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.

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 > or =0.03 microg/L versus 8.5% with troponin T level < 0.03 microg/L (P <.001). In the invasive group, 49% of patients with both ST depression and troponin T level > or =0.03 microg/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 > or =0.03 microg/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 > or =0.03 microg/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 > or =0.03 microg/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.