Recommended duration of anticoagulant prophylaxis
The recommendations are as follows:
1. Provoked DVT (with reversible surgical or nonsurgical provoking factor): 3 months
2. Unprovoked isolated distal DVT (has low risk of recurrence): 3 months
3. Unprovoked proximal DVT or PE: Indefinite therapy if D-dimer positive after 1 month after 3 months of therapy or second VTE episode or based on patient preference if no bleeding risk
4. Cancer: Indefinite therapy or until cancer is active
Recommended delay of surgery in Acute VTE
It is advised to delay surgery until the patients receive atleast 1 month and preferably 3 months of anticoagulation whenever feasible.
However, where surgery needs to be performed:
- Within 1 month of acute VTE: Intravenous UFH should be administered while the INR is less than 2.
- Within 2 weeks of acute VTE: Intravenous heparin may be withheld 6 hours preoperatively and 12 hours postoperatively, if the surgery is short.
- If the acute event was within 2 weeks of major surgery and/or patients have a higher risk of postoperative bleeding, a vena caval filter should be inserted preoperatively or intraoperatively.
- Warfarin should be withheld for only 4 doses if the most recent episode of VTE occurred 1-3 months before surgery. If the patient has been anticoagulated for 3 or more months, 5 doses of warfarin can be withheld before surgery. Preoperatively, subcutaneous UFH or LMWH is needed only for immobilized inpatients with an INR of less than 1.8.
Kearon C, Akl EA. Duration of anticoagulant therapy for deep vein thrombosis and pulmonary embolism. Blood. 2014 Mar 20;123(12):1794-801. doi: 10.1182/blood-2013-12-512681. Epub 2014 Feb 4. PMID: 24497538.