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CDHB

Prophylaxis of VTE

VTE Prophylaxis in Medical Patients

This remains controversial. The administration of LMWH to the majority of medical patients admitted to hospital may reduce the frequency of VTE, but at the same time will lead to more bleeding events, and has not proven to be cost-effective (ACCP 2012).

We recommend a more selective approach which identifies those medical patients at high risk for VTE using the Padua Prediction Score. These patients should then be given LMWH prophylaxis as outlined below.

Acutely ill hospitalized medical patients at low risk of VTE should not be given pharmacologic prophylaxis.

Reference: Barbar et al, J Thromb Haemost, 2010 Nov;8(11):2450-7

• Recommended prophylaxis schedule for patients at high risk, ≥4:
  • Enoxaparin 40 mg subcut daily, provided there are no contraindications (e.g., active bleeding, thrombocytopaenia - platelets <100 x 10⁹/L). The dose may need to be reduced in renal impairment - discuss with Consultant.
  • The duration of prophylactic treatment with heparins must be individualized. It should cover the obvious risk period such as immobilization, but must be stopped as soon as the perceived increased risk has passed.
• For patients at low risk of VTE, <4, thromboprophylaxis with LMWH should not be given.
• Compression stockings are not recommended for either group.

VTE Prophylaxis in Stroke Patients

• Early mobilization and optimal hydration should be maintained from the outset.
• The cause, ischaemic or haemorrhagic, needs to be established.

For patients with ischaemic stroke only, see CDHB Stroke Guidelines, pp55-56 (search for "stroke guidelines" on the CDHB intranet):

• Full-length graduated compression stockings are not to be used routinely. These have been shown to be ineffective at preventing DVT after stroke and can cause tissue damage (Lancet. 2009;373:1958-65).
• Subcutaneous LMWH should be considered after 48h for patients at high risk from DVT such as immobile patients unable to lift one leg off the bed, obese patients, those with past history of DVT/PE or known thrombophilia.
• Give enoxaparin 40 mg subcut daily, less in renal impairment, e.g., 20 mg daily if eGFR <30 mL/min. The best timing for initiation of LMWH after stroke is not known. LMWH use is associated with an increased risk of intracerebral haemorrhage when initiated in the acute phase (<48h); the risk beyond 48h is not well quantified. Fatal PE is rare in the first week after stroke but peaks at the end of week 2.
• A decision regarding the use or otherwise of LMWH for immobile stroke patients should be documented by the end of week 1. Hydration and mobilization remain cornerstones of VTE prophylaxis.

  Note: If LMWH prophylaxis is started, it is important to continue antiplatelet therapy.

VTE Prophylaxis in Spinal Injury

Refer to Traumatic Spinal Cord Injury - Management.

VTE Prophylaxis in Surgical Patients

Surgery is a significant cause of deep vein thrombosis and post-operative death from pulmonary embolism may occur from an unrecognized DVT. The risk of venous thromboembolism depends on the type of surgery, patient characteristics and the underlying disease.

• The various ways to reduce the risk of VTE post-surgery include drugs such as LMWH and oral anticoagulants, compression stockings, and intermittent pneumatic compression.
• There are many guidelines available and all aim to reduce the VTE risk while minimizing the risk of abnormal bleeding. We recommend the Guidelines for the Prevention of Venous Thromboembolism produced by the Department of General Surgery (search for "stroke guidelines" on the CDHB intranet). The following tables are taken from these guidelines, and have been adapted from the CDHB form C240158.

Note: The recommendations below do not apply to patients undergoing thyroid or breast surgery at Christchurch Hospital, and they may not apply to other surgical disciplines. In these situations it is essential to discuss with the Surgeon/Anaesthetist involved what type of VTE prophylaxis (if any), is to be given.

Note: We emphasize that any perioperative anti-thrombotic drug or any of the other treatments listed above, must be confirmed with the Surgeon and/or Anaesthetist involved. They will make the final decision.

VTE Prophylaxis for Orthopaedic Surgery

• Orthopaedic acute patients with fractures of the lower limbs are at high risk for VTE.
• All such patients should receive enoxaparin 40 mg subcut daily while immobile unless contraindicated (see above). A reduced dose may be appropriate if impaired renal function, e.g., 20 mg daily if eGFR <30 mL/min. The duration of LMWH will depend on the clinical circumstances but VTE risk may be high for 2-4 weeks following surgery.
• If anticoagulation is contraindicated then TED stockings or intermittent pneumatic compression should be used.
• Warfarin may be indicated in some patients - discuss with Consultant.

Note: Dabigatran is licensed for prophylaxis of venous thromboembolism following total hip or knee replacement - see below.

Guidelines for Prophylaxis using new Oral Anticoagulants

• Oral thrombin (dabigatran) and factor Xa (rivaroxaban and edoxaban) inhibitors have demonstrated rapid onset of action and predictable pharmacokinetics. At the present time, only dabigatran is funded. None of these three agents can be reversed if excessive bleeding occurs. See Anticoagulant Overdosage.
• Dabigatran is funded by PHARMAC for the prevention of VTE post major orthopaedic surgery, specifically post hip and knee replacements.
• The recommended dose of dabigatran is 110 mg PO within 1-4 hours of the completion of surgery, and then 220 mg PO daily for 10 days after knee replacement, and between 28 to 35 days after hip replacement.
• Dabigatran is excreted mainly by the kidney (fu 0.8), so dosing appropriate to renal function is important.

  Note: Dabigatran may not be suitable for patients with renal impairment, may interact with other medications, and should be used with caution and in lower dose for patients over 75-80 years of age.

• Before using dabigatran, refer to:
  • The PHARMAC website Guidelines for testing and perioperative management of dabigatran and Guidelines for management of bleeding with dabigatran.
  • The Medsafe datasheet on dabigatran.
  • The CDHB Clinical Pharmacology bulletin on dabigatran etexilate (July 2011).
• Before using rivaroxaban, refer to the CDHB Clinical Pharmacology bulletin on rivaroxaban (May 2013).

Topic Code: 9273