A laboratory score at presentation to rule-out serious cardiac outcomes or death in patients presenting with symptoms suggestive of acute coronary syndrome.
BACKGROUND
We evaluated whether a low high-sensitivity cardiac troponin (hs-cTn) cutoff combined with glucose, red cell distribution width (RDW), and the estimated glomerular filtration rate (eGFR) can be used to rule-out a serious cardiac outcome or death in patients presenting with symptoms suggestive of acute coronary syndrome (ACS).


METHODS
This was a prospective observational emergency department (ED) study enrolling consecutive patients presenting with symptoms suggestive of ACS (ClinicalTrials.gov: NCT01994577). The primary outcome was a 7-day composite of myocardial infarction, unstable angina, decompensated congestive heart failure, serious ventricular cardiac arrhythmia, or death. A laboratory score combining glucose, RDW, eGFR with hs-cTnT (Roche) or hs-cTnI (Abbott) was compared to hs-cTn alone using the limit of detection (LoD; hs-cTnT<5ng/l/hs-cTnI<2ng/l) as the cutoff. A benchmark of >99% sensitivity was used to assess the laboratory panel with hs-cTn versus the LoD alone to identify low-risk patients suitable for discharge.


RESULTS
A total of 1095 patients (n=267 composite-outcomes) had measurements of glucose, RDW, eGFR, hs-cTnT, and hs-cTnI at presentation. Applying the hs-cTn LoD alone as the cutoff missed 5 composite-outcomes (sensitivity=98.1%), however the addition of the laboratory panel to the hs-cTn LoD increased the sensitivity to >99% with approximately 10% of the population identified as low-risk. The percentage of low-risk patients was increased to 15% (1 composite-outcome missed) when employing a low measurable hs-cTnI cutoff with the laboratory panel (laboratory score<2 points).


CONCLUSIONS
A laboratory score with hs-cTn may identify low-risk patients suitable for ED discharge at presentation.
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada. Electronic address: kavsakp@mcmaster.ca.
Peter A
PA
Kavsak
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
Colleen
C
Shortt
School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa, Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.
Jinhui
J
Ma
Department of Medicine, McMaster University, Hamilton, ON, Canada.
Natasha
N
Clayton
Division of Emergency Medicine, McMaster University, Hamilton, ON, Canada.
Jonathan
J
Sherbino
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
Stephen A
SA
Hill
Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, Canada.
Matthew
M
McQueen
Division of Cardiology and Population Health Research Institute, McMaster University, Hamilton, ON, Canada.
Shamir R
SR
Mehta
Division of Cardiology and Population Health Research Institute, McMaster University, Hamilton, ON, Canada.
P J
PJ
Devereaux
Division of Emergency Medicine, McMaster University, Hamilton, ON, Canada.
Andrew
A
Worster
D054058:Acute Coronary Syndrome / Q000097:blood / Q000175:diagnosis* / Q000378:metabolism / Q000503:physiopathology; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D019411:Clinical Laboratory Techniques; D003643:Death; D004636:Emergency Service, Hospital; D004906:Erythrocyte Count; D005919:Glomerular Filtration Rate; D006801:Humans; D009206:Myocardium / Q000378:metabolism*; D011379:Prognosis; D014336:Troponin / Q000378:metabolism
D001786:Blood Glucose; D014336:Troponin
Acute coronary syndrome; Death; Emergency department; Heart failure; High-sensitivity cardiac troponin; Myocardial infarction; Rule-out