M. Galvani et al., PROGNOSTIC INFLUENCE OF ELEVATED VALUES OF CARDIAC TROPONIN-I IN PATIENTS WITH UNSTABLE ANGINA, Circulation, 95(8), 1997, pp. 2053-2059
Background Elevations of the MB isoform of creatine kinase (CK) and ca
rdiac troponin T seem to confer an adverse prognosis in unstable angin
a. We examined whether this prognostic tic influence is also present f
or cardiac troponin I (cTnI), a new and even more specific marker of m
yocardial injury. Methods and Results We studied 106 patients with the
clinical diagnosis of unstable angina showing chest discomfort at res
t within 48 hours of admission, ECG evidence of myocardial ischemia, a
nd normal values of total CK over the initial 16 hours of observation.
The primary end point was death or nonfatal myocardial infarction (MI
) at 30 days; the secondary end point was the incidence of cardiac eve
nts at 1 year. Blood was drawn every 8 hours for 3 days. Thirteen pati
ents were excluded because of increased CK-MB mass concentrations with
in 16 hours of admission (non-Q-wave MI) and 2 because of inadequate b
lood sampling. Of the remaining 91 patients, 22 had cTnI elevations on
admission (n=7) or after 8 hours (n=15). At 30 days, no deaths (0%) a
nd 4 MIs (5.8%) occurred in the 69 patients with normal cTnI compared
with 2 deaths (9.1%) and 4 MIs (18.2%) in the 22 patients with elevate
d cTnI. The combined incidence of death and nonfatal MI was 5.8% and 2
7.3%, respectively (P=.02). At 1 year, only 68% of patients with eleva
ted cTnI were free of cardiac events, compared with 90% of those witho
ut elevations (P=.01). Conclusions These data indicate that cTnI is an
important prognostic variable in patients with unstable angina. Eleva
tions of cTnI predict an adverse short- and long-term prognosis.