Atsushi Tanaka

Saga University, Сага Япония, Saga, Japan

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Publications (8)53.16 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We wished to determine whether coronary high-intensity plaques (HIPs) visualized by non-contrast T1-weighted imaging (T1WI) can predict future coronary events. BACKGROUND: Coronary HIPs are associated with characteristics of vulnerable plaques including positive remodeling, lower Hounsfield units, and ultrasound attenuation. However, it remains unclear whether the presence of HIPs is associated with an increased risk of coronary events. We prospectively examined the signal intensity of coronary plaques in 568 patients with suspected or known coronary artery disease (CAD) who underwent non-contrast T1WI to determine the plaque to myocardium signal intensity ratio (PMR). During the follow-up period (median, 55 months), coronary events were observed in 55 patients. Receiver operating characteristic curve analysis identified a PMR of 1.4 as the optimal cutoff for predicting prognosis. Multivariate Cox regression analysis identified the presence of PMR≥1.4 plaques as the significant independent predictor of coronary events (hazard ratio [HR], 3.96; 95% confidence interval [CI], 1.92 to 8.17; p<0.001) compared with the presence of CAD (HR, 3.56; 95%CI, 1.76 to 7.20; p<0.001) and other traditional risk factors. Among the 4 groups based on the PMR cutoff and presence of CAD, coronary event-free survival was lowest in the PMR≥1.4+CAD group and highest in the PMR<1.4+no CAD group. Importantly, the PMR≥1.4+no CAD group had an intermediate rate of coronary events, similar to the PMR<1.4+CAD group. Conclusions: HIPs identified in a non-invasive, quantitative manner are significantly associated with coronary events, and may thus represent a novel predictive factor.
    Journal of the American College of Cardiology 12/2013; · 14.09 Impact Factor
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    ABSTRACT: The goal of coronary plaque burden assessment is to detect vulnerable or high-risk atherosclerotic plaques that are prone to rupture and to stabilize them through pharmacologic and other types of interventions before the development of acute coronary syndrome. In this regard, a reliable, reproducible, and less invasive imaging modality capable of identifying plaque characteristics associated with plaque vulnerability would be immensely useful for evaluating plaque status and predicting future cardiovascular events. Recently, magnetic resonance imaging (MRI) has emerged as a novel modality for atherosclerotic plaque detection and characterization. This review will cover the developments in MRI for characterizing atherosclerosis in carotid and coronary arteries and its use in clinical diagnoses and longitudinal studies to understand the pathophysiology of atherosclerosis.
    Circulation Journal 07/2013; · 3.58 Impact Factor
  • Journal of The American College of Cardiology - J AMER COLL CARDIOL. 01/2010; 55(10).
  • Circulation 12/2009; 120(23):2400-1. · 15.20 Impact Factor
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    ABSTRACT: This study sought to characterize coronary hyperintense plaques (HIP) using noncontrast T(1)-weighted imaging (T1WI) in cardiac magnetic resonance, which was then compared with multislice computed tomography and intravascular ultrasound. Carotid plaque components such as intraplaque hemorrhages and/or lipid-rich necrotic cores can be detected as HIP by noncontrast T1WI. Although coronary HIPs have been successfully detected using this technique, the properties of hyperintense signals in coronary plaques have not yet been systematically evaluated. Thirty-eight lesions from 37 patients with angina pectoris who demonstrated >70% coronary stenosis on multislice computed tomography were evaluated by noncontrast T1WI using a 1.5-T magnetic resonance imager, and 25 lesions were evaluated by intravascular ultrasound. Signal intensity of coronary plaque to cardiac muscle ratio >1.0 was defined as HIP. We divided 25 lesions into the 2 groups, according to the presence or absence of HIP: HIP (n = 18) and non-HIP (n = 7) groups. In comparison with the non-HIP group, the HIP group demonstrated significantly higher coronary plaque to cardiac muscle ratio (1.7 +/- 0.7 vs. 0.9 +/- 0.1, p < 0.01), higher frequency of positive remodeling as observed by both multislice computed tomography (89% vs. 0%, p<0.0001) and intravascular ultrasound (94% vs. 14%, p < 0.001) and ultrasound attenuation (100% vs. 14.3%, p < 0.0001). The frequency of spotty calcification tended to be higher in HIP (89% vs. 50%, p = 0.079). The HIP group also exhibited a significantly lower computed tomography density (-23.2 +/- 20.7 Hounsfield units [HU] vs. 9.6 +/- 20.5 HU, p < 0.01). In addition, the incidence of transient slow-flow phenomena was significantly higher in the HIP group than in the non-HIP group (83% vs. 14%, p < 0.01). The typical HIP case was associated with ultrasound attenuation, positive remodeling, remarkably low computed tomography density, and a high incidence of slow-flow phenomena. Noncontrast T1WI in cardiac magnetic resonance imaging may be useful for the assessment of coronary plaque characterization in patients with coronary artery disease.
    JACC. Cardiovascular imaging 06/2009; 2(6):720-8. · 14.29 Impact Factor
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    ABSTRACT: Acetylcholinesterase inhibitors (AChIs) are widely used in the treatment of mild-to-moderate Alzheimer's disease (AD), but their cholinergic effects could generate adverse side effects in the cardiovascular system. This report presents the cases of 2 patients who experienced adverse side effects of cardiac rhythm with QT prolongation caused by Donepezil. Both of them improved to the original rhythm and shortened QT intervals after the discontinuation of Donepezil. The present cases suggest that the cholinergic effects of Donepezil could induce adverse side effects on cardiac rhythm and careful consideration is needed for the patients treated by Donepezil.
    Internal Medicine 02/2009; 48(14):1219-23. · 0.97 Impact Factor
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    ABSTRACT: Various two-stent techniques have been applied to aggressively treat bifurcation lesions as the introduction of drug-eluting stents (DES) and the importance of the bifurcation angle and three-dimensional (3D) structure has come to be recognized. Recent 64 multislice computed tomography (MSCT) technology provides accurate information about the 3D bifurcation geometry of the coronary arteries and with reproducibility. The purpose of this study is to disclose the coronary bifurcation angle and 3D structure in humans and elucidate the importance of bifurcation angle for the crush technique using MSCT. Two hundred and nine patients who were suspected to have angina pectoris and underwent CT angiography using MSCT were examined. The 3D-volume rendering (VR) image was reconstructed by two technicians and was used for the assessment of each coronary bifurcation angles. The average LMT bifurcation angles (angle LMT-LAD, angle LMT-LCx, angle LAD-LCx) were 143 +/- 13 degrees , 121 +/- 21 degrees , and 72 +/- 22 degrees , respectively, the average angle LAD-D was 138 +/- 19 degrees , the average angle LCx-OM was 134 +/- 23 degrees , the average distal RCA bifurcation angles (angle RCA-4AV, angle RCA-4PD, angle 4AV-4PD) were 152 +/- 15 degrees , 137 +/- 20 degrees , and 61 +/- 21 degrees , respectively. In addition, a percentage of steep angled bifurcation (<110 degrees ) was significantly higher in the LMT (26%) than in other bifurcations (P < 0.05). LMT bifurcation has been shown to have a higher rate of steep angled bifurcation in humans, it is therefore necessary to take the bifurcation angle into consideration in the case of LMT stenting. These data suggest that a bifurcation study using MSCT can clarify the 3D structure of coronary bifurcation and may provide useful information for bifurcation stenting.
    Catheterization and Cardiovascular Interventions 12/2008; 73(5):653-8. · 2.51 Impact Factor
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    ABSTRACT: We examined the importance of prolonged inflation time for optimal sirolimus-eluting stent (SES) or paclitaxel-eluting stent (PES) expansion. Eighty-one de novo lesions deployed single SES or PES between April 2007 and March 2008 were divided into four groups; group 1: 21 SES deployed at 20 atm x 60 sec, group 2: 20 SES deployed with 2-step inflation at 20 atm x 60 sec following 20 atm x 20 sec, group 3: 20 PES deployed same as group 1, group 4: 20 PES deployed same as group 2. The minimal lumen diameter (MLD) and stent expansion ratio (SER; stent cross- sectional area at lesion/balloon cross-sectional area which was calculated according to the compliance chart at the same atmosphere as stent deployment) were compared between group 1 and group 2 in SES, between group 3 and group 4 in PES. The MLD of post 60 sec was significantly higher than that of post 20 sec (2.84 +/- 0.28 mm in group 1, 2.76 +/- 0.33 mm in group 2 vs. 2.54 +/- 0.33 mm in group 2; P = 0.003, 0.045, respectively and 2.94 +/- 0.28 mm in group 3, 3.00 +/- 0.34 mm in group 4 vs. 2.69 +/- 0.35 mm in group 4; P = 0.022, 0.007, respectively). The SER of post 60 sec was significantly higher than that of post 20 sec (79.3% +/- 8.5% in group 1, 80.8% +/- 7.8% in group 2 vs. 71.1% +/- 10.2% in group 2; P = 0.014, 0.011, respectively and 81.1% +/- 7.9% in group 3, 84.3% +/- 9.9% in group 4 vs. 72.6% +/- 10.5% in group 4, P = 0.011, 0.001, respectively). The prolonged delivery inflation for 60 sec may result in a more optimal stent expansion. It is therefore considered to be a useful method for deploying drug-eluting stent.
    Catheterization and Cardiovascular Interventions 11/2008; 73(2):205-11. · 2.51 Impact Factor

Publication Stats

45 Citations
53.16 Total Impact Points

Institutions

  • 2013
    • Saga University
      • Division of Cardiovascular & Renal Medicine
      Сага Япония, Saga, Japan
  • 2008
    • National Cerebral and Cardiovascular Center
      Ōsaka, Ōsaka, Japan
    • Shin Kokura Hospital
      Kitakyūshū, Fukuoka, Japan