Reducing your risk of DVT

Before you go into hospital

If you are taking an oestrogen-containing oral contraceptive (the 'combined pill') or having hormone replacement therapy (HRT) and you will be having an operation, your healthcare team should advise you to consider stopping these medicines temporarily 4 weeks before you have your operation. If you stop taking the combined pill your healthcare team should offer you advice about other forms of contraception.

If you are having an operation and you are already taking a medicine that thins the blood (for example, aspirin) your healthcare team should assess the risks and benefits of stopping this medicine temporarily 1 week before your operation. Aspirin and similar medicines don't offer people who are at risk enough protection from DVT while they are in hospital. If you are going into hospital for any reason your healthcare team should consider and discuss with you other treatments to help prevent DVT.

For some operations, it may be possible for you to have a regional anaesthetic (an anaesthetic that numbs an area of the body). This has a lower risk of leading to DVT than a general anaesthetic. If a regional anaesthetic is suitable for you, your healthcare team should discuss your choice of anaesthetic with you.

Questions you might like to ask your healthcare team before you go into hospital

  • When can I start taking the combined contraceptive pill or
    HRT again?

  • Can I carry on taking other medicines?

  • I am already taking aspirin. Why won't this protect me from DVT?

  • I am already taking warfarin (or heparin). Will I still need treatment to help prevent DVT when I go into hospital?

  • Will I be able to have a regional anaesthetic for my operation?

While you are in hospital

There are a number of steps your healthcare team can take to help reduce your risk of DVT during your stay in hospital. They should make sure you have enough fluids so that you do not become dehydrated. They should also encourage you to move around as soon as you are able.

If you are having an operation as a day patient and you are at risk, your healthcare team may decide to offer you treatment to help prevent DVT. They may ask you to continue the treatment at home after your operation (see when you leave hospital).

Depending on your risk factors you may be offered:

  • anti-embolism stockings or an intermittent pneumatic compression device to help keep the blood in your legs circulating (see below)

  • a medicine known as an anticoagulant that thins the blood and helps prevent blood clots forming (see below).

Before offering you anti-embolism stockings, an intermittent pneumatic compression device or an anticoagulant medicine, your healthcare team should talk to you and/or your family or carers and offer a leaflet about:

  • the risks of DVT

  • what might happen if you develop DVT

  • how to use stockings or devices for helping to prevent DVT

  • how you can reduce your risk of DVT, for example by having enough fluids so that you do not become dehydrated and, if possible, moving around and exercising.

Anti-embolism stockings

Anti-embolism stockings (also known as 'compression stockings') are tight stockings specially designed to reduce the risk of DVT. The stockings squeeze your feet, lower legs and thighs, helping your blood to circulate around your legs more quickly. Your healthcare team should measure your legs before fitting stockings to make sure you are given the right size. If your legs become swollen they should be measured again and new stockings fitted.

It is important to wear the stockings for as much of the time as possible, day and night, whether in hospital or afterwards at home, until you are back to your usual level of activity. Your healthcare team should show you how to use them. Theyshould check regularly to make sure you are using them correctly and offer help so that you get the most benefit from them. If you have ulcers or wounds on your legs your healthcare team should take special care when using anti-embolism stockings.

Your healthcare team should ensure that your stockings are taken off every day to clean the area and check the condition of your skin. If you have pain or discomfort, bruising or blisters, or areas where your skin has changed colour, your healthcare team should make sure you stop using the stockings.

People who should not be offered anti-embolism stockings

You should not be offered anti-embolism stockings if you have had a stroke, you have peripheral arterial disease (narrowing of the arteries leading to your legs), peripheral neuropathy (damage to the sensory nerves), gangrene or a recent skin graft, eczema or fragile skin on your legs, fluid on the lungs caused by heart failure, an allergy to the stocking material, your legs are very swollen or a good stocking fit cannot be achieved.

Intermittent pneumatic compression devices

These are worn around your legs or on your feet (where they are known as foot impulse devices or 'foot pumps'). They inflate automatically at regular intervals. When these devices are inflated they apply pressure, which helps keep the blood in your legs circulating. It is important to use your intermittent pneumatic compression device for as much of the time as possible, both when you are in bed and when you are sitting up in a chair.Your healthcare team should show you how to use the device correctly and check regularly to make sure you are getting the most benefit from it.

People who have had a stroke

If you have had a stroke, you may be offered an intermittent pneumatic compression device. Your healthcare team should explain all the possible benefits and risks of using this device.

You shouldn't be offered any other kind of device to reduce your risk of DVT if you have had a stroke, unless you are taking part in a clinical trial. This is because it isn't clear how helpful they are in reducing the risk of DVT for people who have had a stroke.

There is more information about clinical trials on NHS Choices.

Anticoagulant medicines

Depending on your risk factors, your healthcare team may offer you a type of medicine called heparin or a medicine called fondaparinux. Both of these are anticoagulants, which are medicines that thin the blood and help to stop blood clots forming. Heparin and fondaparinux are usually given by injection.

If you are having total hip or total knee replacement surgery, you may instead be offered a medicine called dabigatran or one called rivaroxaban. These medicines are also anticoagulants. They are taken as tablets.

Heparin is made from animal products. Synthetic alternatives may be available if you are concerned about this, and your healthcare team should discuss the suitability, advantages and disadvantages of the available treatment options with you.

Off-label medicines

At the time of publication some kinds of heparin may be recommended for 'off-label' use in this guideline. Your doctor should tell you this and explain what it means for you.

In the UK, medicines are licensed to show that they work well enough and are safe enough to be used for specific conditions and groups of people. Some medicines can also be helpful for conditions or people they are not specifically for. This is called 'off-label' use. Off-label use might also mean the medicine is taken at a different dose or in a different way to the licence, such as using a cream or taking a tablet. There is more information about licensing medicines on NHS Choices.

Vena caval filter

If your risk of DVT is high but you cannot take anticoagulant medicines and are not able to use anti-embolism stockings or intermittent pneumatic compression devices, you may be offered a temporary vena caval filter. This is an umbrella-shaped device that is inserted into a large vein (usually in your abdomen) to trap any blood clots and stop them moving toward the lungs.

Women who are pregnant or have given birth within the past 6 weeks

If you are pregnant or have given birth within the past 6 weeks and are at risk of developing DVT, your healthcare team should discuss with you the risks and benefits of treatments to help prevention. Before offering you a treatment they should discuss it with other healthcare teams who have experience of using that treatment for women who arepregnant or have recently given birth.

Questions you might like to ask your healthcare team about treatments to help reduce the risk of DVT

  • Please tell me why you have decided to offer me this particular treatment.

  • Are there any side effects associated with this treatment?

  • I am pregnant/breastfeeding. Will this treatment affect my baby?

  • How long will I need to keep having this treatment?

  • Will I need to stay in hospital longer if I'm having this treatment?

When you leave hospital

Before you leave hospital your healthcare team should talk to you and offer you a leaflet about:

  • how to tell whether you might have DVT or pulmonary embolism

  • why it is important to seek medical help and who to contact if you think you might have DVT or pulmonary embolism.

If you are advised to continue treatment with anti-embolism stockings or an anticoagulant medicine for a time after you leave hospital, your healthcare team should tell your GP. Your healthcare team should also make sure you are able to use the treatment or have someone available to help you. They should talk to you and offer you a leaflet about:

  • how to use your treatment after you go home

  • how long to continue the treatment

  • why it is important to follow the advice you are offered about how to use the treatment and for how long

  • how to tell if the treatment is causing you problems

  • why it is important to seek help and who to contact if you think the treatment might be causing a problem.

Questions you might like to ask your healthcare team before you leave hospital

  • How long should I keep wearing the stockings?

  • How do I care for the stockings?

  • How long should I keep using the anticoagulant medicine?

  • What should I do if I can't inject myself?

  • Who should I contact if I am having problems?

  • What should I do if I think I might have DVT or pulmonary embolism? (see below)

How to tell if you might have DVT or pulmonary embolism

It is important to seek medical help if you think you might have DVT or pulmonary embolism.

There are certain signs to look out for after your hospital treatment that may mean you have developed DVT or pulmonary embolism. You should seek help immediately if you experience any of the following in the days or weeks after your treatment.

  • You have pain or swelling in your leg.

  • The skin on your leg feels hot or is discoloured (red, purple or blue), other than bruising around the area where you have had an operation.

  • The veins near the surface of your legs appear larger than normal or you notice them more.

  • You become short of breath.

  • You feel pain in your chest or upper back.

  • You cough up blood.

  • Information Standard