Early Thrombectomy Protects the Internal Capsule in Patients With Proximal Middle Cerebral Artery Occlusion

Abstract

Background and Purpose: Proximal middle cerebral artery (MCA) occlusions impede blood flow to the noncollateralized lenticulostriate artery territory. Previous work has shown that this almost inevitably leads to infarction of the dependent gray matter territories in the striate even if perfusion is restored by mechanical thrombectomy. Purpose of this analysis was to evaluate potential sparing of neighboring fiber tracts, ie, the internal capsule. Methods: An observational single-center study of patients with proximal MCA occlusions treated with mechanical thrombectomy and receiving postinterventional high-resolution diffusion-weighted imaging was conducted. Patients were classified according to internal capsule ischemia (IC+ versus IC−) at the postero-superior level of the MCA lenticulostriate artery territory (corticospinal tract correlate). Associations of IC+ versus IC− with baseline variables as well as its clinical impact were evaluated using multivariable logistic or linear regression analyses adjusting for potential confounders. Results: Of 92 included patients with proximal MCA territory infarctions, 45 (48.9%) had an IC+ pattern. Longer time from symptom-onset to groin-puncture (adjusted odds ratio, 2.12 [95% CI, 1.19–3.76] per hour), female sex and more severe strokes were associated with IC+. Patients with IC+ had lower rates of substantial neurological improvement and functional independence (adjusted odds ratio, 0.26 [95% CI, 0.09–0.81] and adjusted odds ratio, 0.25 [95% CI, 0.07–0.86]) after adjustment for confounders. These associations remained unchanged when confining analyses to patients without ischemia in the corona radiata or the motor cortex and here, IC+ was associated with higher National Institutes of Health Stroke Scale motor item scores (β, +2.8 [95% CI, 1.5 to 4.1]) without a significant increase in nonmotor items (β, +0.8 [95% CI, −0.2 to 1.9). Conclusions: Rapid mechanical thrombectomy with successful reperfusion of the lenticulostriate arteries often protects the internal capsule from subsequent ischemia despite early basal ganglia damage. Salvage of this eloquent white matter tract within the MCA lenticulostriate artery territory seems strongly time-dependent, which has clinical and pathophysiological implications.

Predictors and Outcomes of Salvaging the Corticospinal Tract After Thrombectomy in Basilar Artery Occlusion Stroke

“…Furthermore, early initiation of EVT was linked to a higher chance of CST salvage. Of 25 patients with an onset-to-puncture time of ≤180 min, 19 (76.0%) achieved CST salvage after EVT, which is in line with the results regarding anterior circulation large-vessel occlusion stroke ( 10 ). However, these data should be interpreted with caution, as large heterogeneity exists in the infarct growth rate among patients with BAO and slow progressors may benefit from EVT beyond this time window ( 29 ).…”

“…The strong association between the CST salvage and good clinical outcomes in our study indicated that the eloquence of certain brain areas could have profound effects on outcome after EVT ( 10 , 26 ) and it could be explained by the fact that the intact CST was a predictor of independent walking after stroke ( 27 ). We found that the extent of BAO was associated with CST salvage.…”

“…The primary outcome was a 3-month good functional outcome, defined as an mRS score of 0–2 or 3 if the patients' pre-stroke mRS score was 3 (i.e., clinical recovery to the status prior to the index stroke). Secondary outcomes included 3-month good-to-moderate functional dependence (mRS score, 0–3), 3-month functional independence (mRS score, 0–2), mortality at 3 months, hemorrhagic transformation, sICH, NIHSS score at day 7 or discharge, early neurological improvement (defined as either an NIHSS score at day 7 or discharge ≤1 or a difference between the NIHSS score at day 7 or discharge and at baseline ≥8) ( 10 , 24 ), and final infarct volume. Due to the small sample size, a pre-specified multivariable model was constructed in which clinically important variables (age, sex, baseline NIHSS total score, stroke mechanism, atrial fibrillation (AF), onset-to-puncture time, modified treatment in cerebral ischemia grade, and final infarct volume) were entered as covariates, and a backward stepwise method was used for variable selection.…”

“…It travels through the cerebral crus and the anterior part of the pons that are supplied by perforators originating from the basilar trunk, which accordingly is vulnerable to BAO. Sparing the CST through reperfusion therapy was associated with improved outcomes in anterior circulation stroke, independent of overall salvage of ischemic tissues ( 9 , 10 ). Despite the encouraging result, this association has not been well-investigated in posterior circulation stroke.…”

Preserved Corticospinal Tract Revealed by Acute Perfusion Imaging Relates to Better Outcome After Thrombectomy in Stroke

“…This finding is in line with previous studies that have evidenced that CST affection in chronic stroke stages correlates with more severe persistent deficits after spontaneous recovery 15,16 and worse outcome after MT. [27][28][29][30] However, there are only a few studies that have looked at the structural state of distinct key regions of the human motor network within the first hours after symptom onset and evaluated its association with functional outcome. Preinterventional magnetic resonance imaging-derived complete infarction of basal ganglia, 31 primary motor area, and bilateral centrum semiovale 32 was associated with worse NIHSS at discharge and poor mRS at follow-up, respectively.…”