ASTER2: Aspiration Adds Little to Retriever Thrombectomy

Damian McNamara

June 04, 2019

MILAN — A combination of contact aspiration and stent retriever techniques for thrombectomy following acute cerebral infarction did not significantly improve patient outcomes compared with use of a stent retriever alone.

At the primary endpoint of 3 months, researchers reported successful recanalization among 65% of participants receiving a combined approach compared with 58% of patients in the stent retriever only group.

"This is the first independent, large randomized controlled trial focusing on combined contact aspiration and stent retriever techniques with blinded assessment data," Bertrand Lapergue, MD, PhD, of the Division of Neurology, Stroke Center, Foch Hospital, University of Versailles Saint-Quentin-en-Yvelines, Suresnes, France, said during a media briefing here at the 5th European Stroke Organisation Conference (ESOC) 2019.

Lapergue and colleagues defined success as a modified thrombolysis in cerebral infarction score (mTICI) of 2c or 3, indicating majority or complete reperfusion.

"The ASTER2 trial shows no statistical difference between combined techniques and stent retriever [alone] as a front-line thrombectomy approach," he told Medscape Medical News. "There is no evidence to date to support using a 'maximalist approach' for all patients."

Because of the similar findings, Lapergue suggested clinicians use their judgment. "Choose the strategy you trust and do it quickly," he said when presenting the findings during a packed large clinical trial session at the conference.

The initial Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) trial showed that removing a blood clot using negative pressure aspiration was just as effective as using a stent retriever, as previously reported by Medscape Medical News.

More recently, ASTER2 trial researchers evaluated a combination approach because "there is some evidence that combined techniques could be better than a stent retriever alone — providing more stability and more effectiveness to trap the clot on the first pass," he said. "But there is no data on this strategy in a randomized controlled trial."

The researchers conducted the prospective multicenter ASTER2 trial at 11 centers in France from October 2017 to May 2018. They enrolled 408 adults admitted with a suspected anterior circulation ischemic stroke secondary to a large vessel occlusion. Mean age was 73 years.

A total 203 randomly assigned patients received the combined interventions and another 202 received stent retriever alone in an intent-to-treat analysis. Intervention occurred within 8 hours of symptom onset. Use of a balloon guide catheter was mandatory in both groups, and researchers allowed rescue therapy.

Aiming for Perfection

The 7% point difference in mTICI 2c/3 scores at 90 days, the primary outcome, was not statistically different (65% vs 58%, P = .17).

The investigators chose the mTICI 2c/3 endpoint because it "is strongly associated with lower disability," he said.

Going forward, Lapergue believes researchers can do even better, and would like to aim for TICI 3. "Our group and others have a new target: complete recanalization," he said. Achieving this target could result in a "huge difference in outcomes."

The cohorts also showed no significant difference in modified Rankin Scale scores, a measure of disability, at 3 months.

There were no safety concerns between arms, Lapergue added.

In the future, Lapergue would like to study clot types and determine if the anatomic location of the infarct dictates the optimal approach.

A Reassuring Result

"The fact that there is no great benefit to starting with a combined approach to thrombectomy is reassuring for people doing the procedures," session co-chair Jesse Dawson, MD, consultant physician at the Institute of Cardiovascular and Medical Sciences at the College of Medical, Veterinary & Life Sciences and professor of stroke medicine at University of Glasgow, told Medscape Medical News when asked to comment.

"This means in most cases we can continue using the approach found to be so successful in many clinical trials," he added.

ASTER2 trial is an academic-driven trial sponsored by Foch Hospital in Suresnes, France, and funded by Penumbra, Stryker, Microvention, and the French Health Government. Lapergue and Dawson have disclosed no relevant financial relationships.

5th European Stroke Organisation Conference (ESOC) 2019. Presented May 22, 2019.

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