Role of cardiac troponin in the diagnosis of acute myocardial infarction in comatose patients resuscitated from out-of-hospital cardiac arrest.
BACKGROUND
Troponin is a major diagnostic criterion of acute myocardial infarction (AMI) but in out-of-hospital cardiac arrest (OHCA) patients, its diagnostic value may be altered by cardiopulmonary resuscitation.


METHODS
Single-centre study assessing the diagnostic characteristics of troponin for AMI diagnosis in consecutive patients resuscitated from OHCA between 2002 and 2008 with coronary angiogram (CA) performed on admission. Patients with obvious non-cardiac cause of OHCA, unsustained or absent return of spontaneous circulation were excluded. AMI was defined on CA by the presence of acute occlusion or critical stenosis with intracoronary fresh thrombus easily crossed by an angioplasty wire. Troponin concentration was recorded once on admission and once 6-12h after the OHCA.


RESULTS
A total of 163 patients aged 56 (median) years (interquartile range (IQR) 48-65) was included, all comatose. Most prevalent initial OHCA rhythms were ventricular fibrillation (49%) and asystole (41%). AMI was diagnosed on coronary angiogram in 37% of the patients. Median troponin concentration on admission was 1.7 (0.3-10)ngml(-1) and sensitivity for AMI diagnosis was 72% and specificity 75% for a 2.5ngml(-1) cut-off. A combined criterion comprising ST elevation and troponin >2.5ngml(-1) had a sensitivity of 93% and specificity of 64%. Six to twelve hours after the OHCA, median troponin concentration was 7.6ngml(-1) (1.4-47.5), sensitivity was 84% and specificity 84% for a 14.5ngml(-1) cut-off.


CONCLUSIONS
Troponin I has a good diagnostic value for AMI diagnosis in OHCA patients. In combination with ST elevation, troponin I on admission achieves a very high sensitivity.
Cardiology Department, Lariboisière Hospital, Assistance Publique Hôpitaux de Paris, Paris, France. sebastoso@yahoo.com
Sebastian
S
Voicu
Georgios
G
Sideris
Nicolas
N
Deye
Jean-Guillaume
JG
Dillinger
Damien
D
Logeart
Claire
C
Broche
Benoit
B
Vivien
Pierre-Yves
PY
Brun
Dragos Daniel
DD
Capan
Stéphane
S
Manzo-Silberman
Bruno
B
Megarbane
Frédéric J
FJ
Baud
Patrick
P
Henry
D000368:Aged; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D016887:Cardiopulmonary Resuscitation / Q000379:methods*; D015331:Cohort Studies; D003128:Coma / Q000401:mortality / Q000503:physiopathology* / Q000628:therapy; D017023:Coronary Angiography / Q000379:methods; D016638:Critical Illness / Q000401:mortality / Q000628:therapy; D004562:Electrocardiography / Q000379:methods; D004632:Emergency Medical Services / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D017052:Hospital Mortality / Q000639:trends; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications / Q000175:diagnosis* / Q000401:mortality; D058687:Out-of-Hospital Cardiac Arrest / Q000209:etiology / Q000401:mortality / Q000628:therapy*; D010343:Patient Admission; D012372:ROC Curve; D012016:Reference Values; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D015996:Survival Rate; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood* / Q000378:metabolism
D015415:Biomarkers; D019210:Troponin I