Clinical Investigations: Acute Ischemic Heart Disease
The prognostic and therapeutic implications of increased troponin T levels and ST depression in unstable coronary artery disease: The FRISC II invasive troponin T electrocardiogram substudy*,**,

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Abstract

Background In unstable coronary artery disease, both increased troponin T level and occurrence of ST-segment depression are associated with a worse prognosis. In the Fast Revascularisation in InStability in Coronary disease trial II invasive study, we evaluated whether the troponin T level, alone and combined with ST depression, identified more severe coronary artery disease or a greater efficacy of an early invasive strategy. Methods In the study, 2457 patients with unstable coronary artery disease were randomized to early invasive or noninvasive strategy. Troponin T value and admission electrocardiogram results were available in 2286 patients. Results In the noninvasive cohort, death or myocardial infarction occurred in 16.6% with troponin T level ≥0.03 μg/L versus 8.5% with troponin T level <0.03 μg/L (P <.001). In the invasive group, 49% of patients with both ST depression and troponin T level ≥0.03 μg/L had 3-vessel or left main disease compared with 17% if neither finding was present (P <.001). The invasive strategy reduced death/myocardial infarction at 12 months in the cohort with both ST depression and troponin T level ≥0.03 μg/L from 22.1% to 13.2% (risk ratio, 0.60; 95% confidence interval, 0.43 to 0.82; P =.001). In the cohort with either ST depression or troponin T level ≥0.03 μg/L or neither of these findings, the absolute gain of the invasive strategy was smaller and more uncertain. Conclusion Patients with unstable coronary artery disease with the combination of troponin T level ≥0.03 μg/L and ST depression have a poor prognosis and, in half of the cases, 3-vessel or left main disease. In these patients, an early invasive strategy will substantially reduce death/myocardial infarction. (Am Heart J 2002;143:760-7.)

Section snippets

Patients

In the FRISC II trial, 2457 patients were randomized to an invasive or noninvasive regimen. The details of the design and the main results have been published.12 Inclusion criteria were symptoms of cardiac ischemia associated with either ST depression ≥0.1 mV or T wave inversion ≥0.1 mV in at least 1 lead or elevation of biochemical marker of myocardial damage.

In this study, only patients with plasma samples for central evaluation of the troponin T level and electrocardiographic results for

Electrocardiogram on admission and troponin T level at randomization

Admission electrocardiograms for evaluation regarding STT changes and plasma samples allowing troponin T level analysis were available in 2286 patients (93% of the total study population). The median time elapsed from start of chest pain to collection of blood samples was 39 hours (interquartile range, 27 to 54 hours). Around one third of patients had troponin T level elevation (ie, ≥0.03 μg/L) and ST depression, one third had troponin T level elevation only, and one third had no troponin T

Prognosis in the noninvasive group

An elevated troponin T level and ST depression in electrocardiographic results at entry have been associated with an elevated risk of future events.1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 In this study, the worst prognosis was seen in patients with the combination of troponin T level ≥0.03 μg/L and ST depression, with a 22% rate of death or myocardial infarction and a 5.9% mortality rate at 12 months, both of which were more than twice as high as in the rest of the study population. Also, in the

Acknowledgements

We thank all patients who agreed to participate for their invaluable contribution and the research nurses, monitors, investigators, coordinators, core laboratories, endpoint committee, and data safety monitoring board for their dedicated work.

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*

Supported by and organized in collaboration with the Pharmacia & Upjohn Company. Project organization within the research group also supported by the Swedish Heart-Lung Foundation and Uppsala County Association Against Heart and Lung Diseases.

**

Reprint requests: Erik Diderholm, MD, Department of Cardiology, Cardiothoracic Center, University Hospital, S-751 85 Uppsala, Sweden.

E-mail: [email protected]

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