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Purpose: To investigate the association of the degree of stent expansion, as assessed by optical coherence tomography (OCT), following stent implantation, and clinical outcomes in ST-segment elevation myocardial infarction (STEMI) patients., Methods: STEMI patients from the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) OCT study were selected; Clinical outcomes were collected through 1 year. Stent expansion index is a minimum stent area (MSA) divided by average lumen area (average of proximal and distal reference lumen area). The following variables were measured: MSA (< 4.5mm 2 ), dissection (> 200 µm in width and < 5 mm from stent segment), malapposition (> 200 µm distance of stent from vessel wall), a thrombus (area > 5% of lumen area) were compared., Results: A total of 151 patients were included; after excluding patients with suboptimal OCT quality, the population with available OCT was classified into 2 groups: under-expanded < 90% (N = 72, 51%) and well-expanded ≥ 90% (N = 67, 49%). In the well-expanded group, a significant number of the proximal vessels had a lumen area < 4.5mm 2 (16.1%, p < 0.001) and a greater thrombus burden within stent (56.7%, p = 0.042). The overall 30 day and 1 year major adverse cardiovascular event (MACE) rates were 5% and 6.1%, respectively., Conclusion: Irrespective of the degree of stent expansion, the OCT findings, in STEMI patients, and the MACE at 30 days and one year follow up was low; further, well-expanded stents led to a more significant residual thrombotic burden within the stent but seemed to have insignificant clinical impact. Acknowledged stent optimization criteria, traditionally related to worse outcomes in stable patients, do not seem to be associated with worse outcomes in this STEMI population.

Studies have shown that the quantitative flow ratio (QFR), recently introduced to assess lesion severity from coronary angiography, provides useful prognostic information; however the additive value of this technique over intravascular imaging in detecting lesions that are likely to cause events is yet unclear. We analysed data acquired in the PROSPECT and IBIS-4 studies, in particular the baseline virtual histology-intravascular ultrasound (VH-IVUS) and angiographic data from 17 non-culprit lesions with a presumable vulnerable phenotype (i.e., thin or thick cap fibroatheroma) that caused major adverse cardiac events or required revascularization (MACE) at 5-year follow-up and from a group of 78 vulnerable plaques that remained quiescent. The segments studied by VH-IVUS were identified in coronary angiography and the QFR was estimated. The additive value of 3-dimensional quantitative coronary angiography (3D-QCA) and of the QFR in predicting MACE at 5 year follow-up beyond plaque characteristics was examined. It was found that MACE lesions had a greater plaque burden (PB) and smaller minimum lumen area (MLA) on VH-IVUS, a longer length and a smaller minimum lumen diameter (MLD) on 3D-QCA and a lower QFR compared with lesions that remained quiescent. By univariate analysis MLA, PB, MLD, lesion length on 3D-QCA and QFR were predictors of MACE. In multivariate analysis a low but normal QFR (> 0.80 to < 0.97) was the only independent prediction of MACE (HR 3.53, 95% CI 1.16-10.75; P = 0.027). In non-flow limiting lesions with a vulnerable phenotype, QFR may provide additional prognostic information beyond plaque morphology for predicting MACE throughout 5 years.

Objectives: This study sought to examine the utility of multimodality intravascular imaging and of the endothelial shear stress (ESS) distribution to predict atherosclerotic evolution., Background: There is robust evidence that intravascular ultrasound (IVUS)-derived plaque characteristics and ESS distribution can predict, with however limited accuracy, atherosclerotic evolution; nevertheless, it is yet unclear whether multimodality imaging and ESS mapping enable more accurate prediction of coronary plaque progression., Methods: A total of 44 patients admitted with a myocardial infarction that had successful revascularization and 3-vessel IVUS and optical coherence tomography (OCT) imaging at baseline and 13-month follow-up were included in the study. The IVUS data acquired at baseline in the nonculprit vessels were fused with x-ray angiography to reconstruct coronary anatomy and in the obtained models blood flow simulation was performed and the ESS was estimated. The baseline plaque characteristics and ESS distribution were used to identify predictors of disease progression: defined as a lumen reduction and an increase in plaque burden at follow-up., Results: Seventy-three vessels were included in the final analysis. Baseline ESS and the IVUS-derived but not the OCT-derived plaque characteristics were independently associated with a decrease in lumen area and an increase in plaque burden. Low ESS (odds ratio: 0.45; 95% confidence interval: 0.28 to 0.71; p < 0.001) and plaque burden (odds ratio: 0.73; 95% confidence interval: 0.54 to 0.97; p = 0.030) were the only independent predictors of disease progression at follow-up. The accuracy of the IVUS-derived plaque characteristics in predicting disease progression did not improve when ESS (AUC: 0.824 vs. 0.847; p = 0.127) or when OCT variables and ESS (AUC: 0.842; p = 0.611) were added into the model., Conclusions: ESS and OCT-derived variables did not improve the efficacy of IVUS in predicting disease progression. Further research is required to investigate whether multimodality imaging combined with ESS mapping will allow more reliable vulnerable plaque detection. (Comparison of Biomatrix Versus Gazelle in ST-Elevation Myocardial Infarction [STEMI] [COMFORTABLE]; NCT00962416)., (Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study assessed changes in optical coherence tomography (OCT)-defined plaque composition in patients with ST-elevation myocardial infarction (STEMI) receiving high-intensity statin treatment., Background: OCT is a high-resolution modality capable of measuring plaque characteristics including fibrous cap thickness (FCT) and macrophage infiltration. There is limited in vivo evidence regarding the effects of statins on OCT-defined coronary atheroma composition and no evidence in the context of STEMI., Methods: In the IBIS-4 (Integrated Biomarker Imaging Study-4), 103 patients underwent intravascular ultrasonography and OCT of 2 noninfarct-related coronary arteries in the acute phase of STEMI. Patients were treated with high-dose rosuvastatin for 13 months. Serial OCT imaging was available in 153 arteries from 83 patients. We measured FCT by using a semi-automated method. Co-primary endpoints consisted of the change in minimum FCT (measured in fibroatheromas) and change in macrophage line arc., Results: At 13 months, median low-density lipoprotein cholesterol had decreased from 128 mg/dl to 73.6 mg/dl. Minimum FCT, measured in 31 lesions from 27 patients, increased from 64.9 ± 19.9 μm to 87.9 ± 38.1 μm (p = 0.008). Macrophage line arc decreased from 9.6° ± 12.8° to 6.4° ± 9.6° (p < 0.0001). The secondary endpoint, mean lipid arc, decreased from 55.9° ± 37° to 43.5° ± 33.5°. In lesion-level analyses (n = 191), 9 of 13 thin-cap fibroatheromata (TCFAs) at baseline (69.2%) regressed to non-TCFA morphology, whereas 2 of 178 non-TCFA lesions (1.1%) progressed to TCFAs., Conclusions: In this observational study, we found significant increase in minimum FCT, reduction in macrophage accumulation, and frequent regression of TCFAs to other plaque phenotypes in nonculprit lesions of patients with STEMI treated with high-intensity statin therapy., (Copyright © 2019 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aim: To examine the effect of endothelial shear stress (ESS) on the dynamic changes in plaque phenotype., Methods: Patients with myocardial infarction that had intravascular ultrasound-virtual histology (IVUS-VH) and optical coherence tomography (OCT) at baseline and 13-month follow-up were studied. The IVUS-VH data were used to reconstruct the nonculprit vessels, and in the obtained models the ESS was estimated in 3 mm segments. Plaque morphology was derived in each segment from IVUS-VH and OCT. Disease progression was defined as the presence of ≥2 out of the following criteria: reduction in lumen area, increase in plaque burden and change of plaque morphology to a more vulnerable phenotype. Linear mixed effects models were used to assess the effect of ESS in different phenotypes., Results: Sixty-eight vessels were included in the analysis. Low ESS was associated with plaque progression in all phenotypes. The effect of ESS on plaque burden (p for interaction=0.467) and phenotype (p for interaction=0.188) was similar in all plaque types, whereas the effect of ESS on the changes in lumen dimensions was more prominent in disease-free (β=0.70, p<0.001) than fibrotic/fibrocalcific (β=0.28, p<0.001) or lipid-rich plaques (β=0.15, p=0.015). Standalone IVUS-VH misclassified plaque morphology in one-third of the cases leading to erroneous estimations about the effect of ESS on plaque evolution in different phenotypes., Conclusions: The effect of ESS on plaque progression is similar in all phenotypes and cannot be accurately assessed by standalone IVUS-VH which often misclassifies plaque morphology. Therefore, multimodality imaging should be considered to examine the implications of ESS on plaque evolution., Clinical Trial Registration: NCT00962416; Post-results., Competing Interests: Competing interests: LR reports research grants by Abbott, Sanofi and Regeneron., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: The study sought to assess whether treatment with ticagrelor, as compared with prasugrel and clopidogrel, improves endothelium-dependent dilation throughout the course of the treatment and other vascular biomarkers, including systemic adenosine plasma levels., Background: The in vivo off-target effects of ticagrelor in post-acute coronary syndrome (ACS) patients remain poorly characterized., Methods: Fifty-four stable post-ACS patients were sequentially exposed to each of the 3 oral P2Y 12 inhibitors following a 3-period balanced Latin square crossover design with 4 weeks per treatment in 5 European centers. The primary endpoint was the assessment of endothelial function with pulse amplitude tonometry and expressed as reactive hyperemia index at treatment steady state. Secondary endpoints included reactive hyperemia index after loading or before maintenance regimen, systemic adenosine plasma levels, a wide set of vascular biomarkers, and ticagrelor or AR-C124910XX plasma levels throughout each ticagrelor period. In 9 patients, the evaluation of endothelial function was performed simultaneously by pulse amplitude tonometry and flow-mediated dilation., Results: Reactive hyperemia index did not differ after ticagrelor (1.970 ± 0.535) as compared with prasugrel (2.007 ± 0.640; p = 0.557) or clopidogrel (2.072 ± 0.646; p = 0.685), nor did systemic adenosine plasma levels or vascular biomarkers at any time points. P2Y 12 platelet reactivity units were lower after ticagrelor as compared with clopidogrel at all time points and after maintenance dose as compared with prasugrel. Flow-mediated dilation did not differ after the maintenance dose of ticagrelor as compared with clopidogrel and prasugrel., Conclusions: Ticagrelor did not improve endothelial function or increased systemic adenosine plasma levels as compared with prasugrel and clopidogrel in stabilized patients who suffered from an ACS. (Hunting for the Off-Target Properties of Ticagrelor on Endothelial Function in Humans [HI-TECH]; NCT02587260)., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)