Aneurysm with a cervical artery dissection may not increase risk of stroke later

People who developed a type of aneurysm with a cervical artery dissection (a tear in the inner lining of the neck artery wall), a known cause of stroke, particularly in young adults, did not have an increased risk of stroke within the six months after diagnosis, according to a preliminary study to be presented at the American Stroke Association's International Stroke Conference 2026. The meeting is in New Orleans, Feb. 4-6, 2026, and is a world premier global event dedicated to advancing stroke and brain health science.

Cervical artery dissection (CeAD) causes about 2% of ischemic strokes overall; however, it accounts for up to 25% of strokes in adults younger than 50 years old. Cervical artery dissection occurs when there's a tear in the inner wall of an artery in the neck, and this tear can let blood leak out, forming a clot that may travel and lead to a stroke. In some cases, blood leaking through the tear in the artery wall during a dissection can create a bulge or balloon in the artery, called a dissecting aneurysm.

We have little scientific information about dissecting aneurysm, including how to best diagnose, monitor aneurysm growth and manage the health of people with dissecting aneurysms. We leveraged a large dataset from a global registry to provide a comprehensive overview of dissecting aneurysm diagnosis, monitoring and outcomes."

Muhib Khan, M.D., M.B.B.S., study author, associate professor in neurology, Mayo Clinic, Rochester, Minnesota

In the Antithrombotics for Stroke Prevention in Cervical Artery Dissection (STOP-CAD) subanalysis, researchers performed a secondary analysis of data from the STOP-CAD study, a multicenter, international study. CeAD patients were stratified for the presence of dissecting aneurysm, and researchers examined data for signs that the aneurysm was growing and to identify factors associated with dissecting aneurysm.

The analysis found:

• Dissecting aneurysm is common in people with CeAD and generally is not life-threatening in the short term (first 6 months). Of more than 4,000 participants with CeAD, about one in five (or 19%) developed a dissecting aneurysm.
• People with a dissecting aneurysm were more likely to have a history of migraines, connective tissue disorders and minor neck trauma before the dissection. These risk factors may assist clinicians in monitoring for the development of dissecting aneurysms.
• People with CeAD and dissecting aneurysms did not have a higher risk of having a stroke compared to those with CeAD but no dissecting aneurysms.
• Among those who had a dissecting aneurysm, about 10% showed growth of the aneurysm over 6 months. However, dissecting aneurysm growth also did not lead to a higher risk of stroke.

"Reassuringly, dissecting aneurysm formation was not related to hemorrhagic stroke or increased mortality either," said study co-author Zafer Keser, M.D., an associate professor in neurology at the Mayo Clinic in Rochester, Minnesota. "Our study provides important information to help health care professionals better monitor and manage patients during the first six months after diagnosis of an aneurysm."

A limitation of this study was that it relied on the review of the images by radiologists and trained neurologists; however, there was no standardized and centralized process for assessing how patients fared during the initial months after diagnosis. The analysis also looked back in time (the retrospective design) at the health information for the STOP-CAD study. A year-long study that closely follows patients over time and clearly outlines treatment methods, as well as how researchers interpret the images, would help confirm their results, researchers said.

"The study adds to existing evidence that suggests cervical artery dissections have a low risk of recurrent stroke," said former chair of the International Stroke Conference, Louise D. McCullough, M.D., Ph.D., FAHA. "Having a dissecting aneurysm may not be as scary as we initially thought. It helps us and our patients understand that although there is damage to the artery of the neck that their rate of recurrent stroke is low, and that's reassuring.

"The results could have practical implications, as well. Often, we follow these patients with a lot of imaging that we may not need to do quite as often. These results will probably give us a little bit of pause if we're thinking about doing an intervention such as placing a carotid stent - which would require chronic antiplatelets - if we know the risk of recurrent strokes in patients with dissecting aneurysms is low," said McCullough, the Roy M. and Phyllis Gough Huffington Distinguished Chair of Neurology at McGovern Medical School; chief of neurology at Memorial Hermann Hospital-Texas Medical Center and co-director of UTHealth Neurosciences, all in Houston. McCullough was not involved in the study.

Study details, background and design:

• The study included 4,008 adults (average age of 46 years; 50% were men, 50% women), including 767 participants (19%) with a dissecting aneurysm.
• Participants were 73.5% white adults, 9.2% Hispanic adults, 6% Black adults, 3.7% Asian adults and 16.9% were noted as other race.
• The Stroke Prevention in Cervical Artery Dissection (STOP-CAD) Multicenter Global Registry enrolled patients who were diagnosed with CeAD from 2010 to 2023 at 63 sites from 16 countries and followed for 6 months after diagnosis. The primary coordinating site was the Department of Neurology at the Warren Alpert Medical School of Brown University in Providence, Rhode Island.
• Clinical, imaging, management and outcomes data were collected in a centralized registry up to six months from the initial CeAD presentation in the STOP-CAD study.