Management of
unstable angina is largely determined by symptoms, yet some symptomatic patients stabilize, whereas others develop
myocardial infarction after waning of symptoms. Therefore, markers of short-term risk, available on admission, are needed. The value of 4 prognostic indicators available on admission (
pain in the last 24 hours, electrocardiogram [ECG],
troponin T, and
C-reactive protein [CRP]), and of Holter monitoring available during the subsequent 24 hours was analyzed in 102 patients with Braunwald class IIIB
unstable angina hospitalized in 4 centers. The patients were divided into 3 groups: group 1, 27 with
pain during the last 24 hours and ischemic electrocardiographic changes; group 2, 45 with
pain or electrocardiographic changes; group 3, 30 with neither
pain nor electrocardiographic changes.
Troponin T, CRP, ECG on admission, and Holter monitoring were analyzed blindly in the core laboratory. Fifteen patients developed
myocardial infarction: 22% in group 1, 13% in group 2, and 10% in group 3. Twenty-eight patients underwent revascularization: 37% in group 1, 35% in group 2, and 7% in group 2 (p <0.01 between groups 1 or 2 vs group 3).
Myocardial infarction was more frequent in patients with elevated
troponin T (50% vs 9%, p=0.001) and elevated CRP (24% vs 4%, p= 0.01). Positive
troponin T or CRP identified all
myocardial infarctions in group 3. Only 1 of 46 patients with negative
troponin T and CRP developed
myocardial infarction. Among the indicators available on admission, multivariate analysis showed that
troponin T (p=0.02) and CRP (p=0.04) were independently associated with
myocardial infarction.
Troponin T had the highest specificity (92%), and CRP the highest sensitivity (87%). Positive results on Holter monitoring were also associated with
myocardial infarction (p=0.003), but when added to
troponin T and CRP, increased specificity and positive predictive value by only 3%. Thus, in patients with class IIIB
unstable angina, among data potentially available on admission, serum levels of
troponin T and CRP have a significantly greater prognostic accuracy than symptoms and ECGs. Holter monitoring, available 24 hours later, adds no significant information.