Blood Clots: Do You Know The Risks?

Blood Clots: Do You Know The Risks?

Reports of rare types of blood clots linked to Covid jabs have recently been in the news but, away from these headlines, other worrying statistics have emerged. Did you know, for instance, that more people die from blood clots than breast cancer and road traffic accidents combined? We caught up with two industry experts to assess the risk factors and find out how you can protect yourself. Here’s what you need to know…

First things first – what are blood clots and why do they happen?

A blood clot forms when blood turns from a liquid into a semi-solid mass. “Clotting is a natural process,” says aesthetic doctor Sophie Shotter. “When you cut yourself, platelets flood to the injured area and cause a clot to form, which stops the bleeding. Clotting can, however, become a dangerous problem as blood can become ‘sticky’, causing clots for no obvious reason. These ‘sticky’ clots can dislodge themselves from where they were originally formed and become wedged in the lung, causing a pulmonary embolism. This can, in severe cases, be fatal.” Alternatively, you may develop blood clots through the arterial system where they become wedged in smaller arteries, which may feed the brain, causing a stroke or a block of tissue, causing gangrene, Sophie tells SL. “This process could be triggered by an injury, but in some cases blood clots occur inside vessels where there has been no obvious injury,” she says.

So, what are the different types of blood clot?

There are two main types of blood clots, explains Professor Mark Whiteley, leading consultant venous surgeon and founder of The Whiteley Clinic. “These include clots that stay in place and don’t move (thrombosis) and those that break away from the spot where they developed and move to different areas inside your body (embolism). Depending on what the clot blocks or where it moves, a blood clot can be deadly.”

What about DVT?

When we think of blood clots, deep vein thrombosis (DVT) is perhaps the one that springs to mind, especially in relation to long-haul flights. DVT is a blood clot that forms in a vein, usually in your calf, much deeper than surface veins that cause varicose veins. Being immobile or overweight, increasing age, cancer, HRT and dehydration all increase your risk. On average, around one in 1,000 people develop DVT every year, but the risk is higher for people in these groups.

How common are clots in general?

“One shocking statistic is that one in four people in the UK die of causes related to blood clots every year,” says Sophie. “And in the western world, one in 1,000 adults are affected by a venous thrombosis (i.e., a blood clot in a vein) every year.”

Air is much thinner at altitude, which can change the lining of the veins when flying, increasing your risk of DVT.

What puts you at risk?

Blood clots can potentially affect anyone, although age and some lifestyle and genetic factors may put you at a higher risk. “Sitting at a desk all day, or any type of prolonged inactivity, puts you at risk,” explains Mark. “Plus, one of the most common causes of DVT is prolonged periods of inactivity when travelling long distance. When you significantly reduce the activity in your legs, blood flow becomes sluggish, putting you at a higher risk of a clot forming. An additional problem with flying is that air is very thin at altitude, which can cause a change in the lining of the veins, increasing the risk of developing a thrombus on flights over three to four hours in length. Another risk factor is dehydration, which can change the composition of blood as it becomes more concentrated.” According to the National Blood Clot Alliance, cancer, major surgery, smoking and being over 55 can also be risk factors. Genes may also play a part, so it’s important to know your family history. “Synthetic oestrogens can also increase the risk of blood clots if taken in tablet form, but in patch or cream form this risk is avoided,” Sophie adds. “Although the risk also appears to be lower with bioidentical oestrogen, so this is worth considering if you are on HRT and have a family history of blood clots,” she says.

If you have varicose veins, does that put you more at risk?

Mark explains that having varicose veins does increase the risk of clots in the leg veins. “Blood clots can occur in veins if one of more of the following factors occurs: the blood constituents change, the blood flow changes, or the vein wall changes. In varicose veins, two of these factors are already present. Although it used to be thought that clots in varicose veins weren’t dangerous, this has now been shown to be wrong. A clot in a varicose vein is a superficial venous thrombosis. If it extends near a deep vein, then it has a 1% chance of becoming a pulmonary embolism. Therefore, the sensible thing is to get varicose veins treated before they develop clots.”

If you had the AstraZeneca vaccine, does that increase your risk?

There have recently been reports of an extremely rare but serious condition involving blood clots and the AstraZeneca vaccine. “What we do know is that these clots seem to occur in predominantly younger women and the blood clot is in the head veins around the brain,” says Mark. “It appears that these patients seem to get these clots even with low platelets, suggesting it may be a response of the immune system to the vaccine. However, we also know that coronavirus itself causes blood clots. Getting a blood clot from having Covid is thousands of times more likely than getting a blood clot because of the vaccine.”

Getting a blood clot from having Covid is thousands of times more likely than getting one because of the vaccine.

What are the signs of a blood clot?

Different clots present themselves with different symptoms, explains Mark. “It depends whether your clot is blocking the vessel or only partially blocking it, and whether it breaks off and becomes an embolism. In arteries, blood clots are much more widely known and cause strokes, heart attacks and dead legs. In veins, symptoms can be more subtle. A DVT usually presents with a swollen, tender leg. If the clot is lower down the leg, it may be only the calf that is affected. If the clot is in the thigh veins or pelvis, the whole leg may be swollen and tender. The problem with DVT is that half the people with a swollen and tender leg don’t have a DVT, and half the people who do have one don’t have significant symptoms. Therefore, if there is any suggestion of a DVT, it’s wise to get a scan to be 100% sure. Breathlessness, particularly a sudden acute onset, and chest pain on breathing, can be signs that a clot has broken off and entered the lung. If it’s very severe, you may cough up blood.”

How are blood clots treated?

Treatment depends on where the clot is and the severity of the condition. Blood-thinning medications are commonly used to prevent blood clots from forming or getting bigger. Thrombolytic medications, meanwhile, can break up existing clots. “Blood clots in the arteries of the legs need to be removed surgically,” adds Mark. “While blood clots in the coronary arteries causing a heart attack can be treated by an injection of a drug that breaks down the clot called thrombolysis. Very occasionally, blood clots causing strokes can also be treated with thrombolysis, but this is very specialised and only works in certain cases. Anti-coagulants (blood thinners) don’t break up existing clots, but they stop new blood clotting, preventing a clot from getting bigger and giving the body a chance to break down the blood clot naturally. In addition, the quicker a clot is broken down, the less damage there is to the veins. If anti-coagulant treatments aren’t suitable, you may have a filter inserted into a large vein – the vena cava – in your tummy. This filter traps and stops the blood clot from travelling to your heart or lungs.”

Once you’ve had a blood clot, are you likely to get another one?

“If you’ve had a previous blood clot, then in principle you’re more likely to have another one, especially if your risk factor is still present,” says Sophie. As Mark adds, it all depends on whether the underlying cause has been corrected. “If you’re a smoker and you go on a long flight and get DVT, then you’ll be much more likely to get another if you continue to smoke and still go on long flights, for example. When anyone has a thrombosis or embolism, there is firstly an initial treatment phase to try and stop the immediate problem, followed by an investigation and then follow-up treatment to prevent it from happening again. Ultimately, it’s all down to personal risk factors.”

So, how can you protect yourself?

To keep blood clots at bay, the experts recommend keeping at a healthy weight (ideally with a BMI of 19-25); maintaining healthy blood pressure and cholesterol levels; reducing salt and sugar intake; and staying hydrated. “Staying active is also crucial,” Sophie adds. “This will not only minimise the risk of becoming obese but will also keep blood moving within the legs. Various supplements can also help to keep blood thinner – turmeric, ginger, cayenne pepper, vitamin E, garlic and gingko biloba are all worth looking into.” And if you are heading off on holiday, Mark says wearing compression stockings on a long-haul flight will speed up the flow of blood in the veins, reducing the risk of developing DVT. “Unless there’s a medical reason, a below-knee stocking is sufficient, although getting one properly fitted will give you more pressure and be more effective than a shop-bought one. And whilst on the plane – or in a situation where you can’t move around as often – point and flex your toes and make circles with your feet to keep blood moving.”

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