Certain strokes likely caused by artery widening, not blockages, new MRI data show
According to newly published MRI data, artery blockages might not be to blame for a significant portion of ischemic strokes.
New findings in the journal Circulation contradict this notion, suggesting that artery widening is likely to blame for many lacunar strokes. Around 25% of ischemic strokes are categorized as lacunar strokes; prior data has implicated blockages in small vessels deep within the brain in these types of stroke, but these latest findings suggest that the opposite may be true.
This, experts involved in the research say, could explain why treatments involving aspirin and other antiplatelet drugs are not effective in certain patients.
“Stenosis and dolichoectasia of cranial arteries likely reflect distinct mechanisms,” Joanna Wardlaw, MD, a professor of applied neuroimaging at the University of Edinburgh’s Institute for Neuroscience and Cardiovascular Disease, explained. “Their contributions to lacunar stroke and cerebral small-vessel disease remain contentious. We investigated the associations of large-artery stenosis and arterial widening with stroke subtype, [cerebral small-vessel disease] markers, incident infarcts and clinical outcomes.”
The study included 229 patients with a prior history of lacunar or mild nonlacunar stroke who had previously undergone an MRI at the time of their diagnosis. Exams were compared to additional MRI brain scans completed one year later so that researchers could examine them for signs of cerebral small-vessel disease, large-artery stenosis and arterial widening. Participants also underwent clinical and cognitive assessments.
Large-artery stenosis and elongated or widened basilar arteries were present in 20.5% and 15.7% of participants, respectively. The group did not observe a significant relationship between large-artery stenosis and lacunar strokes, but they did note strong associations between basilar artery dolichoectasia and these types of strokes.
In fact, patients with widened vessels were around four times more likely to experience a lacunar stroke. This finding also was linked to higher cerebral small-vessel disease scores, incident infarcts and greater progression of white matter hyperintensities over one year.
“This 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,” Wardlaw noted. “Recognizing this distinction is crucial, because it explains why conventional treatments like antiplatelet drugs are not as effective for this type of stroke and highlights the urgent need to develop new therapies that target the underlying microvascular damage.”
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She began covering the medical imaging industry for Innovate Healthcare in 2021.