Aspiration thrombectomy failed to improve on thrombolytic therapy alone for treatment of ischemic stroke with large thrombi, the THERAPY trial showed.
The rate of functional independence at 90 days was no different with the endovascular Penumbra system added to IV tissue plasminogen activator (tPA) than with the drug alone (38% versus 30%, OR 1.4, 95% CI 0.6-3.3), reported J Mocco, MD, of New York’s Icahn School of Medicine at Mount Sinai, and colleagues online in Stroke.
Rates of 90-day symptomatic intracranial hemorrhage (9.3% versus 9.7%, P=1.0) and mortality (12 versus 23.9%, P=0.18) were also similar between groups.
Nonetheless, Mocco’s group maintained that “directions of effect for all prespecified outcomes were both internally and externally consistent toward benefit,” adding that aspiration thrombectomy may still be beneficial to some patients with large vessel occlusions.
“The overall direction of the results is consistent with most other trials comparing endovascular intervention and lytics versus lytics alone for both safety and efficacy,” agreed Dharam Kumbhani, MD, of UT Southwestern Medical Center in Dallas, in an interview with MedPage Today.
Yet Kumbhani, who was not involved in the study, noted that it remains to be seen how aspiration thrombectomy compares with stent retrievers. “To the best of my knowledge, there are no large studies comparing the two methods. The updated 2015 American Heart Association/American Stroke Association guidelines recommend stent retrievers as a class I indication since the majority of studies have been performed with this method.”
Mocco’s study did show a unexpectedly good efficacy of IV tPA with alteplase (Activase) in patients with large thrombi, however.
“Despite promising early publications suggesting patients with such thrombi to be particularly resistant to intravenous-alteplase, our data do not seem to support this hypothesis. The good outcome rate in the intravenous-tPA alone cohort of THERAPY is consistent with estimates from broader cohorts of large vessel occlusion patients,” the authors wrote.
Their trial randomized 108 stroke patients to IV alteplase with or without aspiration thrombectomy, who were followed up to 90 days. Participants were eligible for inclusion if they had a large culprit thrombus measuring at least 8 mm in the intracranial internal carotid artery or middle cerebral artery on CT angiography. In addition, all patients were required to have a National Institute of Health Stroke Scale score of 8 or more on baseline.
Enrollment was cut short after presentation of the MR CLEAN study. The final decision came after other studies were published confirming the efficacy of endovascular therapy with stent retrievers, they wrote,”therefore findings are limited and their interpretations require caution.”
Mocco and colleagues pointed to other caveats of their study, including the small sample size that may have led to imbalanced groups despite randomization, as well as the limited generalizability of the data to other populations.
In addition, “the rate of intracranial hemorrhage in this trial was higher in both arms than traditionally noted in other trials, which may be related to differences in definitions to some extent,” Kumbhani said.
Dennis Martin, MD, of Scotland’s University of Edinburgh, agreed that the “obvious next step” is to compare aspiration thrombectomy against stent retrievers directly.
“However, that would depend on whether enough interventional radiologists are interested in the questions. Many may take a more eclectic approach and use the two technologies together,” Martin, who was also not part of Mocco’s investigation, toldMedPage Today.
“Given the results, it is certainly plausible that this approach may be as good, or even better than clot retrieval with a stent retriever,” he concluded.
Kumbhani added,“Another really important area of investigation is the optimal timing of use of these devices and whether they might be able to extend the therapeutic window for stroke treatment beyond 6 hours.”
The study was funded by Penumbra.
Mocco reported consulting for TSP, Cerebrotech, and Rebound Medical.
Other co-authors disclosed relationships with Stryker, Medtronic, Rapid Medical, Penumbra, Codman, Microvention, Neural Analytics, abmedica, H. Lundbeck A/S, Boehringer Ingelheim, Covidien, and Brainsgate.
Kumbhani declared receiving honoraria and grant support from the American College of Cardiology.
Mocco J, et al “Aspiration thrombectomy after intravenous alteplase versus intravenous alteplase alone” Stroke 2016; DOI: 10.1161/STROKEAHA.116.013372.