Time to positivity of a rapid bedside assay for cardiac-specific troponin T predicts prognosis in acute coronary syndromes: a Thrombolysis in Myocardial Infarction (TIMI) 11A substudy.

OBJECTIVES

We sought to determine whether the rapid bedside assay for troponin T identified patients at risk for a more complicated hospital stay and a higher rate of adverse clinical events.

BACKGROUND

In patients with an acute coronary syndrome, the amount of cardiac-specific troponin T released bears a stoichiometric relation to the extent of myocardial damage.

METHODS

In 597 patients with unstable angina or non-Q wave myocardial infarction participating in the Thrombolysis in Myocardial Infarction (TIMI) 11A substudy, a rapid bedside assay and simultaneous quantitative serum measurement for troponin T were obtained at enrollment.

RESULTS

The composite end point of the sum of death, nonfatal myocardial infarction or recurrent ischemia through day 14 occurred in 33.6% of patients with a positive assay compared with only 22.5% of patients with a negative assay (p = 0.01). Those patients in whom the rapid assay became positive in < or = 10 min had the highest mortality rate of 4.2% through day 14 compared with 1.1% in those patients who had either a late-appearing positive assay (> 10 min) or a negative assay. The duration of hospital stay in the 116 patients (19%) with a positive rapid assay at enrollment was a median of 5 days compared with only 3 days in the 481 patients (81%) with a negative rapid assay at enrollment (p = 0.002).

CONCLUSIONS

A positive rapid assay for troponin T at presentation identifies those patients at risk for higher rates of adverse clinical events and longer, more complicated hospital stays. Stratification of patients by time to development of a positive rapid assay identifies those patients at highest mortality risk.