Evaluation of sex differences in acid/base and electrolyte concentrations in acute large vessel stroke

Ischemic stroke is the one of the most severe and debilitating diseases, and despite animal models, there is much to learn about the neuropathology in humans in a way that could inform the development of therapies. We have developed a protocol to collect and evaluate arterial blood immediately distal and proximal from the removed intracranial thrombus during mechanical thrombectomy. These samples provide a unique resource in evaluating acute changes in acid/base and electrolyte concentrations at the time of ischemic stroke. The purpose of this study was to compare acid/base and electrolytes obtained proximal and distal to the occluded intracranial thrombi between male and female acute ischemic stroke subjects at the time of thrombectomy; and to determine whether arterial blood gas values predict outcomes in male and female subjects.

We analyzed the first 49 subjects (age = 67 ± 15.0, 21 males) in the BACTRAC registry. We compared arterial blood gas of blood distal versus proximal to the thrombus during thrombectomy which provided acid/base levels (pH, pCO₂, pO₂, BD, HCO₃^-) and electrolyte values (iCa²⁺, K⁺, and Na⁺). Comparisons were evaluated by one-way repeated measures ANOVA (p < .05). Moderated multiple regression with an interaction term of sex determined predictors of infarct volume, edema volume, and infarct time.

In general, distal intracranial luminal blood sample showed a compensated metabolic acidosis with an elevated oxygen concentration in both blood samples. Analysis indicated several significant differences in the proximal blood samples between sexes (pH, pCO₂, and K⁺). Bicarbonate and base deficit were predictors of infarct time specifically in female subjects.

Acid/base and electrolyte response to ischemic conditions differ between men and women, and these early changes could be used to predict local acid/base changes and how they develop differently in men and women during ischemia. These findings provide a novel insight into the pathology of large vessel stroke in humans, particularly potential variations based on sex.