Endovascular Therapy Eyed For Milder Strokes, Later Time Window

TL;DR

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Two randomized trials published in the New England Journal of Medicine found better functional outcomes with endovascular therapy (EVT) in selected patients with milder strokes or treatment 24 to 72 hours after symptom onset. The results also included safety concerns, including procedural complications in one trial and more symptomatic brain bleeding and deaths in the other; further trials are ongoing.

Two randomized trials in China found that endovascular therapy (EVT), a procedure to remove a clot from a blocked brain artery, was linked to better functional outcomes for selected patients with milder strokes or treatment 24 to 72 hours after symptoms began. Published in the New England Journal of Medicine, the trials also reported safety signals, so the findings do not settle who should receive EVT in these settings.

In the MILD-MT trial, 300 people with mild anterior-circulation ischemic stroke and substantial at-risk brain tissue on imaging were included in the modified intention-to-treat analysis. Participants received EVT alongside medical management or medical management alone, with treatment started within 24 hours. At 90 days, 69.4% of the EVT group had an excellent functional outcome, defined as a modified Rankin Scale score of 0 or 1, compared with 50.0% in the medical-management group. The reported odds ratio was 2.32 (95% CI 1.41-3.81).

The MILD-MT investigators reported symptomatic intracranial hemorrhage within 48 hours in three patients in each group. However, serious procedure-related complications occurred in 13.2% of EVT recipients, including arterial dissection, subarachnoid hemorrhage and embolization in a new territory. The trial also found less neurological deterioration by day seven in the EVT group: 13.9%, compared with 31.4% among those receiving medical management alone.

In LATE-MT, researchers studied patients with anterior-circulation large-vessel occlusion and imaging evidence of salvageable brain tissue 24 to 72 hours after symptom onset. EVT plus standard care was associated with better functional outcomes than standard care alone, with a common odds ratio of 1.74 (95% CI 1.19-2.55). Safety outcomes included symptomatic brain bleeding in 4.8% of EVT patients and none of the control patients; 90-day deaths were 6.0% and 1.8%, respectively.

Evidence Could Broaden Clot-Removal Use

The trials test whether EVT might help patients outside some of the established treatment situations: people whose initial stroke symptoms are mild and patients identified as having salvageable brain tissue well after the usual treatment window. The MILD-MT results also address concern that a mild initial presentation may not rule out later neurological worsening. In that trial, deterioration by day seven was less frequent with EVT.

But the results are not a blanket recommendation to treat all mild or late-presenting strokes. The functional benefits must be weighed against bleeding and procedural risks, particularly given the excess symptomatic hemorrhage and deaths reported in LATE-MT. The findings may inform future guidelines and clinical decisions, but further evidence is needed to define which patients are most likely to benefit safely.

How the Trials Extend EVT Evidence

EVT is used to reopen large blocked brain arteries in acute ischemic stroke. For nearly a decade, its established use has included anterior-circulation large-vessel occlusions treated within 24 hours of the time a patient was last known to be well. Stroke guidelines expanded eligibility earlier in 2026 to include some patients with larger ischemic cores and basilar artery occlusions, based on newer evidence.

MILD-MT enrolled patients at 26 comprehensive stroke centers in China in 2024 and 2025. Its participants had mild symptoms and imaging evidence of substantial tissue at risk. LATE-MT was conducted at 35 comprehensive stroke centers and selected patients using imaging to identify salvageable tissue 24 to 72 hours after onset. Both were multicenter, open-label randomized trials, and both compared EVT added to medical care with medical care alone.

In an accompanying editorial, Gaultier Marnat of Bordeaux University Hospital described the studies as “important advances” in efforts to test EVT in additional settings. He also cautioned that results may not apply equally across populations: the editorial said it remains unclear how patients outside Asia, where cardioembolism is a more common cause of large-vessel occlusion, will fare with EVT for mild symptoms or later treatment.

Patient Selection and Safety Remain Open

The trial findings do not establish that EVT is appropriate for every patient with mild symptoms or for every patient arriving 24 to 72 hours after a stroke. Which imaging features and clinical characteristics identify patients with a favorable balance of benefit and harm remains to be clarified. The safety findings also warrant attention: MILD-MT reported serious procedural complications, while LATE-MT recorded symptomatic bleeding and more deaths in the EVT group.

Marnat noted that some LATE-MT participants received intravenous thrombolysis despite the late treatment window and that most received anticoagulant or antithrombotic therapy within 24 hours after randomization. The editorial raised these treatments as a reason for caution, but the supplied trial report does not establish that they caused the differences in bleeding or deaths. It is also unclear how well the results will generalize to populations outside China. The report does not provide enough information to resolve those questions.

Ongoing Trials May Refine Eligibility

Further evidence is expected from the MOSTE and SELECT LATE trials, which are still underway in France and the United States, respectively. Those studies may add information about treatment for mild strokes and later-presenting patients, including whether results seen in the Chinese trials extend to other populations.

Until additional results are available, the reported trials provide evidence for continued study rather than a settled change in practice. The next key questions are which patients have salvageable tissue and a sufficiently favorable risk profile, and whether benefits and safety outcomes are consistent across different settings.

Key Questions

What is endovascular therapy?

Endovascular therapy is a procedure used to remove a clot blocking a large brain artery. In these trials, researchers tested it alongside medical care against medical care alone.

What did the trials find for mild strokes?

In MILD-MT, 69.4% of EVT patients had an excellent functional outcome at 90 days, compared with 50.0% of patients receiving medical management alone. Serious procedure-related complications occurred in 13.2% of the EVT group.

What did LATE-MT find about treatment after 24 hours?

Among selected patients with salvageable brain tissue treated 24 to 72 hours after onset, EVT was associated with better functional outcomes. The trial also reported symptomatic intracranial hemorrhage in 4.8% of the EVT group and 90-day deaths in 6.0%, compared with 1.8% in the control group.

Do these results mean all mild or late-presenting strokes should receive EVT?

No. The trials studied selected patients, and their benefits and safety risks require further evaluation. They do not establish that EVT is suitable for every person with mild symptoms or a later treatment window.

What research is expected next?

The MOSTE and SELECT LATE trials are ongoing in France and the United States. Their results may help clarify patient selection, safety and whether the findings apply in other populations.

Source: rss