Retrospective Evaluation of Two Fast-track Strategies to Rule Out Acute Coronary Syndrome in a Real-life Chest Pain Population.
BACKGROUND
The European Society of Cardiology (ESC) guideline on non-ST-elevation acute coronary syndrome (N-STE ACS) proposed a new ACS rule-out protocol.


OBJECTIVE
To evaluate this new tool, which uses diagnostic levels of high-sensitivity troponin T (hs-TnT; > 14 ng/L) in a slightly modified version and compare this to a recently proposed approach using undetectable levels of hs-TnT to rule out patients.


METHODS
There were 534 consecutive patients with suspected ACS included. Protocol 1: symptom duration, hs-TnT at 0 and 6-9 h, Global Registry of Acute Coronary Events (GRACE) score, and symptom status at 6-9 h. Protocol 2: a single blood sample of hs-TnT. The primary endpoint was a discharge diagnosis of ACS by blinded adjudication. Secondary endpoints were ACS re-admission < 30 days and 1-year mortality.


RESULTS
Protocol 1 classified 434/534 (81%) patients, with 27.9% being ruled out. All myocardial infarctions were correctly ruled in, but 15 cases of unstable angina were missed, resulting in a sensitivity and negative predictive value of 87.3% (79.6-92.5%) and 87.6% (80.4-92.9%), respectively. Protocol 2 ruled out 17.5% of the population, yielding a sensitivity and negative predictive value of 94.1% (88.2-97.6%) and 90.8% (81.9-96.2%), respectively. Both protocols correctly ruled in 2/3 patients with ACS re-admission < 30 days and 55/56 1-year fatalities.


CONCLUSIONS
The present study confirms the diagnostic value of a modified version of the ESC rule-out protocol (Protocol 1) in N-STE ACS patients, but also suggests that a simpler protocol using undetectable levels of hs-TnT (Protocol 2) could provide a similar or even superior sensitivity.
Department of Internal Medicine, Hudiksvalls Sjukhus, Hudiksvall, Sweden.
Martin
M
Schønemann-Lund
Department of Cardiology, Køge Sygehus, Køge, Denmark.
Mikkel Malby
MM
Schoos
Department of Cardiology, University Hospital of Copenhagen, Herlev Hospital, Herlev, Denmark.
Kasper
K
Iversen
Department of Clinical Biochemistry, University Hospital of Copenhagen, Hillerød Hospital, Hillerød, Denmark.
Steen I
SI
Hansen
Department of Clinical Biochemistry, University Hospital of Copenhagen, Hillerød Hospital, Hillerød, Denmark.
Jørgen
J
Thode
Department of Cardiology, Nykøbing Falster Sygehus, Nykøbing Falster, Denmark.
Peter
P
Clemmensen
Department of Cardiology, University Hospital of Copenhagen, Hillerød Hospital, Hillerød, Denmark.
Rolf
R
Steffensen
D054058:Acute Coronary Syndrome / Q000175:diagnosis* / Q000401:mortality; D000368:Aged; D015415:Biomarkers / Q000097:blood*; D002637:Chest Pain / Q000175:diagnosis* / Q000401:mortality; D002985:Clinical Protocols; D003718:Denmark / Q000453:epidemiology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010359:Patient Readmission / Q000706:statistics & numerical data; D017410:Practice Guidelines as Topic; D011379:Prognosis; D011446:Prospective Studies; D012042:Registries; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014218:Triage / Q000379:methods; D020107:Troponin T / Q000097:blood*
D015415:Biomarkers; D020107:Troponin T
acute coronary syndrome; limit of detection; sensitivity; specificity; triage; troponin; undetectable levels