Does the Merci Retriever Work?

Abstract

In a decade after approval of IV rt-PA for acute stroke, treatment leads to good outcomes in less than half of patients, and hemorrhage rates have not been reduced. Recanalization improves outcome1 but is often delayed and incomplete. Devices offer the promise of rapid recanalization with a greater proportion of good outcomes and fewer hemorrhages. The Merci retrieval system was introduced with hopes of fulfilling this promise. The FDA recently approved this device for removal of thrombus from intracranial arteries in patients with stroke. Despite this approval, the question of whether the device works remains unsettled. The recently published Mechanical Embolus Removal in Cerebral Ischemia (MERCI) trial2 using the Merci retriever claims efficacy based on a recanalization rate that is greater than the spontaneous recanalization rate observed in the Prolyse in Acute Cerebral Thromboembolism (PROACT) II trial control group.3 Recanalization …