Common Stroke Type's Hidden Cause Identified by Scientists

For roughly one in four stroke patients, the root cause may not be the fatty deposits in arteries long blamed for the condition. A fresh study from the University of Edinburgh suggests that lacunar strokes—a common form of ischemic stroke—actually originate from a different problem: the widening and deterioration of tiny blood vessels deep inside the brain.

This finding, published in the medical journal Circulation, could reshape how doctors understand and treat these strokes. It may also explain why many patients fail to respond to standard therapies like aspirin and anticoagulants, the researchers note.

Study Tracks 229 Patients Over a Year

The research team followed 229 individuals who had either a lacunar stroke or a mild non-lacunar stroke. Immediately after the event, participants underwent brain scans and clinical tests. One year later, they were reassessed to track any changes.

The results were striking: narrowed arteries from fatty plaque showed no link to lacunar strokes. Instead, widened arteries emerged as a clear marker. Patients with this arterial dilation faced more than a fourfold increase in their risk of suffering a lacunar stroke.

According to the scientists, this expansion likely stems from small vessel disease—a condition that progressively damages the brain's microvasculature over time.

Implications for Treatment and Prevention

The team concludes that future research and treatment for lacunar strokes should pivot toward studying and repairing this microvascular damage, rather than solely focusing on preventing blood clots.

Professor Joanna Wardlaw, the study's lead author and a specialist in brain imaging and cardiovascular medicine at the University of Edinburgh, said the findings provide strong evidence that lacunar strokes are not caused by blockages in major arteries due to fat. "It's a dysfunction in the tiny vessels within the brain itself," she explained.

Understanding this difference is very important because it explains the limited effectiveness of current treatments that focus on preventing clots, and it underscores the need to develop new therapies that directly target damage to the small blood vessels.

In general, a stroke occurs when blood flow to part of the brain is interrupted by a blockage or a bleed, leading to brain cell damage. Key risk factors include high blood pressure, smoking, high cholesterol, diabetes, and obesity. Prevention has traditionally relied on clot-preventing drugs like aspirin.