Background: The aim of this study was to evaluate the effectiveness of glycoprotein (GP) IIb/IIIa receptor inhibitors in acute myocardial infarction (AMI) patients in case of unsuccessful and failed thrombolysis.
Methods: Eighty-four patients hospitalized within 4 hours of symptom onset were randomized (single blind) into two groups. Regardless of the group, placebo or GP IIb/IIIa inhibitors were administered to patients who did not present with reperfusion signs (failed thrombolysis) 30 min after starting thrombolysis and 30-60 min after the end of full thrombolysis in patients with pain recurrence and ST-segment elevation (unsuccessful thrombolysis). Reperfusion was assessed by the creatine kinase peak occurring within 12 hours, by the observation of rapid ST-segment reduction (50-70% within 1 hour) in the 12-lead ECG continuous tracing, by the rapid regression of pain and by the development of early ventricular arrhythmias. Group 1 patients (n = 42) received, during failed thrombolysis or after 30-60 min of effective thrombolysis but with pain recurrence and ST-segment elevation (unsuccessful thrombolysis), treatment with i.v. GP IIb/IIIa inhibitors, heparin according to the TIMI 14 trial, and aspirin. Group 2 patients (n = 42) received a full dose of recombinant tissue-type plasminogen activator (rt-PA 100 mg) and placebo either during failed thrombolysis or, after 30 min of effective thrombolysis but with pain recurrence and ST-segment elevation, and standard heparin treatment and aspirin.
Results: In group 1, 39 patients showed rapid reperfusion (4 +/- 3 min); 22 patients received rt-PA 65 mg and 20 patients received rt-PA 100 mg and subsequent GP IIb/IIIa inhibitor treatment. Coronary angiography, performed after 12-72 hours showed patency of the infarct-related artery in 39 patients whose clinical picture was suggestive of rapid reperfusion during administration of a bolus of GP IIb/IIIa inhibitors. In group 2, no patients showed reperfusion and they were submitted to rescue coronary angioplasty (p < 0.05). Side effects occurred in 3 cases in group 1 and in 2 cases in group 2. Patients receiving GP IIb/IIIa inhibitors showed a reduced incidence of stent treatment (p = NS) and a significant reduction in the occurrence of events (angina) within 30 days of treatment (p = NS).
Conclusions: Our data suggest that in patients with AMI and failed thrombolysis, treatment with GP IIb/IIIa receptor inhibitors is feasible. The increase in the risk of bleeding was acceptable. The most important result was that this combination is safe.