut apposition, neointimal hyperplasia thickness, and stent coverage on each stent were evaluated. Rate of tissue prolapse was higher in TCFAs group than Non-TCFAs group after PCI (1.4±4.6 vs 0.3±1.6 p=0.03). Mean NIH thickness was singnificantly thinner in TCFAs group than Non-TCFAs group at 9 months follow-up (67.2±35.5 vs 145.1±48.7 p<0.001). The percentage of uncovered strut was significantly greater in TCFAs group than Non-TCFAs group (10.1±9.7 vs 4.8±4.3 p=0.05). The percentage of malapposed struts was also significantly higher in TCFAs group than Non-TCFAs group (2.1±4.7 vs 0.3±0.5 p=0.003) at 9 months follow-up. In the multivariate analyisis using generalized mixed linear model showed that TCFAs was an independent predictor to increase the percentage of uncovered strut. However, lesion type(B2 or C) was independent predictors to lower the percentage of malapposed strut.CONCLUSIONS:OCT imaging showed that TCFAs slowed the progression of endothelialization on stent strut in Non-ST segment elevated acute cornary syndrome. TCFAs was an independent predictor to increase the percentage of uncovered strut.