World Stroke Day Q&A with Professor David Werring

What inspired you to specialise in clinical neurology and specifically in stroke research?

I was always interested in the brain but my interest in neurology was stimulated when I did a BSc in Neuroscience at St Thomas’ Hospital. Neurology seemed more interesting than other specialities as there are so many symptoms, syndromes and diagnoses. My interest in stroke began as a Junior House Officer in the early 1990s. I noticed that people with heart attacks were treated urgently and transferred to the coronary care unit for specific treatment, while people with stroke were admitted to general medical wards and had no specific interventions. If they had a brain scan it was often delayed for many days. There was a feeling that stroke was not a treatable disease and not much optimism about prospects for treatment – although I do remember helping recruit patients to the International Stroke Trial of acute antithrombotic therapy. I felt that things needed to improve and had an idea that I might one day specialise in stroke. 

I began my training in neurology in the mid-1990s at Queen Square, but at this time there was very little interest in stroke, which was not really considered a neurological disease. On the advice of trusted mentors (David Marsden, Alan Thompson, Ian MacDonald) I did a PhD in brain imaging, mainly in multiple sclerosis, using advanced MRI scans including diffusion-weighted sequences. Around this time, in the late 1990s, it became clear that diffusion-weighted MR imaging was an extraordinarily powerful diagnostic test for acute stroke and other types of MRI scans could also reveal in exquisite detail the consequences of injury to the smallest blood vessels in the brain (both ischaemic and haemorrhagic tissue damage).

What are the most effective strategies for preventing strokes, especially in high-risk populations?

In terms of secondary prevention (that is, preventing another stroke in someone who has had one) oral anticoagulation for atrial fibrillation (an irregular heartbeat, commonly found in older people, that increases stroke risk five-fold) is hugely effective, reducing the risk by two-thirds. Overall blood pressure control is probably the most important risk factor to diagnose and treat to prevent first and recurrent strokes. If everybody regularly checked for and treated their blood pressure and the irregular heartbeat of atrial fibrillation from mid-life onwards then many strokes could be prevented.

What are the most exciting developments in stroke research now?

Most people are now aware that we have highly effective treatments for ischaemic stroke (mechanical thrombectomy, where a clot can be removed from a large artery in the brain). So, I think the most exciting next frontier in stroke is to tackle brain haemorrhage, which globally causes nearly one in three strokes, but due to its severity (it is often fatal or disabling) causes as much disability overall as the more common ischaemic stroke. We have had several first positive clinical trials in ICH in 2024, showing that minimally invasive surgery and acute blood pressure lowering within a care bundle are effective. In my team, we recently found that anticoagulants can be safely used in people after an acute ischaemic stroke when there have previously been major concerns about bleeding into the area of stroke damage. We also found that people with brain microbleeds – tiny pinpoint areas of previously bleeding commonly seen on routine stroke brain scans in the stroke unit or outpatient clinic – can probably safely receive antiplatelet drugs like aspirin or anticoagulants after they have had an ischaemic stroke or transient ischaemic attack (a TIA or mini-stroke). We are also finding out more about what might cause brain haemorrhage in a very common disease of ageing that causes brain haemorrhage and dementia called cerebral amyloid angiopathy (CAA) and plan to start an exciting clinical soon to reduce the build-up of the amyloid beta protein that causes it.

How is technology, such as AI and machine learning, used to improve stroke diagnosis and treatment?

Current types of AI are well suited to using brain imaging to better diagnose and treat stroke. Certain types of AI are routinely used now to help find blood clots and assess people for acute treatment in the NHS. These show great promise, especially in smaller hospitals that do not have access to expert brain scan experts (neuro-radiologists), though more research is needed to understand how they should be best used. AI also shows promise in using vast amounts of routinely collected clinical data from brain scans, physiological measurements (e.g., blood pressure, pulse) and blood tests to develop predictive models to provide better information about prognosis and even, potentially, to allow us to evaluate the effects of treatments in routine care or to do more efficient clinical trials. 

Can you share an inspiring patient recovery story that highlights the importance of timely stroke intervention? 

Stroke recovery can be dramatic, particularly when treatment is given quickly. All stroke doctors will remember certain patients. I recall seeing a man in his fifties a few years ago, with atrial fibrillation, who suddenly and unexpectedly collapsed with an inability to move or speak and who soon went into a coma. He had a severe type of stroke due to a blockage of a large artery at the back of the brainstem called the basilar artery. Untreated, this type of stroke can cause either death or a ‘locked in’ syndrome (where the person cannot move or speak but is aware). Our team were able to make a rapid diagnosis and do a thrombectomy to remove the clot, and he made such a good recovery that he was able to leave the hospital the next day, taking an anticoagulant drug to protect him against further strokes due to the atrial fibrillation that we had discovered. He was able to go back to work very soon after. Untreated, he would have either died or faced a life of dependency and disability in a nursing home.

Related

• Meet the expert: Professor David Werring
• Professor David Werring's research profile
• UCL Queen Square Institute of Neurology
• Clinical Neuroscience: Stroke Medicine MSc