Abstract

Objective To investigate the combination of clinical data, exercise testing and biomarkers for evaluation of patients with chest pain without ST-segment deviation or troponin elevation.

Design Prospective cohort design

Settting Two teaching hospitals in Spain

Patients 422 patients presenting to the emergency department were studied. Leukocyte count, C-reactive protein (CRP), pregnancy-associated plasma protein-A (PAPP-A) and N-terminal pro-brain natriuretic peptide (NT-proBNP) were determined. A validated clinical risk score (number of points according to pain characteristics and risk factors) was used for clinical evaluation and early exercise testing was performed.

Main outcome measures Adverse events (death, myocardial infarction or revascularization) during a median 60 weeks follow-up.

Results By ROC curve analysis, the association between death or myocardial infarction and adverse events was not significant with leukocyte count (p=0.3, p=0.3) or CRP (p=0.5, p=0.8), border-line significant with PAPP-A (p=0.07, p=0.04) and strongly significant with NT-pro-BNP (p=0.0001, p=0.0001). By Cox regression including clinical risk score, exercise testing result and biomarkers, exercise testing was the independent predictor of revascularization (p=0.0001), whereas risk score (p=0.03) and NT-proBNP (p=0.0004) predicted death or myocardial infarction. Inclusion of NT-proBNP improved the accuracy of the model for death or myocardial infarction (C-statistic 0.84 vs 0.76, p=0.01). The combination of clinical score and NT-proBNP afforded the stratification in high (17.2%, p=0.0001), intermediate (5.3%) and low (1.1%) risk categories of death or myocardial infarction.

Conclusions NT-proBNP provides incremental prognostic information above that given by clinical history and exercise testing in patients with chest pain without ST-segment deviation and negative troponin.