Abstract 3487: Enoxaparin Reduces Recurrent MI and Death in Patients with STEMI Undergoing Fibrinolysis who Achieve Early ST Resolution: The ExTRACT-TIMI 25 ECG Study
Background: Early and sustained reperfusion are major goals in the treatment of STEMI. ST segment resolution (STRes) is an early non-invasive marker of epicardial reperfusion. In the ExTRACT-TIMI 25 ECG study, we used STRes to compare enoxaparin (ENOX) with unfraction-ated heparin (UFH) in combination with lysis.
Methods: ExTRACT-TIMI 25 randomized 20,479 pts with STEMI undergoing lysis to adjunctive therapy with ENOX v. UFH and demonstrated a significant 17% reduction in the risk of the primary endpoint of death or non-fatal re-MI by 30 days with ENOX. STRes at 180 min was analyzed in 3208 pts. STRes was defined as complete (>70%), partial (30–70%), or none (<30%).
Results: There was no difference in the rate of complete STRes between ENOX and UFH at 180 min (46.3% v. 49.4%, p=NS). However, among patients who achieved complete STRes, treatment with ENOX reduced significantly the rate of death or non-fatal re-MI at 30 days compared to pts who achieved only partial or no STRes (p for interaction=0.004).(Figure⇓) A similar pattern in reduction in death/re-MI was seen by 8 day after lysis. (2.4 v. 6.7%, p=0.001 with complete STRes, 9.5 v. 8.6%, p=0.65 with partial STRes, and 12.0 v. 14.4%, p=0.6 with no STRes)(p for interaction=0.012), and when comparing re-MI and death separately.
Conclusion: ENOX is associated with a significant reduction in death or non-fatal re-MI in patients who achieved complete STRes at 180 min. These data support the view that ENOX improves clinical outcomes by preventing re-occlusion rather than by facilitating early reperfusion.