title: Distinct morphological features of ruptured culprit plaque for acute coronary events compared to those with silent rupture and thin-cap fibroatheroma: a combined optical coherence tomography and intravascular ultrasound study.
abstract: OBJECTIVE
  The study sought to identify specific morphological characteristics of ruptured culprit plaques (RCP) responsible for acute events, and compare them with ruptured nonculprit plaques (RNCP) and nonruptured thin-cap fibroatheroma (TCFA) in patients presenting with acute coronary syndromes (ACS).
  
  
  BACKGROUND
  Nonruptured TCFA and multiple ruptured plaques are detected in the same patients with ACS. It remains unknown whether certain morphological characteristics determine rupture of TCFA and subsequently result in ACS.
  
  
  METHODS
  We analyzed 126 plaques (RCP = 49, RNCP = 19, TCFA = 58) from 82 ACS patients using optical coherence tomography (OCT) and intravascular ultrasound (IVUS). Fibrous cap thickness was determined by OCT. Plaque burden and lumen area were measured with IVUS.
  
  
  RESULTS
  Fibrous cap was thinner in RCP (43 ± 11 μm) and RNCP (41 ± 10 μm) than in TCFA (56 ± 9 μm, p < 0.001 and p < 0.001, respectively). Plaque burden was greater in RCP (82 ± 7.2%), compared with RNCP (64 ± 7.2%, p < 0.001) and TCFA (62 ± 12.5%, p < 0.001). Lumen area was smaller in RCP (2.1 ± 0.9 mm(2)), compared with RNCP (4.6 ± 2.3 mm(2), p = 0.001) and TCFA (5.1 ± 2.7 mm(2), p < 0.001). The fibrous cap thickness <52 μm had good performance in discriminating ruptured plaque from TCFA (area under the curve [AUC] = 0.857, p < 0.001), and plaque burden >76% and lumen area <2.6 mm(2) had good performance in discriminating RCP from RNCP and TCFA (AUC = 0.923, p < 0.001 and AUC = 0.881, p < 0.001, respectively).
  
  
  CONCLUSIONS
  Fibrous cap thickness is a critical morphological discriminator between ruptured plaques and nonruptured TCFA, while plaque burden and lumen area appear to be important morphological features of RCP. These findings suggest that plaque rupture is determined by fibrous cap thickness, and a combination of large plaque burden and luminal narrowing result in ACS.
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Jinwei
authors.initials: J
authors.lastname: Tian
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China.
authors.forename: Xuefeng
authors.initials: X
authors.lastname: Ren
authors.affiliation: Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Rocco
authors.initials: R
authors.lastname: Vergallo
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Xing
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China.
authors.forename: Huai
authors.initials: H
authors.lastname: Yu
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Haibo
authors.initials: H
authors.lastname: Jia
authors.affiliation: Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Tsunenari
authors.initials: T
authors.lastname: Soeda
authors.affiliation: Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Iris
authors.initials: I
authors.lastname: McNulty
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China; Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Sining
authors.initials: S
authors.lastname: Hu
authors.affiliation: Biostatistic Center, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Hang
authors.initials: H
authors.lastname: Lee
authors.affiliation: Department of Cardiology, The Second Affiliated Hospital of Harbin Medical University, and The Key Laboratory of Myocardial Ischemia, Chinese Ministry of Education, Harbin, China. Electronic address: yubodr@163.com.
authors.forename: Bo
authors.initials: B
authors.lastname: Yu
authors.affiliation: Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Ik-Kyung
authors.initials: IK
authors.lastname: Jang
mesh_terms: D054058:Acute Coronary Syndrome / Q000000981:diagnostic imaging* / Q000453:epidemiology; D000328:Adult; D000368:Aged; D006335:Heart Injuries / Q000000981:diagnostic imaging* / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D058226:Plaque, Atherosclerotic / Q000000981:diagnostic imaging* / Q000453:epidemiology; D011859:Radiography; D041623:Tomography, Optical Coherence / Q000379:methods; D018084:Ultrasonography, Interventional / Q000379:methods
keywords: acute coronary syndrome(s); lumen narrowing; plaque vulnerability; plaque rupture; thin-cap fibroatheroma