title: Troponin-positive, MB-negative patients with non-ST-elevation myocardial infarction: An undertreated but high-risk patient group: Results from the National Cardiovascular Data Registry Acute Coronary Treatment and Intervention Outcomes Network-Get With The Guidelines (NCDR ACTION-GWTG) Registry.
abstract: BACKGROUND
  Despite the 2000 and 2007 redefinition of myocardial infarction (MI), patients who are troponin (Tn) positive ([+]) but MB negative ([-]) may not be considered to have MI, particularly in the absence of known coronary disease (prior MI or revascularization; coronary artery disease [CAD]). How this affects treatment and outcomes has not been well described.
  
  
  METHODS
  Direct arrival patients with non-ST elevation MI (NSTEMI) enrolled in the American College of Cardiology NCDR ACTION-GWTG Registry were included. Patients missing marker data who were Tn (-) and had CAD were excluded. Troponin (+) patients were categorized as MB (+) (n = 11,563) or MB (-) (n = 4,501). Treatments and in-hospital outcomes were compared between the 2 groups using logistic regression.
  
  
  RESULTS
  Of the 16,064 NSTEMI patients, 28% were MB (-). The MB (-) patients were older (median age 68 vs 65 years) and had more comorbidities (hypertension 71% vs 66%, diabetes 31% vs 27%, heart failure 22% vs 19%; all Ps < .01). After adjusting for baseline characteristics, MB (-) patients were significantly less likely to receive clopidogrel, antithrombins, glycoprotein IIb/IIIa antagonists, or angiography (all Ps < .001). In-hospital mortality was lower in MB (-) patients (3.8% vs 4.9%, P < .01), which remained significant after adjusting for baseline variables (odds ratio 0, 69, 95% CI 0.6-0.9, P = .002).
  
  
  CONCLUSIONS
  Patients without known CAD who have NSTEMI and are MB (-) have a higher risk profile but are less likely to receive guideline-recommended acute pharmacologic treatment than those who are MB (+). Given the relatively high mortality in this group, increased emphasis on improving quality of care in Tn (+)/MB (-) patients is warranted.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Pauley Heart Center, Virginia Commonwealth University, Richmond, VA, USA. mkontos@mcvh-vcu.edu
authors.forename: Michael C
authors.initials: MC
authors.lastname: Kontos
authors.forename: James A
authors.initials: JA
authors.lastname: de Lemos
authors.forename: Fang-Shu
authors.initials: FS
authors.lastname: Ou
authors.forename: Stephan D
authors.initials: SD
authors.lastname: Wiviott
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Foody
authors.forename: L Kristin
authors.initials: LK
authors.lastname: Newby
authors.forename: Anita
authors.initials: A
authors.lastname: Chen
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Roe
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000991:Antithrombins / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D000077144:Clopidogrel; D017023:Coronary Angiography; D052279:Creatine Kinase, MB Form / Q000097:blood*; D004359:Drug Therapy, Combination; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality / Q000628:therapy; D009204:Myocardial Revascularization / Q000379:methods; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use; D017410:Practice Guidelines as Topic; D011379:Prognosis; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013988:Ticlopidine / Q000031:analogs & derivatives / Q000627:therapeutic use; D014336:Troponin / Q000097:blood*; D014481:United States / Q000453:epidemiology
chemical_list: D000991:Antithrombins; D015415:Biomarkers; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D010975:Platelet Aggregation Inhibitors; D014336:Troponin; D000077144:Clopidogrel; D052279:Creatine Kinase, MB Form; D013988:Ticlopidine