The International Stroke Conference (ISC) 2025, held in Los Angeles, unveiled pivotal findings from recent trials concerning endovascular therapy for patients with distal occlusion stroke. Both the DISTAL and DISCOUNT trials were halted prematurely due to indications of potential harm and insufficient evidence of benefit in the endovascular group. The studies sought to evaluate the efficacy of endovascular therapy in acute ischemic stroke patients with distal vessel occlusion, within a specified timeframe from symptom onset. Despite initial hopes, results showed no significant advantage over standard care, raising critical questions about the treatment's viability.
The DISTAL trial, which included 163 participants, ceased early following concerns of harm and low statistical power to demonstrate a benefit. Similarly, the DISCOUNT trial faced termination for comparable reasons. The primary outcome measured was the rate of favorable recovery, defined by a modified Rankin Scale (mRS) score of 0 or 1 at 90 days post-treatment. The trials involved patients experiencing an acute ischemic stroke due to distal vessel occlusion within six hours of symptom onset, or within 24 hours if salvageable brain tissue was detected.
Patients enrolled in the trials had a median National Institutes of Health Stroke Scale admission score of 6, reflecting moderate stroke severity. Intravenous thrombolysis was administered to 65.4% of participants prior to considering endovascular intervention. However, the anticipated benefits of endovascular therapy did not materialize. In the key outcome measurement at three months, only 60% of those receiving endovascular treatment achieved a good clinical outcome (mRS score ≤ 2), compared to 77% in the control group receiving usual care.
The incidence of symptomatic intracranial hemorrhage was notably higher in the endovascular group, affecting 5.4% of patients contrasted with 2.2% in the standard care group. These findings suggest that the risks may outweigh the benefits for this treatment modality in distal occlusion cases.
“At the current time, we need to be super careful about considering endovascular therapy in these patients with distal occlusions, especially because the DISCOUNT trial suggested possible harm,” said Mayank Goyal, MD, from the University of Calgary, Canada.
The ESCAPE-MeVO trial, another large-scale study presented at ISC 2025 and supported by grants from the Canadian Institutes for Health Research and Medtronic to the University of Calgary, echoed similar results as DISTAL. Both trials concluded with neutral outcomes, reinforcing the lack of clear benefit from endovascular therapy for distal occlusions.
“The two larger trials — DISTAL and ESCAPE-MeVO — show exactly the same conclusion — a neutral outcome. This means the results are reliable,” stated Urs Fischer, MD, from University Hospital Bern, Switzerland.
“No matter how one considers these data, there is no question that they represent the current ground zero of evidence to inform decision making regarding the use of thrombectomy for stroke due to medium- and distal-vessel occlusion. The data clearly show that thrombectomy for distal-vessel occlusions should not be an assumed default care pathway,” emphasized J Mocco, MD, from Icahn School of Medicine at Mount Sinai Health System in New York.
In addressing concerns over the timing and efficacy of reperfusion during these trials, Michael Hill, MD, MSc, from the University of Calgary noted:
“No one doubts that better reperfusion leads to better outcomes. In the DISTAL and ESCAPE trials reperfusion rates were around 72-75% in the endovascular arms — there is scope for improvement here which could be dependent on new devices and improved operator skills.”
Despite these findings, researchers remain cautiously optimistic about future possibilities.
“I don’t think this is the end of the story," Urs Fischer remarked.
Mayank Goyal also expressed hope for future advancements despite current challenges:
“Perhaps a phoenix can rise out of the ashes.”
“These trials of distal occlusions can be very difficult to perform as there can be huge heterogeneity in terms of the area of the brain affected. There is no obvious subgroup that shows a benefit at the moment, but we are planning to merge all the data together from the three studies that will enable a more detailed look at subgroups,” he added.
Currently, a fourth Chinese trial is underway exploring endovascular therapy for distal occlusion stroke patients. This ongoing research may provide further insights into potential subgroup benefits or alternative strategies that could enhance clinical outcomes.
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