Anticoagulanti Orali Diretti
Direct oral anticoagulants (DOAs) are currently used for long term prevention of thromboembolic events in non valvular atrial fibrillation, for thromboprophylaxis after hip and knee replacement surgery, and for treatment and secondary prophylaxis of venous thromboembolism and pulmonary embolism. For this, the number of patients who are taking DOAs and who need elective or emergency surgery is increasing. Because at the moment there are not enough data and experience, the perioperative management of direct oral anticoagulants is controversial.
The absence of experience do not allow to issue recommendations, but only advices for the management of hemorrhagic and thrombotic risk in case of surgical procedures in this category of patients. In case of surgery at mild hemorrhagic risk it is useful to stop direct oral anticoagulants at least 48 hours before the surgery. In case of surgery at moderate or severe hemorrhagic risk it is useful to stop DOAs at least 5 days before the surgery to be sure of complete elimination of the drug. In any case before any surgical procedure, we need to perform a diluted thrombin time (Hemoclot) in case of a direct thrombin inhibitor such as dabigatran or a calibrated anti FXa assay by the use of chromogenic substrates in case of direct factor Xa inhibitors such as rivaroxaban, apixaban and edoxaban to evaluate their concentration. For patients at mild thrombotic risk we do not need "bridging" with low molecular weight heparin, but in case of patients at moderate or high thrombotic risk, if we stop DOAs for 5 days or more, we need "bridging" with low molecular weight heparin. For emergency surgery, it is useful to delay surgery for a period of time from one to three drug half-lives in patients with normal renal function, if possible, avoiding to use haemostatic agents as prophylaxis. If this is not possible, we can use haemostatic products such as prothrombin complex concentrates (PCCs), activated prothrombin complex concentrates (FEIBA) and activated recombinant factor VII (rFVIIa), although at the moment there are only anedoctal reports about the use of haemostatic products for the reversal of the anticoagulant effect of these drugs, in these cases.