What is DVT and what steps can we take to prevent and treat it?

DVT leg pain diagnoses by vascular surgeon Michael Gaunt in Bury St Edmunds hospital.

Deep vein thrombosis (DVT) is when a blood clot forms in a deep vein. It often occurs in the leg but can also occur in the arms, pelvis or elsewhere. - Credit: Getty Images/iStockphoto

Deep vein thrombosis (DVT) is not rare, and it is important to be aware of the signs, as well as steps that can be taken to prevent and treat it, says leading vascular surgeon Michael Gaunt

Mr Gaunt, who runs clinics within hospitals in Cambridge, Bury St Edmunds and Harley Street in London, says the Covid-19 vaccine rollout has resulted in more patients coming forward with concerns.

Here he explains what to look out for and when to seek specialist advice.

Q: What is DVT and is it dangerous?

DVT is when a blood clot forms in a deep vein. It often occurs in the leg, particularly the calf, but can occur in the arms, pelvis or elsewhere. Blood normally flows quickly through the veins and is helped back up the legs and body, against gravity, by the muscles moving and pumping.

Consultant vascular surgeon, Michael Gaunt, at the BMI St Edmunds Hospital at Bury St Edmunds.

Consultant vascular surgeon Michael Gaunt advises seeking specialist medical advice if you're experiencing persistent pain and swelling in the leg or if it feels hot and tender when pressing your calf muscle. - Credit: Denise Bradley

The system relies on one-way valves to allow the blood to go up the leg, but not down. Normally this works very well but when you are immobile for a long time, in a hospital bed or on a long haul flight, for example, there is more chance of the blood pooling in the veins, especially if it is thicker than normal because you are dehydrated.

If a clot forms and then travels from the deep veins and lodges in the arteries of the lungs, it can be extremely dangerous. This is called a pulmonary embolism and it can range from a small pain when you breathe in right through to collapse, cardiac arrest and death.

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Q: Who is prone to DVT?

People with severe varicose veins; those who are pregnant or have recently given birth; patients on certain types of contraceptive pill or HRT; people who have had fractures; those who have had a previous DVT or a family history of it, and those with some blood conditions. Other medical conditions such as cancer, diabetes, heart failure, poor heart function, may also put people at increased risk.

Q: What are the signs of DVT?

There might be persistent pain and swelling, and the leg might feel hot and tender when you press the muscle. It looks like an infection and often it is treated as such, but it isn’t, it is an inflammation. In bad conditions, the DVT affects the whole leg, making it swollen with a slightly blue tinge. You will probably also feel awful.

Q: What is the treatment for DVT?

DVT can be treated very quickly these days with oral anticoagulants, which are much more convenient than previous treatments. These just thin the blood and the patient doesn’t need monitoring in the same way as they used to. In my experience, the pain goes away after a few days.

Q: What steps can people take to help prevent a DVT?

Signs and treatment for deep vein thrombosis from vascular surgeon Michael Gaunt in Cambridgeshire.

You can help prevent DVT by ensuring you drink plenty of fluids, wear compressions socks on long flights and can be prescribed with coagulants or take preventative medical steps. - Credit: Getty Images/iStockphoto

With long haul travel, I believe people put themselves at risk even before they step on the plane. They are quite possibly already dehydrated because they have got up early and not had much to drink before setting off.

They then get to the airport, where there’s a lot of standing around, get on the plane and are mostly encouraged to stay in their seat. The air conditioning dries them out and they often drink coffee or alcohol, which dehydrates them further.

To reduce your risk, drink plenty of fluids before, during, and after the journey; wear compression socks and make sure you move about and change your posture during the flight. For those at very high risk, we might consider prescribing oral coagulants for the flight or taking other preventative medical steps.

Q: If you have had a DVT are you more likely to develop a clot from the Covid-19 vaccine?

As far as I am aware, there has not been any mention of a link, but the talk of thrombosis has made people more anxious. We have seen more patients coming into the clinic recently because they have noticed swelling or pain in the calf and want reassurance.

This is easy for us to do. It is very quick to exclude a clot by carrying out an ultrasound scan in the clinic or doing a blood test. The main concern regarding the vaccine is not DVT but something called cerebral venous sinus thrombosis (CVST), which is very rare.

Possible symptoms of this might include a severe headache (which is not helped by painkillers, seems to be getting worse or may be made worse by lying down or bending over), blurred vision, nausea or vomiting, difficulty with speech, weakness, drowsiness and seizures.

People are also advised to look out for new, unexplained pinprick bruising, bleeding under the skin or a fine rash suddenly appearing, as well as shortness of breath, chest pain, leg swelling or persistent abdominal pain. You can get these symptoms with a lot of other conditions but if you are worried then get them checked out.

Q: Should I have my Covid-19 vaccination?

Yes. You are much, much more at risk of dying if you don’t have the vaccine. The risks of a blood clot following a Covid-19 vaccination are incredibly low. At the moment they think it is about 1 in 600,000. The risk of getting a thrombosis from Covid itself is much, much higher – thrombosis is one of the many ways that Covid kills people.

All treatments are a balance of risks and benefits and many people take much riskier medication than a Covid-19 vaccine to treat all sorts of conditions. People are asking me at the moment how long they should wait to fly after having their jab. This is hard because we have no data yet, but the risk seems to be in the three to four weeks afterwards, so it would seem reasonable to suggest waiting that long. 

For more information visit michaelgaunt.com, email megsecretaries@michaelgaunt.com or call 01223 305858.