Hiroyuki Ito

Saitama Medical University, Saitama, Saitama, Japan

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Publications (18)52.06 Total impact

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    ABSTRACT: A 55-year-old female with a history of hypertension was admitted for dyspnea, epigastralgia and nausea. A chest X-ray showed pulmonary congestion. Transthoracic echocardiography (TTE) revealed severe left ventricular dysfunction with akinesis of the infero-posterior wall and Doppler color-flow mode showed mild aortic regurgitation (AR). Noninvasive positive pressure ventilation, intravenous heparin and diuretics were administered. Follow-up TTE revealed a dissection flap as well as momentary and wide AR only during isovolumetric relaxation. Contrast-enhanced computed tomography of the chest revealed Stanford type A aortic dissection. A momentary and wide AR in echocardiograms might serve as an important and useful indicator of aortic dissection in patients with acute myocardial infarction and congestive heart failure.
    General Thoracic and Cardiovascular Surgery 10/2015; DOI:10.1007/s11748-015-0595-y
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    ABSTRACT: Eicosapentaenoic acid (EPA) has been reported to augment endothelial function and improve clinical outcomes in patients with coronary artery disease (CAD). The purpose of this study was to determine whether EPA could improve residual endothelial dysfunction despite adequate lipid-lowering with statin in CAD patients. Eighty patients with established CAD, who had been on statin treatment and had serum low-density lipoprotein cholesterol (LDL-C) levels <100 mg/dl, were randomly assigned to receive either 1,800 mg of EPA daily plus statin (EPA group, n = 40) or statin alone (Control group, n = 40). Lipid profiles and flow-mediated dilation (FMD) were assessed just before and after more than 3 months of treatment in both groups. Only patients who had impaired FMD (<6 %) before randomization were enrolled. After treatment for 5.2 ± 1.7 months, the EPA group showed a significant increase in the serum concentration of EPA and EPA to arachidonic acid (AA) (EPA/AA) ratio (62.5 ± 38.1 to 159.8 ± 53.8 μg/ml, 0.45 ± 0.34 to 1.20 ± 0.55, p < 0.01 for both). In the EPA group, serum triglycerides significantly decreased (150.7 ± 92.9 to 119.3 ± 60.7 mg/dl, p = 0.02), whereas no significant change was seen in the Control group. FMD, the primary study endpoint, showed a significant improvement in the EPA group (2.6 ± 1.6 % to 3.2 ± 1.6 %, p = 0.02), whereas no significant change was observed in the Control group (2.7 ± 1.6 % to 2.4 ± 1.7 %, p = 0.29). EPA improved endothelial function and impaired FMD in patients with established CAD who were on optimal statin therapy.
    Cardiovascular Drugs and Therapy 10/2013; 28(1). DOI:10.1007/s10557-013-6496-3 · 3.19 Impact Factor
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    Journal of the American College of Cardiology 03/2013; 61(10). DOI:10.1016/S0735-1097(13)60609-9 · 16.50 Impact Factor
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    ABSTRACT: Aortopulmonary artery fistula is uncommon, but the clinical outcome is often lethal. A 76-year-old man with a history of acute thoracic aortic dissection 6 years previously was admitted with dyspnea. A chest x-ray showed pleural effusion and pulmonary congestion. Transthoracic echocardiography revealed preserved systolic function, but continuous and abnormal flow from the distal aortic arch into the pulmonary artery (PA). Transesophageal echocardiography (TEE) in the Doppler color-flow mode demonstrated a left-to-right shunt between a large distal aortic arch aneurysm and the left PA via an aortopulmonary fistula and a pressure gradient across the shunt of 56 mmHg. Contrast-enhanced computed tomography showed that the aneurysm compressed the PA. Aortography also revealed a large distal aortic arch aneurysm and almost simultaneous contrast enhancement of the aorta and the PA. Right-heart catheterization showed a significant increase in oxygen saturation between the right ventricle and the PA. A left-to-right shunt due to a distal aortic arch aneurysm rupturing into the left PA was diagnosed based on these findings. TEE was very helpful in confirming the presence and precise location of the fistula.
    Echocardiography 01/2013; 30(3). DOI:10.1111/echo.12092 · 1.25 Impact Factor
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    Journal of the American College of Cardiology 03/2012; 59(13). DOI:10.1016/S0735-1097(12)61774-4 · 16.50 Impact Factor
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    ABSTRACT: How coronary distensibility contributes to stable or unstable clinical manifestations remains obscure. We postulated that the heterogeneous plaque distensibility is associated with unstable clinical presentations in patients with acute coronary syndrome (ACS). Seventeen and 19 ACS-related and -unrelated lesions, respectively, were visualized using intravascular ultrasound imaging with simultaneous intracoronary pressure recording. Systolic and diastolic lumen cross-sectional areas were measured at the lesion site and at five evenly spaced sites between the proximal and distal reference sites. The coronary distensibility index and stiffness index β were calculated for each site and averaged for each coronary segment. Maximal distensibility index, standard deviation and the difference between maximal and minimal distensibility indices within each segment were significantly higher in the ACS-related than -unrelated plaques (5.6 ± 2.3 vs. 3.7 ± 1.8, p < 0.001, 2.1 ± 0.9 vs. 1.1 ± 0.6, p < 0.001 and 5.3 ± 2.3 vs. 2.8 ± 1.5, p < 0.001, respectively). Moreover, the difference in the distensibility index between the lesion site of ACS-related plaques and the immediate proximal site was significantly larger (2.88 ± 2.35 vs. 1.17 ± 1.44, p = 0.022) than that in ACS-unrelated plaques. Coronary artery distensibility is longitudinally more heterogeneous in ACS-related than-unrelated plaques, especially between the lesion and the immediate proximal site.
    Clinical Research in Cardiology 02/2012; 101(7):545-51. DOI:10.1007/s00392-012-0424-6 · 4.56 Impact Factor
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    ABSTRACT: The slurries-containing tetra-n-butyl ammonium bromide (TBAB) solution and its semiclathrate hydrate have attracted a lot of interest as latent heat transport media. These hydrate slurries contain some microparticles of crystal, and the size and shape of these hydrate particles could affect the mobility of slurries. Hence, it is essential to investigate the efficient hydrate-slurry preparation methods and the effect of hydrate particles on the fluid property of slurries for the application to latent heat transport media. In the present study, the effect of agitation on particle size distribution and aggregation of particles was studied to prepare easily flowing TBAB hydrate slurries that were suitable for fluid transport. First of all, the effects of impeller rotational speed and impeller type on the particle size and frequency of aggregation were investigated. The results suggested that the particle size distribution and the frequency of particle aggregation are strongly affected by the intensity of shear rate and its uniformity, which was controllable with impeller type and its rotation speed.
    International Journal of Chemical Engineering 01/2012; 2012. DOI:10.1155/2012/856120
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    ABSTRACT: In the present study, isolated mixing regions (IMRs) in an agitated vessel using a paddle or disk-turbine impeller have been visualized experimentally, and their structural properties and formation mechanism are investigated in detail. A set of thin filaments spirally wrapping around the core of a toroidal isolated mixing region is observed under laminar-flow conditions, where the Reynolds number is smaller than 60. This filament rotates in both directions of horizontal and vertical circulating flows. The three-dimensional geometrical structure of a filament in an IMR depends on the periodical perturbations caused by the rotating impeller. We have succeeded in the determination of the three-dimensional geometrical structure of a filament in an IMR based on the relationship between the movement of a fluid particle and filament numbers and/or wire turns. Interestingly, the wire turns of filaments are opposite to movement of fluid particles.
    Journal of chemical engineering of Japan 01/2011; 44(11):845-851. DOI:10.1252/jcej.11we045 · 0.64 Impact Factor
  • KAGAKU KOGAKU RONBUNSHU 01/2010; 36(1):1-16. DOI:10.1252/kakoronbunshu.36.1 · 0.44 Impact Factor
  • Shunsuke Hashimoto · Hiroyuki Ito · Yoshiro Inoue
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    ABSTRACT: Isolated mixing region in agitated vessel with rotated two-bladed paddle impeller and no baffle was visualized experimentally and its structural property was investigated in detail. A set of thin filaments spirally wrapping around the core of the toroidal isolated mixing region is observed under low Reynolds number conditions, which is smaller than 60. Three-dimensional geometrical structure of filament in isolated mixing region depends on the periodical perturbations caused by the rotating impeller. We have succeeded in the determination of three-dimensional geometrical structure of filament in isolated mixing region based on relation between the movement of fluid particle and filament numbers and/or wire turns. Interestingly, the wire turns of filaments are opposite to movements of fluid particles.
    Chemical Engineering Science 12/2009; 64(24):5173-5181. DOI:10.1016/j.ces.2009.08.024 · 2.34 Impact Factor
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    ABSTRACT: Preventing left ventricular (LV) remodeling after coronary artery bypass graft surgery (CABG) is important to avoid long-term congestive heart failure. The present study evaluated the effects of angiotensin converting enzyme inhibitors (ACEIs) and beta-blockers on LV remodeling. Twenty-three patients with angina pectoris and 36 with old myocardial infarction underwent CABG. We assessed end diastolic volume index (EDVI), end systolic volume index (ESVI), and ejection fraction (EF) using left ventriculography before and after CABG. Changes in EDVI, ESVI, and EF were studied in the ACEI, beta-blocker, and control groups. Although EDVI was reduced in the ACEI group, ESVI and EF improved only slightly, whereas in the group given beta-blockers, ESVI was reduced, EF improved, and EDVI was minimally reduced. These results indicate that ACEIs and beta-blockers both protect against LV remodeling, although through different mechanisms.
    International Heart Journal 08/2008; 49(4):385-90. · 1.07 Impact Factor
  • International Heart Journal 01/2008; 49(4):385-390. DOI:10.1536/ihj.49.385 · 1.07 Impact Factor
  • Hiroyuki Ito · Nobuo Yoshimoto
    Nippon rinsho. Japanese journal of clinical medicine 06/2003; 61 Suppl 5:17-21.
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    ABSTRACT: TdP is a serious complication of AV block. We report a case of complete AV block with QT prolongation who had bouts of TdP resistant to lidocaine and isoproterenol. Temporary pacing could not be performed, because insertion of a pacing lead triggered TdP that deteriorated into ventricular fibrillation. Nicorandil, a potassium channel opener, shortened the QT interval and abolished TdP. This may suggest that potassium channel opening drugs are clinically effective against TdP associated with bradycardia-dependent QT prolongation.
    Pacing and Clinical Electrophysiology 05/1999; 22(4 Pt 1):686-8. DOI:10.1111/j.1540-8159.1999.tb00516.x · 1.13 Impact Factor
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    ABSTRACT: A new method was devised to estimate infarct size using dual single photon emission computed tomography with thallium-201 and technetium-99m pyrophosphate. Designating the ratio of infarct area to whole myocardial volume as %MI, the correlation of %MI with other markers of left ventricular dysfunction was examined: peak creatine kinase, ejection fraction and left ventricular asynergy. As %MI correlated well with these markers, it is considered that %MI will be useful for estimating infarct size and predicting the severity of left ventricular dysfunction in the early stage of acute myocardial infarction.
    Japanese Circulation Journal 04/1999; 63(3):155-9. DOI:10.1253/jcj.63.155
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    ABSTRACT: Flecainide and pilsicainide, Class IC antiarrhythmic drugs with slow kinetics, were administered to a 64-year-old man experiencing ventricular tachycardia. Both drugs suppressed the arrhythmia, but caused ST segment elevation in leads II, III, and aVF. No evidence of ischemic heart disease was detected. Withdrawal of the drugs eliminated the ST change. Because these drugs frequently are used to treat tachyarrhythmias in patients who may present with chest pain, this rare ECG manifestation of Class IC drugs should be recognized to avoid misdiagnosis of acute inferior myocardial infarction.
    Journal of Cardiovascular Electrophysiology 09/1998; 9(8):855-8. DOI:10.1111/j.1540-8167.1998.tb00125.x · 2.96 Impact Factor
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    ABSTRACT: A 49-year-old male was admitted to our hospital because of chest pain. The pain occurred simultaneously with tachycardia-dependent left bundle branch block (LBBB) during exercise-stress and atropine-stress electrocardiogram (ECG) and on 24-h ambulatory ECG monitoring. Myocardial perfusion and metabolic scintigraphy with Tl-201 and I-123 BMIPP, respectively, showed no evidence of ischemia. Coronary arteriography revealed no atherosclerotic lesions, but did show a fistula between three major coronary arteries and the main pulmonary artery. The left-to-right shunt was undetectably small. Administration of diltiazem and metoprolol suppressed LBBB by attenuating the heart rate response to exercise, and reduced the chest pain. Therefore we presume that the exertional chest pain was not caused by myocardial ischemia but by the tachycardia-dependent LBBB. Coronary artery-pulmonary artery fistula is the most common type of coronary artery fistulae found incidentally in adulthood. Involvement of three major coronary branches is, however, rare. The case is discussed with a review of the literature.
    Japanese Heart Journal 04/1998; 39(2):247-53. DOI:10.1536/ihj.39.247 · 0.40 Impact Factor
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    ABSTRACT: Recently, slurries with phase change materials (hereafter, PCM) having latent heat have been received much attention as a high-density heat transportation system. So far, it has been reported that the thermal ability of slurries containing tetra-n-butyl ammonium salt solutions and their semi-clathrate hydrate: tetra-n-butyl ammonium bromide (TBAB) and fluoride (TBAF) as latent heat transport media is favorable. In the present study, the viscosity characteristics of TBAB or TBAF solutions and their hydrate-slurries were measured at various concentrations of solutions by use of a stress-control-type rheometer with parallel-plate device. The apparent viscosity of both solution and hydrate slurries increases as the temperature decreases, which may be caused by the increase of solid (hydrate particle) fraction in solution. The hydrate slurries exhibit the behavior like pseudo-plastic fluid. The viscosity characteristics of these hydrate slurries can be treated by use of only solid fraction despite different unit-cell structure between TBAB and TBAF hydrates. In addition, a very small amount of surfactant drastically reduces the apparent viscosity of hydrate slurries, which may be caused by the electric repulsion of surfactant-adsorbed hydrate particles. NOMENCLATURE C: concentration [wt%] H f : hydrate fraction in slurries [-] m, n: arbitrary real number [-] T: temperature [K] !: shear rate [s -1 ] ": apparent viscosity [Pa • s] #: shear stress [Pa] INTRODUCTION Gas hydrates are one of clathrate inclusion compounds, which are stabilized by guest species in the cavity of cages. These hydrate cages are composed of the hydrogen-bonded water molecules. The hydrate structure mainly depends on the size and shape of enclathrated guest species.

Publication Stats

47 Citations
52.06 Total Impact Points


  • 2008–2013
    • Saitama Medical University
      • Saitama Medical Center
      Saitama, Saitama, Japan
  • 2012
    • Osaka University
      • Graduate School of Engineering Sciences
      Suika, Ōsaka, Japan