Rahimian, Nasrin

Background Evidence to guide the optimal timing of antiplatelet and oral anticoagulants (OACs) therapy after hemorrhagic infarction (HI) versus parenchymal hematoma (PH) is limited and inconsistent, leading to substantial variation in practice. This study's goal was to study the practice pattern and compare clinical outcomes associated with early‐versus‐delayed initiation of antiplatelet/OACs after hemorrhagic transformation (HT). Methods This multicenter, retrospective, cross‐sectional study included patients with acute ischemic stroke and HT. Patients with an HI or PH were categorized by HT to antithrombotic initiation time, and their outcomes—30‐day HT exacerbation, composite outcomes of recurrent stroke/systemic emboli, 90‐day vascular death, and functional outcomes—were compared. Results Of 748 patients, 496 received antiplatelets, and 252 received OACs after HT. The median HT‐to‐antiplatelet time was significantly shorter after HI than PH (1 [interquartile range, 0–2] versus 3 [interquartile range, 1–5] days; P <0.001). There were no statistically significant differences in HT exacerbation and composite outcomes (30‐day), as well as vascular death and unfavorable functional outcomes (90‐day), between patients who received same‐day, early (HI, <1 day; PH, <3 days), or late (HI, >1 day; PH, >3 days) antiplatelets after either HI or PH. Among patients on OACs, those with HI had shorter median HT‐to‐OAC time than PH (7 [interquartile range, 2–15] versus 15 [interquartile range, 7–32] days; P <0.001). Although HT exacerbation rates (30‐day) were comparable between early (HI, <7 days; PH, <15 days) and late (HI, >7 days; PH, >15 days) OAC initiation after either HI or PH, late initiation after PH was accompanied by higher rates of composite outcomes (30‐day) than early initiation (20.7% versus 3%; P =0.044). Regression models adjusted for demographics, National Institutes of Health Stroke Scale, and stroke severity showed no statistically significant association between early initiation of antiplatelets or OACs with HT exacerbation risk. Conclusions Our study found no statistically significant difference in HT exacerbation between early and late initiation of antiplatelets or OACs among patients with HI/PH, while prolonged delay among patients with PH were accompanied by increased systemic thromboembolic events. Although these findings offer preliminary clinical insight, prospective studies are needed.

Background: Studies have suggested that administering antithrombotics—oral anticoagulants (OACs) and antiplatelets (APLT)—after acute ischemic stroke(AIS) with hemorrhagic transformation (HT) is safe and can reduce ischemic recurrence. However, the safety of their early initiation after HT remains unclear. Method: This study utilized data from nine centers across several countries. The study population included patients with AIS who subsequently experienced HT. Patients with a specific HT type—hemorrhagic infarction(HI) or parenchymal hematoma(PH)—were categorized based on the time between HT and antithrombotic initiation, and their outcomes were compared. Outcomes included 30-day HT exacerbation and composite outcomes of recurrent stroke and systemic emboli, as well as 90-day vascular death and functional outcome. Results: Of 748 patients,496 received APLT, and 252 were prescribed OACs after HT. The median HT-to-APLT time was significantly shorter among HI patients than PH patients(1[IQR:0-2] vs. 3[IQR:1-5] days,p<0.001). The rates of 30-day HT exacerbation and composite outcomes, as well as 90-day vascular death and unfavorable functional outcomes, did not significantly differ between patients who received same-day, early (HI:<1day;PH:<3days), or late (HI:>1day;PH:>3days) APLTs after either HI or PH. Among patients who received OACs, those with HI had a significantly shorter median HT-to-OAC time than PH (7[IQR:2-15] vs. 15[IQR:7-32] days,p<0.001). However, 30-day HT exacerbation rates were comparable between early (HI:<7days;PH:<15days) and late (HI:>7days;PH:>15days) OAC initiation among patients with either HI or PH, late initiation among patients with PH was associated with higher rates of 30-day composite outcomes than early initiation(20.7% vs. 3%,p=0.044). Based on regression models adjusted for NIHSS and stroke severity, early initiation of APLTs or OACs was not associated with increased risk of HT exacerbation. Conclusion: Findings suggest that the same-day initiation of APLTs after HI or PH-1, and within 1-3days following PH-2, might not be associated with HT exacerbation or worsening outcomes. Similarly, OACs initiated 2-7days after HI and 7-15days after PH may not be associated with worsened patients' outcomes, whereas delays beyond these timeframes can be associated with higher thromboembolic risk.