1. Articles from atsushi tanaka

    1-24 of 78 1 2 3 4 »
    1. Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study

      Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study

      Background The major underlying mechanisms contributing to acute coronary syndrome are plaque rupture, plaque erosion, and calcified nodule. Artery-to-artery embolic myocardial infarction (AAEMI) was defined as ST-segment-elevation myocardial infarction caused by migrating thrombus formed at the proximal ruptured plaque. The aim of this study was to investigate the prevalence and clinical features of AAEMI by using optical coherence tomography. Methods and Results This study retrospectively enrolled 297 patients with ST-segment-elevation myocardial infarction who underwent optical coherence tomography before percutaneous coronary intervention. Patients were divided into 4 groups consisting of plaque rupture, plaque erosion, calcified nodule, and AAEMI according to optical ...

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    2. NIRS-IVUS for Differentiating Coronary Plaque Rupture, Erosion and Calcified Nodule in Acute Myocardial Infarction

      NIRS-IVUS for Differentiating Coronary Plaque Rupture, Erosion and Calcified Nodule in Acute Myocardial Infarction

      Objectives This study sought to investigate the ability of combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS) to differentiate plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN) in acute myocardial infarction (AMI). Background Most acute coronary syndromes occur from coronary thrombosis based on PR, PE, or CN. In vivo differentiation among PR, PE, and CN is a major challenge for intravascular imaging. Methods The study enrolled 244 patients with AMI who had a de novo culprit lesion in a native coronary artery. The culprit lesions were assessed by both NIRS-IVUS and optical coherence tomography (OCT). Maximum lipid core burden ...

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    3. Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention

      Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention

      Background: Optical flow ratio (OFR) is a recently developed method for functional assessment of coronary artery disease based on computational fluid dynamics of vascular anatomical data from intravascular optical coherence tomography (OCT). The purpose of this study was to investigate the relationship between OFR and fractional flow reserve (FFR) in stent-treated arteries immediately after percutaneous coronary intervention (PCI). Methods and Results: The OFR and FFR were measured in 103 coronary arteries immediately after successful PCI with a stent. An increase in the OFR and FFR values within the stent was defined as in-stent ∆OFR and ∆FFR, respectively. The values of ...

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    4. Optical Coherence Tomography Comparison of Percutaneous Coronary Intervention Among Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction

      Optical Coherence Tomography Comparison of Percutaneous Coronary Intervention Among Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction

      Background: Acute myocardial infarction (AMI) is caused by coronary plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN). We used optical coherence tomography (OCT) to compare stent expansion immediately after primary percutaneous coronary intervention (PCI) in patients with AMI caused by PR, PE, or CN. Methods and Results: In all, 288 AMI patients were assessed by OCT before and immediately after PCI, performed with OCT guidance according to OPINION criteria for stent sizing and optimization. The frequency of OCT-identified PR (OCT-PR), OCT-PE, and OCT-CN was 172 (60%), 82 (28%), and 34 (12%), respectively. Minimum stent area was smallest in ...

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    5. Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

      Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters

      Background Although previous studies demonstrated that microcatheter-derived fractional flow reserve (mc-FFR) tends to overestimate lesion severity compared to pressure wire-derived FFR (pw-FFR), the clinical utility of mc-FFR remains obscure. The extent of differences between the two FFR systems and its relation to a lesion-specific parameter remain unknown. In this study, we sought to compare mc-FFR with pw-FFR and determine the lower and upper mc-FFR cut-offs predicting ischemic and non-ischemic stenosis, using an ischemic and a clinical FFR threshold of 0.75 and 0.80 as references, respectively. We further explored optical coherence tomography (OCT) parameters influencing the difference in FFR ...

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    6. Automatic fibroatheroma identification in intravascular optical coherence tomography volumes

      Automatic fibroatheroma identification in intravascular optical coherence tomography volumes

      Coronary heart disease is the most common type of heart disease that leads to heart attacks. The identification of vulnerable plaques, especially the thin-cap fibroatheroma (TCFA), is crucial to the diagnosis of coronary artery disease. Intravascular optical coherence tomography (IVOCT), an emerging imaging modality, has been proven to be useful for the identification of vulnerable plaques. In this work, we propose an approach to identify the volumes with fibroatheroma frames automatically. In the proposed method, we first detect the lumen using a graph-search based method from unfolded images. Then a region of interest starting from the lumen boundary is cropped ...

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    7. 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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    8. 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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    9. 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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    10. 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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    11. 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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    12. 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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    13. 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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    14. 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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    15. 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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    16. 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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    17. 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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    18. 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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    19. 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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    20. 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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    21. 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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