Adenosine diphosphate-induced platelet aggregation might contribute to poor outcomes in atrial fibrillation-related ischemic stroke

Center of Pressure- and Machine Learning-based Gait Score and Clinical Risk Factors for Predicting Functional Outcome in Acute Ischemic Stroke

OBJECTIVES

To investigate whether machine learning (ML)-based center of pressure (COP) analysis for gait assessment, when used in conjunction with clinical information, offers additive benefits in predicting functional outcomes in patients with acute ischemic stroke.

STUDY DESIGN

A prospective, single-center cohort study.

SETTING

A tertiary hospital setting.

PARTICIPANTS

A total of 185 patients with acute ischemic stroke, capable of walking 10 meters with or without a gait aid by day 7 post-admission. From these patients, 10,804 pairs of consecutive footfalls were included for analysis.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The dependent variable was a three-month poor functional outcome, defined as modified Rankin scale scores ≥ 2. For independent variables, 65 clinical variables including demographics, anthropometrics, comorbidities, laboratory data, questionnaires, and drug history were included. Gait function was evaluated using a pressure-sensitive mat. Time-series COP data were parameterized into spatial and temporal variables and analyzed with logistic regression and two ML models (LightGBM, and multilayer perceptron [MLP]). We derived output GAIT scores from the best-performing model analyzed COP data, and constructed multivariable logistic regression models using clinical variables and the GAIT scores.

RESULTS

Among the included patients, 70 (37.8%) experienced unfavorable outcomes. The MLP model demonstrated the highest predictive performance with an area under the receiver operating characteristic curve (AUROC) of 0.799. Multivariable logistic regression identified age, initial National Institute of Health Stroke Scale, and initial Fall Efficacy Scale-International as associated factors with unfavorable outcomes. The combined multivariable logistic regression incorporating COP-derived output scores improved the AUROC to 0.812.

CONCLUSIONS

Gait function, assessed through COP analysis, serves as a significant predictor of functional outcome in acute ischemic stroke patients. Machine learning-based COP analysis, when combined with clinical data, enhances the prediction of poor functional outcomes.

Predicting short-term outcomes in atrial-fibrillation-related stroke using machine learning

Background

Prognostic prediction and the identification of prognostic factors are critical during the early period of atrial-fibrillation (AF)-related strokes as AF is associated with poor outcomes in stroke patients.

Methods

Two independent datasets, namely, the Korean Atrial Fibrillation Evaluation Registry in Ischemic Stroke Patients (K-ATTENTION) and the Korea University Stroke Registry (KUSR), were used for internal and external validation, respectively. These datasets include common variables such as demographic, laboratory, and imaging findings during early hospitalization. Outcomes were unfavorable functional status with modified Rankin scores of 3 or higher and mortality at 3 months. We developed two machine learning models, namely, a tree-based model and a multi-layer perceptron (MLP), along with a baseline logistic regression model. The area under the receiver operating characteristic curve (AUROC) was used as the outcome metric. The Shapley additive explanation (SHAP) method was used to evaluate the contributions of variables.

Results

Machine learning models outperformed logistic regression in predicting both outcomes. For 3-month unfavorable outcomes, MLP exhibited significantly higher AUROC values of 0.890 and 0.859 in internal and external validation sets, respectively, than those of logistic regression. For 3-month mortality, both machine learning models exhibited significantly higher AUROC values than the logistic regression for internal validation but not for external validation. The most significant predictor for both outcomes was the initial National Institute of Health and Stroke Scale.

Conclusion

The explainable machine learning model can reliably predict short-term outcomes and identify high-risk patients with AF-related strokes.

Purinergic Receptors of the Central Nervous System: Biology, PET Ligands, and Their Applications

Purinergic receptors play important roles in central nervous system (CNS). These receptors are involved in cellular neuroinflammatory responses that regulate functions of neurons, microglial and astrocytes. Based on their endogenous ligands, purinergic receptors are classified into P1 or adenosine, P2X and P2Y receptors. During brain injury or under pathological conditions, rapid diffusion of extracellular adenosine triphosphate (ATP) or uridine triphosphate (UTP) from the damaged cells, promote microglial activation that result in the changes in expression of several of these receptors in the brain. Imaging of the purinergic receptors with selective Positron Emission Tomography (PET) radioligands has advanced our understanding of the functional roles of some of these receptors in healthy and diseased brains. In this review, we have accumulated a list of currently available PET radioligands of the purinergic receptors that are used to elucidate the receptor functions and participations in CNS disorders. We have also reviewed receptors lacking radiotracer, laying the foundation for future discoveries of novel PET radioligands to reveal these receptors roles in CNS disorders.

Sanhuang Xiexin decoction promotes good functional outcome in acute ischemic stroke

OBJECTIVES

To explore the efficiency and safety of Sanhuang Xiexin decoction in the treatment of acute ischemic stroke (AIS) patients after endovascular intervention examination.

METHODS

In this prospective observational study, 121 AIS patients admitted in our hospital were enrolled from January 2012 to December 2015. They were randomly divided into two groups, 61 patients received Sanhuang Xiexin decoction + basic treatment (SX group) and 60 patients received basic treatment (control group). The prescription of Sanhuang Xiexin decoction was taken in the SX group, with one dose (100 ml), twice a day for 7 days orally. For all patients, blood samples were drawn on the first morning and sixth morning after endovascular intervention examination under fasting state for Fib (fibrinogen), PAgT (platelet aggregation test), CRP (C-reactive protein), and TMAO (trimethylamine oxide) tested. Estimate the changes in plasma Fib, PAgT, CRP, and TMAO levels and the syndrome of fire-heat scores.

RESULTS

The plasma Fib, PAgT, CRP, and TMAO levels in the SX group were significantly lower than those in the control group (P_Fib  < 0.01, P_PAgT  < 0.01, P_CRP  = 0.02, P_TMAO  < 0.01). The syndrome of fire-heat scores in the SX group was significantly lower than that in the control group (p < 0.01). The incidences of ischemic cerebrovascular events within 3 and 6 months after endovascular intervention treatment in the SX group were lower than those in the control group (P_3 month  = 0.04, P_6month  = 0.03).

CONCLUSIONS

The prescription of Sanhuang Xiexin is efficient and safe in the treatment of AIS patients after endovascular intervention examination through reducing the inflammatory factors.

Effect of apixaban compared with warfarin on coagulation markers in atrial fibrillation

Objectives

Compare the effect of apixaban and warfarin on coagulation and primary haemostasis biomarkers in atrial fibrillation (AF).

Methods

The biomarker substudy from the Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation trial included 4850 patients with AF randomised to treatment with apixaban or warfarin. Sixty per cent of patients used vitamin K antagonist (VKA) within 7 days before randomisation. Prothrombin fragment 1+2 (F1+2), D-dimer, soluble CD40 ligand (sCD40L) and von Willebrand factor (vWF) antigen were analysed at randomisation and after 2 months of study treatment.

Results

In patients not on VKA treatment at randomisation, F1+2 and D-dimer levels were decreased by 25% and 23%, respectively, with apixaban, and by 59% and 38%, respectively, with warfarin (p<0.0001 for treatment differences for both). In patients on VKA at randomisation, F1+2 and D-dimer levels increased by 41% and 10%, respectively, with apixaban and decreased by 37% and 11%, respectively, with warfarin (p<0.0001 for treatment differences for both). sCD40L levels were slightly increased at 2 months, regardless of VKA or randomised treatment. Apixaban and warfarin also both reduced vWF antigen regardless of VKA treatment. The efficacy (stroke) and safety (bleeding) of apixaban compared with warfarin was similar irrespectively of biomarker levels at 2 months.

Conclusions

Treatment with apixaban compared with warfarin for stroke prevention in patients with AF was associated with less reduction in thrombin generation and fibrin turnover. This effect of apixaban could contribute to the clinical results where apixaban was superior to warfarin both in stroke prevention and in reducing bleeding risk.

Trial registration number

NCT00412984.

Insulin resistance in ischemic stroke

Insulin resistance often refers to a pathological condition in which cells fail to respond to the normal actions of insulin. Increasing literature has noted a critical role of insulin resistance in the pathogenesis of ischemic stroke. Insulin resistance plays an important role in the pathogenesis of ischemic stroke via enhancing advanced changes of atherosclerosis. A variety of literature indicates that insulin resistance enhances platelet adhesion, activation and aggregation which are conducive to the occurrence of ischemic stroke. Insulin resistance also induces hemodynamic disturbances and contributes to the onset of ischemic stroke. In addition, insulin resistance may augment the role of the modifiable risk factors in ischemic stroke and induce the occurrence of ischemic stroke. Preclinical and clinical studies have supported that improving insulin resistance may be an effective measure to prevent or delay ischemic stroke.

Antiplatelet Therapy Combinations and Thrombogenicity in Patients with Non-Valvular Atrial Fibrillation

BACKGROUND AND OBJECTIVES

Combination antiplatelet therapy reduces the risk of ischemic stroke compared with aspirin monotherapy in non-valvular atrial fibrillation (NVAF) patients. The underlying mechanism, however, remains unclear. In addition, the association between platelet inhibition and thrombogenicity in NVAF has not been evaluated.

SUBJECTS AND METHODS

We randomized 60 patients with NVAF that were taking 100 mg of aspirin daily (>1 month) to adding 75 mg of clopidogrel daily (CLPD group), 100 mg of cilostazol twice daily (CILO group), or 1000 mg of omega-3 polyunsaturated fatty acid twice daily (PUFA group). Biomarkers (von Willebrand factor antigen [vWF:Ag], fibrinogen, D-dimer, and high-sensitivity C-reactive protein [hs-CRP]) and platelet reactivity (PR), which were the levels stimulated by adenosine diphosphate (ADP), thrombin-receptor agonist peptide, collagen, and arachidonic acid, were measured at baseline and 30-day follow-up.

RESULTS

Combination antiplatelet therapy significantly reduced vWF:Ag and fibrinogen levels (7.7 IU/dL, p=0.015 and 15.7 mg/dL, p=0.005, respectively), but no changes were found in D-dimer and hs-CRP levels. The CLPD and CILO groups showed fibrinogen and vWF:Ag level reductions (24.9 mg/dL, p=0.015 and 9.3 IU/dL, p=0.044, respectively), whereas the PUFA group did not show any differences in biomarkers. Irrespective of regimen, the changes in fibrinogen and vWF:Ag levels were mainly associated with the change in ADP-mediated PR (r=0.339, p=0.008 and r=0.322, p=0.012, respectively).

CONCLUSION

In patients with NVAF, combination antiplatelet therapy showed reductions for vWF:Ag and fibrinogen levels, which may be associated with the inhibitory levels of ADP-mediated PR. The clinical implications of these findings need to be evaluated in future trials.

Total adiponectin is inversely associated with platelet activation and CHA₂DS₂-VASc score in anticoagulated patients with atrial fibrillation

Background. Adiponectin (APN) possesses anti-inflammatory and antiatherogenic effects. Atrial fibrillation (AF) is burdened by enhanced systemic inflammation and platelet activation, as documented by increased blood levels of soluble CD40L (sCD40L). The interplay between APN and platelet activation in AF is still undefined. Materials and Methods. Circulating levels of APN and sCD40L were measured in 257 anticoagulated nonvalvular AF patients. Exclusion criteria were as follows: prosthetic heart valves, cardiac revascularization in the previous year, severe cognitive impairment, chronic infectious or autoimmune diseases, and active cancer. Results. Mean age was 72.9 (±8.7) years and 41.6% were female. Serum APN and plasmatic sCD40L were inversely correlated (R −0.626, P < 0.001). A progressive increase of sCD40L across tertiles of CHA₂DS₂-VASc score was observed (rS 0.473, P < 0.001), whilst APN was inversely correlated (rS −0.463,  P < 0.001). A multivariable linear regression analysis showed that CHA₂DS₂-VASc score (B −0.227, P < 0.001) and sCD40L (B −0.524, P < 0.001) correlated to APN. Conclusions. AF patients at high risk of stroke disclose low and high levels of APN and sCD40L, respectively, suggesting a role for APN if it favors platelet activation in vivo in this clinical setting. Enhancing APN levels may be a future goal to reduce the risk of vascular outcomes in AF patients.