[Development and prospective validation of an ischemic risk score for acute chest pain patients with normal high-sensitivity troponin I levels and without obvious ST-segment deviation].

Objective: To develop and prospectively validate a risk score for acute chest pain patients with normal high-sensitivity troponin I (hs-TnI) levels and without obvious ST-segment deviation in China. Methods: Chest pain patients admitted to the emergency department of Beijing Anzhen Hospital from September 2014 to July 2015 were enrolled. Baseline characteristics of patients met inclusion criteria including normal hs-TnI levels and without obvious ST-segment deviation were included. The endpoint (major adverse cardiovascular events) was a composite of acute myocardial infarction, percutaneous coronary intervention, coronary artery bypass graft, and all-cause death within 3 months after initial presentation. Predictors were screened and used to develop the risk score model by logistic regression analysis in a retrospective cohort. Then, the risk score model was evaluated in a prospective validation cohort. Results: The study population of derivation cohort included 1 735 consecutive chest pain patients. Finally, 1 030 eligible patients were enrolled. Multivariate regression analysis defined five independent predictors: male gender (β=0.88); history of chest pain (β value of moderate and high suspicion of coronary heart artery was 2.70 and 3.51 respectively); electrocardiogram (β=0.84); ≥60 years old (β=0.51) and ≥3 risk factors (β=0.85).The range of weighted score was set as 0-13. The area under a receiver operating characteristic (ROC) curve was 0.75 (95% CI 0.72-0.78) in the final model. Major adverse cardiovascular events rates increased in proportion to score increase ( P< 0.01). The internal validity used bootstrap technique showed the same predictor factors as the final model, and its area under a ROC curve was 0.75(95% CI 0.72-0.78).MACE rates in the low risk group (score 0-3), intermediate risk group (score 4-7), and high risk group (score 8-13) were 1.3% (1/77) ,19.0% (22/116) ,and 42.2% (122/289) in the prospective validation cohort, respectively ( P< 0.01). Conclusion: The developed ischemic risk score is feasible for risk stratification of acute chest pain patients with normal hs-TnI and without obvious ST-segment deviation, this score might be helpful to the decision making of treatment and management strategies for these patients.