Clopidogrel therapy is mandatory for six weeks after the placement of bare-metal stents, three to six months after myocardial infarction, and at least 12 months after placement of drug-eluting stents.
Because of the hypercoagulable state induced by surgery, early withdrawal of antiplatelet therapy for secondary prevention of cardiovascular disease increases the risk of postoperative myocardial infarction and death five- to 10-fold in stented patients who are on continuous dual antiplatelet therapy.
The shorter the time between revascularization and surgery, the higher the risk of adverse cardiac events. Elective surgery should be postponed beyond these periods, whereas vital, semi-urgent, or urgent operations should be performed under continued dual antiplatelet therapy.
The risk of surgical haemorrhage is increased by approximately 20 percent by aspirin or clopidogrel alone, and 50 percent by dual antiplatelet therapy.
The present clinical data suggest that the risk of a cardiovascular event when stopping antiplatelet agents preoperatively is higher than the risk of surgical bleeding when continuing these drugs, except during surgery in a closed space (e.g., intracranial, posterior eye chamber) or surgeries associated with massive bleeding and difficult hemostasis.