Patient selection for high sensitivity cardiac troponin testing and diagnosis of myocardial infarction: prospective cohort study

Figures

• 

  Fig 1. Flow diagram summarising enrolment of unselected patients and those selected for cardiac troponin testing in the UK and US. ED=emergency department; STEMI=ST segment elevation myocardial infarction. *Troponin used only to guide clinical care in patients with suspected acute coronary syndrome

• 

  Fig 2. Prevalence of elevated high sensitivity cardiac troponin concentrations and type 1 myocardial infarction in unselected patients and those selected for cardiac troponin testing in the UK and US

• 

  Fig 3. Influence of prevalence on positive predictive value of elevated high sensitivity cardiac troponin concentration for diagnosis of type 1 myocardial infarction. Red dots represent populations of unselected patients in the emergency department (n=1054) and selected patients in the UK (n=5815) and US (n=1631). Blue dots represent reported positive predictive values for high sensitivity cardiac troponin by prevalence of type 1 myocardial infarction in previously published cohorts using high sensitivity cardiac troponin T (black text) and high sensitivity cardiac troponin I (red text) assays.25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 Data for positive predictive values for high sensitivity troponin T cohorts were extracted from a recent systematic review and meta-analysis published by Zhelev et al.46 Dot size reflects number of patients in each cohort (small dot <500 patients, medium dot 500-1500 patients, large dot >1500 patients). Blue line represents central estimate of positive predictive value with 95% confidence interval (dashed red lines) derived from unselected emergency department population in the UK

• 

  Fig 4. Influence of clinical characteristics on positive predictive value of elevated high sensitivity cardiac troponin for diagnosis of type 1 myocardial infarction in patients selected for troponin testing in the UK (top panel) and US (bottom panel). Solid line represents positive predictive value across whole population, with dashed lines representing 95% confidence intervals