Hiroshi Yabushita

Bio: Hiroshi Yabushita is an academic researcher from Kindai University. The author has contributed to research in topics: Myocardial infarction & Sudden death. The author has an hindex of 9, co-authored 17 publications receiving 2782 citations. Previous affiliations of Hiroshi Yabushita include Harvard University.

Characterization of Human Atherosclerosis by Optical Coherence Tomography

Abstract: Background— High-resolution visualization of atherosclerotic plaque morphology may be essential for identifying coronary plaques that cause acute coronary events. Optical coherence tomography (OCT) is an intravascular imaging modality capable of providing cross-sectional images of tissue with a resolution of 10 μm. To date, OCT imaging has not been investigated in sufficient detail to assess its accuracy for characterizing atherosclerotic plaques. The aim of this study was to establish objective OCT image criteria for atherosclerotic plaque characterization in vitro. Methods and Results— OCT images of 357 (diseased) atherosclerotic arterial segments obtained at autopsy were correlated with histology. OCT image criteria for 3 types of plaque were formulated by analysis of a subset (n=50) of arterial segments. OCT images of fibrous plaques were characterized by homogeneous, signal-rich regions; fibrocalcific plaques by well-delineated, signal-poor regions with sharp borders; and lipid-rich plaques by signal...

Quantification of Macrophage Content in Atherosclerotic Plaques by Optical Coherence Tomography

Abstract: Background—Macrophage degradation of fibrous cap matrix is an important contributor to atherosclerotic plaque instability. An imaging technology capable of identifying macrophages in patients could provide valuable information for assessing plaque vulnerability. Optical coherence tomography (OCT) is a new intravascular imaging modality that allows cross-sectional imaging of tissue with a resolution of 10 m. The aim of this study was to investigate the use of OCT for identifying macrophages in fibrous caps. Methods and Results—OCT images of 26 lipid-rich atherosclerotic arterial segments obtained at autopsy were correlated with histology. Cap macrophage density was quantified morphometrically by immunoperoxidase staining with CD68 and smooth muscle actin and compared with the standard deviation of the OCT signal intensity at corresponding locations. There was a high degree of positive correlation between OCT and histological measurements of fibrous cap macrophage density (r0.84, P0.0001) and a negative correlation between OCT and histological measurements of smooth muscle actin density (r0.56, P0.005). A range of OCT signal standard deviation thresholds (6.15% to 6.35%) yielded 100% sensitivity and specificity for identifying caps containing 10% CD68 staining. Conclusions—The high contrast and resolution of OCT enables the quantification of macrophages within fibrous caps. The unique capabilities of OCT for fibrous cap characterization suggest that this technology may be well suited for identifying vulnerable plaques in patients. (Circulation. 2003;107:113-119.)

Evaluation of intracoronary stenting by intravascular optical coherence tomography

Abstract: Background: Conventional contrast cineangiography and intravascular ultrasound (IVUS) provide a limited definition of vessel microstructure and are unable to evaluate dissection, tissue prolapse, and stent apposition on a size scale less than 100 μm. Objective: To evaluate the use of intravascular optical coherence tomography (OCT) to assess the coronary arteries in patients undergoing coronary stenting. Methods: OCT was employed in patients having percutaneous coronary interventions. Images were obtained before initial balloon dilatation and following stent deployment, and were evaluated for vessel dissection, tissue prolapse, stent apposition, and stent asymmetry. IVUS images were obtained before OCT, using an automatic pull back device. Results: 42 stents were imaged in 39 patients without complications. Dissection, prolapse, and incomplete stent apposition were observed more often with OCT than with IVUS. Vessel dissection was identified in eight stents by OCT and two by IVUS. Tissue prolapse was identified in 29 stents by OCT and 12 by IVUS; the extent of the prolapse (mean (SD)) was 242 (156) μm by OCT and 400 (100) μm by IVUS. Incomplete stent apposition was observed in seven stents by OCT and three by IVUS. Irregular strut separation was identified in 18 stents by both OCT and IVUS. Conclusions: Intracoronary OCT for monitoring stent deployment is feasible and provides superior contrast and resolution of arterial pathology than IVUS.

Long-term nitrate treatment increases cardiac events in patients with healed myocardial infarction

Abstract: BACKGROUND Nitrates dilate coronary arteries, ameliorate myocardial ischemia, minimize left ventricular remodeling, and reduce mortality in patients with acute myocardial infarction. However, the effects of long-term treatment with nitrates on cardiac events in patients with healed myocardial infarction are not known. METHODS AND RESULTS A total of 1,002 patients with healed myocardial infarction (789 male and 213 female) were randomly divided into 2 groups: treatment with nitrates or nontreatment. The mean observation period was 18.0 +/- 19.9 months. Primary end points were nonfatal and fatal recurrent myocardial infarction, death from congestive heart failure, and sudden death. Baseline characteristics of the 2 groups were also compared to determine any effects on outcome. Among the 621 cases treated with nitrates, 41 cases (6.6%) experienced cardiac events during the observation period, whereas only 12 of the 381 cases that were not treated with nitrates (3.1%) had cardiac events. This difference was statistically significant (p < 0.05; odds ratio 2.17; 95% confidence interval 1.13-4.19). There were no differences in the incidence of noncardiac death or being lost to follow-up between the 2 groups. Although the precise mechanism of this increase in the occurrence of cardiac events by long-term treatment with nitrates is not clear, nitrate tolerance with possible rebound and neurohormonal effects may be involved. CONCLUSION Long-term treatment with nitrates increased cardiac events in patients with healed myocardial infarction.

From vulnerable plaque to vulnerable patient: a call for new definitions and risk assessment strategies: Part II.

Abstract: Atherosclerotic cardiovascular disease results in >19 million deaths annually, and coronary heart disease accounts for the majority of this toll. Despite major advances in treatment of coronary heart disease patients, a large number of victims of the disease who are apparently healthy die suddenly without prior symptoms. Available screening and diagnostic methods are insufficient to identify the victims before the event occurs. The recognition of the role of the vulnerable plaque has opened new avenues of opportunity in the field of cardiovascular medicine. This consensus document concludes the following. (1) Rupture-prone plaques are not the only vulnerable plaques. All types of atherosclerotic plaques with high likelihood of thrombotic complications and rapid progression should be considered as vulnerable plaques. We propose a classification for clinical as well as pathological evaluation of vulnerable plaques. (2) Vulnerable plaques are not the only culprit factors for the development of acute coronary syndromes, myocardial infarction, and sudden cardiac death. Vulnerable blood (prone to thrombosis) and vulnerable myocardium (prone to fatal arrhythmia) play an important role in the outcome. Therefore, the term "vulnerable patient" may be more appropriate and is proposed now for the identification of subjects with high likelihood of developing cardiac events in the near future. (3) A quantitative method for cumulative risk assessment of vulnerable patients needs to be developed that may include variables based on plaque, blood, and myocardial vulnerability. In Part I of this consensus document, we cover the new definition of vulnerable plaque and its relationship with vulnerable patients. Part II of this consensus document focuses on vulnerable blood and vulnerable myocardium and provide an outline of overall risk assessment of vulnerable patients. Parts I and II are meant to provide a general consensus and overviews the new field of vulnerable patient. Recently developed assays (eg, C-reactive protein), imaging techniques (eg, CT and MRI), noninvasive electrophysiological tests (for vulnerable myocardium), and emerging catheters (to localize and characterize vulnerable plaque) in combination with future genomic and proteomic techniques will guide us in the search for vulnerable patients. It will also lead to the development and deployment of new therapies and ultimately to reduce the incidence of acute coronary syndromes and sudden cardiac death. We encourage healthcare policy makers to promote translational research for screening and treatment of vulnerable patients.

2012 ACCF/AHA/ACP/AATS/PCNA/SCAI/STS guideline for the diagnosis and management of patients with stable ischemic heart disease: executive summary: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines, and the American College of Physicians, American Association for Thoracic Surgery, Preventive Cardiovascular Nurses Association, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons.

Abstract: Jeffrey L. Anderson, MD, FACC, FAHA, Chair Jonathan L. Halperin, MD, FACC, FAHA, Chair-Elect Alice K. Jacobs, MD, FACC, FAHA, Immediate Past Chair 2009–2011 [§§][1] Sidney C. Smith, Jr, MD, FACC, FAHA, Past Chair 2006–2008 [§§][1] Cynthia D. Adams, MSN, APRN-BC, FAHA[§§][1] Nancy M

The Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2009)

Abstract: The Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2009)

In Vivo Endoscopic Optical Biopsy with Optical Coherence Tomography

Abstract: Current medical imaging technologies allow visualization of tissue anatomy in the human body at resolutions ranging from 100 micrometers to 1 millimeter. These technologies are generally not sensitive enough to detect early-stage tissue abnormalities associated with diseases such as cancer and atherosclerosis, which require micrometer-scale resolution. Here, optical coherence tomography was adapted to allow high-speed visualization of tissue in a living animal with a catheter-endoscope 1 millimeter in diameter. This method, referred to as "optical biopsy," was used to obtain cross-sectional images of the rabbit gastrointestinal and respiratory tracts at 10-micrometer resolution.