Saccular Aneurysm No Bar to Thrombolysis in Ischemic Stroke

Megan Brooks

October 08, 2021

Intravenous thrombolysis (IVT) seems to be relatively safe for acute ischemic stroke patients who have even larger-sized saccular unruptured intracranial aneurysms (UIAs), a Finnish study suggests.

"I think there is now sufficient evidence that saccular aneurysms should not be considered a contraindication for thrombolysis," Jyri Virta, MD, PhD, with the Department of Neurosurgery and Neurology, University of Helsinki, Finland, told Medscape Medical News.

However, for stroke patients with large fusiform posterior circulation UIAs, IVT may increase the risk for aneurysm rupture, the data suggest.

"Large fusiform aneurysms can rupture after thrombolysis if the patients are treated with anticoagulants as well. Overall, patients with such unstable aneurysms pose a clinical dilemma and treatment should be optimized individually for every such patient," Virta said.

Th study was published online October 6 in Neurology.

Rupture Rare With Saccular Aneurysms

"Great strides have been made to offer IVT to as many acute stroke patients as possible. Because of lacking data, especially large intracranial aneurysms have been considered a contraindication for thrombolysis. We aimed to clarify this topic," Virta said.

The researchers determined the frequency of intracranial hemorrhage (ICH) following IVT in 3953 ischemic stroke patients treated at a comprehensive stroke center over 15 years (2005-2019).

A total of 132 (3.3 %) patients had a total of 155 UIAs (141 saccular and 14 fusiform). The mean diameter of UIAs was 4.7 mm; 18.7% measured ≥7 mm and 9.7% ≥10 mm in diameter.

None of the 141 saccular UIAs ruptured following IVT, "suggesting that thrombolysis is safe in these cases," Virta said.

He noted that IVT has been reported to be administered to acute ischemic stroke patients with 300 saccular UIAs (including patients in this study) and none of them have ruptured.

However, three patients (2.3%) with large fusiform basilar artery UIAs suffered a fatal rupture at 27 hours, 43 hours, and 19 days after thrombolysis. All three were on anticoagulation following IVT and anticoagulation took effect during the UIA rupture.

Among the total cohort, any ICH and symptomatic ICH were detected in 18.9% and 8.3% of patients, respectively.

Experts Weigh In

Reached for comment, Daniel G. Hackam, MD, PhD, with the Division of Clinical Pharmacology at Western University in London, Canada, said the study is "interesting and would suggest, at least for saccular aneurysms, that these are not a contraindication to thrombolysis in acute ischemic stroke."

"The high rate of ICH in large fusiform aneurysms would suggest that these are a true contraindication to thrombolysis in this setting. However, it would have been nice if the numbers of fusiform aneurysm were higher. They only had 14 cases of these," Hackam told Medscape Medical News.

Also weighing in on the results for Medscape Medical News, Sarah Song, MD, MPH, vascular neurologist at Rush University Medical Center in Chicago, noted that, "Overall, whenever someone has a history of an unruptured aneurysm, especially a large aneurysm, it's a pause, or a consideration, as to whether thrombolysis will be safe to the extent that we quote it will, based upon previous studies."

Given that IV tissue plasminogen activator (tPA) is the only medication approved by the US Food and Drug Administration for acute ischemic stroke, "this can put physicians in a bind when determining how to treat these patients,” said Song, an American Academy of Neurology fellow.

"This study shows that in their fairly large cohort, the rupture of a saccular aneurysm from IV tPA, even when large, was uncommon, lending credence to the fact that tPA is likely safe regardless of size of saccular aneurysm," Song noted.

"Fusiform posterior aneurysms are different in pathophysiology and in outcomes, however, which the study does well to define," she added.

The study was funded by Helsinki University Hospital. Virta, Hackam and Song have disclosed no relevant financial relationships.

Neurology. Published online October 6, 2021. Abstract

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