Coronary Artery Disease
Incremental prognostic value of serum levels of troponin T and C-reactive protein on admission in patients with unstable angina pectoris

https://doi.org/10.1016/S0002-9149(98)00458-5Get rights and content

Abstract

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.

Section snippets

Patient population

The study population consisted of 102 consecutive patients (73 men and 29 women, aged 30 to 75 years [mean 64 ± 9 years]) hospitalized with Braunwald class IIIB unstable angina over a period of 12 months in 4 Italian hospitals (Table I). The mean time between the last anginal episode and hospitalization was 11 ± 7 hours (range 1 to 48). We excluded patients aged >75 years, patients with other cardiac diseases, those with an ejection fraction <40%,1 and those with inflammatory or neoplastic

Results

A total of 15 patients developed myocardial infarction, 12 during hospitalization and 3 during the 3-month follow-up period (1 of whom died) (Table II). There was no difference in the incidence of myocardial infarction between university and peripheral hospitals (5 of 39 vs 10 of 63; p = NS). Ten of 63 patients in the 3 district hospitals, and all 39 patients in the university hospital underwent coronary angiography: 2 had no critical stenoses, 21 had 1-vessel disease, and 26 had multivessel

Discussion

The conflicting results observed with several indicators of prognosis in patients with unstable angina can be explained by the inclusion of patients with a different severity of angina, by the inclusion of non–Q-wave myocardial infarction, by the different periods of admission from symptom onset, and with different end points considered.

In clinical practice, however, prognosis of individual patients is based on synthesis of several indicators such as clinical history, objective findings,

Acknowledgements

We wish to thank Frank Dini, MD, and Daniele Bernardi, MD, of the General Hospital in Barga, Gabriele Giorgi, MD, of the General Hospital in Frascati, and Nadia Aspromonte, MD, and Maria Antonietta Pala, MD, of the Santo Spirito Hospital in Rome for their participation. We are also indebted to the nurses of the coronary care unit at Policlinico Gemelli for their assistance, and to Vanessa Perrin and Lucia De Angelis for their assistance in the preparation of the manuscript.

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This study was supported in part by Grant 94.00518.PF41 from the Italian National Research Council, targeted project “Prevention and Control Disease Factors,” Rome, Italy, by Grant PL951505 from the European Community BIOMED 2 Programme, and by Associazione Ricerche Coronariche, Catholic University, Rome, Italy. Manuscript received December 8, 1997; revised manuscript received and accepted May 6, 1998.

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