title: Early identification of acute myocardial infarction by activated protein C--protein C inhibitor complex.
abstract: BACKGROUND
  Increased coagulation activity due to coronary thrombosis in a ruptured plaque should result in activation of the protein C anticoagulant system with formation of complexes between activated protein C (APC) and the protein C inhibitor (PCI), which reflects coagulation activity. We hypothesized that elevated APC-PCI concentration might allow earlier detection of ongoing myocardial infarction than traditional biochemical markers. We have evaluated a newly devised immunofluorimetric assay for measuring plasma concentration of APC-PCI complexes among patients with suspected acute coronary syndrome.
  
  
  METHODS
  Blood samples were taken from 340 patients (median 71 years, range 31-97) with suspected acute coronary syndrome at first presentation in the emergency department. Electrocardiogram was recorded and APC-PCI, Troponin I and Creatine kinase-MB concentrations were repeatedly measured 3 times at 6 h interval.
  
  
  RESULTS
  The 74 patients who were eventually diagnosed with myocardial infarction had a higher median level of APC-PCI complex than those without myocardial damage; 0.27 vs. 0.20 microg/L (p = 0.001). In a multivariate regression model, APC-PCI level in the fourth quartile (>0.32 microg/L) independently predicted myocardial infarction with an odds ratio of 3.7 (95% CI 1.4-9.6, p < 0.01).
  
  
  CONCLUSIONS
  Early APC-PCI elevation can be detected among patients with a normal first Troponin I and non-ST-elevation myocardial infarction and provides additional risk assessment in acute coronary syndrome.
authors.affiliation: Department of Cardiology, Lund University, Malmö University Hospital, Sweden. johan.holm@skane.se
authors.forename: Pallonji
authors.initials: P
authors.lastname: Bhiladvala
authors.forename: Karin
authors.initials: K
authors.lastname: Strandberg
authors.forename: Johan
authors.initials: J
authors.lastname: Stenflo
authors.forename: Johan
authors.initials: J
authors.lastname: Holm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001681:Biological Assay; D001780:Blood Coagulation Tests; D003402:Creatine Kinase / Q000097:blood; D004562:Electrocardiography; D005069:Evaluation Studies as Topic; D005260:Female; D005470:Fluorometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis; D011486:Protein C / Q000378:metabolism*; D018046:Protein C Inhibitor / Q000097:blood / Q000378:metabolism*; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013997:Time Factors; D019210:Troponin I / Q000097:blood
chemical_list: D011486:Protein C; D018046:Protein C Inhibitor; D019210:Troponin I; D003402:Creatine Kinase