The risk of stent thrombosis after coronary arterial stent implantation.

a w a t t a c s t v k p s ne of the most dreaded complications after percutaneous oronary arterial angioplasty is stent thrombosis. This erious untoward event usually results in acute myocardial nfarction with high mortality. Stent thrombosis often ocurs early, within 30 days of implantation, in patients who eceive bare metal coronary arterial stents. However, paients undergoing drug-eluting stent implantation infreuently develop late stent thrombosis many months and ven years after the deployment of these devices. Fortuately, stent thrombosis is a rather uncommon event. Factors that favor stent thrombosis include technical roblems during stent implantation; patients who undergo tent placement after an acute coronary syndrome or when iabetes mellitus is present; and patients with an intrinsic esistance to antiplatelet therapy. The most important facor leading to stent thrombosis is discontinuation of antiplatelet herapy, particularly clopidogrel administration. Because ate stent thrombosis is mainly a complication of drug-eluting tent deployment, prolonged clopidogrel and aspirin therapy s essential for such individuals. As already noted, bare etal stent thrombosis usually occurs during the first 30 ays after stent implantation, and thus, clopidogrel therapy ay be discontinued after at least 1 month of administration n these patients. However, many cardiologists favor 3 onths of continuous clopidogrel therapy after bare metal tent placement. Healing of the endothelium over drugluting stents has been shown to be impaired secondary to ntimetabolites impregnated in the stent coating. Incomlete endothelial healing has been documented occasionally n patients who received a drug-eluting stent more than 2 ears earlier. It is believed that incomplete endothelial overing of stent struts is the cause of incipient stent thromosis. Consequently, aspirin and clopidogrel therapy should e continued for at least 12 months after drug-eluting stent lacement. At this time, it is still unclear whether dual ntiplatelet therapy can be discontinued after as little as 12 onths of continuous administration in patients with drugluting stents. Ongoing studies are addressing this issue, and