title: Histopathological effects of delayed reperfusion after middle cerebral artery occlusion in the anesthetized baboon.
abstract: In patients with middle cerebral artery (MCA) territory stroke, attempts to recanalize the brain are currently being extended beyond the classic 3-h time window. Mechanical thrombectomy is particularly attractive as it may carry lesser risks of severe hemorrhagic transformation than thrombolysis. However, whether late reperfusion per se promotes hemorrhagic transformation and increases infarct volume as compared to permanent occlusion is unclear. There is no study of the histopathologic sequelae of late reperfusion following MCA occlusion (MCAo) in the non-human primate. Five young adult baboons completed a specially designed protocol of 20-h MCAo (under etomidate anaesthesia), followed by 4-week survival and finally perfusion-fixation. Infarct volume was measured histologically using validated stereological methods. The results were compared to our previously published series of 6 h and permanent MCAo performed with identical experimental and post mortem procedures. An infarct was present in each baboon, consistently involving the caudate head, internal capsule and putamen; the adjacent inferior frontal cortex was involved in one subject. Infarct volume was significantly larger than with 6 h MCAo, as expected, but did not differ from permanent MCAo. There was no evidence of hemorrhage around the infarcted area in any animal. We found that following a 20 h ischemic episode, the infarct volume was similar to that found with permanent occlusion, with no evidence of hemorrhagic transformation. Cautiously extrapolating to the human situation, our findings suggest that even late mechanical recanalization may not promote brain damage and could be considered in selected cases.
authors.affiliation: INSERM U 320 and INSERM E 0218, Centre CYCERON, University of Caen, France.
authors.forename: Cyrille
authors.initials: C
authors.lastname: Giffard
authors.forename: Alan R
authors.initials: AR
authors.lastname: Young
authors.forename: Florence
authors.initials: F
authors.lastname: Mézenge
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Derlon
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Baron
mesh_terms: D000758:Anesthesia; D000818:Animals; D020520:Brain Infarction / Q000209:etiology / Q000473:pathology*; D004195:Disease Models, Animal; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D048530:Papio anubis; D015424:Reperfusion; D013194:Staining and Labeling; D013997:Time Factors