Troponin T and quantitative ST-segment depression offer complementary prognostic information in the risk stratification of acute coronary syndrome patients

Abstract

ObjectivesOur primary objective was to examine the prognostic relationship between baseline quantitative ST-segment depression (ST↓) and cardiac troponin T (cTnT) elevation. The secondary objectives were to: 1) examine whether ST↓ provided additional insight into therapeutic efficacy of glycoprotein IIb/IIIa therapy similar to that demonstrated by cTnT; and 2) explore whether the time to evaluation impacted on each marker’s relative prognostic utility. BackgroundThe relationship between the baseline electrocardiogram (ECG) and cTnT measurements in risk-stratifying patients presenting with acute coronary syndromes (ACS) has not been evaluated comprehensively. MethodsThe study population consisted of 959 patients enrolled in the cTnT substudy of the Platelet IIb/IIIa Antagonism for the Reduction of Acute coronary syndrome events in a Global Organization Network (PARAGON)-B trial. Patients were classified as having no ST↓ (n = 387), 1 mm ST↓ (n = 433), and ST↓ ≥2 mm (n = 139). Forty-percent (n = 381) were classified as cTnT-positive based on a definition of ≥0.1 ng/ml. ResultsSix-month death/(re)myocardial infarction rates were 8.4% among cTnT-negative patients with no ST↓ and 26.8% among cTnT-positive patients with ST↓ ≥2 mm. On ECGs done after 6 h of symptom onset, ST↓ ≥2 mm was associated with higher risk compared to its presence on ECGs done earlier (odds ratio [OR] 7.3 vs. 2.1). In contrast, the presence of elevated cTnT within 6 h of symptom was associated with a higher risk of adverse events compared with elevations after 6 h (OR 2.4 vs. 1.5). ConclusionsQuantitative ST↓ and cTnT status are complementary in assessing risk among ACS patients and both should be employed to determine prognosis and assist in medical decision making.