Stroke is one of the leading causes of death and long-term disability around the world. Every year, millions of people suffer strokes that can affect speech, memory, movement, balance, and independence.
Some people recover well, while others are left with permanent disabilities that change daily life forever.
There are different types of stroke, but the most common kind is called ischemic stroke. This happens when blood flow to part of the brain becomes blocked. Without enough oxygen and nutrients, brain cells begin to die within minutes.
For many years, doctors believed that most strokes were mainly caused by fatty buildup inside large arteries. These fatty deposits, often called plaques, can narrow blood vessels and reduce blood flow. When a clot forms around these narrowed areas, it can block blood supply to the brain and trigger a stroke.
Because of this understanding, doctors commonly use medicines such as aspirin and other antiplatelet drugs to help prevent blood clots and reduce stroke risk. These medications work well for many patients.
However, scientists have long noticed that these treatments do not seem to work as effectively for one important type of stroke called lacunar ischemic stroke.
Now, researchers from the University of Edinburgh and the UK Dementia Research Institute have uncovered evidence that may explain why.
Their new study suggests that lacunar stroke is not mainly caused by fatty blockages in large arteries as previously believed. Instead, the researchers found that changes in the brain’s tiny blood vessels may play a much bigger role.
The findings were published in the journal Circulation.
Lacunar stroke is caused by damage to the brain’s smallest blood vessels, a condition known as small vessel disease. This type of stroke accounts for around one-quarter of ischemic strokes in the United Kingdom each year. Although the affected blood vessels are tiny, the consequences can still be severe.
Lacunar strokes can damage thinking ability, memory, walking, balance, and independence. They are also strongly linked to dementia and repeated strokes later in life.
Despite their importance, scientists have struggled to fully understand why these strokes happen. Without a clear understanding of the cause, developing effective treatments has been difficult.
To investigate further, the research team studied 229 people who had experienced either lacunar stroke or another mild type of stroke. The participants underwent detailed health assessments, memory and thinking tests, and brain MRI scans shortly after their stroke and again one year later.
The MRI scans allowed scientists to closely examine changes happening inside the brain over time.
Researchers compared two different problems in blood vessels. One was fatty narrowing of large arteries, which doctors have traditionally blamed for many strokes. The other was widening and enlargement of arteries inside the brain.
The results surprised the researchers.
They found that fatty narrowing of large arteries was not strongly linked to lacunar stroke or small vessel disease. Instead, this kind of narrowing was more common in other stroke types.
In contrast, widening of arteries inside the brain showed a very strong connection with lacunar stroke. People with widened brain arteries were more than four times more likely to have lacunar stroke.
The researchers also discovered that these enlarged arteries were linked to worsening small vessel disease and faster brain damage over time.
Another important finding involved “silent” strokes. These are tiny areas of brain damage caused by interrupted blood supply that may not cause immediate symptoms. A person may not realize they have had a silent stroke, but the damage can build up over time and contribute to memory problems, walking difficulties, and dementia.
During the study, more than one in four participants developed new silent strokes even though they were receiving standard stroke prevention treatments.
This finding helps explain why common medications such as aspirin may not provide enough protection for people with lacunar stroke.
Scientists now believe that treatments aimed only at preventing blood clots in large arteries may not address the real problem happening inside the brain’s small blood vessels.
The discovery is already helping researchers develop new treatment strategies. One ongoing study called the LACunar Intervention Trial 3, or LACI-3, is testing drugs that directly target small blood vessel damage inside the brain.
The trial is studying medications including cilostazol and isosorbide mononitrate to see whether they can better protect the brain, reduce future strokes, and slow problems with memory and mobility.
Professor Joanna Wardlaw from the University of Edinburgh explained that understanding the true cause of lacunar stroke is extremely important because it changes the direction of treatment research.
The findings suggest that doctors may eventually need a completely different approach for treating this type of stroke compared to other stroke forms.
The study also highlights how complex stroke disease really is. Not all strokes develop in the same way, and treatments that help one type may not work well for another.
Researchers say much more work is still needed to fully understand why these artery changes happen and how best to stop them. However, the discovery offers new hope that more effective treatments for lacunar stroke could be developed in the future.
The findings may also help doctors better predict which patients are at higher risk of future brain damage, dementia, and repeated strokes.
Overall, the study challenges long-held beliefs about stroke and opens the door to a new understanding of how tiny blood vessels deep inside the brain may quietly contribute to serious disease over time.
If you care about stroke, please read studies that diets high in flavonoids could help reduce stroke risk, and MIND diet could slow down cognitive decline after stroke.
For more health information, please see recent studies about antioxidants that could help reduce the risk of dementia, and tea and coffee may help lower your risk of stroke, dementia.
Source: University of Edinburgh.
