A study led by the University of Edinburgh and the UK Dementia Research Institute has challenged the conventional understanding of lacunar strokes, which account for about a fifth of all strokes in the UK, or roughly 35,000 cases annually, according to the British Heart Foundation. Unlike ischaemic strokes, which are typically caused by blockages in larger arteries, lacunar strokes have been thought to result from damage to tiny blood vessels in the brain. However, the new research suggests that the underlying mechanism may be the widening of arteries deep within the brain, not narrowing.
The analysis, published in the journal Circulation, involved 229 individuals who had experienced lacunar or mild non-lacunar strokes. The researchers found no link between lacunar strokes and arterial narrowing. Instead, patients with widened arteries were four times more likely to suffer a lacunar stroke.
This finding could explain why conventional treatments such as anti-platelet drugs are often ineffective for this type of stroke, according to the researchers. Professor Joanna Wardlaw of the University of Edinburgh’s Institute for Neuroscience and Cardiovascular Disease said the study provides strong evidence that lacunar stroke is not caused by fatty blockage of larger arteries, but by disease of the small vessels within the brain itself. She added that recognising this distinction is crucial because it explains why anti-platelet drugs are not as effective and highlights the urgent need for new therapies targeting microvascular damage.
The study also linked widened arteries to a higher risk of silent strokes, which occur without obvious symptoms. More than one in four patients had silent strokes during the study despite receiving treatment. Experts have called for new treatments to address the underlying damage to small blood vessels in the brain.
The findings are already being used in ongoing studies exploring lacunar stroke treatments, including the LACunar Intervention Trial 3 (LACI-3). Maeva May, director of policy at the Stroke Association, noted that stroke research is chronically underfunded, with less than 1% of total UK research funding spent on the condition. She said the findings illustrate the value of research and its potential to change the lives of stroke patients.
She called for such studies to become a national priority across the NHS, government, and the wider research community. Lacunar strokes can lead to severe issues with thinking, memory, movement, and ultimately dementia. The exact mechanism by which widened arteries cause these strokes remains unclear, as does the timeline for potential new therapies based on this research.
The specific drugs being tested in the LACI-3 trial have not been disclosed, and it is unknown what risk factors contribute to the widening of arteries in the brain.