SUMMARY We measured brain tissue Po 2 in the frontal and occipital cortices, mid-brain and basal ganglia in monkeys for up to 5 hours after 16 min global brain ischemia to gain some insight into those factors responsible for the selective vulnerability of the brain to ischemic anoxia. Brain tissue Po 2 measurements were made with gold microelectrodes with tip diameters of 5 to 10 nm. Reoxygenation of the different brain regions occurred at different "apparent" cerebral perfusion pressures and times postischemia. Areas of low susceptibility to ischemic brain damage, such as the frontal cortex, were not consistently reoxygenated at lower perfusion pressures or earlier postischemia than were areas of high susceptibility such as the occipital cortex, basal ganglia and midbrain. These findings support earlier observations that perfusion defects and brain histologic changes are multifocal in nature after global brain ischemia. We suggest that the selective vulnerability of the brain to ischemia is attributable to the development of regional edema and a local increase in tissue pressure during ischemia thereby decreasing cerebral perfusion pressure and leading to local perfusion defects after restoration of circulation. Also, that the selective vulnerability of the brain is attributable to variable degrees of neuronal-glial edema and regional shifts in brain water during ischemia leading to the development of local perfusion defects and the expansion of lesions from areas of high to low vulnerability.Stroke, Vol. 10, No. 1, 1979THE SELECTIVE vulnerability of the brain to ischemia-anoxia was recognized as early as 1858 by Brown-Sequard. 1 To explain this phenomenon, O. Vogt 2 and C. Vogt 3 hypothesized a greater sensitivity of neurons to "toxic factors" (i.e., pathoclisis) while Spielmeyer 4 suggested a major role of "vascular factors" such as arterial compression and vascular obstruction. Scholz 6 proposed that the selective vulnerability of the brain was due to a combination of both toxic and vascular factors.Present-day proponents of these earlier hypotheses are Ames and associates 68 (vascular factors) and Brierley and associates 9 (pathoclisis). Chiang et al. 7 showed that vascular obstruction occurred as a result of endothelial "bleb" formation, capillary "pinching" due to swollen astrocytic foot processes, and red blood cell and platelet aggregation. Brierley argued that the "no-reflow phenomenon" does not explain the selective vulnerability of the brain because so anatomically diffuse a process as vascular obstruction does not account for the frequently observed laminar destruction of cortical layers or viable neurons adjacent to dead neurons. There is little doubt that neuronal death after ischemia can occur without the no-reflow phenomenon as shown by Levy and Plum 10 but this does not preclude some role for perfusion defects in the pathogenesis of ischemic brain damage. Indeed, we" and Hossmann et al. 12 have clearly demonstrated delayed development of brain hypoperfusion within 1 hour after global brain...

Introduction: Automated CT Perfusion (CTP) technology offers the potential to distinguish irreversibly damaged tissue from “at-risk,” potentially salvageable tissue. Regional Cerebral Blood Flow (CBF) < 30% has been identified as a good predictor of infarct core on CTP. Randomized trials investigating mechanical thrombectomy for large artery occlusion (LAO) acute ischemic stroke (AIS) have excluded patients with large core infarcts. We investigated the relationship between infarct core, as predicted by CTP, compared to the gold standard of DWI MRI, after revascularization of a proximal, anterior circulation, LAO AIS. Hypothesis: CBF < 30% overestimates core infarct size compared to DWI MRI in at least one-third of patients with occlusions of the internal carotid artery (ICA) or middle cerebral artery (MCA) M1 or M2 segments treated with endovascular therapy achieving thrombolysis in cerebral infarction (TICI) grade 2b or 3. Methods: From a large healthcare system’s stroke network database, we conducted a retrospective analysis comparing infarct core (CBF < 30%; RAPID iSchemaView) and post-revascularization DWI MRI (ADC < 620cc; RAPID iSchemaView) in patients with ICA, M1, or M2 LAO AIS between November 2016 and June 2017 with TICI 2b or 3 reperfusion. Results: Over an 8-month period, 25 cases were identified with pre-treatment CTP, post-intervention MRI, and TICI 2b/3 revascularization of an ICA, M1, or M2 occlusion. Mean age was 61.1 years old and median NIHSS was 16. Mean duration from last known well time to CTP and MRI was 4.2 and 27.1 hours, respectively. Sixteen patients were treated with IV TPA and endovascular intervention, while 9 underwent only endovascular intervention. Median time to revascularization was 5.6 hours. CTP overestimated infarct size compared to follow-up MRI in 9/25 (36%) cases by an average of 17.8cc. Pearson correlation coefficient between CTP core infarct size and MRI infarct size was non-significant (r = 0.17, p = 0.41). Conclusions: Core infarct size may be overestimated by CTP in a substantial number of patients with revascularization of proximal, anterior circulation LAO AIS. Caution should be exercised when using core infarct estimation of CBF < 30% to exclude patients from endovascular therapy.

To report a single-center experience of the technical success and clinical 90-day outcomes of MT for anterior circulation ELVOs performed by interventional radiologists. Materials: A retrospective review identified 178 consecutive patients from January 2016 to March 2018 who underwent MT for anterior circulation ELVOs within 6 hours of symptom onset and initial NCCT ASPECTS 6, or presenting >6 hours but further selected with CT perfusion. Eight interventional radiologists performed the procedures. Technical and clinical outcomes were compared to the HERMES dataset. Results: Eight patients were excluded for spontaneous revascularization. The average age was 66 years versus 68 years for HER-MES. The average NIHSS was 17 for both groups. Vessel occlusions included: M1 59% (100/170) versus 69% (439/633), M2 12% (20/ 170) versus 8.0% (51/633), ICA 29% (50/170) versus 21% (133/ 633), and tandem ICA origin/M1 17% (29/170) (not reported in all trials), respectively. The overall mTICI 2b/3 reperfusion rate was 87% (148/170) versus 72% (405/633), respectively (p<0.05). The mRS 90-day outcome 0-2 rate was 40% (68/170) versus 46% (223/ 645), respectively (p¼0.14). Major procedural complications were 3.5% (6/171) including 2 ICA dissections, 1 M2 MCA air embolization, 1 MCA wire perforation, 1 femoral hematoma requiring transfusion, and 1 anaphylaxis. Symptomatic intracranial hemorrhage rate was 4.1% (7/171) versus 4.4% (28/633), respectively. Conclusions: This single-center experience describes similar technical success and 90-day outcomes for MT of anterior ELVOs by interventional radiologists to the HERMES data set.

Background and Purpose: Acute stroke patients who receive intravenous (IV) alteplase have historically remained on bedrest for the first 24 hours after infusion completion. We sought to determine the safety and feasibility of mobilizing patients with low NIHSS between 6 and 24 hours post-alteplase infusion. Methods: Patients with NIHSS ≤5 after IV alteplase infusion were included. We excluded patients also undergoing mechanical thrombectomy. Subjects were stratified into an early mobilization group and a standard care group based on nursing compliance with an early mobilization protocol. Safety endpoints included falls, neurological deterioration in NIHSS (increase of ≥ 2 points), and physiological events (defined by out-of-range vital signs). Each safety endpoint was quantified for both groups. Additionally, demographic characteristics and past medical history were compared between the groups to identify any statistically significant differences (p < 0.05). Results: Between June 2020 and April 2021, 93 acute stroke patients received IV alteplase and had an NIHSS of ≤5 following thrombolytic therapy. Of the included subjects, 54 received early mobilization while 39 did not. There were no statistically significant differences in gender, race, or past medical history between the two groups. Among safety endpoints, there were no reported instances of falls, neurological deterioration in NIHSS, or significant physiological events in either group. Conclusions: Our study demonstrates that instituting early mobilization as soon as 6 hours after alteplase infusion completion is safe and feasible mild acute stroke patients. Future studies should explore efforts to increase the number of patients who receive early mobilization and investigate functional outcomes between patients receiving early mobilization compared to standard medical care.

Introduction: Despite randomized trials demonstrating the benefit of endovascular therapy (EVT), large artery occlusion (LAO) acute ischemic stroke (AIS) remains associated with high mortality. Identifying factors associated with mortality for patients presenting with LAO AIS can assist in therapeutic decision-making and prognostication. Hypothesis: Among patients with LAO AIS, factors associated with 90-day mortality include older age, higher presenting NIHSS score, and lower final Thrombolysis in Cerebral Infarction (TICI) score. Methods: From November 2016 to April 2019, we conducted a retrospective analysis from a large healthcare system’s stroke network registry of patients presenting with ICA and/or MCA occlusions. Ninety-day mortality status from registry follow-up was corroborated with the Social Security Death Index. A multivariable logistic regression model was fitted to determine demographic and clinical characteristics associated with 90-day mortality. Results: Among 796 patients with 800 encounters, mean age was 68 years, 52% were women, mean presenting NIHSS was 14, and 97% presented within 24 hours of last known well time. Fifty-one percent were treated with EVT. Mortality rate for the entire cohort was 25%. In a univariate analysis, there were significant differences in age, gender, race, blood glucose, presenting NIHSS, hypertension, atrial fibrillation, CTP core volume, CTP delayed perfusion volume, EVT treatment, number of passes for EVT, final TICI score, and discharge mRS, between patients with and without 90-day mortality. In the multivariable model, increasing age (per 10 years, OR 1.54, 95% CI 1.20, 1.97) and higher discharge mRS (per 1 point, OR 4.47, 95% CI 3.05, 6.55) were associated with 90-day mortality. Female gender (OR 0.57, 95% CI 0.27, 1.18) and final TICI score of 2B or better (OR 0.42, 95% CI 0.18, 1.01) were protective against 90-day mortality. Conclusions: Increasing age and worse discharge functional outcome are associated with 90-day mortality after LAO AIS. Female gender and better revascularization after EVT are associated with lower mortality. Additional studies are required to refine mortality outcome prediction models for patients presenting with LAO AIS.