Ability of Minor Elevations of Troponins I and T to Predict Benefit From an Early Invasive Strategy in Patients With Unstable Angina and Non-ST Elevation Myocardial InfarctionResults From a Randomized Trial

Abstract

Because of the wide spectrum of risk among patients with unstable angina and non–ST-segment elevation myocardial infarction (UA/NSTEMI), the American College of Cardiology/American Heart Association (ACC/AHA) Guidelines for the management of this condition recommend risk stratification as one of the most important initial steps in evaluating and treating these patients.¹ Routine risk assessment is especially important given the approximately 1.4 million hospital admissions annually in the United States for UA/NSTEMI.¹ Baseline levels of cardiac specific troponin I (cTnI) and T (cTnT) have been shown in numerous studies to be potent predictors of risk in this population.^1-3 In addition, several groups have shown that the troponins can identify patients who derive particular benefit from treatment with glycoprotein IIb/IIIa inhibitors and low–molecular-weight heparin.^4-7 However, few data are available on the ability of troponin to predict the benefit of an invasive vs a conservative approach to management, ie, whether or not to refer the patient for cardiac catheterization and revascularization, if appropriate (a routine "invasive" approach), or to follow a "conservative" strategy, with cardiac procedures performed only if the patient exhibits spontaneous or provoked recurrent ischemia. Furthermore, controversy exists over the optimal troponin thresholds to use for such clinical decision making. In particular, the clinical relevance of low levels of troponin elevation among patients with UA/NSTEMI remains unclear.