Association Between Free Triiodothyronine to Free Thyroxine Ratio and Hemorrhagic Transformation After Intravenous Thrombolysis in Acute Ischemic Stroke Patients.

BACKGROUND: Hemorrhagic transformation (HT) is a critical complication following intravenous thrombolysis (IVT) in acute ischemic stroke (AIS). Emerging evidence indicates thyroid homeostasis' potential role in cerebrovascular outcomes, with the free triiodothyronine to free thyroxine (FT3/FT4) ratio demonstrating superior predictive value over isolated thyroid hormone measurements. This observational study works on elucidating the relation between pre-treatment FT3/FT4 ratios and post-thrombolytic HT occurrence in AIS populations. METHOD: The research consecutively enrolled AIS patients receiving IVT therapy between January 2020 and August 2024. Clinical information from patients was gathered, and to examine the link between the FT3/FT4 ratio and post-IVT HT, we performed both multivariate and univariate logistic regression analyses. The optimal cutoff value was identified through the ROC curve analysis. The relation between clinical outcomes in HT patients and the FT3/FT4 ratio was further assessed using correlation analysis. RESULT: A cohort of 251 patients with AIS was recruited; among them, 46 patients experienced HT following IVT. Multivariate regression analysis presented a notable correlation between the FT3/FT4 ratio and the occurrence of HT, with an OR of 0.444 [95% CI 0.209-0.946, p = 0.035]. The area under the ROC curve (AUC) of the FT3/FT4 ratio for discriminating HT from non-HT was 0.774 (95% CI 0.695-0.853, p < 0.001), with an optimal cutoff value of 0.211. Correlation analysis demonstrated that FT3/FT4 levels were negatively related to baseline NIHSS score (r = -0.317, p = 0.032), In patients with HT, the NIHSS score at 24 h following thrombolysis (r = -0.367, p = 0.012) and the mRS score at 3 months post-onset (r = -0.394, p = 0.007) demonstrated significant correlations. CONCLUSION: In patients with AIS, lower FT3/FT4 levels were found to be a potential predictive marker for HT. Nevertheless, no association was observed between FT3/FT4 levels and HT types. Moreover, lower FT3/FT4 levels were indicative of poorer clinical outcomes in HT patients.