RESUMEN
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.