Not all patients presenting with acute coronary syndrome (ACS) are able to receive reperfusion therapy. These include patients who present late (after 12 h) or who have bleeding diathesis. Studies have found a number of factors affect the decision to reperfuse. Other treatment options are needed for those patients with acute ST-elevation myocardial infarction (STEMI). Low-molecular weight heparin, such as enoxaparin, now offers these patients the opportunity for successful intervention. Several clinical trials have determined its superiority over unfractionated heparin as an adjunct during thrombolytic therapy. Currently, a trial is underway to determine the effect of enoxaparin in combination with tirofiban in patients with STEMI ineligible for reperfusion therapy. Blinded data for the entire patient cohort shows excellent efficacy and safety in these patients.