Predictors of 30-day cardiovascular events in patients with prior percutaneous coronary intervention or coronary artery bypass grafting.

Objectives: Risk stratification of patients with potential acute coronary syndrome (ACS) is difficult. Patients with prior revascularization are considered higher risk, but they can also have symptoms from noncardiac causes. This study evaluated whether the presenting clinical characteristics were predictive of an increased risk of 30-day cardiovascular events in patients with prior revascularization presenting to the emergency department (ED) with symptoms of potential ACS.

Methods: This was a secondary analysis of the DISPO-ACS study, a 2000-patient, four-site, randomized controlled trial of patients presenting with potential ACS. Process outcomes were evaluated using point-of-care cardiac markers compared to standard laboratory-based markers. Data included demographics, history, presenting symptoms, laboratory and electrocardiogram (ECG) results, hospital course, and 30-day cardiovascular events (death, acute myocardial infarction [AMI], revascularization). The association between presenting characteristics and 30-day cardiovascular events was assessed using univariable analysis and logistic regression; odds ratios (ORs) with 95% confidence intervals (CIs) are given.

Results: Of 2,000 patients enrolled, 611 had prior revascularization (538 percutaneous coronary intervention [PCI], 232 coronary artery bypass graft [CABG], 159 both). The mean (±SD) age was 66 (±14) years, 44% were female, and 22% were black. By 30 days, 101 patients (17%) had cardiovascular events (81 during the index visit, 20 during follow-up). There were four deaths, 28 AMIs, and 67 revascularizations within 30 days; 20 patients had multiple endpoints. Being male (OR = 1.67, 95% CI = 1.07 to 2.62) or nonblack (OR = 1.95, 95% CI = 1.07 to 3.56) or having a family history of coronary artery disease (CAD; OR = 2.09, 95% CI = 1.32 to 3.3), elevated lipids (OR = 1.71, 95% CI = 1.04 to 2.82), prior AMI (OR = 1.79, 95% CI = 1.16 to 2.76), abnormal ECG on arrival (OR = 2.1, 95% CI = 1.33 to 3.34), and a positive initial troponin (OR = 14.7, 95% CI = 6.8 to 32.2) were predictive of cardiovascular events. The multivariable model found family history of CAD (OR = 2.06, 95% CI = 1.26 to 3.36), abnormal initial ECG (OR = 1.89, 95% CI = 1.16 to 3.09), and positive initial troponin (OR = 13.3, 95% CI = 5.9 to 29.6) remained predictive of 30-day cardiovascular events.

Conclusions: In patients with prior revascularization, the initial ECG and early cardiac marker elevations, but not clinical presentation, predict odds of 30-day death, AMI, or revascularization.