Risk stratification of patients presenting to the emergency department (ED) with suspected cardiac chest pain (CP) and an undifferentiated electrocardiogram (ECG) is difficult. We hypothesized that in these patients a risk score incorporating clinical, ECG, and myocardial contrast echocardiography (MCE) variables would accurately predict adverse events occurring within the next 48 hours.
Methods and Results
Patients with CP lasting for ≥30 min who did not have ST segment elevation on the ECG, were enrolled. Regional function (RF) and myocardial perfusion (MP) were assessed by MCE. A risk model was developed in the initial 1166 patients (cohort 1), and validated in subsequent 720 patients (cohort 2). Any abnormality or ST changes on ECG (OR 2.5, 95% CI:1.4–4.5, p=0.002, and OR 2.9, 95% CI:1.7–4.8, p<0.001, respectively), abnormal RF with normal MP (OR 3.5, 95% CI:1.8–6.5, p<0.001), and abnormal RF with abnormal MP (OR 9.6, 95% CI:5.8–16.0, p<0.001) were found to be significant multivariate predictors of non-fatal myocardial infarction or cardiac death. The estimate of the probability of concordance for the risk model was 0.82 for cohort 1 and 0.83 for cohort 2. The risk score in both cohorts stratified patients into 5 distinct risk groups with event rates ranging from 0.3% to 58%.
A simple predictive instrument has been developed from clinical, ECG, and MCE findings obtained at the bedside that can accurately predict events occurring within 48 hours in patients presenting to the ED with suspected cardiac CP and an ECG that is not diagnostic for acute ischemic injury. Its application could enhance care of CP patients in the ED. For instance, patients with a risk score of 0 could be discharged from the ED without further work-up. However, this needs to be validated in a multi-center study.