Low serum magnesium levels are associated with malignant cerebral edema after mechanical thrombectomy in patients with large vessel occlusion. 

Abstract Objective: Malignant cerebral edema (MCE) following mechanical thrombectomy (MT) is a major challenge in the management of patients with acute ischemic stroke (AIS). This study investigates the relationship between serum magnesium level and MCE after successful recanalization. Methods: Data from 190 consecutive patients who received successful recanalization due to acute anterior circulation occlusions in our institution between January 2017 and January 2020, were collected and analyzed. Baseline serum magnesium levels for all patients receiving MT were obtained prior to the MT. Based on the development of MCE, we divided patients into two groups. Univariate and multivariate analyses were performed to investigate whether Magnesium was an independent predictor of MCE. The receiver operating characteristic (ROC) curve and area under the curve (AUC) were determined. Results: Of the 190 patients, 33 (17.4%) developed MCE. Patients with MCE had lower serum magnesium levels compared to those without MCE (0.77 [0.73-0.82] vs. 0.84 [0.80-0.91], p<0.001). The multivariate logistic analysis showed that serum magnesium level (odds ratio [OR]: 0.000, 95% confidence interval [CI]: 0.000-0.051, p=0.003) was significantly associated with the development of MCE. The ROC curve analysis revealed that serum magnesium level could predict MCE with an AUC of 0.743 (95% CI: 0.641-0.846, p<0.001). Serum magnesium <0.80 mmol/L could predict MCE with a sensitivity of 82.8% and a specificity of 63.6%. Patients with lower Magnesium had a higher incidence of hypertension, higher NIHSS scores on admission, and a higher incidence of MCE. Conclusions: Low baseline serum magnesium on admission is associated with an increased risk of MCE in patients following MT. Assessing serum magnesium levels could be an important clinical tool for identifying patients at high risk for MCE.