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Any patient admitted to hospital is potentially at risk of developing a blood clot. This leaflet will explain what a blood clot is, who is most at risk of getting one, what you can do to help reduce your risk and what we can do to help reduce it further. It will also tell you what symptoms might suggest the presence of a blood clot and what you should do if you experience any of them.


What is a Venous Thromboembolic Event (VTE)?

Deep vein thrombosis (DVT) is the name given to a blood clot which forms inside a vein. Typically these clots form inside the veins of the legs, interrupting blood flow and making the leg swollen and painful. DVT may cause long term effects, a so called post thrombotic syndrome with painful swollen legs, varicose veins and ulcers.

Sometimes clots can break off and travel to the lung, becoming lodged in one of the lungs. This is called a pulmonary embolism (PE) and can cause pain, breathlessness and lack of oxygen in the blood. On rare occasions PE can be life threatening.

DVT and PE are known under the collective term of venous thrombo-embolism (VTE).


How common is Venous Thromboembolism (VTE)?


Prior to the introduction of thrombosis risk assessment and routine preventative measures, VTE was believed to cause more than 25,000 deaths per year in the UK that, potentially, could have been prevented. At least half of these were likely to have been associated with a hospital admission. VTE following hospital admission caused at least 10 times more deaths than Methacillin Resistant Staph Aureus (MRSA) and 5 times more deaths than the combined number from breast cancer, AIDS and road traffic accidents. Up to one in three surgical patients may develop a DVT if no preventative measures are used and seven out of ten deaths from VTE in hospital occur in medical patients (those who have not had an operation).


Am I at particular risk of developing a VTE?

Any patient can be at risk of developing a VTE. There are, however, several factors that may increase the chances of this happening including:

  • Previous history of VTE.
  • Strong family history of VTE.
  • Age – the older you are the higher the risk.
  • Acute and longstanding medical illness including heart failure, respiratory disease, cancer and major infections.
  • Prolonged immobility / bed rest.
  • Obesity.
  • Taking oestrogen containing medication such as Hormone Replacement Therapy (HRT) or the Pill (combined oral contraceptive pill) but not the Mini-pill (progesterone-only pill).
  • Pregnancy, where the risk is present throughout pregnancy and for at least six weeks after delivery.
  • Major surgery including hip or knee replacements.


What can I do to reduce the risk of developing VTE?

Before I come into the hospital for planned surgery:

  • Keep mobile – move around as much as possible in the weeks leading up to your planned surgery.
  • Keep well hydrated; try to drink between 2 - 3L of fluid daily.
  • Take care when travelling – if you can, in the month before your planned surgery, avoid long uninterrupted journeys lasting over three hours.
  • If you need to travel on a long journey, try to move your legs regularly. If travelling by car, have a break and walk around every one to two hours.
  • Talk to your doctor if you are taking the Pill, but not the mini-pill or Hormone Replacement Therapy (HRT) - these medicines may increase your risk of developing a DVT or PE so your doctor may advise you to stop taking them in the weeks leading up to your planned surgery.


If you do stop taking the Pill, in order to avoid any unplanned pregnancy, make sure that you use alternative contraceptive methods prior to your operation.


When I come into hospital:

You will be assessed for your risk of developing a VTE. If necessary you will be prescribed various preventative methods (thrombo-prophylaxis) to reduce the risk of developing a VTE whilst in hospital.

  • Mobilise (move around) as soon as possible following surgery as guided by your doctor, nurse or physiotherapist. If you are confined to bed do foot exercises, where you bend and straighten your ankles quickly. If you keep your knees straight during the exercise you will stretch your calf muscles.
  • Keep well hydrated - if you are allowed to do so, drink plenty of fluids. If not, your doctors will administer fluids directly into your veins.
  • Anti-embolic stockings help reduce the risk of VTE. If your doctor thinks these would be helpful for you, the nurses will fit you with a suitable pair.
  • In the operating theatres and in certain clinical areas, the clinical team may use intermittent compression devices that are fitted to the lower limbs, to help reduce the risk of developing a VTE.
  • Medication: If your doctor thinks that you are at high risk of developing a VTE then medication may be prescribed which stops the blood clotting so quickly.
  • Before being prescribed anticoagulant medication you will be assessed for risk of bleeding.
  • In this Trust the medication normally used is Enoxaparin (Clexane®) which is given as an injection under the skin. For some orthopaedic operations a tablet may be prescribed instead. In future, depending on the outcome of clinical testing, this might also become available to prevent VTE in other patients.
  • Staff will observe and assess you for the development of any symptoms suggestive of VTE.


Not all methods of thromboprophylaxis are suitable for every patient. Your doctor will review which methods will be used to reduce your risk of VTE.

If you are already taking an anticoagulant medication, like Warfarin, your doctor will only prescribe Enoxaparin if you have to stop this for any reason.


After I go home:

Your doctor will assess your risk of developing a VTE as some patients may need to continue taking Enoxaparin (Clexane®) and after certain orthopaedic operations patients might be given a short course of tablets to prevent VTE once they go home.

Keep as active as possible once you are at home.

If you are given anti-embolic stockings consider wearing them until you return to your normal level of mobility (moving about). The use of thromboprophylaxis is very effective at reducing the risk of developing a VTE.

However thrombotic events can still occur despite appropriate preventative measures being taken.

Should this, unfortunately, happen medications are available which are very effective at treating VTE.


What are the symptoms of VTE and what should I do if I have them?

The most common symptoms for a deep vein thrombosis include any combination of the following:

  • Pain, tenderness and swelling of one leg which may only effect the calf
  • Redness of the leg


The most common symptoms for a pulmonary embolism include any combination of the following:

  • Shortness of breath
  • Chest pain made worse by deep breathing
  • Dry cough (or occasionally coughing up blood)


If you experience any of the above symptoms immediately seek medical advice from either your GP or from the A&E Department at St. Peter’s Hospital.


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