Prognostic Value of Cystatin C in Acute Ischemic Stroke Patients with Intravenous Thrombolysis

Background: Less is known about the prognostic value of serum cystatin C in acute ischemic stroke (AIS) patients treated with intravenous thrombolysis (IVT). The aim of the present study was to examine the association between serum cystatin C levels and prognosis of AIS patients after IVT. Methods: Serum cystatin C was measured within 24 hours after recombinant tissue plasminogen activator (rt-PA) treatment in 280 consecutively recruited patients with AIS. The main outcomes included combination of death and major disability, death, major disability (modified Rankin Scale score 3-5) and vascular events at 3-month follow-up. Results: During the 3-month follow-up, 94 patients (33.6%) experienced death or major disability (28 deaths and 66 major disability) and 49 patients (17.5%) experienced vascular events. After multivariate adjustment, serum cystatin C was significantly associated with an increased risk of the combined outcome of death and major disability (OR=4.51, P = 0.006). Adding serum cystatin C quartiles to a model containing conventional risk factors improved the predictive power for the combined outcome of death and major disability (continuous net reclassification index 43.88%, P < 0.001; categorical net reclassification index 9.15%, P = 0.013; integrated discrimination improvement 2.31%, P = 0.025). Similar phenomena were also observed in major disability and vascular events. Conclusions: Higher levels of serum cystatin C in AIS patients after IVT were independently associated with increased risks of poor functional outcomes and vascular events, especially combining conventional risk factors, suggesting that serum cystatin C might improve risk prediction for poor prognosis in AIS patients receiving rt-PA treatment.