Clinical significance of a single measurement of troponin-I and C-reactive protein at admission in 1773 consecutive patients with acute coronary syndromes

Abstract

Background The clinical significance of biochemical markers of myocardial damage or inflammation has not been prospectively established in populations representing the whole spectrum of acute coronary syndromes. We investigated whether the elevation of these biomarkers at admission has a prognostic value that is independent and incremental to baseline clinical variables and quantitative electrocardiographic ischemia. Methods We measured blood levels of cardiac troponin I (cTnI) and C-reactive protein (CRP) in 1773 consecutive patients admitted to 31 Italian coronary care units within 12 hours from an episode of acute coronary syndrome. Primary and secondary outcomes were (1) 30-day incidence of death or nonfatal (re)infarction and (2) death alone. Results In a multivariate model, cTnI was independently associated with the risk of death or (re)infarction (OR, 1.8; 95% CI, 1.2 to 2.6; P = .002) and death (OR, 2.2; 95% CI, 1.4 to 3.4; P < .001), whereas CRP was of borderline significance for the primary outcome but was associated with death (OR, 1.4; 95% CI, 1.0 to 2.1; P = .06, and OR, 1.7; 95% CI, 1.1 to 2.6; P = .01, respectively). However, the inclusion of the biomarkers did not increase the prognostic capacity of the clinical risk model (C-index of both models with and without biomarkers was 0.73 for the primary outcome measures and 0.80 for the secondary outcome measures). CRP further stratified cTnI-negative patients. The prognostic significance of the biomarkers was similar in patients with and in those without persistent ST-segment elevation. Conclusions In acute coronary syndromes, the elevation of cTnI and CRP at admission has an independent prognostic value that is not incremental to baseline clinical variables and quantitative electrocardiographic ischemia.