ASTER: Contact aspiration comparable to stent retrievers for thrombectomy in ischemic stroke

Issue: April 2017

Contact aspiration in patients with ischemic stroke caused by large vessel occlusion may be a feasible frontline strategy for thrombectomy, according to results from the ASTER trial presented at the International Stroke Conference.

“The gold standard of ischemic stroke treatment with large vessel occlusion is mechanical thrombectomy with a stent retriever technique,” researcher Bertrand Lapergue, MD, of the Foch Hospital, University of Versailles Saint Quentin en Yvelines, in Suresnes, France, said during a press conference, noting that the rate of successful reperfusion, as defined by a modified Thrombolysis in Cerebral Infarction (TICI) score of 2b or 3, with stent retrievers is 71%. “This is good, but we need to increase the rate of successful reperfusion and full reperfusion (TICI 3).”

A direct first-pass aspiration technique, or contact aspiration (ADAPT, Penumbra), has shown promise, according to Lapergue, with data from retrospective studies suggesting it can increase reperfusion in this patient population. The strategy is a distal aspiration technique in which an operator advances a microcatheter directly in contact with the clot and then connects to an aspiration pump.

In the prospective, randomized, controlled, open-label ASTER trial, Lapergue and colleagues compared contact aspiration with a stent retriever as a frontline strategy for treatment of acute ischemic stroke. The study was conducted at eight centers in France.

A total of 381 patients with suspected ischemic anterior circulation stroke secondary to large vessel occlusion who experienced symptom onset within 6 hours were randomly assigned to thrombectomy with contact aspiration (n = 192) or stent retriever with a balloon guide catheter (n = 189). If the assigned technique failed after three attempts, another technique could be used for the procedure at the operator’s discretion.

The primary outcome was successful reperfusion, defined as a modified TICI score of 2b or 3, at the end of treatment. The secondary outcomes included successful reperfusion after the assigned treatment technique, procedural times, need for a rescue technique, complications and modified Rankin Scale score at 3 months.

At the end of the endovascular procedure, rates of successful reperfusion did not differ between patients who received the contact aspiration technique first and those who received the stent retriever procedure first (85.4% vs. 83.1%, respectively; OR = 1.2; 95% CI, 0.68-2.1; P = .53). Rates of full perfusion were also comparable (37.5% vs. 38.6%, respectively; OR = 0.95; 95% CI, 0.63-1.45; P = .82). The use of rescue therapy, however, was greater in the contact aspiration-first arm compared with the stent retriever-first arm (32.8% vs. 23.8%; OR – 1.56; 95% CI, 0.99-2.46; P = .053).

Similarly, rates of successful reperfusion after the frontline strategy alone were not significantly different between patients who received the contact aspiration technique and those who received the stent retriever procedure (contact aspiration, 63%; stent retriever, 67.7%; OR = 0.81; 95% CI, 0.53-1.24; P = .33). The same was also true for rates of full reperfusion after the frontline strategy alone (contact aspiration, 28.6%; stent retriever, 35.4%; OR = 0.73; 95% CI, 0.47-1.13; P = .15).

The researchers also found no difference between the contact aspiration and the stent retriever study arms after the total procedure in terms of new embolization (3.6% vs. 2.6%; P = .75), arterial perforation (2.6% vs. 1.6%; P = .69) and arterial dissection (2.6% vs. 1.1%; P =. 37). Results were also similar after the frontline strategy alone for rates of new embolization (3.1% vs. 2.1%; P = .58), arterial perforation (2.1% vs. 1.1%; P = .72) and arterial dissection (2.1% vs. 0.5%; P = .45).

Additionally, rates of symptomatic intracranial hemorrhage at day 1 were comparable between patients who received contact aspiration first and those who received stent retriever first (5.2% vs. 6.3%; P = .63), as were rates of new infarct at day 1 (5.3% vs. 8.5%; P = .22).

“The ASTER trial is the first independent and large randomized controlled trial focusing on a new strategy and comparing it with the gold standard,” Lapergue said. “ASTER showed no statistical difference between aspiration and stent but reports similar efficacy and safety endpoints between the two arms.”

Subgroup analyses, assessment of clinical outcomes and cost-effectiveness analyses will be presented at the European Stroke Organization Conference in May. – by Melissa Foster

Reference:

Lapergue B, et al. LB2. Presented at: International Stroke Conference; Feb. 22-24, 2017; Houston.

Disclosure: Lapergue reports receiving an unrestricted research grant from Penumbra.