Introduction In the setting of mechanical thrombectomy for emergent large vessel occlusion (ELVO), we have for the first time developed a protocol to collect and evaluate blood immediately distal and proximal from the removed intracranial thrombus. 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 is to compare acid/base and electrolyte differences obtained proximal and distal to the occluded intracranial thrombus in acute ischemic stroke patients.

Methods We developed the BACTRAC protocol: an IRB-approved tissue banking strategy for ELVO (clinicaltrials.gov NCT03153683). We compared arterial blood gases (ABG) of blood distal versus proximal to the thrombus during thrombectomy. Comparisons were evaluated by Paired Samples T-Tests (p<0.05).

Results We analyzed the first 24 subjects (age=65±0.54, 11 males) in the BACTRAC registry. Preliminary results demonstrate that, while pH is nonsignificant, distal blood in relation to proximal blood showed significantly lower oxygen (p=0.010), carbon dioxide (p=0.001), bicarbonate (p=0.002), ionized calcium (p=0.001), and potassium (p=0.001). Sodium concentration was significantly higher (p=0.002) in distal blood. These results suggest alterations occurring intravascularly during ischemia.

Conclusion These findings provide a novel insight into the pathology of large vessel stroke in humans, particularly in regard to identifying acute changes in acid/base balance and electrolyte concentrations that occur during stroke.

Disclosures J. Fraser: None. S. Martha: None. L. Collier: None. S. Davis: None. A. Abdulnasser: None. S. Grupke: None. K. Pennypacker: None.