title: Prognostic implications of creatine kinase-MB elevation after percutaneous coronary intervention: results from the Evaluation of Drug-Eluting Stents and Ischemic Events (EVENT) registry.
abstract: BACKGROUND
  Creatine kinase-MB (CK-MB) elevation after percutaneous coronary intervention (PCI) has been associated with increased risk for mortality. Although most studies have defined periprocedural myocardial infarction (pMI) as an elevation in CK-MB >3× upper limit of normal (ULN), use of different CK-MB assays and variation in site-specific definitions of the ULN may limit the value of such relative thresholds.
  
  
  RESULTS
  We used data from the multicenter Evaluation of Drug-Eluting Stents and Ischemic Events (EVENT) registry to examine the impact of variations in site-specific thresholds for CK-MB elevation on the incidence of pMI as well as the relationship between absolute peak levels of CK-MB after PCI and 1-year mortality. The study cohort consisted of 6347 patients who underwent nonemergent PCI and had normal CK-MB at baseline. Across the 59 study centers, the ULN for CK-MB ranged from 2.6 to 10.4 ng/mL (median, 5.0 ng/mL), and there was an inverse relationship between the site-specific ULN and the incidence of pMI (defined as CK-MB elevation >3× ULN). Although any postprocedure elevation of CK-MB was associated with an adverse prognosis, in categorical analyses, only CK-MB ≥50 ng/mL was independently associated with increased 1-year mortality (hazard ratio, 4.71; 95% confidence interval, 2.42 to 9.13; P<0.001). Spline analysis using peak CK-MB as a continuous variable suggested a graded, nonlinear relationship with 1-year mortality, with an inflection point at ≈30 ng/mL.
  
  
  CONCLUSIONS
  Among unselected patients undergoing PCI, there is a graded relationship between CK-MB elevation after PCI and 1-year mortality that is particularly strong for large CK-MB elevations (>30 to 50 ng/mL). Future studies that include pMI as a clinical end point should consider using a core laboratory to assess CK-MB (to ensure consistency) and raising the threshold for defining pMI above current levels (to enhance clinical relevance).
authors.affiliation: Saint Luke's Mid America Heart Institute, University of Missouri-Kansas City, Kansas City, MO 64111, USA.
authors.forename: Jason B
authors.initials: JB
authors.lastname: Lindsey
authors.forename: Kevin F
authors.initials: KF
authors.lastname: Kennedy
authors.forename: Joshua M
authors.initials: JM
authors.lastname: Stolker
authors.forename: Ian C
authors.initials: IC
authors.lastname: Gilchrist
authors.forename: Debabrata
authors.initials: D
authors.lastname: Mukherjee
authors.forename: Steven P
authors.initials: SP
authors.lastname: Marso
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pencina
authors.forename: Neal S
authors.initials: NS
authors.lastname: Kleiman
authors.forename: David J
authors.initials: DJ
authors.lastname: Cohen
mesh_terms: D000368:Aged; D017130:Angioplasty; D015331:Cohort Studies; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000401:mortality / Q000503:physiopathology / Q000628:therapy; D052279:Creatine Kinase, MB Form / Q000235:genetics / Q000378:metabolism*; D054855:Drug-Eluting Stents / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000209:etiology*; D011183:Postoperative Complications; D011379:Prognosis; D012008:Recurrence; D012016:Reference Values; D012307:Risk Factors; D016019:Survival Analysis
chemical_list: D052279:Creatine Kinase, MB Form