Thrombectomy Helps Large Core Strokes

Patients with large core acute ischemic strokes benefited from endovascular therapy in a Japanese randomized controlled trial, on par with outcome improvements seen in the pivotal trials for smaller infarctions.

Treatment with thrombectomy, clot aspiration, or both more than doubled the proportion of patients alive without severe disability at 90 days, reported Shinichi Yoshimura, MD, PhD, of Hyogo College of Medicine in Nishinomiya, Japan, at the American Stroke Association’s International Stroke Conference (ISC), held virtually and live in New Orleans.

Intervention for patients with an Alberta Stroke Program Early CT Score (ASPECTS) of 3 to 5 at baseline increased the proportion with a modified Rankin scale (mRS) score of 0 to 3 at 90 days to 31.0% compared with 12.7% with best medical treatment alone (relative risk [RR] 2.43, 95% CI 1.35-4.37, P=0.002).

The proportion with a 90-day mRS of 0-2 indicating good functional outcome was 14.0% versus 6.9%, respectively, with a wide confidence interval that was not statistically significantly (RR 1.70, 95% CI 0.42-6.93) in the 203-patient RESCUE-Japan LIMIT trial, which was simultaneously published in the New England Journal of Medicine.

Guidelines have recommended treating such strokes only with ASPECTS of 6 or higher, indicating smaller strokes on the 10-point scale, based on the relative two-fold increase in 90-day mRS 0-2 in such patients in the REVASCAT, MR CLEAN, and SWIFT-PRIME trials, up to a four-fold improvement in the EXTEND-IA trial.

The “magical” year when those trials emerged in 2015 changed the field dramatically but left “a big gray zone” of exclusions, including patients with a large territory of the brain already infarcted, noted Mitchell Elkind, MD, of NewYork-Presbyterian/Columbia University Irving Medical Center in New York City, who is the immediate past president of the American Heart Association.

Expanding thrombectomy use to that group is perhaps the hottest topic in the field, as evidenced by a number of ongoing randomized trials, of which this is the first to provide answers, said conference program vice-chair Tudor G. Jovin, MD, of the Cooper Neurological Institute in Camden, New Jersey.

“It looks like they benefit just as much as patients with smaller amounts of baseline infarct,” he said. “What is surprising to me is the magnitude of the benefit, which is similar to what we see in the moderate or small baseline infarcts. And it really begs the question whether we should care about the size of the baseline infarct when we take these patients for thrombectomy.”

An estimated 35% to 40% more strokes could be treated by thrombectomy if large baseline infarct patients were candidates.

A recent retrospective study of thrombectomy for extensive baseline infarcts with ASPECTS of 5 or less had suggested no benefit but a higher risk for mortality and symptomatic intracerebral hemorrhage. An accompanying editorial noted the concern about futile recanalization for brain areas beyond salvage and the potential for harm by reperfusion injury, including hemorrhage.

RESCUE-Japan LIMIT randomized adults at 45 Japanese centers within 6 hours of onset (or within 24 hours if there was DWI-FLAIR mismatch) of symptoms from internal carotid artery or M1 occlusion who didn’t have high risk of hemorrhage. Thrombolytics were used sparingly, with a similar proportion across groups (27 in the endovascular group and 29 in the medical treatment-only group).

Still, any intracerebral hemorrhage within 48 hours was elevated for the endovascular therapy arm compared with the medical treatment-only arm (58.0% vs 31.0%, RR 1.85, 95% CI 1.33-2.58).

On the other hand, symptomatic intracerebral hemorrhage was not significantly elevated, though still numerically more common at 9.0% versus 4.9%, respectively (RR 1.84, 95% CI 0.64-5.29).

“Our field has picked off that low-hanging fruit if you will — the patients with small area of infarcted brain, big area of hypoperfusion — but perhaps most of the patients we are going to face in the future don’t fit neatly into that category, so we’re going to need a lot of additional studies focused on individual patient types to move forward,” Elkind concluded at an ISC press conference he moderated.

One limitation was that the trial excluded the largest of the large core infarcts, noted Jovin at the same press conference. “But I would submit that the [ASPECTS] 0 to 1’s are fairly rare, especially in the early time window.”

Another limitation was the question of generalizability to U.S. practice, which uses more thrombolytics and less CT than MRI compared with Japan.

“This was just 200 patients but very promising results, and I hope we will see confirmation of these results by the other randomized trials that are ongoing,” Jovin added.

These trials include TESLA (estimated primary completion in July), IN EXTREMIS LASTE (slated to be fully finished this month), SELECT2 (expected to be completed in November), and TENSION (not due until at least 2023).