Thromboprophylaxis for Non-Covid Patients

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Thromboprophylaxis Flowchart

Increased Risk of VTE With Low Risk of Bleeding

* for non-licensed doses consider checking anti-Xa level after 5 doses to exclude accumulation.  See paragraph on Xa activity below.

1. The standard dose of dalteparin is 5000iu od by SC injection
2. Patients >100kg may be underdosed with 5000iu which is why we are recommending higher (non-licensed) doses if very overweight
3. Patients with renal impairment have increased risk of accumulation of LMWH and caution should be used in these patients.
4. Surgical patients should also have Anti-Embolism Stockings (AES).
5. Medical patients should be considered for AES.

When to Give Dalteparin

1. Medical inpatients – 4pm
2. Surgical inpatients with significant reduction mobility – 4pm night before surgery, then 4pm subsequent days
3. Surgical inpatients with normal mobility/ admitted on day of surgery – 4hrs post op or 4pm whichever is later, then 4pm subsequent days

Increased Risk of VTE with High Risk of Bleeding

1. Do not prescribe pharmacological prophylaxis if patient has one or more bleeding risk factors unless requested by consultant
2. Consider mechanical prophylaxis eg AES unless contraindicated
3. Document all assessments and provide patient information on VTE

When Not to use Anti-embolic Stockings (AES)

1. Peripheral vascular disease
2. Leg ulcers or other local painful skin condition
3. Deformity
4. Large thigh circumference or gross oedema
5. Acute stroke

Thromboprophylaxis for Acute Stroke

1. Do not prescribe dalteparin or AES for patients with acute stroke but consider intermittent pneumatic compression if immobile.  If using IPC, start within 3 days
2. When using IPC, provide it for 30 days or until patient is mobile or discharged, whichever is sooner

Duration of Thromboprophylaxis

1. Pharmacological prophylaxis – usually stopped at discharge, or earlier if no longer at high thrombotic risk
2. Extended pharmacological thromboprophylaxis is indicated in specific patients eg eg post THR/TKR, or where there is likely to be significant temporary immobility when discharged home, this is senior decision
3. AES – continue until patient discharged and returned to pre admission levels of mobility

Monitoring Platelet Count

1. Risk of Heparin Induced Thrombocytopenia (HIT) is less with LMWH than with Unfractionated Heparin (UFH)
2. Patients given any heparin should have a baseline platelet count
3. Medical and surgical patients receiving LMWH do not need routine platelet monitoring except for CABG patients who should have platelet count every 2-3 days for 14 days..
4. Post-operative patients including obstetric cases receiving UFH should have platelet count every 2–3 days from days 4 to 14 or until heparin is stopped.
5. Post-operative patients who have been exposed to heparin in the previous 100 days and are receiving any type of heparin should have a platelet count determined 24 h after starting heparin.

Monitoring Anti-Xa Activity

1. Anti-Xa activity is used to monitor for accumulation of LMWH when using non licensed doses after 5 doses once a steady state has been achieved
2. An anti-Xa level should be taken 3-4 hours after the dose as indicated by * in table above
3. Target level for prophylaxis is 0.1-0.3 U/mL

Procedures on Prophylactic LMWH

1. Prophylactic LMWH will generally remain in the system for 12 hours following a dose, this may be longer with renal failure.
2. Consider the bleeding risk of the procedure when deciding on interruption and restarting of LMWH.
3. Neuroaxonal anaesthesia and lumbar puncture should be performed >12 hours following last dose of LMWH. The next dose of LMWH should be delayed for 4 hours after the procedure (24 hours for a traumatic or multiple punctures). Epidural catheters should be removed 12 hours after the last dose of LMWH. Above timings should be doubled if GFR<30.

Pre-existing Antiplatelet and Anticoagulant Therapy

1. Do not regard low dose antiplatelet therapy as adequate prophylaxis for VTE.
2. Do not offer heparin to those on full anticoagulant therapy