Safety and Efficacy of Mechanical Embolectomy in Acute Ischemic Stroke

TLDR

The only FDA‑approved treatment for acute ischemic stroke is intravenous tPA within 3 hours of symptom onset. The study evaluated the safety and efficacy of the Merci Retriever mechanical embolectomy device for patients ineligible for tPA within 8 hours of stroke onset. In a prospective, nonrandomized multicenter trial, 151 patients ineligible for tPA underwent Merci Retriever deployment, achieving recanalization in 46% overall and 48% of those treated. Recanalization occurred in 46% of patients—significantly higher than the 18% historical control—while 7.1% experienced procedural complications and 7.8% had symptomatic hemorrhage; successful recanalization was associated with better 90‑day outcomes (46% vs 10% good mRS, 32% vs 54% mortality).

Abstract

The only Food and Drug Administration (FDA)-approved treatment for acute ischemic stroke is tissue plasminogen activator (tPA) given intravenously within 3 hours of symptom onset. An alternative strategy for opening intracranial vessels during stroke is mechanical embolectomy, especially for patients ineligible for intravenous tPA.We investigated the safety and efficacy of a novel embolectomy device (Merci Retriever) to open occluded intracranial large vessels within 8 hours of the onset of stroke symptoms in a prospective, nonrandomized, multicenter trial. All patients were ineligible for intravenous tPA. Primary outcomes were recanalization and safety, and secondary outcomes were neurological outcome at 90 days in recanalized versus nonrecanalized patients.Recanalization was achieved in 46% (69/151) of patients on intention to treat analysis, and in 48% (68/141) of patients in whom the device was deployed. This rate is significantly higher than that expected using an historical control of 18% (P<0.0001). Clinically significant procedural complications occurred in 10 of 141 (7.1%) patients. Symptomatic intracranial hemorrhages was observed in 11 of 141 (7.8%) patients. Good neurological outcomes (modified Rankin score < or =2) were more frequent at 90 days in patients with successful recanalization compared with patients with unsuccessful recanalization (46% versus 10%; relative risk [RR], 4.4; 95% CI, 2.1 to 9.3; P<0.0001), and mortality was less (32% versus 54%; RR, 0.59; 95% CI, 0.39 to 0.89; P=0.01).A novel endovascular embolectomy device can significantly restore vascular patency during acute ischemic stroke within 8 hours of stroke symptom onset and provides an alternative intervention for patients who are otherwise ineligible for thrombolytics.