title: Shock index: a simple clinical parameter for quick mortality risk assessment in acute myocardial infarction.
abstract: BACKGROUND
  Primary percutaneous coronary intervention (PCI) has become the preferred reperfusion strategy in patients with ST-segment elevation myocardial infarction and cardiogenic shock. Early identification of patients at risk for developing cardiogenic shock allows rapid decision making to determine reperfusion and transportation to a PCI centre. The aim of this analysis was to evaluate shock index (SI) as a marker for patients at risk of cardiogenic shock.
  
  
  METHODS
  A total of 644 consecutive patients (73% male) with acute myocardial infarction with ST elevations were analyzed retrospectively. Primary PCI was performed in 92% of patients, and 7% of patients underwent rescue PCI. The SI parameter was defined as the ratio of heart rate to systolic blood pressure at hospital admission.
  
  
  RESULTS
  SI (odds ratio [OR], 81.26; 95% confidence interval [CI], 9.76-676.51; P<0.001), age (OR, 1.17; 95% CI, 1.08-1.26; P<0.001), and diabetes (OR, 4.94; 95% CI, 1.44-16.97; P<0.011) were independent predictors of mortality. In the group of patients with SI≥0.8, 20% died, whereas in the group with SI<0.8, 4% of patients died (P<0.01).
  
  
  CONCLUSIONS
  The proposed clinical parameter SI correlates with patients' prognosis and could therefore be used as a simple indicator of mortality risk of acute myocardial infarction. The simplicity of this proposed index makes its use accessible in large-scale clinical practices for risk stratification during first contact with patients.
authors.affiliation: Cardiocenter, 3rd Faculty of Medicine, Charles University Prague, University Hospital Kralovske Vinohrady, Prague, Czech Republic. dbilk@email.cz
authors.forename: Dana
authors.initials: D
authors.lastname: Bilkova
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Motovska
authors.forename: Petr
authors.initials: P
authors.lastname: Widimsky
authors.forename: Jaroslav
authors.initials: J
authors.lastname: Dvorak
authors.forename: Libor
authors.initials: L
authors.lastname: Lisa
authors.forename: Tomas
authors.initials: T
authors.lastname: Budesinsky
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D016001:Confidence Intervals; D017023:Coronary Angiography; D018153:Czech Republic / Q000453:epidemiology; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications* / Q000401:mortality / Q000628:therapy; D016017:Odds Ratio; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D012770:Shock, Cardiogenic / Q000175:diagnosis* / Q000209:etiology / Q000401:mortality; D016019:Survival Analysis; D015996:Survival Rate / Q000639:trends