Coronary artery stents: appropriate use of adjunctive pharmacotherapy to prevent stent thrombosis.

In 1986, the first metallic stent was implanted inside a human coronary artery in order to reduce the incidence of abrupt vessel occlusion and restenosis after percutaneous coronary balloon angioplasty. Little was known at that time regarding the adequate anticoagulation regimen needed and the initial enthusiasm was soon marred by a high rate of thrombotic stent closure that usually occurred 2 days to 4 weeks after stent implantation. Antithrombotic drugs such as heparin, aspirin (acetylsalicylic acid), low molecular weight heparins, dextran, dipyridamole and warfarin (coumadin) were incorporated in a series of trials which reduced the risk of stent thrombosis, but increased substantially the rate of bleeding complications and the length of hospitalisation. The greatest breakthrough came with the improvement in stent deployment techniques using intravascular ultrasound-guided, high-pressure balloon inflation inside the stent, and the understanding of the central role of platelet activation in stent thrombosis. These 2 factors have led to 'optimal stent deployment' with high-pressure ballooning after stent deployment and the simultaneous use of more potent antiplatelet agents in conjunction with aspirin. Newly developed selective inhibitors of the platelet glycoprotein IIb/IIIa receptor and new stent designs have also recently been integrated into clinical practice and are currently being evaluated in clinical trials.