There is a growing awareness of the role
of cardiac troponin-I (cTnl) in detecting patients with
unstable angina (UA) who are at high-risk of subsequent
cardiac events, for whom prompt intervention is highly
indicated.
Objective: To evaluate role of cTnl in detecting this
high-risk subgroup of UApatients.
Patients andMethods: Quantitative serumcTnl level
was measured in 100 patients withUA, 12h, 24h and 48h
after admission to the hospital; serum CK &CK-MB
activity was also measured at the same time intervals to
exclude acuteML The studied population was classified
into two groups; group I included 55 patientswho showed
normal cTnl level (< 0.6ng/ml) and group II included 45
patients who had such abnormal level (> 0.6ng/ml).
Resting 12 lead-ECGswas done on admission, twice daily,
and whenever needed. All patients underwent coronary
and LV angiographic studies before hospital discharge
andwere clinically followedup for threemonths to detect
any of the following adverse events: death, progression
of UA toMI or need for emergency PTCA / CABG.
Results: Compared to group I, group II patients had
statistically significant highermean age (P< 0.05), higher
prevalence of diabetes (P < 0.05), higher incidence of
Braunwald class III UA (P< 0.01), and higher incidence
of marked ST-T changes (P < 0.001). Male sex,
hypertension or hypercholesterolemiawas not statistically
different between both groups.Quantitative angiographic
data revealed a higher mean of percentage diameter
stenosis (P
0.05) in group II compared to group I. Nearly all those
who had subsequent adverse cardiac events showed a
positive test for serum cTnl.
Conclusion: An abnormal cTnl serum level is
commonly associated with severe UA,more extensive
and complex coronary artery disease, high-risk
angiographic anatomy of the culprit lesion and a poor
clinical outcome in patients with UA. Serum cTnl is a
simple and non-invasive test,which can be used to stratify
patients with unstable angina into low- and high-risk
groups very early (within 48h) in the course of the disease;
so it is useful in targeting the new, potent and often costly
lines ofmanagement such as revascularization procedures
and the newer antithrombotic andantiplatelet agents for
the high-risk UA population.
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