Low-normal free triiodothyronine and high leukocyte levels in relation to stroke severity and poor outcome in acute ischemic stroke with intracranial atherosclerotic stenosis

BACKGROUND: It is uncertain that the effect of free triiodothyronine (FT3) within normal ranges on initial severity and early functional outcomes in acute ischemic stroke (AIS) patients with Intracranial Atherosclerotic Stenosis (ICAS). The predictive values of white blood cell (WBC) and FT3 are also unclear in symptomatic ICAS (sICAS) patients. METHODS: We consecutively reviewed 848 ischemic stroke patients admitted into Xiangya Hospital within 72 h after symptom onset. sICAS was defined as AIS patient with degree of ICAS ≥50% proved by magnetic resonance angiography, computed tomography angiography or digital subtraction angiography. WBC and FT3 were assessed within 24 h after admission. Neurological severity was evaluated on admission using the National Institutes of Health Stroke Scale (NIHSS). Stroke outcomes were defined by the modified Rankin Scale (mRS) on the 14th day after admission. RESULTS: Logistic regression analysis showed that hypertension, lower FT3 and higher WBC concentrations independently associated with severe stroke [FT3 (odds ratio(OR) = 0.543, 95% confidence interval(95% CI): 0.383-0.769); hypertension (OR = 0.436, 95% CI: 0.238-0.800); WBC (OR = 1.17; 95% CI:1.041-1.316]. Besides, lower FT3, higher FT4, higher WBC and higher plasma glucose concentrations independently associated with unfavorable outcomes [FT3 (OR = 0.460; 95% CI: 0.306-0.690); FT4 (OR = 1.151; 95% CI: 1.055-1.255); WBC (OR = 1.178; 95% CI: 1.039-1.334); Plasma glucose (OR = 1.160; 95% CI: 1.002-1.342)]. CONCLUSIONS: Lower FT3 levels within normal ranges and higher WBC count are independently associated with the severity and early poor prognosis of sICAS simultaneously, FT3 and WBC count might be important biomarkers for sICAS patients.