Platelet GP IIb-IIIa Receptor Antagonists in Primary Angioplasty: Back to the Future

Coronary artery disease and acute myocardial infarction still represent the leading cause of mortality in developed countries. Therefore, great efforts have been made in the last decades to improve reperfusion strategies and adjunctive antithrombotic therapies. In fact, despite optimal epicardial recanalisation, a large proportion of patients still experience impaired reperfusion and in-stent thrombosis. The adjunctive use of glycoprotein (GP) IIb-IIIa inhibitors may certainly contribute in the reduction of such complications, especially when administered in the early phase of infarction. In fact, in this phase a larger platelet composition of the thrombus and the presence of a larger amount of viable myocardium, as compared to a delayed phase, may increase the benefits from this therapy and counterbalance the potential higher risk of bleeding. A large body of evidence has been accumulated on the benefits from GP IIb-IIIa inhibitors in terms of prevention of stent thrombosis, and benefits in mortality, especially among high-risk patients and as upstream strategy. Therefore, based on current available data, GP IIb-IIIa inhibitors can be recommended as early as possible (upstream strategy) among high-risk patients, such as those with advanced Killip class or anterior myocardial infarction (MI), and those presenting within the first three hours. Even though it is not universally accepted, in our opinion this strategy should be implemented in a pre-hospital setting (in ambulance) or at first hospital admission (Emergency Room or Coronary Care Unit, irrespective of whether they are in the spoke or hub hospitals). Peri-procedural intracoronary administration of GP IIb-IIIa inhibitors has not provided additional benefits as compared to intravenous administration and therefore cannot be recommended. Even though the vast majority of trials have been conducted with abciximab, several meta-analyses comparing small molecules (mainly high-dose tirofiban rather than eptifibatide) versus abciximab showed similar angiographic and clinical results between the molecules. Several recent investigations and meta-analyses have documented the higher risk of stent thrombosis associated with bivalirudin as compared to unfractionated heparin (UFH). Being that these results are independent from the use of GP IIb-IIIa inhibitors, UFH should still remain the anticoagulation therapy of choice in ST-segment elevation myocardial infarction (STEMI) patients. Minimisation of bleeding complications by extensive use of the radial approach, in the setting of STEMI, may further contribute to the adoption of a more aggressive antithrombotic and antiplatelet therapy incorporating the use of GP IIb-IIIa inhibitors. The establishment of dedicated networks for STEMI, and the large STEMI campaign, will certainly contribute to increase the proportion of patients presenting at first medical contact within the early phase (3 h) of infarction and therefore highly suitable for a more aggressive pharmacoinvasive approach with upstream administration of GP IIb-IIIa inhibitors. In fact, although the current therapeutic targets of increased rates of timely reperfusion, mainly by primary percutaneous coronary intervention (PCI), has been achieved, a deep look into the future in the fight against MI will certainly put aborting infarction as the major desirable target to be achieved.