1. Articles from atsushi tanaka

    1-24 of 72 1 2 3 »
    1. Intracoronary pressure increase due to contrast injection for optical coherence tomography imaging

      Intracoronary pressure increase due to contrast injection for optical coherence tomography imaging

      Background Optical coherence tomography (OCT) requires intracoronary injection of contrast media to remove blood from the field of view during image acquisition. Contrast injection may cause a temporal increase in intracoronary pressure. The aim of this study was to compare the intracoronary pressure during contrast injection between OCT and coronary angiography . Methods We measured intracoronary pressure by using a pressure guidewire during contrast injection for OCT and angiography in 30 coronary arteries (mean fractional flow reserve = 0.90 ± 0.03). Contrast media was injected into coronary artery through the guiding catheter by using a mechanical injector pump. Results Intracoronary pressure ...

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    2. Plaque burden can be assessed using intravascular optical coherence tomography and a dedicated automated processing algorithm: a comparison study with intravascular ultrasound

      Plaque burden can be assessed using intravascular optical coherence tomography and a dedicated automated processing algorithm: a comparison study with intravascular ultrasound

      Aims Plaque burden (PB) measurement using intravascular optical coherence tomography (IVOCT) is currently thought to be inferior to intravascular ultrasound (IVUS). We developed an automated IVOCT image processing algorithm to enhance the external elastic lamina (EEL) contour. Thus, we investigated the accuracies of standard IVOCT and an IVOCT enhancement algorithm for measuring PB using IVUS as the reference standard. Methods and results The EEL-enhancement algorithm combined adaptive attenuation compensation, exponentiation, angular registration, and image averaging using three sequential frames. In two different laboratories with intravascular imaging expertise, PB was quantified on 200 randomized, matched IVOCT and IVUS images by four ...

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    3. Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      Imaging assessment and accuracy in coronary artery autopsy: comparison of frequency-domain optical coherence tomography with intravascular ultrasound and histology

      ptical coherence tomography (OCT) is a coronary artery imaging technique with high resolution. Second-generation frequency-domain OCT (FD-OCT) technology allows safer and faster clinical application compared with first-generation time-domain OCT (TD-OCT). Only limited validation studies compare FD-OCT with other modes of analysis: histology, which is the current gold standard, and intravascular ultrasound (IVUS). This study therefore aims to demonstrate the accuracy of FD-OCT images compared with IVUS and histology. FD-OCT and IVUS images were acquired from 203 segments from 31 coronary arteries obtained at autopsy from 20 cadavers. Of these, 30 randomly-selected pairs were used to create three classifications of plaque ...

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    4. Stabilization of High Risk Coronary Plaque on Optical Coherence Tomography and Near-Infrared Spectroscopy by Intensive Lipid-Lowering Therapy With Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitor

      Stabilization of High Risk Coronary Plaque on Optical Coherence Tomography and Near-Infrared Spectroscopy by Intensive Lipid-Lowering Therapy With Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) Inhibitor

      A 70-year-old woman with hypertension and dyslipidemia underwent drug-eluting stent implantation in the mid-left anterior descending artery (LAD) due to acute coronary syndrome (ACS). Optical coherence tomography (OCT) during the index procedure showed lipid-rich plaque in non-culprit lesions of the proximal LAD and mid-right coronary artery (Figure B,E). Near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) showed plaque with high lipid burden in both sites (Figure C,F). Intensive lipid-lowering therapy with combined strong statin and proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor was started after the index procedure. Scheduled 10-month follow-up OCT and NIRS-IVUS showed increase in minimum fibrous cap thickness ...

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    5. Role of Optical Coherence Tomography in the Diagnosis of Spontaneous Coronary Artery Dissection

      Role of Optical Coherence Tomography in the Diagnosis of Spontaneous Coronary Artery Dissection

      Spontaneous coronary artery dissection (SCAD) is an infrequent and often missed diagnosis among patients with acute coronary syndrome (ACS), especially young healthy females. Unfortunately, SCAD can result in significant morbidity, such as ischemia and infarction. Currently, there has been a surge in the diagnosis of SCAD due to the widespread use of new intracoronary imaging modalities, especially optical coherence tomography (OCT).However, no specific guidelines exist concerning appropriate treatment for SCAD. Moreover, the role of intracoronary imaging with OCT has yet to be fully established. The aim of our review is to provide a comprehensive contemporary update of SCAD; the ...

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    6. In vivo optical coherence tomography imaging and histopathology of healed coronary plaques

      In vivo optical coherence tomography imaging and histopathology of healed coronary plaques

      Background and aims The aims of this study were to assess agreement between optical coherence tomography (OCT) and histopathology for healed coronary plaques (HCPs) in human coronary arteries ex vivo , and to evaluate the prevalence and characteristics of HCPs in vivo . Methods Ex vivo OCT images were co-registered with histopathology in 144 cross-sections with ≥50% stenosis. Of these, 30 randomly selected pairs were employed to define morphological features of OCT for HCPs (OCT-derived HCPs); the remaining 114 pairs were used to evaluate the accuracy of OCT in detecting histologically-defined HCPs. In a clinical study, 60 target lesions from 60 patients ...

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    7. Effect of Early Pitavastatin Therapy on Coronary Fibrous-Cap Thickness Assessed by Optical Coherence Tomography in Patients With Acute Coronary Syndrome : The ESCORT Study

      Effect of Early Pitavastatin Therapy on Coronary Fibrous-Cap Thickness Assessed by Optical Coherence Tomography in Patients With Acute Coronary Syndrome : The ESCORT Study

      Objectives The aim of the present study was to assess the effect of early statin therapy on fibrous-cap thickness in coronary plaques of patients with acute coronary syndrome (ACS) by using optical coherence tomography. Background Statins can contribute to the stabilization of coronary plaques. Methods This is a prospective, randomized, active-controlled, single-center study. Patients with ACS and untreated dyslipidemia were enrolled and randomly allocated (ratio 1:1) to either the early statin group (received pitavastatin 4 mg/day from baseline) or the late statin group (received pitavastatin 4 mg/day from 3 weeks after the baseline). Optical coherence tomography was ...

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    8. Prognosis of spontaneous coronary artery dissection treated by percutaneous coronary intervention with optical coherence tomography

      Prognosis of spontaneous coronary artery dissection treated by percutaneous coronary intervention with optical coherence tomography

      Background Although about half of patients with spontaneous coronary artery dissection (SCAD) face ongoing necrosis, conservative therapy is recommended due to a high complication rate in angiography-guided percutaneous coronary intervention (PCI). The aim of this study was to investigate clinical outcomes of SCAD treated by optical coherence tomography (OCT)-guided PCI. Methods This study consisted of consecutive 306 patients with acute coronary syndrome (ACS) who underwent OCT-guided PCI. Based on the culprit lesion morphology by OCT, patients were assigned to four groups: a SCAD group, a plaque rupture (PR) group, a calcified nodule (CN) group, and an undetermined etiology (UE ...

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    9. Automatic Fibroatheroma Identification from Intravascular Optical Coherence Tomography Images

      Automatic Fibroatheroma Identification from Intravascular Optical Coherence Tomography Images

      Vulnerable plaque identification is important in coronary heart disease diagnosis. Intravascular Optical Coherence Tomography (IVOCT) is an imaging modality which can characterize the appearance of vulnerable plaques. However, current used manual reading of the images is time consuming and subjective. Therefore, an automated and objective assessment of the plaque is necessary. This paper proposes a method for automatic identification of potential vulnerable plaque such as fibroatheroma in IVOCT images. In the proposed method, a graph search based method is applied to detect the region of interest (ROI) including the inner lumen border and outer border. Then various appearance features including ...

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    10. Optical Coherence Tomography Predictors for Edge Restenosis After Everolimus-Eluting Stent Implantation

      Optical Coherence Tomography Predictors for Edge Restenosis After Everolimus-Eluting Stent Implantation

      Background— Stent edge restenosis (SER) remains a potential limitation of drug-eluting stents. The aim of this study was to determine optical coherence tomography (OCT) predictors for angiographic late SER after everolimus-eluting stent implantation. Methods and Results— We retrospectively analyzed 319 patients who underwent OCT immediately after everolimus-eluting stent implantation and scheduled 9- to 12-month follow-up angiography. The binary angiographic SER rate was 10% (32/319) in the patients, 8.4% (32/382) in lesions, and 4.4% (33/744) in stent edge segments. In the stent edge segments at post stenting, OCT-derived lipidic plaque (61% versus 20%; P <0.001 ...

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    11. Assessment of Vascular Response after Stent Implantation by Intracoronary Optical Coherence Tomograph

      Assessment of Vascular Response after Stent Implantation by Intracoronary Optical Coherence Tomograph

      Optical coherence tomography (OCT) is a high resolution (10-20 μm) imaging modality that provides microscopic visualization of the coronary artery including vascular response after stent implantation. Compared to conventional intravascular ultrasound, OCT can more clearly identify findings immediately after stent implantation, such as tissue protrusion, stent edge dissection, and incomplete stent strut apposition. Furthermore, OCT allows clinicians to accurately assess the late acquired stent malapposition and strut coverage which could be a surrogate marker for stent thrombosis after drug-eluting stent (DES) implantation. OCT can evaluate not only the extent and amount of neointima but also the tissue characteristics of neointimal ...

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    12. Reduction of in-stent thrombus immediately after percutaneous coronary intervention by pretreatment with prasugrel compared with clopidogrel: An optical coherence tomography study

      Reduction of in-stent thrombus immediately after percutaneous coronary intervention by pretreatment with prasugrel compared with clopidogrel: An optical coherence tomography study

      Background Prasugrel is a new-generation thienopyridine antiplatelet agent that provides more consistent and prompt platelet inhibition than clopidogrel. The aim of this study was to compare in-stent thrombus inhibition effect of pretreatment with prasugrel and clopidogrel by using optical coherence tomography (OCT) immediately after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). Methods We performed OCT immediately after PCI in 108 ACS patients pretreated with either prasugrel ( n = 51) or clopidogrel ( n = 57). OCT detected thrombus/plaque protrusion in all stented segments. Results Although stent volume (190.4 ± 119.1 mm 3 vs. 189.4 ± 95.8 mm 3 ...

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    13. Optical coherence tomography assessment of efficacy of thrombus aspiration in patients undergoing a primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

      Optical coherence tomography assessment of efficacy of thrombus aspiration in patients undergoing a primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

      Objective: We used optical coherence tomography (OCT) to assess the impact of thrombus aspiration before angioplasty on poststenting tissue protrusions in patients undergoing a primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Methods and results: A total of 188 patients with STEMI who underwent thrombus-aspiration PCI ( n =113) or standard PCI ( n =75) were examined in this study. OCT was performed immediately after primary PCI to assess lesion morphology in the stented segment. The minimum stent area was similar between the thrombus-aspiration PCI group and the standard PCI group [7.4 interquartile range (IQR): 5.8–9 ...

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    14. Optical coherence tomography assessment of efficacy of thrombus aspiration in patients undergoing a primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

      Optical coherence tomography assessment of efficacy of thrombus aspiration in patients undergoing a primary percutaneous coronary intervention for acute ST-elevation myocardial infarction

      Objective: We used optical coherence tomography (OCT) to assess the impact of thrombus aspiration before angioplasty on poststenting tissue protrusions in patients undergoing a primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI). Methods and results: A total of 188 patients with STEMI who underwent thrombus-aspiration PCI ( n =113) or standard PCI ( n =75) were examined in this study. OCT was performed immediately after primary PCI to assess lesion morphology in the stented segment. The minimum stent area was similar between the thrombus-aspiration PCI group and the standard PCI group [7.4 interquartile range (IQR): 5.8–9 ...

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    15. Multi-laboratory inter-institute reproducibility study of IVOCT and IVUS assessments using published consensus document definitions

      Multi-laboratory inter-institute reproducibility study of IVOCT and IVUS assessments using published consensus document definitions

      Aims The aim of this study was to investigate the reproducibility of intravascular optical coherence tomography (IVOCT) assessments, including a comparison to intravascular ultrasound (IVUS). Intra-observer and inter-observer variabilities of IVOCT have been previously described, whereas inter-institute reliability in multiple laboratories has never been systematically studied. Methods and results In 2 independent laboratories with intravascular imaging expertise, 100 randomized matched data sets of IVOCT and IVUS images were analysed by 4 independent observers according to published consensus document definitions. Intra-observer, inter-observer, and inter-institute variabilities of IVOCT qualitative and quantitative measurements vs. IVUS measurements were assessed. Minor inter- and intra-observer variability ...

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    16. Optimal threshold of postintervention minimum stent area to predict in-stent restenosis in small coronary arteries: An optical coherence tomography analysis

      Optimal threshold of postintervention minimum stent area to predict in-stent restenosis in small coronary arteries: An optical coherence tomography analysis

      Objectives The aim of this study was to determine the best threshold of postintervention minimum stent area (MSA) assessed by optical coherence tomography (OCT) to predict long-term in-stent restenosis (ISR) for 2.5 mm-diameter everolimus-eluting stents (EES). Background Percutaneous coronary intervention (PCI) for small coronary arteries remains challenging. Stent underexpansion is a strong predictor of late ISR. Methods We performed a retrospective analysis of 69 lesions in 69 patients undergoing PCI with 2.5 mm-diameter stents using OCT for the assessment of postintervention MSA and subsequent 9-month angiographic follow-up. Results The rates of angiographic ISR and target lesion revascularization were ...

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    17. Vasa Vasorum Restructuring in Human Atherosclerotic Plaque Vulnerability

      Vasa Vasorum Restructuring in Human Atherosclerotic Plaque Vulnerability

      Background Previous studies have suggested that vasa vasorum (VV) is associated with plaque progression and vulnerability. Objectives The aim of this study was to investigate the relationship between coronary neovascularization structures and plaque characteristics. Methods We included 53 patients who underwent optical coherence tomography to observe the proximal left anterior descending coronary artery. Patients were classified into 5 groups according to lesion characteristics: normal; fibrous plaque (FP); fibroatheroma (FA); plaque rupture (PR); and fibrocalcific plaque (FC). We defined signal-poor tubuloluminal structures recognized in cross-sectional and longitudinal profiles located in adventitial layer as VV, and within plaque as intraplaque neovessels. Two ...

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    18. Optimizing flushing parameters in intracoronary optical coherence tomography: an in vivo swine study

      Optimizing flushing parameters in intracoronary optical coherence tomography: an in vivo swine study

      Intracoronary optical frequency domain imaging (OFDI), requires the displacement of blood for clear visualization of the artery wall. Radiographic contrast agents are highly effective at displacing blood however, may increase the risk of contrast-induced nephropathy. Flushing media viscosity, flow rate, and flush duration influence the efficiency of blood displacement necessary for obtaining diagnostic quality OFDI images. The aim of this work was to determine the optimal flushing parameters necessary to reliably perform intracoronary OFDI while reducing the volume of administered radiographic contrast, and assess the influence of flushing media choice on vessel wall measurements. 144 OFDI pullbacks were acquired together ...

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    19. Successful Stenting With Optical Frequency Domain Imaging Guidance For Spontaneous Coronary Artery Dissection

      Successful Stenting With Optical Frequency Domain Imaging Guidance For Spontaneous Coronary Artery Dissection

      A 51-year-old woman was urgently admitted because of chest pain. Emergent coronary angiography revealed diffuse stenosis from the proximal to distal portion of the right coronary artery (RCA) with Thrombolysis In Myocardial Infarction (TIMI) flow grade 2 (Figure 1 ). No stenosis was seen in the left coronary artery. Intravascular ultrasound (IVUS) images revealed an intracoronary hematoma from the posterior descending artery (PDA) to the ostium of the RCA, but could not demonstrate the entry point of the hematoma (Figure 1 ). Optical frequency domain imaging (OFDI; Terumo, Tokyo, Japan) images clearly demonstrated, not only intracoronary hematoma from the PDA to the ...

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    20. Comparison of vascular response between everolimus-eluting stent and bare metal stent implantation in ST-segment elevation myocardial infarction assessed by optical coherence tomography

      Comparison of vascular response between everolimus-eluting stent and bare metal stent implantation in ST-segment elevation myocardial infarction assessed by optical coherence tomography

      Aims The long-term safety of second-generation everolimus-eluting stents (EESs) in ST-segment elevation myocardial infarction (STEMI) remains unclear. The aim of this study was to evaluate the late vascular response after stent implantation in STEMI between EES and bare-metal stent (BMS) by using optical coherence tomography (OCT). Methods and results A prospective OCT examination was performed in 102 patients at 10 months after stent implantation for treatment of STEMI. A total of 1253 frames with 12 772 struts in 61 EESs and 776 frames with 8594 struts in 41 BMSs were analysed. There were no significant differences in the percentage of ...

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    21. Effect of Atorvastatin Therapy on Fibrous Cap Thickness in Coronary Atherosclerotic Plaque as Assessed by Optical Coherence Tomography The EASY-FIT Study

      Effect of Atorvastatin Therapy on Fibrous Cap Thickness in Coronary Atherosclerotic Plaque as Assessed by Optical Coherence Tomography The EASY-FIT Study

      Background The detailed mechanism of plaque stabilization by statin therapy is not fully understood. Objectives The aim of this study was to assess the effect of lipid-lowering therapy with 20 mg/day of atorvastatin versus 5 mg/day of atorvastatin on fibrous cap thickness in coronary atherosclerotic plaques by using optical coherence tomography (OCT). Methods Seventy patients with unstable angina pectoris and untreated dyslipidemia were randomized to either 20 mg/day or 5 mg/day of atorvastatin therapy. OCT was performed to assess intermediate nonculprit lesions at baseline and 12-month follow-up. Results Serum low-density lipoprotein cholesterol level was significantly lower ...

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