Tsivgoulis, Georgios

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.

ImportancePatients with atrial fibrillation (AF) who have ischemic stroke despite taking oral anticoagulation therapy (OAT) have a very high risk of recurrence. Left atrial appendage occlusion (LAAO) is a mechanical stroke prevention strategy that may provide additional protection in patients with thromboembolic events under OAT.ObjectiveTo compare percutaneous LAAO with continuing OAT alone regarding stroke prevention in patients with AF who had a thromboembolic event despite taking OAT.Design, Setting, and ParticipantsThis cohort study was a propensity score–matched comparison of the STR-OAC LAAO cohort, an international collaboration of 21 sites combining patients from multiple prospective registries of patients who underwent LAAO between 2010 and 2022. STR-OAC LAAO cohort patients who had follow-up longer than 3 months were propensity score–matched to a previously published control cohort comprising patients from an established international collaboration of investigator-initiated prospective studies. This control cohort included patients with nonvalvular AF, recent ischemic stroke or transient ischemic attack, and follow-up longer than 3 months who were taking OAT before the index event. Analyses were adjusted for imbalances in gender, age, hypertension, diabetes, and CHA2 DS2-VASc score.ExposureLeft atrial appendage occlusion vs continuation of oral anticoagulation therapy alone (control group).Main Outcomes and MeasuresThe primary outcome was time to first ischemic stroke.ResultsFour hundred thirty-three patients from the STR-OAC LAAO cohort (mean [SD] age, 72 [9] years; 171 [39%] females and 262 [61%] males; mean [SD] CHA2 DS2-VASc score, 5.0 [1.6]) were matched to 433 of 1140 patients (38%) from the control group. During 2-year follow-up, 50 patients experienced ischemic stroke: an annualized event rate of 2.8% per patient-year in the STR-OAC LAAO group vs 8.9% per patient-year in the control group. Left atrial appendage occlusion was associated with a lower risk of ischemic stroke (hazard ratio, 0.33; 95% CI, 0.19-0.58; P &amp;lt; .001) compared with the control group. After LAAO, OAT was discontinued in 290 patients (67%), and the remaining 143 patients (33%) continued OAT after LAAO as an adjunctive therapy.Conclusions and RelevanceIn patients with nonvalvular AF and a prior thromboembolic event despite taking OAT, LAAO was associated with a lower risk of ischemic stroke compared with continued OAT alone. Randomized clinical trial data are needed to confirm that LAAO may be a promising treatment option for this population with a very high risk of stroke.

Background Initial studies investigating correlations between stroke etiology and clot composition are conflicting and do not account for clot size as determined by area. Radiological studies have shown that cardioembolic strokes are associated with shorter clot lengths and lower clot burden than non-cardioembolic clots. Objective To report the relationship between stroke etiology, extracted clot area, and histological composition at each procedural pass. Methods As part of the multi-institutional RESTORE Registry, the Martius Scarlett Blue stained histological composition and extracted clot area of 612 per-pass clots retrieved from 441 patients during mechanical thrombectomy procedures were quantified. Correlations with clinical and procedural details were investigated. Results Clot composition varied significantly with procedural passes; clots retrieved in earlier passes had higher red blood cell content (H4=11.644, p=0.020) and larger extracted clot area (H4=10.730, p=0.030). Later passes were associated with significantly higher fibrin (H4=12.935, p=0.012) and platelets/other (H4=15.977, p=0.003) content and smaller extracted clot area. Large artery atherosclerotic (LAA) clots were significantly larger in the extracted clot area and more red blood cell-rich than other etiologies in passes 1–3. Cardioembolic and cryptogenic clots had similar histological composition and extracted clot area across all procedural passes. Conclusion LAA clots are larger and associated with a large red blood cell-rich extracted clot area, suggesting soft thrombus material. Cardioembolic clots are smaller in the extracted clot area, consistent in composition and area across passes, and have higher fibrin and platelets/other content than LAA clots, making them stiffer clots. The per-pass histological composition and extracted clot area of cryptogenic clots are similar to those of cardioembolic clots, suggesting similar formation mechanisms.