DISTAL Compares Mechanical Thrombectomy Versus Thrombolysis Alone in MDVO Stroke

February 5, 2025—The American Stroke Association (ASA) announced the presentation of the DISTAL study, which is investigating whether endovascular therapy plus best medical treatment reduces disability more than thrombolysis alone in medium distal vessel occlusion (MDVO).

The preliminary late-breaking science was presented at the ASA’s International Stoke Conference 2025 held February 5-7 in Los Angeles, California, and published online in The New England Journal of Medicine.

According to ASA, DISTAL demonstrated that mechanical thrombectomy in medium- or small-sized arteries of the brain is a safe treatment for a common type of stroke; however, it did not lessen disability more than best medical treatment (including thrombolysis, if indicated) alone.

In the ASA press release, Marios Psychogios, MD, the study’s lead author, noted that an estimated 20% to 40% of patients with ischemic stroke have an MDVO.

The DISTAL study enrollment was conducted between December 2021 and July 2024, with the final assessment completed in October 2024. The study was conducted at 55 hospitals in Switzerland, Germany, Belgium, Spain, Portugal, Italy, the Netherlands, Sweden, Israel, Finland, and the United Kingdom.

The study was composed of 543 adult patients with disabling stroke symptoms. Imaging tests confirmed an MDVO in all participants.

Patients were randomly selected to receive either standard stroke care with intravenous thrombolysis if deemed eligible or standard stroke care/intravenous thrombolysis plus endovascular treatment to remove the clot.

The effectiveness of the treatment was measured by the patient’s disability and need for assistance in daily activities 90 days after the stroke.

As outlined in the ASA press release, the study’s 90-day follow-up findings included the following:

• No significant difference in disability in patients receiving endovascular therapy plus standard medical care versus those receiving standard care alone.
• Rates of death were similar 15.5% (endovascular therapy plus standard care) versus 14% (standard care alone).
• Rates of severe symptomatic brain bleeds were 5.9% (endovascular therapy plus standard care) versus 2.6% (standard care alone).

ASA noted that the lack of added benefit was confirmed when investigators analyzed specific subsets of patients, such as those who did not receive intravenous thrombolysis and those who had more severe strokes.

The investigators are currently conducting a detailed analysis of whether endovascular therapy was more or less effective in different subgroups of participants, perhaps enabling them to identify characteristics that might be associated with a more positive outcome following the treatment, advised the ASA press release.

“Given the high and rising prevalence of ischemic strokes in aging populations, stroke in medium distal vessels represents a significant and growing health concern,” commented Dr. Psychogios in the ASA press release. “While these strokes were traditionally thought to have a favorable prognosis, findings from recent studies suggest that only half of people regain functional independence, underscoring the urgent need for more effective treatments.”

Dr. Psychogios, Head of Diagnostic and Interventional Neuroradiology at the University Hospital in Basel, Switzerland, added, “We were surprised at the overall outcome of the participants, which was worse than we anticipated based on retrospective data.”

He concluded, “While the results of the DISTAL trial might seem discouraging, we see it as a wake-up call to continue investigating treatment options for medium or distal vessel occlusion patients as outcomes appear to be more severe than expected and evidence-based effective treatment options are still lacking.”

Urs Fischer, MD, Director of Neurology at the University Hospital in Bern, Switzerland, and DISTAL Coprincipal Investigator, stated in the press release, “Endovascular therapy with the current techniques may not always provide extra benefits, so it could be worth reconsidering it as the standard treatment for medium distal vessel blockages. However, it is a safe option that can still be considered for select people on a case-by-case basis.”