Venous Thromboembolism Flashcards
What is a VTE?
A thrombus is a clump of platelets, fibrin, red blood cells and white blood cells. These can form in both the arterial and venous circulation. A thrombus, or part of one, that enters the left side of the circulatory system can enter the heart and may result in subsequent blockage in peripheral arteries either in the lower limbs or in the cerebral circulation. The former is known as a deep vein thrombosis (DVT) and the latter may cause a thromboembolic stroke.
If a thrombus, or part of one, enters the right side of the circulatory system it may block part of the pulmonary arterial circulation. This is known as a pulmonary embolism (PE).
the common presenting symptoms of a DVT and a PE.
Important components for the clinical diagnosis of VTE include risk factors such as immobilization, presence of cancer, confinement to bed, previous major surgery, prior VTE and - specific for DVT - whole limb enlargement, one-sided calf enlargement and dilatation of superficial veins. Additional items specific for PE include tachycardia, dyspnea chest pain and hemoptysis
Do not offer anti-embolism stockings to people who have:
suspected or proven peripheral arterial disease
peripheral arterial bypass grafting
peripheral neuropathy or other causes of sensory impairment
any local conditions in which anti-embolism stockings may cause damage – for example, fragile ‘tissue paper’ skin, dermatitis, gangrene or recent skin graft
known allergy to material of manufacture
severe leg oedema
major limb deformity or unusual leg size or shape preventing correct fit.
Use caution and clinical judgement when applying anti-embolism stockings over venous ulcers or wounds.
Elective knee replacement
Offer VTE prophylaxis to people undergoing elective knee replacement surgery whose VTE risk outweighs their risk of bleeding. Choose any one of:
- aspirin (75 or 150 mg) for 14 days.
- LMWH for 14 days combined with anti-embolism stockings until discharge.
- Rivaroxaban, within its marketing authorisation, is recommended as an option for the prevention of venous thromboembolism in adults having elective total hip replacement surgery or elective total knee replacement surgery.
how can people reduce their risk of VTE
keeping well hydrated and, if possible, exercising and becoming more mobile
Acutely ill medical patients
Offer pharmacological VTE prophylaxis for a minimum of 7 days to acutely ill medical patients whose risk of VTE outweighs their risk of bleeding:
- Use LMWH as first-line treatment.
- If LMWH is contraindicated, use fondaparinux sodium
Define PE
If it dislodges and travels to the lungs, it is called a pulmonary embolism, which in some cases can be fatal.
Assessing the risk of VTE and bleeding - On admission, identify all patients at increased risk of VTE. ♦ Medical patients are at increased risk if:
- Mobility is significantly reduced for ≥3 days, OR
- they are expected to have ongoing reduced mobility and
have one or more risk factors for VTE
Assessing the risk of VTE and bleeding - On admission, identify all patients at increased risk of VTE. ♦ Surgical and trauma patients are at increased risk if one or more of the following applies:
- surgical procedure with a total intravenous anaesthetic
and surgical time >90 minutes, or 60 minutes if the surgery involves the pelvis or lower limb, - acute surgical admission with inflammatory or intraabdominal condition,
- significant reduction in mobility,
- one or more risk factors for VTE
Assessing the risk of VTE and bleeding - On admission, identify all patients at increased risk of VTE.
♦ Assess all patients for risk of bleeding before giving
pharmacological VTE prophylaxis.
- Do NOT give prophylaxis to patients with any risk factor
for bleeding, unless risk of VTE outweighs
bleeding risk.
♦ Reassess risk of bleeding and VTE within 24 hours of
admission and if clinical situation changes to ensure:
- the methods of prophylaxis being used are suitable and
are being used correctly,
- any adverse effects are identified.
Reducing the risk of VTE
Mobilise the patient as soon as possible.
♦ Give pharmacological prophylaxis if appropriate;
- start treatment as soon as risk has been assessed,
- continue until the patient’s mobility is no longer reduced
and they are not at risk of VTE.
Types of VTE prophylaxis
Mechanical prophylaxis
♦ anti-embolism stockings (thigh or knee length).
♦ foot impulse devices.
♦ intermittent pneumatic compression devices (thigh or knee length).
Pharmacological prophylaxis ♦ LMWH ♦ UFH – for patients with renal failure. ♦ Fondaparinux sodium. Also consider dabigatran or rivaroxaban for prophylaxis after hip or knee replacement surgery.
Anti-embolism stockings
♦ Measure legs and use correct sized stockings.
♦ Use stockings that provide graduated compressi
produce a calf pressure of 14-15mmHg.
♦ Patients should wear stockings continuously whilst mobility is reduced with removal daily for hygiene purposes.
Cautions
Anaesthesia
♦ For considerations around anaesthesia
Patients taking antiplatelet or anticoagulant therapy
♦ Assess the risks and benefits of stopping antiplatelet
therapy one week prior to elective surgery.
If at risk of VTE, consider risk of bleeding and comorbidities
- if the risk of VTE outweighs the risk of bleeding: give
additional pharmacological prophylaxis.
if the risk of bleeding outweighs the risk of VTE: use
mechanical prophylaxis.
o NOT give pharmacological or mechanical prophylaxis:
- to patients already taking vitamin K antagonists
(e.g. warfarin), providing these are continued and kept in
therapeutic range,
to patients already receiving full anticoagulant therapy.
Do NOT regard aspirin or other antiplatelet agents as
adequate prophylaxis for VTE.
Patients taking oral contraceptives or HRT
♦ Advise women to stop taking these 4 weeks prior to
elective surgery.
Risk factors for VTE
♦ Active cancer or cancer treatment ♦ Age >60 years ♦ Admission to critical care ♦ Dehydration ♦ Known thrombophilia ♦ Obesity (BMI >30kg/m2) ♦ One or more medical comorbidities ♦ Personal history or first degree relative with history of VTE ♦ Use of hormone replacement therapy ♦ Use of oestrogen containing contraceptives ♦ Varicose veins with phlebitis ♦ Pregnancy or up to 6 weeks post-partum
