How to prevent stroke: new research and treatments

Why is research into strokes so important? 

It’s vital because stroke is happening more often nowadays and it is the third leading cause of death and disability worldwide. 1 in 4 people will have a stroke in their lifetime.  

A stroke disrupts blood flow to parts of your brain, which can damage brain cells, affecting your movement, feeling, vision, speech or thinking. 

When I started training as doctor in the 1990s, there was little we could do for people who’d had a stroke other than good nursing care and rehabilitation.

Since then, clinical trials have revolutionised how we care for the commonest type of stroke, (called ischaemic stroke), where a blood vessel supplying your brain is blocked by a clot. Now we can get rid of the clot with medicine (called thrombolysis) or a procedure via a blood vessel (called mechanical thrombectomy). These treatments can dramatically improve the long-term impact on the person. 

But research into the other types of stroke, caused by bleeding in the brain, (called haemorrhagic stroke) has lagged. 

There’s still so much more we need to do to reduce the burden of stroke.  

Every year more than 100,000 people have a stroke in the UK and it’s one of the UK’s biggest killers, causing around 27,000 deaths each year.  

Stroke is also the single biggest cause of severe disability in the UK. And beyond the physical symptoms, survivors often experience invisible effects such as fatigue and emotional distress.

What do we still need to learn about the causes of stroke? 

We know that most, particularly ischaemic strokes, are linked to atherosclerosis (the build-up of fatty material in blood vessels), small vessel disease (where small blood vessels become damaged) and the abnormal heart rhythm atrial fibrillation.  

However, a significant number of strokes remain cryptogenic, meaning the cause is unclear. This is especially true for younger patients, whose stroke rates are rising and who often lack traditional risk factors.  

Vaping may prove to be a risk factor in the same way smoking is.

Research is increasingly focused on these cases, exploring possible links to diet, obesity, and other aspects of modern living. For example, we’re only beginning to research the effects of vaping and it may prove to be a risk factor in the same way smoking is.

At the other end of the spectrum, older patients may have multiple contributing factors, making it difficult to pinpoint the exact cause. 

Advances in how we use imaging technology and biomarkers (indicators of biological processes happening in our bodies) are helping us to identify underlying mechanisms that cause stroke, even when standard tests do not give clear results. 

For example, there may be some people who have a standard carotid Doppler ultrasound test and it does not show that an artery in their neck is significantly narrowed. But a PET scan – an imaging technique that labels specific molecules – might show that the atherosclerosis in their neck was active, which could have caused the stroke and could be suitable for treatment. 

How can research help us prevent strokes? 

There are three main ways we can prevent strokes: lifestyle changes, screening and medicines.  

Research could help identify the most effective approaches to reduce the rising numbers of people who are living with obesity, eating an unhealthy diet and who are physically inactive – all factors that can increase the risk of a stroke. 

Research is helping us to work out if screening tools like a heart tracing, blood test, or smart watch can predict who is at risk of having a stroke so we can offer them personalised prevention.

There’s also ongoing research into new medicines or ways to combine existing medicines – known as polypills – which can be useful when trying to treat multiple risk factors that can lead to stroke, such as high blood pressure and cholesterol.  

Researchers are also looking into how, once people have already had a stroke, they can reduce their risk of having another one by getting the right support to make lifestyle changes alongside any medicine they are given. 

Trials can also help us understand how to better use existing and new medicines.  

For example, the BHF-funded clinical trial I am leading, ASPIRING, is looking at whether antiplatelet medicines such as aspirin and clopidogrel can be used to prevent people who have had a haemorrhagic stroke having another stroke or a heart attack.  

While these antiplatelet medicines are used for people who have had an ischaemic stroke, at the moment most people who’ve had a haemorrhagic stroke tend to be kept off them because of the uncertainty about further bleeding in the brain.  

However, my earlier BHF-funded clinical trial, RESTART, showed that restarting antiplatelet medicines is safe for people who’d had a haemorrhagic stroke, and may prevent heart attacks and strokes. Now ASPIRING will look at starting these medicines in most haemorrhagic stroke survivors, following over 4000 people for up to 5 years. 

How might stroke treatment and recovery evolve in the future? 

Haemorrhagic strokes are mostly treated as early as possible with blood pressure lowering medicine. Recent studies have found that this can be effective when given in the ambulance on the way to hospital. 

But the challenge is how to diagnose a haemorrhagic stroke in an ambulance when you do not have a brain scanner. So, scientists are working on whether we could develop a reliable biomarker test to help paramedics diagnose haemorrhagic stroke in the ambulance. 

Clinical trials have not shown consistent benefits for surgery after haemorrhagic stroke. But a minimally invasive procedure that removes blood in the brain showed promising results. More clinical trials of these procedures and drugs are being performed in the search for effective treatments for haemorrhagic stroke.

For ischaemic strokes, there’s growing interest in the development of thrombectomy carried out with robots. This could help ensure more people can get treated with this procedure, as there’s currently a shortage of radiologists who can do this, especially in rural areas of the country. 

In rehabilitation, techniques like vagus nerve stimulation (delivering an electrical current to the nerve that connects your heart and brain) and digitally delivered therapy are being explored, though more evidence is needed to show how effective these therapies are.  

Regenerative medicine is looking at using cell therapies and repurposed drugs to help the brain repair itself, especially in the first few months following a stroke. These therapies are still decades off being widely used but they do offer hope for the future.

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