Toxic metal Burden in Intracranial Thrombi Retrieved During Mechanical Thrombectomy: An Observational Study

Background: Acute ischemic stroke caused by intracranial large vessel occlusion is associated with significant morbidity and mortality. Emerging evidence suggests that environmental exposures, including toxic metals, may be associated with cerebrovascular disease. However, the presence of toxic metals within intracranial thrombi and their relationship with clinical features of acute ischemic stroke remain largely unexplored. Materials and Methods: We conducted an observational cohort study including 59 patients with acute ischemic stroke due to large vessel occlusion treated with mechanical thrombectomy between November 2023 and April 2024. Retrieved thrombi were analyzed for aluminum, cadmium, nickel, and lead concentrations using Inductively Coupled Plasma–Mass Spectrometry. Histological and immunohistochemical analyses were performed to characterize thrombus composition. Associations between thrombus metal concentrations and clinical, radiological, and procedural variables, including NIHSS scores and first-pass recanalization, were assessed. Results: Significant correlations were observed between metals: aluminum with cadmium (r = 0.733, P < 0.001) and nickel (r = 0.558, P = 0.001). Cadmium was positively associated with first-pass recanalization (FPR) success (r = 0.648, P < 0.001), while lead correlated with National Institutes of Health Stroke Scale (NIHSS) at onset (r = 0.502, P < 0.001). In 29% of thrombi containing all 4 metals, aluminum was inversely related to NIHSS at 12 hours (r = −0.775, P < 0.001). Conclusion: This study identifies significant associations between thrombus toxic metal concentrations and clinical outcomes, suggesting that thrombus metal composition may be relevant to acute ischemic stroke characteristics.