European guidelines on perioperative venous thromboembolism prophylaxis: Patients with preexisting coagulation disorders and after severe perioperative bleeding.

: In patients with inherited bleeding disorders undergoing surgery, we recommend assessment of individual risk for venous thromboembolism, taking into account the nature of the surgery and anaesthetic, type and severity of bleeding disorder, age, BMI, history of thrombosis, the presence of malignancy and other high-risk comorbidities. Venous thromboembolism risk should be balanced against the increased bleeding risk associated with anticoagulant use in patients with known bleeding disorders (Grade 1C). In these patients undergoing major surgery, we recommend against routine postoperative use of pharmacological thromboprophylaxis, especially for patients with haemophilia A and B (Grade 1B). Glomerular filtration rate should be assessed before initiation of each direct oral anticoagulant, and also at least once a year or more frequently as needed, such as postoperatively before the resumption of therapeutic direct oral anticoagulant administration, when it is suspected that renal function could decline or deteriorate (Grade 1C). Reduced dosages of low molecular weight heparins may be used relatively safely during transient severe (<50 × 10 l) thrombocytopaenia (Grade 2C). Monitoring of anti-Xa levels may be used to adjust the doses of low molecular weight heparin in patients with moderate or severe thrombocytopaenia (Grade 2C). The delay between major gastrointestinal bleeding and resuming warfarin should be at least 7 days (Grade 2C). For patients at a high risk of thromboembolism and with a high bleeding risk after surgery, we consider that administering a reduced dose of direct oral anticoagulant on the evening after surgery and on the following day (first postoperative day) after surgery is a good practice (Grade 2B).