Prognostic implications of elevated troponin in patients with suspected acute coronary syndrome but no critical epicardial coronary disease: a TACTICS-TIMI-18 substudy.
OBJECTIVE
The purpose of this study is to determine whether there is clinical significance to elevated troponin I in patients with suspected acute coronary syndromes (ACS) with non-critical angiographic coronary stenosis.


BACKGROUND
Elevation of troponin in patients admitted with ACS symptoms with non-critical coronary artery disease (CAD) may result from coronary atherothrombosis not evident using standard angiography or from other ischemic and non-ischemic causes that may confer increased risk for future events.


METHODS
Patients with ACS enrolled in the Treat Angina With Aggrastat and Determine Cost of Therapy With Invasive or Conservative Strategy-Thrombolysis In Myocardial Infarction (TACTICS-TIMI)-18 were included. Of 2,220 patients enrolled in the trial, 895 were eligible. Patients were divided into four groups according to troponin status on admission and presence of significant angiographic stenosis. Baseline brain natriuretic peptide (BNP) and C-reactive protein (CRP) were obtained on all patients.


RESULTS
The median troponin I levels were 0.71 ng/ml in patients with CAD compared with 0.02 ng/ml in patients without CAD (p <0.0001). Troponin-positive patients with or without angiographic CAD had higher CRP and BNP levels compared with troponin-negative patients (p <0.01 for both). The rates of death or reinfarction at six months were 0% in troponin-negative patients with no CAD, 3.1% in troponin-positive patients with no CAD, 5.8% in troponin-negative patients with CAD, and 8.6% in troponin-positive patients with CAD (p=0.012).


CONCLUSIONS
Elevated troponin in ACS is associated with a higher risk for death or reinfarction, even among patients who do not have significant angiographic CAD. The mechanisms conferring this adverse prognosis merit further study.
Dokainish
Hisham
H
Section of Cardiology, Baylor College of Medicine, Houston, Texas 77030, USA.
Pillai
Manu
M
Murphy
Sabina A
SA
DiBattiste
Peter M
PM
Schweiger
Marc J
MJ
Lotfi
Amir
A
Morrow
David A
DA
Cannon
Christopher P
CP
Braunwald
Eugene
E
Lakkis
Nasser
N
D000789:Angina, Unstable / Q000097:blood* / Q000401:mortality; D002097:C-Reactive Protein / Q000032:analysis; D023921:Coronary Stenosis / Q000097:blood; D006801:Humans; D009203:Myocardial Infarction / Q000097:blood* / Q000401:mortality; D020097:Natriuretic Peptide, Brain / Q000097:blood; D011379:Prognosis; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D016019:Survival Analysis; D013577:Syndrome; D019210:Troponin I / Q000097:blood*
D019210:Troponin I; D020097:Natriuretic Peptide, Brain; D002097:C-Reactive Protein