Stent Thrombosis and Duration of Dual Antiplatelet Therapy

Stent thrombosis (ST) is a rare complication following coronary stenting; however given the associated serious consequences, in particular death and myocardial infarction, it remains a source of considerable concern for cardiologists. Although no differences have been found between drug-eluting stents (DES) and bare-metal stents (BMS) in terms of early ST, some studies have reported adverse outcomes associated with DES as compared to BMS at long-term follow-up. Delayed endothelial coverage of the stent struts, inflammation and local hypersensitivity due to the interaction between the drug and polymer coating have been characterized to be typical for DES compared to BMS and may prolong the window of vulnerability to ST. Consequently the recommended duration of dual antiplatelet therapy (DAT) was longer with DES than with BMS. Results from studies investigating the optimal duration of DAT remain inconclusive and the current recommendation seems to be that patients undergoing DES implantation should have DAT for at least 6-12 months. Our treatment strategy requires more detailed analysis and should improve as we understand more about the impact of the newer generation DES and variability in antiplatelet therapy response, in addition to the effects of novel therapeutic agents and the availability of more data on the optimum duration of DAT.