Abedi, Vida

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.

Abstract Aims We developed new machine learning (ML) models and externally validated existing statistical models [ischaemic stroke predictive risk score (iScore) and totalled health risks in vascular events (THRIVE) scores] for predicting the composite of recurrent stroke or all-cause mortality at 90 days and at 3 years after hospitalization for first acute ischaemic stroke (AIS). Methods and results In adults hospitalized with AIS from January 2005 to November 2016, with follow-up until November 2019, we developed three ML models [random forest (RF), support vector machine (SVM), and extreme gradient boosting (XGBOOST)] and externally validated the iScore and THRIVE scores for predicting the composite outcomes after AIS hospitalization, using data from 721 patients and 90 potential predictor variables. At 90 days and 3 years, 11 and 34% of patients, respectively, reached the composite outcome. For the 90-day prediction, the area under the receiver operating characteristic curve (AUC) was 0.779 for RF, 0.771 for SVM, 0.772 for XGBOOST, 0.720 for iScore, and 0.664 for THRIVE. For 3-year prediction, the AUC was 0.743 for RF, 0.777 for SVM, 0.773 for XGBOOST, 0.710 for iScore, and 0.675 for THRIVE. Conclusion The study provided three ML-based predictive models that achieved good discrimination and clinical usefulness in outcome prediction after AIS and broadened the application of the iScore and THRIVE scoring system for long-term outcome prediction. Our findings warrant comparative analyses of ML and existing statistical method–based risk prediction tools for outcome prediction after AIS in new data sets.

Background: Current ischemic stroke (IS) subtyping systems are very labor-intensive and costly to implement in large samples. There is a need to develop phenotyping approaches for genetic and other studies that can be implemented using generally available items captured in electronic medical records. Objective: In this report, we seek to validate a simplified approach using results from a genetic association study. Specifically, the strength of association for known genetic signals in the NINDS Stroke Genetics Network study (SiGN) is compared between the established IS subtyping systems (TOAST and Causative Classification System (CCS) subtypes) and phenotyping based on a single item within the CCS. Methods: Non-mutually exclusive “Simple” IS subtypes were defined from single CCS items as follows: 1) Small vessel stroke- lacunar infarct on imaging (with no other imaging or other requirements); 2) large artery stroke - vascular imaging showing > 50% stenosis or <50% stenosis with plaque rupture or thrombosis judged to be due to atherosclerosis in clinically relevant artery; and 3) cardioembolic stroke - persistent or paroxysmal atrial fibrillation. We compared the GWAS signals using these definitions to the published SiGN GWAS results for TOAST and CCS, among those of European ancestry only. Results: The Table shows that, for loci significant in SiGN GWAS study, the “Simple” IS subtypes had similar strengths of association and p-values compared to results from TOAST and the causative and phenotypic CCS subtypes. Conclusions: “Simple” IS subtypes perform as well in GWAS analyses as more complex phenotyping systems and could potentially be derived through automated or semi-automated methods applied to electronic medical record systems. Since the ‘Simple” phenotypes were based on high quality CCS data, the current findings reflect optimal performance. Additional validation studies will be required for implementation in other settings.