Endovascular treatment (EVT) is the best treatment for acute ischemic stroke with large vessel occlusion (LVO) and makes it possible to analyze the blood contents from the occluded vascular compartments. In this study, we attempted to evaluate regional changes in blood gas values and electrolytes in the occluded vessels, aiming to determine whether these changes can predict outcomes in LVO patients receiving EVT.

We prospectively observed 45 consecutive ischemic stroke patients with LVO of the anterior circulation who underwent EVT. We collected the arterial blood proximal to the occlusion site before and after EVT, and the blood within the core of the occluded vascular compartment (distal to the thrombus) and evaluated the labs for blood gas values and electrolytes. Femoral samples were obtained under physiological flow conditions to represent systemic arterial blood.

Compared with the femoral arterial blood samples, significant decreases in K+, Ca2+, HCO3−, BE, HCT, tHbc, and TCO2 levels were observed in the proximal luminal blood before EVT. Decreases in K+ and Ca2+ levels were also observed in the proximal luminal blood after EVT. Proximal/femoral ratio of pH and Na+ was associated with short-term clinical outcomes at 72 hours after EVT. A higher proximal/femoral Na+ ratio was associated with successful recanalization. Further analysis after propensity score matching showed significant changes in blood gas and electrolyte among different arterial locations in ICA and MCA LVO participants. Linear regression analyses indicated that the proximal/femoral ratio of pH, Na+, pCO2, HCO3, and TCO2 before EVT were associated with decrease in NIHSS score at 72 hours in ICA-LVO group.

Obvious changes in several parameters of arterial blood gas and electrolyte from the ischemic vasculature occur during hyperacute stroke. Proximal/femoral pH and Na+ ratio before EVT may be associated with short-term clinical outcome, which deserve to be further investigated.