Background: Mechanical thrombectomy improves clinical outcomes in patients with large vessel occlusions, even with large core. Surprisingly, reduction in stroke volumes only explains a small portion of the clinical benefit of reperfusion. Secondary spreading depolarization (SD) occur frequently after stroke in the penumbra and may be another mechanism of secondary injury. We investigated whether the degree of reperfusion was associated with occurrence of SD. Methods: We assessed subjects undergoing hemicraniectomy for malignant hemispheric stroke who underwent ECoG monitoring of SD. SD was scored using standard criteria. We assessed final reperfusion status as good (TICI 3 or chronic occlusion), intermediate (TICI 2b), or poor (re-occlusion or failed reperfusion). We used a negative binomial model to assess differences between each of the three groups, adjusted for the duration of monitoring as an offset variable. Results: We identified 13 subjects who underwent successful SD monitoring after decompressive craniectomy, 4 with good reperfusion or chronic occlusion, 6 with intermediate reperfusion, and 3 with poor reperfusion. There was a highly significant difference between good reperfusion and intermediate or poor reperfusion. Incident Rate Ratio (IRR) for intermediate vs. good= 168.28, p<0.0001. Poor vs good IRR= 239.94, p<0.0001. There was no significant difference between intermediate and poor (IRR=0.07, p=0.5346). The estimated average number of SD in each group are Good- mean=0.25, 95% CI: 0.03 to 2.08. Intermediate- mean=51.53, 95% CI: 26.89 to 98.77. Poor- mean=77.80, 95% CI: 31.28 to 193.48 Conclusions: Complete reperfusion in cases of large vessel occlusion is associated with near abolition of peri-infarct SD. Given the association of SD with worse outcomes in stroke due to metabolic stress, spreading ischemia, glutamate excitotoxicity, and edema progression, the observed clinical benefits of large core thrombectomy may be due to prevention of secondary SD. These observations raise the possibility that preventing triggered secondary SD in patients with incomplete reperfusion could be an effective strategy to improve outcomes.
Carlson et al. (Thu,) studied this question.