Aspiration-assisted stent retrieval was noninferior to aspiration thrombectomy for the treatment of acute ischemic stroke, a randomized trial showed.
Patients assigned to aspiration thrombectomy with 3-dimensional stent retriever therapy or aspiration alone had similar degrees of recanalization, 87.2% and 82.3% getting to a modified Thrombolysis in Cerebral Infarction (mTICI) grade 2 or 3 after the procedure, respectively (difference 4.9%, 90% CI -3.6% to 13.5%), according to Adrian Siddiqui, MD, PhD, of the University at Buffalo in New York, and collaborators of the Penumbra Separator 3D study,
Within 24 hours of the procedure, device (4.1% versus 5.0%, difference -0.92%, 95% CI -6.71% to 4.88%) and procedure-related (10.2% versus 14.0%, difference -3.80%, 95% CI -12.86% to 5.27%) serious adverse events also occurred at similar rates between groups, they wrote online in JAMA Neurology.
The proportion of study participants that had a 90-day modified Rankin Scale score in the 0-2 range also was statistically indistinguishable (45.3% versus 45.8%, P>0.99).
“The present study provides class 1 evidence for the noninferiority of the 3-D stent retriever with aspiration versus aspiration alone in acute ischemic stroke.” the authors said. Their findings were consistent across subgroups.
In an accompanying editorial, Diederik Dippel, MD, PhD, of Erasmus University Medical Center in the Netherlands, emphasized that Siddiqui’s group compared aspiration-assisted stent retrieval with aspiration alone as the control.
“This is peculiar, because the evidence for aspiration as an effective treatment is not as substantial as for stent thrombectomy,” he said. “In essence, this study can be considered a noninferiority analysis comparing a novel treatment against an active control that, from a logical and scientific point of view, we are not sufficiently certain is effective.”
“Further studies should make clear in which cases aspiration or aspiration-assisted stent thrombectomy should be preferred. In our center, the default approach is stent thrombectomy, but we revert to aspiration when a large and loose cellular thrombus is suspected,” according to the editorialist.
The investigators enrolled 198 patients with large-vessel intracranial occlusions presenting presenting within 8 hours of stroke onset from 2012 to 2015 (238 additional patients were eligible but not enrolled). Study sites consisted of 25 North American centers.
Patients were eligible for the study if they had a NIH Stroke Scale (NIHSS) score of at least 8. The median baseline NIHSS score of participants ended up being 18.0.
Rates of 90-day mortality (19.4% versus 26.0% for aspiration, P=0.31) and symptomatic intracranial hemorrhage (3.1% versus 5.0%, P=0.72) showed no difference between groups, consistent with the main findings of the trial.
However, several caveats to the study are to be noted. For one, the 15% noninferiority margin may have been too lenient, Siddiqui’s group acknowledged, “because such a difference in reperfusion rates could lead to significant differences in clinical outcomes.” Inclusion of mTICI 2 patients in the primary endpoint also meant that those with less than 50% reperfusion were counted as having been successfully recanalized (recently, mTICI 2b has become the standard).
“Similar to recent randomized endovascular stroke trials, a major limitation of this study is that the participating investigators were not masked to the treatment arm,” the researchers added.
“Our challenge for the near future will be to increase the proportion of patients recovering substantially after thrombectomy,” according to Dippel. “We will have to continue evaluating new devices and improve our logistics, but we should be prepared to look beyond mechanical solutions and carefully reconsider medical approaches, such as antiplatelet and antithrombotic medication, in improving the outcome after thrombectomy.”
The study was funded by Penumbra.
Siddiqui disclosed no relevant relationships with industry.
Dippel disclosed a relevant relationship with the MR CLEAN trial, which was partly funded by the Dutch Heart Foundation and various device companies. He disclosed support from the Netherlands Cardiovascular Research Initiative, Brain Foundation Netherlands, and Stryker.