Thromboprophylaxis for Medical Admissions

Assessment of VTE and bleeding risk

All patients must have their risk of venous thromboembolism (VTE) assessed at admission using the medical admissions VTE prophylaxis risk assessment proforma (link only active if accessing via NHS network) and then every 72 hours.

Different specialty specific algorithms apply for surgical, trauma & orthopaedics and obstetrics (refer to AthenA).

Further information on assessment:

  • Do not offer pharmacological prophylaxis to patients with risk factors for bleeding shown in table 2 below. Instead, offer anti-embolic stockings.
  • Patients with at least one thrombosis risk factor with no contraindications should be offered VTE prophylaxis with low molecular weight heparin (LMWH). 

Table 1 – Indicators of patients at increased risk of VTE (thrombosis risk factors)

Regard patient as being at increased risk of VTE if they have one or more of the following risk factors:

  • Age >60 years of age
  • Dehydration
  • Obesity (BMI >30kg/m2)
  • Any significant medical illness (e.g. heart, metabolic, endocrine, or respiratory disease; acute infection; inflammatory condition)
  • Use of hormone replacement therapy (HRT)
  • Use of oestrogen-containing contraceptive
  • Active cancer or cancer treatment
  • Known thrombophilia
  • Pregnancy or <6 weeks post-partum
  • Varicose veins with phlebitis
  • Personal history or 1st degree relative with a history of VTE
  • Significantly reduced mobility for 3 days or more
  • Critical care admission (e.g. HDU, ICU)

Table 2 – Indicators of patients at high risk of bleeding and contraindication to pharmacological VTE prophylaxis

Regard patient at risk of bleeding, and a contraindication to pharmacological VTE prophylaxis, if they have any of the following risk factors:

  • Active bleeding
  • Recent stroke (within 3 months)
  • Acute gastro-duodenal ulcer
  • Acute bacterial endocarditis - discuss with cardiologist
  • Known hypersensitivity (including heparin induced thrombocytopenia, HIT)
  • Thrombocytopenia (platelets <75 x 109/L)
  • Concurrent use of oral anticoagulant
  • Concurrent use of therapeutic heparin
  • Untreated inherited bleeding disorders (e.g. haemophilia, von Willebrand disease)
  • Acquired bleeding disorders, e.g. acute liver failure
  • Uncontrolled hypertension (BP ≥230/120mmHg)
  • Epidural / spinal anaesthesia or lumbar puncture in previous 4 hours or expected within next 12 hours
  • Any other procedure with high bleeding risk
  • Neurosurgery, spinal or eye surgery

N.B. Patients with an Acute Coronary Syndrome or suspected DVT/PE should receive fondaparinux or treatment dose LMWH as appropriate following local clinical guidelines.

General management and treatment options

For patients with no thrombosis risk factors, VTE prophylaxis with enoxaparin (LMWH of choice in NHS Ayrshire & Arran) is not required.

For patients with at least one thrombosis risk factor and no contraindications, offer VTE prophylaxis with enoxaparin SC 40mg once daily. 

Prophylactic enoxaparin dosing adjustments

Enoxaparin dose is dependent on weight and renal function. Refer to guidance on enoxaparin dose adjustment below in patients with:

  • weight <50kg or >100kg
  • creatinine clearance (CrCl) <30ml/minute.

Precautions with epidural / spinal anaesthesia and lumbar puncture

Do not give LMWH if epidural / spinal anaesthesia or lumbar puncture in previous 4 hours or expected within 12 hours.

General recommendations

  • Ensure adequate hydration.
  • Reassess VTE risk and bleeding risk every 72 hours, or sooner if patient's condition changes. 
  • Document all assessments and any changes in medical notes
  • Document in medical notes if patient is excluded from VTE prophylaxis

 

Guideline reviewed February 2026
Page updated April 2026



;