title: The prognostic value of creatine kinase elevations extends across the whole spectrum of acute coronary syndromes.
abstract: OBJECTIVE
  The study investigated the relationship among creatine kinase (CK) elevations, clinical characteristics and cardiac events across the whole spectrum of acute coronary syndromes (ACS).
  
  
  BACKGROUND
  Elevated serum levels of cardiac enzymes have been shown to be a major prognostic determinant in acute myocardial ischemia. Yet prior to this report, the relation between cardiac enzyme levels and other prognostic determinants across the entire spectrum of ACS has not been explored by a large clinical study.
  
  
  METHODS
  We evaluated the relation between the maximum CK ratio (CK level/upper limit of normal) in the early hours following admission and cardiac events at six months in 11,725 patients enrolled in a large trial of ACS.
  
  
  RESULTS
  Patients with higher risk characteristics, such as older age, female gender, hypertension, diabetes, prior coronary events or heart failure, more frequently presented without ST-segment elevation on the electrocardiogram and tended to develop lesser enzyme elevations. After adjusting for significant baseline predictors of cardiac events, a continuous correlation was observed between the CK ratio and death (chi-square 63.04, p < 0.0001) and (re)infarction or death (chi-square 55.48, p < 0.0001). This correlation was similar for patients with and without ST-segment elevation. The adjusted incidence of cardiac events at follow-up began to rise even for CK levels within the normal range, the steepest part of the curve residing between one and three times the upper limit of normal. In patients with a CK ratio of >1 to 2 compared with those within the normal range, the adjusted odds ratio for death was 1.26 (95% confidence interval [CI] 0.98 to 1.63), and 1.59 (95% CI 1.38 to 1.90) for (re)infarction and death. For all CK levels, the event rate was higher among patients without ST-segment elevation.
  
  
  CONCLUSIONS
  Although high-risk patients with ACS often develop lesser CK elevations, this study demonstrated that even minor enzyme elevations appear to have important and independent prognostic implications.
authors.affiliation: Department of Cardiology, Niguarda Hospital, Milan, Italy. ssavoni@tin.it
authors.forename: Stefano
authors.initials: S
authors.lastname: Savonitto
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Granger
authors.forename: Diego
authors.initials: D
authors.lastname: Ardissino
authors.forename: Laura
authors.initials: L
authors.lastname: Gardner
authors.forename: Claudio
authors.initials: C
authors.lastname: Cavallini
authors.forename: Marcello
authors.initials: M
authors.lastname: Galvani
authors.forename: Filippo
authors.initials: F
authors.lastname: Ottani
authors.forename: Harvey D
authors.initials: HD
authors.lastname: White
authors.forename: Paul W
authors.initials: PW
authors.lastname: Armstrong
authors.forename: E Magnus
authors.initials: EM
authors.lastname: Ohman
authors.forename: Karen S
authors.initials: KS
authors.lastname: Pieper
authors.forename: Robert M
authors.initials: RM
authors.lastname: Califf
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Topol
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000097:blood*; D003402:Creatine Kinase / Q000097:blood*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality; D016017:Odds Ratio; D011379:Prognosis; D012008:Recurrence; D013577:Syndrome
chemical_list: D003402:Creatine Kinase