title: Plasma myeloperoxidase concentration predicts the presence and severity of coronary disease in patients with chest pain and negative troponin-T.
abstract: BACKGROUND
  A non-negligible proportion of patients with chest pain with negative cardiac troponin may harbor a disrupted coronary plaque. A marker of plaque rupture upstream from myocardial necrosis may help identify high-risk patients among this patient population. The purpose of this study was to investigate the correlation of plasma myeloperoxidase (MPO) concentration and angiographic coronary disease among patients with suspected troponin-negative coronary syndromes.
  
  
  METHODS
  Patients presenting with chest pain and negative cardiac troponin-T concentration and undergoing coronary angiography were enrolled in our study. Plasma MPO concentration was measured using a single blood sample collected prior to cardiac catheterization. The primary angiographic endpoint was the presence of at least one coronary stenosis causing a 70% or more diameter reduction; secondary endpoints were number of diseased vessels, presence of coronary thrombus, and lesion ulceration. The main clinical endpoint was coronary revascularization.
  
  
  RESULTS
  Three hundred and eighty-nine patients were enrolled. Presence of coronary stenosis causing a 70% or more diameter reduction increased with increasing quartiles of myeloperoxidase concentration (P<0.0001), as did the presence of coronary thrombus (P<0.0001) and plaque ulceration (P<0.0001). The need for percutaneous coronary revascularization also increased with increasing quartiles of systemic myeloperoxidase levels (P<0.0001). Coronary surgical revascularization did not differ among myeloperoxidase quartiles.
  
  
  CONCLUSIONS
  Among patients with chest pain without troponin elevation, a single measurement of plasma MPO concentration can help identify patients with a higher risk of having significant coronary stenoses and high-risk angiographic features.
authors.affiliation: American University of Beirut Medical Center, Division of Cardiology, Beirut, Lebanon. ar20@aub.edu.lb
authors.forename: Abdallah G
authors.initials: AG
authors.lastname: Rebeiz
authors.forename: Hani M
authors.initials: HM
authors.lastname: Tamim
authors.forename: Rima M
authors.initials: RM
authors.lastname: Sleiman
authors.forename: Antoine G
authors.initials: AG
authors.lastname: Abchee
authors.forename: Zeina
authors.initials: Z
authors.lastname: Ibrahim
authors.forename: Maurice Y
authors.initials: MY
authors.lastname: Khoury
authors.forename: Sonia
authors.initials: S
authors.lastname: Youhanna
authors.forename: Hadi N
authors.initials: HN
authors.lastname: Skouri
authors.forename: Samir E
authors.initials: SE
authors.lastname: Alam
mesh_terms: D000368:Aged; D000787:Angina Pectoris / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy; D015906:Angioplasty, Balloon, Coronary; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D023921:Coronary Stenosis / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000628:therapy; D005260:Female; D006801:Humans; D007861:Lebanon; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D009195:Peroxidase / Q000097:blood*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D020107:Troponin T / Q000097:blood*
chemical_list: D015415:Biomarkers; D020107:Troponin T; D009195:Peroxidase