Abstract 11302: Improved Risk Stratification in Patients with ST-Elevation Myocardial Infarction Treated with Fibrinolysis by Combining New Q-Waves on the Initial Electrocardiogram with ST-Segment Resolution -- Observations from the CLARITY-TIMI 28 Trial
Background: In STEMI pts, the presence of new Q-waves on the initial ECG and less ST-segment resolution after reperfusion (STRes) are both associated with poor cardiovascular (CV) outcomes. The interaction between initial Q-waves and STRes in pts treated with fibrinolytic therapy is uncertain.
Methods: The CLARITY-TIMI 28 trial randomized STEMI pts treated with fibrinolysis to clopidogrel or placebo. ECGs were evaluated for new pathologic Q-waves on presentation and STRes after fibrinolysis in 3322 pts. Pts were stratified into four groups based on the presence or absence of an initial Q-wave and the presence or absence of complete (>70%) STRes at 90 minutes.
Results: An initial Q-wave was associated with a significant increase in the rate of CV death or CHF regardless of whether the pt had complete STRes, and, in pts with Q-waves, successful reperfusion as assessed by complete STRes was associated with improved outcomes. A similar pattern was observed for the individual outcomes of CV death and CHF. The combination of initial Q-wave status and STRes identified pts at low, moderate, and high risk for the composite of CV death or CHF at 30 days (see figure). Pts without an initial Q-wave and with complete STRes had a 1.9% risk of CV death or CHF, while pts with an initial Q-wave and without complete STRes had an 11.1% risk of CV death or CHF (OR 6.4, p<0.001). Pts without an initial Q-wave and without complete STRes or with an initial Q-wave and with complete STRes had an intermediate risk (6.0%, OR 3.3, p=0.005, and 4.4%, OR 2.4, p=0.048, respectively), with no significant difference between these two groups (p=0.258).
Conclusions: In STEMI pts treated with fibrinolysis, assessing for new initial Q-waves and STRes at 90 minutes allows additional refinement of pt risk. Pts with Q-waves have an increased rate of adverse outcomes overall, but in this subset of pts, successful reperfusion as assessed by STRes is associated with improved outcomes.
- © 2011 by American Heart Association, Inc.