Sodium Levels and Outcomes Following Endovascular Thrombectomy for Ischemic Stroke

BACKGROUND: Hyponatremia has been associated with worse outcomes in patients with ischemic stroke. Previous studies measured sodium levels at variable times after stroke onset. Patients treated with endovascular thrombectomy have sodium levels measured close to stroke onset. Our aim was to evaluate the association between admission sodium levels and outcome following endovascular thrombectomy. METHODS: Consecutive patients undergoing endovascular thrombectomy with admission sodium levels were identified from a prospective registry. The primary outcome was functional independence, defined as a modified Rankin scale score of 0, 1, or 2 at 3 months. Secondary outcomes included early neurological recovery (reduction in National Institutes of Health Stroke Scale score =8 points from baseline or score of 0-1 at 24 hours), ordinal shift of modified Rankin scale scores at 3 months, symptomatic intracranial hemorrhage, 7-day mortality, and 3-month mortality. RESULTS: A total of 710 patients were included (42.5% women; mean +/- SD age, 66.4 +/- 14.9 years). The mean +/- SD admission sodium level was 139 +/- 3 mmol/L. Multivariable logistic regression analysis demonstrated that higher admission sodium level (per 1-mmol/L increase) was an independent predictor of functional independence (odds ratio [OR], 1.06 [95% CI, 1.01-1.11]; P=0.03), early neurological recovery (OR, 1.07 [95% CI, 1.01-1.13]; P=0.02), and 3-month modified Rankin scale scores (OR, 0.94 [95% CI, 0.89-0.99]; P=0.02). The Youden optimal prognostic cutoff for functional independence was an admission sodium level of =136 mmol/L (P=0.04). There were no associations between sodium levels and symptomatic intracranial hemorrhage, 7-day mortality, or 3-month mortality. CONCLUSIONS: Admission sodium levels are an independent predictor of functional outcomes following endovascular thrombectomy. Whether admission sodium levels would be of value in decision-support tools for endovascular thrombectomy should be evaluated in future studies.