Each year 25,000 people in the UK die from venous thromboembolism (VTE). The mortality rate is greater than the number of deaths attributable to breast cancer, AIDS and road traffic accidents combined, and 25 times greater than the number of people who die as a result of MRSA infection.1 However, an international study, ENDORSE, found that only 50% of hospitalised patients at risk for VTE received recommended prophylaxis. Furthermore, new research reveals there is widespread ignorance of the risk of developing hospital-acquired blood clots, among patients. In a study of 1,000 members of the public, not one respondent identified hospital-acquired clots as a cause for concern when going into hospital, despite it being the biggest cause of death. The study published by Lifeblood, the thrombosis charity, also revealed that only half of those who had undergone surgery had the risk of hospital-acquired clots discussed with them. “This is a widespread, life-threatening problem – both healthcare professionals and the public have a part to play to ensure that this leading cause of death is prevented as much as possible. This research clearly shows that there is a huge education gap concerning hospitalacquired blood clots,” said Professor Beverly Hunt, medical director of Lifeblood. The charity is calling for patients to engage in discussion with healthcare professionals and to ensure they are fully informed about the risks involved. Nurse specialist, Kim Carter, Lifeblood nursing director, added: “New National Institute for Health and Clinical Excellence (NICE) guidance on the prevention of hospital-acquired blood clots, together with the demand from the NHS Commissioning Framework that 90% of all adult patients are assessed for their risk of hospital-acquired clots on admission to hospital, has brought this problem to the top of the current inpatient safety agenda. It is essential to raise public awareness of this issue.” Hospital-acquired clots are known medically as “venous thromboembolism” (VTE), which is the collective term for deep vein thromboses (DVT) and pulmonary embolism. DVT occurs when a blood clot occurs in a deep vein, usually in the leg or pelvis, while pulmonary embolism is a serious and potentially fatal condition where one of the blood vessels in the lungs becomes blocked with a clot that has travelled from another part of the body, usually a DVT in the legs. Guidelines published by NICE, in partnership with the National Clinical Guideline Centre for Acute and Chronic Conditions, recommend that all patients should be assessed for risk of developing blood clots on admission to hospital and given preventative treatment that suits their individual needs. Options include blood-thinning drugs such as heparin, anti-embolism stockings and foot impulse or pneumatic devices. Importantly, this advice covers all patients admitted to hospital – including those having day-case procedures – and not just those patients having surgery. The guideline gives recommendations on how to assess if patients are at risk of developing VTE, and importantly their risk of bleeding before blood-thinning drug treatments are used. This includes considering if patients are likely to have reduced mobility for three or more days, the type of procedure they are being admitted for, the age of patients and any pre-existing conditions. Specific recommendations are also given for women who are pregnant or have given birth within the previous six weeks. Professor Tom Treasure, chair of the NICE Guideline Development Group and professor of cardio-thoracic surgery said: “This NICE guideline is vital in helping to save lives lost each year because of preventable VTE in hospital patients. Put simply, all patients without exception should be assessed on being admitted to hospital for risk of developing a blood clot, and then given preventative treatment that is appropriate for them. VTE is a silent killer – so it’s the responsibility of medical professionals to take the very simple steps set out in the guideline which can help prevent unnecessary deaths and long term illnesses.” Dr Fergus Macbeth, clinical director at NICE, added: “There is a real clinical need for this guideline. It has been reported that measures to prevent VTE in hospital patients are used inconsistently and, in many cases, patients at significant risk of developing a blood clot do not get any preventative treatment at all. Importantly, this guideline covers all patients, not only those having surgery, setting out very clearly what medical staff should now do to assess and address VTE risk.” Comprising over 500 pages, some key aspects of the recommendations include the following:
Assessment of risk
The NICE guidelines state that medical patients should be regarded as being at increased risk of VTE if they have had, or are expected to have, significantly reduced mobility for three days or more; and have one or more of the risk factors, shown in Figure 1. NICE states that surgical patients and patients with trauma should be regarded as being at increased risk of VTE if they meet one of the following criteria:
• They are undergoing a surgical procedure with a total anaesthetic and surgical time of more than 90 minutes, or 60 minutes if the surgery involves the pelvis or lower limb.
• The patient is an acute surgical admission with an inflammatory or intra-abdominal condition.
• Significant reduction in mobility is expected.
• The patient has one or more of the risk factors outlined in Figure 1.
However, the guidance stresses that all patients should be assessed for risk of bleeding before offering pharmacological VTE prophylaxis, which should not be offered to patients with any of the risk factors for bleeding shown in Figure 2, unless the risk of VTE outweighs the risk of bleeding. The guidelines state that a patient’s risk of bleeding and VTE should be reassessed within 24 hours of admission, and whenever the clinical situation changes, to ensure that the VTE prophylaxis methods used are suitable and are being correctly used. This is also important in order to identify any adverse events that may arise.
Reducing risk of VTE
The NICE guidelines state that patients should not be allowed to become dehydrated unless clinically indicated and they should be encouraged to mobilise as soon as possible. Aspirin or other antiplatelet agents should not be regarded as adequate prophylaxis for VTE, while consideration should be given to offering temporary inferior vena caval filters to patients who are at very high risk of VTE (such as patients with a previous VTE event or an active malignancy) and for whom mechanical and pharmacological VTE prophylaxis are contraindicated. Before starting VTE prophylaxis, patients and/or their families or carers should be provided with verbal and written information on:
• The risks and possible consequences of VTE.
• The importance of VTE prophylaxis and its possible side effects.
• The correct use of VTE prophylaxis (for example, anti-embolism stockings, foot impulse or intermittent pneumatic compression devices).
• How patients can reduce their risk of VTE (such as keeping well hydrated and, if possible exercising and becoming more mobile).
The choice of mechanical VTE prophylaxis should be based on individual patient factors including clinical condition, surgical procedure and patient preference. These may include:
• Anti-embolism stockings.
• Foot impulse devices.
• Intermittent pneumatic compression devices.
NICE points out that anti-embolism stockings are not recommended for patients 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 stockings may cause damage e.g. fragile “tissue paper” skin, dermatitis, gangrene or recent skin graft, known allergy to material of manufacture, cardiac failure, severe leg oedema or pulmonary oedema from congestive heart failure, unusual leg size or shape, or major limb deformity preventing correct fit. Patients should have their legs measured and the correct size of stocking provided, while patients should be shown how to use them by adequately trained staff. Patients on the ward who have foot impulse or intermittent pneumatic compression devices should also be encouraged to use them for as much of the time as is possible and practical, both when in bed and when sitting in a chair. In addition to mechanical devices, pharmacological prophylaxis should commence as soon as possible after risk assessment has been completed and be continued until the patient is no longer at increased risk of VTE. The choice of pharmacological agents should be based on local policies and individual patient factors, including clinical condition (such as renal failure) and patient preferences.
Surgical patients
The NICE guidance states that patients should be advised to consider stopping oestrogen-containing oral contraceptives four weeks before elective surgery. An assessment of the risks and benefits of stopping pre-existing established antiplatelet therapy one week before surgery should also be undertaken, while hospitals may wish to consider involving the multidisciplinary team in this process. They should consider regional anaesthesia for individual patients, in addition to other methods of VTE prophylaxis, as it carries a lower risk of VTE than general anaesthesia. In addition, factors such as patients’ preferences should also be considered. The guidance adds that, if regional anaesthesia is used, the hospital should plan the timing of pharmacological VTE prophylaxis to minimise the risk of epidural haematoma.
Patients with stroke
NICE warns that anti-embolism stockings for VTE prophylaxis should not be offered to patients who are admitted for stroke. It states that clinicians should consider offering prophylactic-dose LMWH (or UFH for patients with renal failure) if a diagnosis of haemorrhagic stroke has been excluded, and the risk of bleeding (haemorrhagic transformation of stroke or bleeding into another site) is assessed to be low, and the patient has one or more of the following:
• Major restriction of mobility.
• Previous history of VTE.
• Dehydration.
• Comorbidities (such as malignant disease).
Until the patient can have pharmacological VTE prophylaxis, a foot impulse or intermittent pneumatic compression device may be considered.
Discharge
As part of the discharge plan, patients and/or their families or carers should be offered verbal and written information on:
• The signs and symptoms of deep vein thrombosis and pulmonary embolism.
• The correct and recommended duration of use of VTE prophylaxis at home (if discharged with prophylaxis).
• The importance of using VTE prophylaxis correctly and continuing treatment for the recommended duration.
• The signs and symptoms of adverse events related to VTE prophylaxis.
• The importance of seeking help and who to contact if they have any problems using the prophylaxis.
• The importance of seeking medical help if deep vein thrombosis, pulmonary embolism or another adverse events is suspected.
Commenting on the NICE guideline, Professor Ian Gilmore, president of the Royal College of Physicians, said: “This NICE guideline on VTE will help heighten awareness among health professionals of a dangerous but preventable condition. Patients may not always have symptoms to give a warning – but occasionally VTE can cause pain and swelling in the leg. “The importance of assessing patients on admission, not a day or so afterwards, is raised, along with the need to re-assess patients within 24 hours of admission and whenever the clinical situation changes. With this guideline, health professionals can now work consistently to help reduce the risk of VTE occurring, and so help reduce the toll of long-term ill health or even death, that has previously occurred.” The NICE guideline, Reducing the risk of venous thromboembolism in patients admitted to hospital, is available at www.nice.org.uk/CG92
Reference
1 Figures cited in the second report of session 2004-5 of The House of Commons Health Committee, The Prevention of Venous Thromboembolism in Hospitalised Patients.