Trial of Abciximab With and Without Low-Dose Reteplase for Acute Myocardial Infarction

Abstract

Background —Low-dose alteplase with standard-dose abciximab enhances reperfusion 90 minutes after acute myocardial infarction (MI). We combined standard-dose abciximab with low-dose reteplase for acute MI in 2 phases. Two heparin doses were also explored. Methods and Results —Phase A patients were randomized 4:1 to receive an abciximab bolus with infusion alone (n=63) or with 5 U, 7.5 U, 10 U, 5 U+2.5 U, or 5 U+5 U of reteplase (total n=241). Phase B tested the best phase A strategy (abciximab plus 5 U+5 U reteplase, expressed as abciximab-reteplase 5+5 U; n=115) against 10 U+10 U reteplase alone (n=109). The primary end point was Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow at 60 to 90 minutes. In phase A, 62% of the abciximab-reteplase 5+5 U group had TIMI grade 3 flow versus 27% of the abciximab-only patients ( P =0.001). In phase B, 54% of the abciximab-reteplase 5+5 U group had grade 3 flow versus 47% of the reteplase-only patients ( P =0.32). Grade 3 flow rates were 61% for a 60 U/kg heparin bolus and abciximab-reteplase 5+5 U, 51% for a 40 U/kg heparin bolus and abciximab-reteplase 5+5 U ( P =0.22), and 47% for reteplase alone ( P =0.05 versus the 60 U/kg heparin group). Major bleeding rates in phase A were 3.3% for abciximab alone and 5.3% for abciximab-reteplase 5+5 U; rates in phase B were 9.8% for abciximab-reteplase 5+5 U and 3.7% for reteplase alone. Major bleeding was similar with standard- or low-dose heparin (6.3% versus 10.5%, P =0.30). Conclusions —In this phase II trial, adding reteplase to abciximab treatment of acute MI versus reteplase alone enhanced the incidence of early complete reperfusion after the initiation of therapy in the emergency department.