Improved in-hospital outcomes in acute coronary syndromes (unstable angina/non-ST segment elevation myocardial infarction) despite similar TIMI risk scores

Abstract

Background: The Thrombolysis In Myocardial Infarction (TIMI) Risk Score has been shown to predict prognosis in acute coronary syndromes (ACS) comprised of unstable angina (UA) and non-ST segment elevation myocardial infarction (STEMI). We sought to evaluate the impact of newer antiplatelet and antithrombotic therapies for ACS, such as glycoprotein IIb/IIIa inhibitors (GPI) and low molecular weight heparin (LMWH), on in-hospital outcomes over time in patients (pts) with similar TIMI risk scores.

Methods: The baseline demographics and clinical outcomes of pts with ACS (UA and non-STEMI) in 1998 (Group 1998) and 2000 (Group 2000) at a single large university medical center were compared using a prospectively collected database. In-hospital major adverse cardiac events (MACE) included death, MI, or recurrent angina that resulted in urgent revascularization. Risk was estimated by utilizing the TIMI Risk Score, which uses 7 predictor variables: age > 65 years, at least 3 risk factors for coronary artery disease, prior coronary stenosis of 50%, ST segment deviation on EKG, severe angina, prior aspirin use, and elevated cardiac biomarkers.

Results: Comparing Group 1998 (n = 563) and Group 2000 (n = 604), there was no difference between the mean TIMI Risk Score (2.90 1.52 vs. 2.91 1.52; p = 0.97), demonstrating a similar risk profile. Nevertheless, significant improvement in in-hospital MACE (9.1% vs. 2.8%; p < 0.001) was noted. The improvement in MACE was due to differences in rates of recurrent angina, without significant differences in death and myocardial infarction. This occurred temporally in association with a significant increase in GPI (1.0% vs. 8.3%; p < 0.01) and LMWH (0.0% vs. 15.6%; p < 0.001) use within 24 hours of presentation, and the increased utilization of intracoronary stenting (46.6% vs. 64.6%; p = 0.005), findings which were confirmed with multivariate analysis.

Conclusion: Despite similar TIMI Risk Scores, the in-hospital outcomes of pts with ACS have improved over time. This temporal change is associated with the greater use of newer antiplatelet and antithrombotic therapies and increased utilization of intracoronary stenting.