Reducing the risk of venous thromboembolism (deep vein thrombosis and pulmonary embolism) in inpatients having surgery: summary of NICE guidance

Why read this summary?

Deep vein thrombosis occurs in over 20% of patients having major surgery and over 40% of patients having major orthopaedic surgery. The postoperative risk of pulmonary embolism can be as high as 5% in the highest risk groups. However, many patients are probably not currently receiving adequate prophylactic measures.^{1 2} This article summarises the most recent guidance from the National Institute for Health and Clinical Excellence (NICE) on how to reduce the risk of venous thromboembolism in inpatients having surgery.³

Recommendations

NICE recommendations are based on systematic reviews of best available evidence. When minimal evidence is available, a range of consensus techniques is used to develop recommendations. In this summary, recommendations derived primarily from consensus techniques are indicated with an asterisk (*).

Assess patient for risk factors

Assess patients for the following risk factors, and inform all patients of the risks of venous thromboembolism and the effectiveness of prophylaxis.

• • Age over 60 years

• • Obesity (body mass index ≥30)

• • Continuous travel of more than three hours during the four weeks before or after surgery

• • Immobility (for example, paralysis or limb in plaster)

• • Personal or family history of venous thromboembolism

• • Varicose veins with associated phlebitis

• • Active cancer or cancer treatment

• • Active heart or respiratory failure

• • Severe infection

• • Acute medical illness

• • Recent myocardial infarction or stroke

• • Inflammatory bowel disease (for example, Crohn's disease and ulcerative colitis)

• • Use of oral contraceptives or hormonal replacement therapy

• • Pregnancy or puerperium

• • Certain specific haematological or systemic causes of prothrombotic state (such as antiphospholipid syndrome, Behçet's disease, central venous catheter in situ, inherited thrombophilias, myeloproliferative diseases, nephrotic syndrome, paraproteinaemia, paroxysmal nocturnal haemoglobinuria).

General prevention of venous thromboembolism

• • Offer all surgical inpatients a mechanical method of prophylaxis (graduated compression or antiembolism stockings, intermittent pneumatic compression, or foot impulse devices) except where contraindicated (for example, do not offer graduated compression stockings to patients with peripheral arterial disease or diabetic neuropathy.

• • Offer both mechanical prophylaxis and low molecular weight heparin to all inpatients having orthopaedic surgery (and inpatients having other surgery who have one or more of the risk factors listed above). Fondaparinux, within its licensed indications, may be used as an alternative to low molecular weight heparin.

• • Offer thigh length stockings (worn until usual level of mobility), but knee length stockings may be used to improve compliance or fit. The compression should be about 18 mm Hg at the ankle, 14 mm Hg at the mid-calf, and 8 mm Hg at the upper thigh.

• • Healthcare professionals trained in the use of compression stockings should show patients how to wear them correctly. Monitor use and provide help if necessary.*

• • Consider regional instead of general anaesthesia. If regional anaesthesia is used, plan the timing of pharmacological prophylaxis carefully to minimise the risk of haematoma.

• • Encourage patients to become mobile as soon as possible after surgery and to do leg exercises if immobile.*

• • Ensure the patient does not become dehydrated.*

• • Consider risks and benefits of stopping pre-existing established anticoagulation or antiplatelet therapy before surgery.*

Advice to patients

• • Warn patients that the immobility associated with continuous travel of more than three hours in the four weeks before or after surgery may increase the risk of venous thromboembolism.*

• • Advise patients to consider stopping combined oral contraception four weeks before elective surgery.

• • Give patients (as part of their discharge plan) oral and written information on the signs and symptoms of deep vein thrombosis and pulmonary embolism, the correct use of prophylaxis at home, and the implications of not using the prophylaxis correctly.*

Specific strategies

• For recommended prevention strategies for specific types of inpatient surgery, see the table.

Prevention for specific types of inpatient surgery

Type of surgery	Patient has no risk factors	Patient has ≥1 risk factors
Hip replacement	Mechanical prophylaxis plus LMWH or fondaparinux	Mechanical prophylaxis plus LMWH or fondaparinux (continue for four weeks)
Hip fracture	Mechanical prophylaxis plus LMWH or fondaparinux (continue for four weeks)	Mechanical prophylaxis plus LMWH or fondaparinux (continue for four weeks)
Other orthopaedic	Mechanical prophylaxis plus LMWH or fondaparinux	Mechanical prophylaxis plus LMWH or fondaparinux
Cardiac	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH (if no other anticoagulants used)
General	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH or fondaparinux
Gynaecological (excluding caesarean)	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH
Neurosurgery (including spinal surgery)	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH (except patients with ruptured cranial or spinal vascular malformations if the lesion has not been secured)
Thoracic	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH
Urological	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH
Vascular	Mechanical prophylaxis	Mechanical prophylaxis plus LMWH

LMWH=low molecular weight heparin.

Overcoming barriers

Some clinicians hold strong views about the overall benefits of reducing the risk of deep vein thrombosis or pulmonary embolism with drugs that increase the risk of bleeding. The balance of risks cannot be quantified from clinical experience, and moreover, a recent adverse experience tends to affect objective consideration.⁴ The highly valued concept of clinical judgment conflicts with recognition that adherence to an evidence based guideline may be safer for doctors as well as for patients.

NICE has developed tools to help organisations implement the guidance (see www.nice.org.uk/page.aspx?o=tools).

Further information about the guidance

Background

This latest guideline presents the most comprehensive and up to date systematic review and analysis of the evidence on methods to reduce the risk of venous thromboembolism. It is the first guideline of its type to consider the cost effectiveness of the various options for prophylaxis.

Methodology

The guideline was developed according to NICE guideline methodology (see www.nice.org.uk/page.aspx?o=114219) by the National Collaborating Centre for Acute Care. The collaborating centre convened a development group of clinicians and patient representatives to oversee the work and help to develop the recommendations.

The group conducted an extensive systematic review of the literature, assessed the quality of the literature, and used a combined meta-analysis approach to compare the effectiveness of the various methods of prophylaxis. An economic model was developed to ascertain the most cost effective strategies.

The guideline went through an external consultation with stakeholders. The development group assessed the comments, re-analysed the data where necessary, and modified the guideline.

NICE has produced four different versions of the guideline: a full version; a quick reference guide; a version known as the “NICE guideline” that summarises the recommendations; and a version for patients and the public. All these versions are available from the NICE website (www.nice.org.uk/CG046) or the National Collaborating Centre for Acute Care's website (www.rcseng.ac.uk/surgical_research_units/nccac/).

The guideline will be updated as needed. Information about the progress of any update will be posted on the NICE website (www.nice.org.uk/CG046). NICE hopes to audit the uptake of the guideline and provide the data in any future update.

Future research

The guideline recommends that future research be carried out to determine accurate current estimates of the risk of venous thromboembolism, whether low molecular weight heparin should be started before or after surgery, and the effectiveness of combining different methods of mechanical prophylaxis.

Guideline development group

The guideline development group comprises Nigel Acheson, Ricky Autar, Colin Baigent, Kim Carter, Simon Carter, Philippa Davies, Enrico De Nigris, David Farrell, Saoussen Ftouh, David Goldhill, Jennifer Hill, Peter Katz, John Luckit, Robin Offord, Arash Rashidian, Carlos Sharpin, Adam Thomas, Tom Treasure, David Wonderling.