Search

Spin‐transfer torque (STT) and spin‐orbit torque (SOT) form the core of spintronics, allowing for the control of magnetization through electric currents. While the sign of SOT can be manipulated through material and structural engineering, it is conventionally understood that STT lacks a degree of freedom in its sign. However, this study presents the first demonstration of manipulating the STT sign by engineering heavy metals adjacent to magnetic materials in magnetic heterostructures. Spin torques are quantified through magnetic domain‐wall speed measurements, and subsequently, both STT and SOT are systematically extracted from these measurements. The results unequivocally show that the sign of STT can be either positive or negative, depending on the materials adjacent to the magnetic layers. Specifically, Pd/Co/Pd films exhibit positive STT, while Pt/Co/Pt films manifest negative STT. First‐principle calculations further confirm that the sign reversal of STT originates from the sign reversal of spin polarization of conduction electrons. [ABSTRACT FROM AUTHOR]

Objectives: To investigate whether post‐stroke statin therapy reduces subsequent major vascular events in statin‐naïve patients with pretreatment low‐density lipoprotein cholesterol (LDL‐C) below the recommended target (≤70 mg/dL for atherosclerotic stroke and ≤100 mg/dL for non‐atherosclerotic stroke) at stroke onset. Methods: Patients from an ongoing stroke registry who had an ischemic stroke between 2011 and 2020 were screened. Statin naïve patients with baseline LDL‐C below the target were assessed. The effect of post‐stroke statin therapy on major vascular events (composite of recurrent stroke, myocardial infarction, and death) was investigated using weighted Cox regression analyses using stabilized inverse probability treatment weighting. Results: The baseline LDL‐C level of the 1,858 patients (mean age 67.9 ± 15.3 years, 61.4% men, 13.2% atherosclerotic stroke) included in the study was 75.7 ± 17.0 mg/dL. Statins were prescribed to 1,256 (67.7%) patients (low‐to‐moderate intensity, 23.5%; high intensity, 44.1%). Post‐stroke statin therapy was associated with a lower risk of major vascular events during 1‐year follow‐up (weighted hazard ratio 0.55, 95% confidence interval 0.42–0.71). In a subgroup of patients who were at very high risk of atherosclerotic cardiovascular disease with LDL‐C <55 mg/dL or patients who were not at very high risk of atherosclerotic cardiovascular disease with LDL‐C <70 mg/dL, post‐stroke statin therapy was also associated with a reduction in major vascular events (weighted hazard ratio 0.45, 95% confidence interval 0.29–0.70). The intensity of the most beneficial statin varied by subtype of stroke. Interpretation: Statin therapy may improve vascular outcomes after ischemic stroke, even in cases of LDL‐C below the target without pre‐stroke lipid‐lowering therapy. ANN NEUROL 2024;95:876–885 [ABSTRACT FROM AUTHOR]

Objective: We evaluated the efficacy of endovascular thrombectomy (EVT) on the functional outcome of patients with acute basilar artery occlusion and low posterior circulation acute stroke prognosis early computed tomography score (PC‐ASPECTS). Methods: We identified patients with acute ischemic stroke due to basilar artery occlusion and PC‐ASPECTS of 6 or less, presenting within 24 h between August 2008 and April 2022. The primary outcome was a favorable functional outcome, defined as a modified Rankin Scale (mRS) score of 0–3 at 90 days. The secondary outcomes included an mRS score of 0–2, a favorable shift in the ordinal mRS scale, the occurrence of symptomatic intracranial hemorrhage (sICH), and mortality at 90 days. We compared the outcome of patients treated with EVT and those without EVT, using the inverse probability of treatment weighting methods. Results: Out of 566 patients, 55.5% received EVT. In the EVT group, 106 (33.8%) achieved favorable outcomes, compared to 56 patients (22.2%) in the conservative group. EVT significantly increased the likelihood of achieving a favorable outcome compared to conservative treatment (relative risk [RR] 1.39, 95% confidence interval [CI], 1.11–1.74, p = 0.004). EVT was associated with a favorable shift in the mRS (RR 1.85, 95% CI, 1.49–2.29, p < 0.001) and reduced mortality without an increase in the risk of sICH. It did not have an impact on achieving an mRS score of 0–2. Interpretation: Patients with acute basilar artery occlusion and a PC‐ASPECTS of 6 or less might benefit from EVT without an increasing sICH. ANN NEUROL 2024;95:788–799 [ABSTRACT FROM AUTHOR]

Introduction: Patients with atrial fibrillation-related stroke (AF-stroke) are prone to developing rapid ventricular response (RVR). We investigated whether RVR is associated with initial stroke severity, early neurological deterioration (END) and poor outcome at 3 months. Methods: We reviewed patients who had AF-stroke between January 2017 and March 2022. RVR was defined as having heart rate >100 beats per minute on initial electrocardiogram. Neurological deficit was evaluated with National Institutes of Health Stroke Scale (NIHSS) score at admission. END was defined as increase of ≥2 in total NIHSS score or ≥1 in motor NIHSS score within first 72 h. Functional outcome was score on modified Rankin Scale at 3 months. Mediation analysis was performed to examine potential causal chain in which initial stroke severity may mediate relationship between RVR and functional outcome. Results: We studied 568 AF-stroke patients, among whom 86 (15.1%) had RVR. Patients with RVR had higher initial NIHSS score (p < 0.001) and poor outcome at 3 months (p = 0.004) than those without RVR. The presence of RVR [adjusted odds ratio (aOR) = 2.13; p = 0.013] was associated with initial stroke severity, but not with END and functional outcome. Otherwise, initial stroke severity [aOR = 1.27; p = <0.001] was significantly associated with functional outcome. Initial stroke severity as a mediator explained 58% of relationship between RVR and poor outcome at 3 months. Conclusion: In patients with AF-stroke, RVR was independently associated with initial stroke severity but not with END and functional outcome. Initial stroke severity mediated considerable proportion of association between RVR and functional outcome. [ABSTRACT FROM AUTHOR]

Background and Purpose: Endovascular thrombectomy (EVT) has benefits in selected patients 6–24 h after stroke onset. However, the response to EVT >24 h after stroke onset is still unclear. We compared the early response to EVT in patients with different time windows. Methods: Patients who underwent EVT in an emergency setting were enrolled and categorized according to when EVT was performed: within 6 (early), 6–24 (late), and >24 h (very late) after stroke onset. Early neurological improvement (ENI) and deterioration (END) were defined as improvement and worsening, respectively, of National Institutes of Health Stroke Scale (NIHSS) score by ≥4 points after EVT. The three groups' clinical characteristics and response to EVT were compared. We also investigated factors associated with ENI and END. Results: During study period, 274 patients underwent EVT (109 early, 104 late, and 61 very late). Patients who underwent EVT very late were younger (p = 0.007), had smaller ischemic cores, and had lower initial NIHSS scores (8 ± 5) than those who underwent EVT early (14 ± 6) and late (13 ± 7; p < 0.001). Stroke mechanisms also differed according to the time window (p < 0.001): cardioembolism was more common after early EVT, whereas large-artery atherosclerosis was more prevalent among patients who underwent EVT very late. ENI was significantly more common after early (60.6%) and late EVT (51.0%) than after very late EVT (29.5%; p = 0.001); however, rates of END did not differ (11.0%, 13.5%, and 4.9%, respectively). ENI was independently associated with male, higher NIHSS score, and early and late EVT. END was associated with failure of recanalization. Conclusions: ENI was more observed and associated with early and late EVT. Highly selected patients receiving very late EVT may not benefit from ENI but may still have a chance to prevent END. The occurrence of END was associated not with time window but with failure of recanalization. [ABSTRACT FROM AUTHOR]

Background: Clinical-diffusion mismatch (CDM) and perfusion-diffusion mismatch (PDM) are used to select patients for endovascular thrombectomy (EVT) in the late-window period. As CDM well reflects true penumbra, we hypothesized that patients with CDM and PDM would respond better to EVT than those with PDM only at the late-window period. Methods: Acute ischemic stroke patients who received EVT 6–24 h after stroke onset were included. PDM (perfusion-/diffusion-weighted image (DWI) lesion volume >1.8) was used to select candidates for EVT in this time-period in our center. CDM was defined according to the DAWN trial criteria. Response to EVT was compared between patients with and without CDM. Early neurological improvement (ENI) was defined as improvement >4 points on National Institutes of Health Stroke Scale (NIHSS) score 1 day after EVT. Multivariable analysis was performed to investigate independent factors associated with ENI. The correlation between DWI lesion volume and NIHSS score was investigated in those with and without CDM. Results: Among 94 patients enrolled, all patients had PDM and 44 (46.3%) had CDM. Forty-eight patients (51.1%) showed ENI. The prevalence of hypertension, initial NIHSS score, improvement in NIHSS score after EVT, and prevalence of ENI were greater in patients with CDM than those without. ENI was independently associated with onset-to-door time (odds ratio [95% confidence interval]: 0.998 [0.997–1.000]; p = 0.042), complete recanalization (23.912 [2.238–255.489]; p = 0.009), initial NIHSS score (1.180 [1.012–1.377]; p = 0.034), and the presence of CDM (5.160 [1.448–18.386]; p = 0.011). The correlation between DWI lesion volume and initial NIHSS score was strong in patients without CDM (r = 0.731) but only moderate in patients with CDM (r = 0.355). Conclusion: Patients with both CDM and PDM had a better response to late-window EVT than those with PDM only. [ABSTRACT FROM AUTHOR]