To determine if oxidation-reduction potential (ORP) parameters from plasma are associated with collateral circulation status in patients with middle cerebral artery (MCA) occlusions.

Collateral circulation is important in cerebral perfusion in ischemic strokes. Monitoring ORP may be useful for assessing collateral status and treatment efficacy.

This pilot study was nested within a prospective cohort study measuring ORP in peripheral venous plasma of patients with stroke symptoms. The pilot population included patients with MCA (M1/M2) occlusions treated with endovascular therapy. Two ORP parameters were examined at admission (pre-treatment), day 2 (after treatment), and discharge: static ORP (sORP, mV), an indicator of oxidative stress, and capacity ORP (cORP, uC), an indicator of antioxidant reserves. Collateral status was retrospectively graded based on Miteff’s system, categorized as good (grade 1) and reduced (grade 2 or 3). Collateral circulation was examined with clinical characteristics and ORP using chi-square tests and t-tests and an alpha=0.2.

Twelve patients were included: 8 (67%) and 4 (33%) had good and reduced collaterals, respectively. A stroke mismatch was more common with good collaterals than reduced collaterals, 75% vs. 0%, p=0.03. The average time to endovascular therapy was similar for patients with good and reduced collaterals (91(29) vs. 85(41) minutes, p=0.77). Admission sORP and cORP were comparable between groups (p=0.32 and p=0.53, respectively). On day 2, compared to good collaterals, patients with reduced collaterals had higher sORP (201(30) mV vs. 170(16) mV, p=0.04) and lower cORP (0.14(0.02) uC vs. 0.22(0.05) uC, p=0.02). Discharge sORP and cORP remained significantly worse with reduced collaterals compared to good collaterals, p=0.12, and p=0.06.

Patients with good collaterals had better redox status (sORP) and higher antioxidant capacity (cORP) after IA treatment compared to patients with reduced collaterals. This study provides preliminary evidence that ORP parameters worsen after endovascular therapy in patients with reduced collaterals.