For decades, many doctors believed that blocked arteries caused by fatty buildup were the main reason behind most strokes.
This idea shaped the way stroke prevention has been treated around the world. Medicines such as aspirin became standard because they help stop blood clots from forming in narrowed blood vessels.
But now, scientists say one common type of stroke may have a very different cause than previously thought.
Researchers from the University of Edinburgh and the UK Dementia Research Institute have found evidence suggesting that lacunar ischemic stroke is not mainly caused by fatty blockages in large arteries. Instead, damage and abnormal widening in the brain’s tiny blood vessels may be the real problem.
The research was published in the medical journal Circulation.
Stroke happens when blood supply to part of the brain becomes interrupted. Brain cells need a constant flow of oxygen-rich blood to survive. When blood flow stops, brain cells begin dying very quickly.
Some strokes happen because blood vessels burst and bleed, while others happen because arteries become blocked. The blocked type is called ischemic stroke and is the most common form.
Lacunar stroke is a special type of ischemic stroke caused by disease affecting the brain’s smallest blood vessels. Even though the affected vessels are very small, the condition can still cause major health problems.
People who suffer lacunar strokes may develop weakness, trouble walking, poor balance, speech problems, memory decline, or difficulties with thinking. Over time, repeated damage from these tiny strokes can increase the risk of dementia and long-term disability.
Scientists have struggled for years to understand exactly why lacunar strokes happen. Existing treatments often do not prevent future brain damage as effectively as doctors hoped.
To investigate the problem, researchers followed 229 patients who had experienced either lacunar stroke or another mild form of stroke.
Participants received detailed medical examinations, memory and thinking assessments, and MRI brain scans shortly after their stroke. Researchers repeated the MRI scans one year later to track changes happening inside the brain.
The team focused on two possible blood vessel problems. The first was fatty narrowing inside large arteries, which has traditionally been blamed for stroke risk. The second was enlargement and widening of arteries within the brain itself.
The study produced some surprising results.
Fatty narrowing of large arteries did not appear strongly connected to lacunar stroke or to worsening small vessel disease. Instead, this type of narrowing was more common in people with other kinds of stroke.
However, widened arteries inside the brain showed a strong link with lacunar stroke. Patients with enlarged brain arteries were more than four times more likely to have lacunar stroke compared to others.
Researchers also found that these abnormal artery changes were linked to faster progression of brain damage.
One especially concerning finding involved “silent” strokes. These are very small areas of brain injury that happen without obvious warning signs. A person may never realize a silent stroke occurred, but the damage can slowly build up over time.
Silent strokes can affect memory, thinking, balance, mood, and movement. They are also linked to dementia later in life.
During the study, more than one-quarter of participants developed new silent strokes despite receiving standard stroke prevention medicines.
This helps explain why commonly used antiplatelet drugs such as aspirin may not work well enough for lacunar stroke patients. These medications mainly target clot formation in larger blood vessels, but they may not address the underlying disease affecting the brain’s tiny vessels.
The findings are now helping shape new treatment research.
Scientists are currently testing whether drugs that directly protect the brain’s small blood vessels may work better. One ongoing study called LACI-3 is examining medicines including cilostazol and isosorbide mononitrate.
Researchers hope these treatments might reduce future strokes, slow brain damage, and help prevent problems such as dementia, memory loss, and walking difficulties.
Professor Joanna Wardlaw, one of the study leaders, said recognizing the difference between lacunar stroke and other stroke types is very important. She explained that understanding the true cause may help scientists finally develop more effective treatments.
The study also highlights an important lesson in medicine: diseases that appear similar may actually develop through very different biological processes.
This means one treatment approach may not work equally well for all patients.
The researchers say more studies are still needed to understand why some people develop widening of brain arteries and how doctors can stop or reverse the damage.
Even so, the findings represent a major step forward in stroke research. They challenge long-standing assumptions and suggest that protecting the brain’s smallest blood vessels could become an important future strategy for preventing stroke and dementia.
As populations around the world continue aging, understanding these hidden brain vessel problems may become increasingly important for protecting memory, mobility, and quality of life in older adults.
If you care about stroke, please read studies about how to eat to prevent stroke, and diets high in flavonoids could help reduce stroke risk.
For more health information, please see recent studies about how Mediterranean diet could protect your brain health, and wild blueberries can benefit your heart and brain.
Source: University of Edinburgh.
