title: Safety and efficacy of mechanical embolectomy in acute ischemic stroke: results of the MERCI trial.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Neurology, University of California, 505 Parnassus Avenue, San Francisco, CA 94143-0114, USA. smithw@neurology.ucsf.edu
authors.forename: Wade S
authors.initials: WS
authors.lastname: Smith
authors.forename: Gene
authors.initials: G
authors.lastname: Sung
authors.forename: Sidney
authors.initials: S
authors.lastname: Starkman
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Saver
authors.forename: Chelsea S
authors.initials: CS
authors.lastname: Kidwell
authors.forename: Y Pierre
authors.initials: YP
authors.lastname: Gobin
authors.forename: Helmi L
authors.initials: HL
authors.lastname: Lutsep
authors.forename: Gary M
authors.initials: GM
authors.lastname: Nesbit
authors.forename: Thomas
authors.initials: T
authors.lastname: Grobelny
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Rymer
authors.forename: Isaac E
authors.initials: IE
authors.lastname: Silverman
authors.forename: Randall T
authors.initials: RT
authors.lastname: Higashida
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Budzik
authors.forename: Michael P
authors.initials: MP
authors.lastname: Marks
mesh_terms: D000792:Angiography; D001921:Brain / Q000473:pathology; D002545:Brain Ischemia / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D002543:Cerebral Hemorrhage / Q000473:pathology; D017128:Embolectomy / Q000379:methods*; D004617:Embolism; D005500:Follow-Up Studies; D006801:Humans; D015999:Multivariate Analysis; D011446:Prospective Studies; D012044:Regression Analysis; D015424:Reperfusion; D012306:Risk; D020521:Stroke / Q000175:diagnosis / Q000601:surgery*; D017131:Thrombectomy / Q000379:methods*; D015912:Thrombolytic Therapy / Q000379:methods*; D013997:Time Factors; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D010959:Tissue Plasminogen Activator