Thrombocytopenia and In-hospital outcomes in patients with acute ischemic stroke undergoing intravenous thrombolysis: Findings from a nationwide registry study in China

Background and Objective Our study aimed to evaluate the associations between platelet count (PC) and in-hospital outcomes for patients with stroke after rt-PA intravenous thrombolysis. Methods We identified patients who had been hospitalized with a primary diagnosis of stroke and had received rt-PA intravenous thrombolysis from June 2015 to July 2019 at participating hospitals in the Chinese Stroke Center Alliance. PC measured before intravenous thrombolysis was categorized into the following four groups: severe thrombocytopenia (PC<100 × 109/L), mild thrombocytopenia (100≤PC<150 × 109/L), normal PC (150≤PC≤450 × 109/L), and thrombocythemia (PC>450 × 109/L). Outcomes were determined from clinical data collected during hospitalization. The primary clinical outcome was symptomatic intracranial hemorrhage (sICH). Secondary outcomes were mortality, bleeding events, gastrointestinal (GI) hemorrhage, and in-hospital stroke recurrence. We used multivariate logistic regression models to evaluate the associations between PC and outcomes. Results We included 44,882 individuals with a median age of 66 years, of whom 34.7% were female, 951 (2.1%) had severe thrombocytopenia, 7218 (16.1%) had mild thrombocytopenia, 36,522 (81.4%) had a normal PC, and 191 (0.4%) had thrombocythemia. Both severe and mild thrombocytopenia groups had higher risks of bleeding events (adjusted OR 1.30; 95% CI,1.01-1.67; p= 0.045; adjusted OR 1.32; 95% CI,1.19-1.46; p<0.001) and sICH (adjusted OR 1.48;95% CI,1.13-1.94; p=0.005; adjusted OR 1.43;95% CI,1.27-1.60; p<0.001) than the normal PC group. Patients with 100≤PC<150 × 109/L also had a higher risk of in-hospital stroke recurrence (adjusted OR 1.12; 95% CI,1.02-1.22; p=0.02). Conclusions Intravenous thrombolysis brings a high risk of sICH given PC<150 × 109/L, especially PC<100 × 109/L. It indicated that PC<100 × 109/L is a reasonable contraindication to thrombolysis.