Postoperative Anticoagulation Guidelines
Risk Stratification Using Caprini Score
All surgical patients should undergo VTE risk assessment using the validated Caprini score, which stratifies patients into four risk categories that directly guide prophylaxis intensity and duration. 1, 2
The Caprini model assigns weighted points to risk factors:
- 1 point factors: Minor surgery, varicose veins, inflammatory bowel disease 2
- 2 point factors: Arthroscopic surgery, major open surgery, malignancy 2
- 3 point factors: History of VTE, family history of VTE 2
- 5 point factors: Stroke, elective lower extremity arthroplasty 2
Risk categories and corresponding VTE rates:
- Very low risk (Caprini 0): <0.5% VTE risk 1, 2
- Low risk (Caprini 1-2): ~1.5% VTE risk 1, 2
- Moderate risk (Caprini 3-4): ~3.0% VTE risk 1, 2
- High risk (Caprini ≥5): ~6.0% VTE risk 1, 2
Prophylaxis Regimens by Risk Category
Very Low Risk (Caprini 0)
No pharmacologic or mechanical prophylaxis is required beyond early ambulation. 1
Low Risk (Caprini 1-2)
Use mechanical prophylaxis with intermittent pneumatic compression (IPC) over no prophylaxis. 1
Moderate Risk (Caprini 3-4)
For patients without high bleeding risk, use pharmacologic prophylaxis with either:
- Enoxaparin 40 mg subcutaneously once daily, OR 1, 3
- Unfractionated heparin 5000 units subcutaneously twice or three times daily 1, 3
Continue for 10-14 days postoperatively. 3
For patients with high bleeding risk, use mechanical prophylaxis with IPC until bleeding risk diminishes, then initiate pharmacologic prophylaxis. 1
High Risk (Caprini ≥5)
Use pharmacologic prophylaxis with LMWH or low-dose UFH (same dosing as moderate risk) PLUS add mechanical prophylaxis with elastic stockings or IPC. 1
For cancer patients undergoing abdominal or pelvic surgery, extend prophylaxis to 4 weeks (28 days) with LMWH. 1, 2
Recent validation studies demonstrate that patients with Caprini scores ≥7 derive the most significant benefit from chemoprophylaxis, with a 14-fold variation in VTE risk across the risk spectrum. 4 Patients with scores ≥11 represent an extremely high-risk subgroup with up to 59% DVT incidence despite standard prophylaxis, suggesting these patients may need intensified regimens. 5
Timing of Initiation
Initiate pharmacologic prophylaxis within 12-24 hours postoperatively once hemostasis is secure. 3
For patients on chronic therapeutic anticoagulation requiring surgery:
- Discontinue warfarin 5 days before surgery 1
- Initiate bridging with LMWH when INR <2.0 1
- Give last LMWH dose on the morning of the day before surgery 1
- Resume warfarin the evening after surgery if hemostasis achieved 1
- Resume therapeutic-dose LMWH at 48 hours postoperatively once hemostasis assured 1
- Prophylactic-dose LMWH can be initiated at 12 hours after surgery 1
High Bleeding Risk Management
For patients at high bleeding risk or where bleeding consequences are severe, use mechanical prophylaxis (preferably IPC) until bleeding risk diminishes, then add pharmacologic prophylaxis. 1
Continue IPC until the patient is fully ambulatory. 3
Duration of Prophylaxis
Standard duration: 10-14 days for most non-cancer surgeries 1, 3
Extended duration (up to 28-35 days) for:
- High-risk patients (Caprini ≥5) undergoing cancer surgery in abdomen/pelvis 1, 2
- Total hip or knee arthroplasty 1
- Bariatric surgery 6
Common Pitfalls to Avoid
Do NOT use IVC filters for primary VTE prophylaxis. 1, 3
Do NOT perform routine surveillance duplex ultrasound. 1, 3
Do NOT withhold pharmacologic prophylaxis based solely on surgical specialty (e.g., plastic surgery). 3
Do NOT rely on mechanical prophylaxis alone in moderate-to-high risk patients unless bleeding risk is prohibitive. 3