title: Endothelial microparticles correlate with high-risk angiographic lesions in acute coronary syndromes.
abstract: BACKGROUND
  Endothelial Microparticles (EMP) are small fragments of endothelial cell membrane shed during apoptosis or activation. Our group has previously reported elevations of EMP in patients with coronary artery disease (CAD), thrombotic thrombocytopenic purpura (TTP), pre-eclampsia, multiple sclerosis (MS), and severe hypertension (HTN). In the present study, we evaluate the possible relationship between EMP levels and the angiographic severity and characteristics of coronary obstructive lesions.
  
  
  METHODS
  We studied a total of 43 patients undergoing coronary angiography. Fifteen had presented with acute myocardial infarction (MI), 20 with unstable anginas (UA), 5 with stable angina (SA) and 3 with congestive heart failure. Coronary angiography was reviewed and coronary lesions were classified using the Ambrose classification. Coronary stenoses were classified as high and low risk. High-risk included lesions with eccentric appearance (type II), presence of thrombi, or multiple irregularities. Low-risk lesions were defined as concentric or type I. Lesions were also analyzed by degree of stenosis and history of acute coronary syndrome (ACS). EMP in plasma was assayed by flow cytometry.
  
  
  RESULTS
  EMP in eccentric type II or multiple irregular lesions (high-risk) were 2.5-fold higher than in type I or concentric (low-risk) lesions, p<0.05. Lesions with thrombi had three-fold higher EMP than those without (p=0.05). Mild stenosis (>20%-<45%) had three-fold higher EMP than more severe (>45%), and five-fold higher than those without stenosis (p<0.01). Among patients with type II lesions, those with first ACS episode had four-fold higher EMP levels than those with recurrent ACS (p<0.01).
  
  
  CONCLUSIONS
  High EMP was associated with high-risk angiographic lesions including eccentric type II, multiple irregular, and lesions with thrombi. Mild to moderate stenosis was associated with higher EMP levels than severe stenosis. EMP may be a useful marker in detecting endothelial injury and risk of ACS as defined by angiography.
authors.affiliation: Wallace H. Coulter Platelet Laboratory, Department of Medicine, Divisions of Hematology/Oncology, School of Medicine, University of Miami, 1600 NW 10th Ave., Box R-36A (Rm. 7028), Miami, FL 33136, USA.
authors.forename: Leon
authors.initials: L
authors.lastname: Bernal-Mizrachi
authors.forename: Wenche
authors.initials: W
authors.lastname: Jy
authors.forename: Christian
authors.initials: C
authors.lastname: Fierro
authors.forename: Rick
authors.initials: R
authors.lastname: Macdonough
authors.forename: Hermes A
authors.initials: HA
authors.lastname: Velazques
authors.forename: Joshua
authors.initials: J
authors.lastname: Purow
authors.forename: Joaquin J
authors.initials: JJ
authors.lastname: Jimenez
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Horstman
authors.forename: Alexandre
authors.initials: A
authors.lastname: Ferreira
authors.forename: Eduardo
authors.initials: E
authors.lastname: de Marchena
authors.forename: Yeon S
authors.initials: YS
authors.lastname: Ahn
mesh_terms: D000208:Acute Disease; D000328:Adult; D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000209:etiology*; D042783:Endothelial Cells / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D013577:Syndrome