title: Clinical and morphological presentations of acute coronary syndrome without coronary plaque rupture - An intravascular ultrasound study.
abstract: BACKGROUND
  Although acute coronary syndrome (ACS) mainly arises from plaque ruptures (PR), precise mechanisms underlying ACS without PR are unknown. We sought to examine clinical, angiographic and intravascular ultrasound (IVUS) characteristics of ACS without PR.
  
  
  RESULTS
  Culprit lesions of 161 ACS patients were categorized by the presence or absence of PR (PR group: n=57, Non-PR group: n=104). Lower abdominal circumference (86±10cm vs 90±9cm, p=0.02), lower prevalence of myocardial infarction (53% vs 82%, p=0.0002), and higher prevalence of definite vasospasm (15% vs 2%, p=0.006) were found in Non-PR group. Morphologically, Non-PR group was associated with simpler Ambrose classification (36% vs 14%, p=0.004), less hypoechoic plaque (45% vs 65%, p=0.04) and lower incidence of IVUS-detected thrombus (21% vs 54%, p<0.0001), compared with PR group. On quantitative IVUS, although minimum lumen area (MLA) was similar between the groups, vessel (14.2±5.4mm(2) vs 17.5±5.1mm(2), p=0.0002) and plaque (11.6±5.0mm(2) vs 14.9±4.9mm(2), p<0.0001) areas were significantly smaller at MLA site in Non-PR group than in PR group. On multivariate analysis, average plaque area was only an independent IVUS-predictor of non-rupture ACS (odds ratio: 0.85, p=0.01).
  
  
  CONCLUSIONS
  Compared to ACS with PR, non-rupture ACS arise from more hyperechoic (allegedly "stable") plaque with smaller vessel and plaque area, leading to lower incidence of thrombotic occlusion. Coronary vasospasm might be a possible pathogenic mechanism underlying non-rupture ACS.
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan. Electronic address: tsujita@kumamoto-u.ac.jp.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Tsujita
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Kenshi
authors.initials: K
authors.lastname: Yamanaga
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Naohiro
authors.initials: N
authors.lastname: Komura
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sakamoto
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyazaki
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Oimatsu
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Masanobu
authors.initials: M
authors.lastname: Ishii
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Noriaki
authors.initials: N
authors.lastname: Tabata
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Tomonori
authors.initials: T
authors.lastname: Akasaka
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sueta
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Eiichiro
authors.initials: E
authors.lastname: Yamamoto
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Yamamuro
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Izumiya
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Sunao
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Sunao
authors.initials: S
authors.lastname: Nakamura
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kaikita
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Hokimoto
authors.affiliation: Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kumamoto University, Kumamoto, Japan; Department of Cardiovascular Medicine, National Cerebral and Cardiovascular Center Hospital, Suita, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Ogawa
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging*; D000368:Aged; D000369:Aged, 80 and over; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging*; D012307:Risk Factors; D018084:Ultrasonography, Interventional / Q000379:methods*
keywords: Catheterization; Imaging; Myocardial infarction; Plaque; Ultrasonics