Dual Antiplatelet Therapy of Clopidogrel and Aspirin in Secondary Prevention of Ischemic Stroke: Evidence and Indications

Malignancy-associated ischemic stroke: Implications for diagnostic and therapeutic workup

BACKGROUND

Patients with malignancies have an increased risk of suffering ischemic stroke via several mechanisms such as coagulation dysfunction and other malignancy-related effects as well as iatrogenic causes. Moreover, stroke can be the first sign of an occult malignancy, termed as malignancy-associated ischemic stroke (MAS). Therefore, timely diagnostic assessment and targeted management of this complex clinical situation are critical.

FINDINGS

Patients with both stroke and malignancy have atypical ages, risk factors, and often exhibit malignancy-related symptoms and multiple lesions on neuroimaging. New biomarkers such as eicosapentaenoic acid and blood mRNA profiles may help in distinguishing MAS from other strokes. In terms of treatment, malignancy should not be considered a contraindication, given comparable rates of recanalization and complications between stroke patients with or without malignancies.

CONCLUSION

In this review, we summarize the latest developments in diagnosing and managing MAS, especially stroke with occult malignancies, and provide new recommendations from recently emerged clinical evidence for diagnostic and therapeutic workup strategies.

Population pharmacokinetic-pharmacodynamic modeling of clopidogrel for dose regimen optimization based on CYP2C19 phenotypes: A proof of concept study

Clopidogrel is an antiplatelet drug used to reduce the risk of acute coronary syndrome and stroke. It is converted by CYP2C19 to its active metabolite; therefore, poor metabolizers (PMs) of CYP2C19 exhibit diminished antiplatelet effects. Herein, we conducted a proof-of-concept study for using population pharmacokinetic-pharmacodynamic (PK-PD) modeling to recommend a personalized clopidogrel dosing regimen for individuals with varying CYP2C19 phenotypes and baseline P2Y12 reaction unit (PRU) levels. Data from a prospective phase I clinical trial involving 36 healthy male participants were used to develop the population PK-PD model predicting the concentrations of clopidogrel, clopidogrel H4, and clopidogrel carboxylic acid, and linking clopidogrel H4 concentrations to changes in PRU levels. A two-compartment model effectively described the PKs of both clopidogrel and clopidogrel carboxylic acid, and a one-compartment model of those of clopidogrel H4. The CYP2C19 phenotype was identified as a significant covariate influencing the metabolic conversion of the parent drug to its metabolites. A PD submodel of clopidogrel H4 that stimulated the fractional turnover rate of PRU levels showed the best performance. Monte Carlo simulations suggested that PMs require three to four times higher doses than extensive metabolizers to reach the target PRU level. Individuals within the top 20th percentile of baseline PRU levels were shown to require 2.5-3 times higher doses than those in the bottom 20th percentile. We successfully developed a population PK-PD model for clopidogrel considering the impact of CYP2C19 phenotypes and baseline PRU levels. Further studies are necessary to confirm actual dosing recommendations for clopidogrel.

Anticoagulation Options for Cranial Procedures: A Comparative Review of Aspirin, Plavix, and Aggrastat

Anticoagulation therapy is critical to avoiding thrombotic events in patients following cranial surgery. Although Aspirin, Plavix, and Aggrastat are used as anticoagulants for this purpose, there is no consensus on which agent is the most effective and safe. In this comparative study, we analyze the current evidence on the efficacy and safety of these three anticoagulants in the context of cranial surgeries. This review focuses on the advantages and disadvantages of each anticoagulant, such as its pharmacokinetics, indications, contraindications, and possible consequences. The outcomes of this study will help physicians choose the best anticoagulant for their patients based on individual patient characteristics and the kind of cranial procedure. Aggrastat's potential to be included as a recommended anticoagulant for cranial procedures warrants further study.

Efficacy and Safety of Anticoagulant Therapy Versus Antiplatelet Therapy in Acute Ischemic Stroke Patients with Atrial Fibrillation

The efficacy and safety of anticoagulant therapy in patients with acute ischemic stroke (AIS) and atrial fibrillation (AF) remain uncertain. This study enrolled 431 AIS and AF patients from Nanjing Drum Tower Hospital between January 2019 and December 2021 and followed for 365 days to determine the associations between anticoagulants and clinical outcomes by assessing modified Rankin Scale (mRS) score, recurrent ischemic stroke/systemic embolism (IS/SE), all-cause mortality, intracranial hemorrhage (ICH) and major bleeding. Final analysis included 400 eligible patients and divided them into antiplatelet group (n  =  191) and anticoagulant group (n  =  209). Anticoagulant therapy was associated with excellent (mRS 0-1; adjusted odds ratio (aOR), 2.63; 95% confidence interval (CI), 1.61-4.30) and favorable functional outcomes (mRS 0-2; aOR, 2.82; 95% CI, 1.69-4.70) and lower risk of all-cause mortality (adjusted hazard ratio (aHR), 0.35; 95% CI, 0.21-0.57), ICH (aHR, 0.45; 95% CI, 0.23-0.87) and major bleeding (aHR, 0.51; 95% CI, 0.28-0.94), without increasing the risk of recurrent IS/SE (aHR, 0.75; 95% CI, 0.45-1.24). In conclusion, anticoagulant therapy may be a more effective and safer option than antiplatelet therapy for AIS patients with AF.

Probing the drug delivery strategies in ischemic stroke therapy

Ischemic stroke, which is caused by a sudden clot in the blood vessels, may cause severe brain tissue damage and has become a leading cause of death globally. Currently, thrombolysis is the gold standard primary treatment of ischemic stroke in clinics. However, the short therapeutic window of opportunity limits thrombolysis utility. Secondary cerebral damage caused by stroke is also an urgent problem. In this review, we discuss the present methods of treating ischemic stroke in clinics and their limitations. Various new drug delivery strategies targeting ischemic stroke lesions have also been summarized, including pharmaceutical methods, diagnostic approaches and other routes. These strategies could change the pharmacokinetic behavior, improve targeted delivery or minimize side effects. A better understanding of the novel approaches utilized to facilitate drug delivery in ischemic stroke would improve outcomes.

Clinical significances and features of prompt brain CT scan after intracranial artery stenting: analysis of 501 cases

Cerebral hemorrhage is a serious complication of intracranial artery stenting that could be fatal without timely identification and treatment. Prompt brain CT scan would help to evaluate whether cerebral hemorrhage occurs, however, the diverse features of the CT scan immediately after stenting could influence the judgement sometimes. Therefore, we analyzed and summarized these features to help to determine the clinical significance of these CT features. The prompt CT features after stenting were classified into three types. Type I indicates that no high-density shadows. Type II indicates that high-density shadows scattered in the infarct areas and/or subarachnoid spaces without mass effect. Type III indicates high-density shadows scattered in and/or out of the infarct areas and/or subarachnoid space with obvious mass effects. Based on this classification, the patients in both Type I and II would continue the double anti-platelet treatment (DAPT) and anti-coagulation treatment, while the later need closer monitoring. However, patients in Type III must immediately withdraw the DAPT and anti-coagulation treatment with close monitoring and surgical intervention was needed when necessary. Nineteen (3.79%) patients were classified into Type III, and 5 (1.00%) of the 19 were accepted surgical intervention. Two of these patients died (0.40%). The prompt CT scan timely distinguishing the cerebral hemorrhage was necessary after intracranial artery stent angioplasty. Additionally, based on the different prompt CT features to take different therapeutic strategies after stenting would achieve better outcomes for ischemic stroke or transient ischemic stroke (TIA) patients underwent intracranial artery endovascular therapy.

Neuroprotective Efficacy of an Aminopropyl Carbazole Derivative P7C3-A20 in Ischemic Stroke

AIM

NAMPT is a novel therapeutic target of ischemic stroke. The aim of this study was to investigate the effect of a potential NAMPT activator, P7C3-A20, an aminopropyl carbazole derivative, on ischemic stroke.

METHODS

In vitro study, neuron protection effect of P7C3-A20 was investigated by co-incubation with primary neurons subjected to oxygen-glucose deprivation (OGD) or oxygen-glucose deprivation/reperfusion (OGD/R) injury. In vivo experiment, P7C3-A20 was administrated in middle cerebral artery occlusion (MCAO) rats and infarct volume was examined. Lastly, the brain tissue nicotinamide adenine dinucleotide (NAD) levels were detected in P7C3-A20 treated normal or MCAO mice.

RESULTS

Cell viability, morphology, and Tuj-1 staining confirmed the neuroprotective effect of P7C3-A20 in OGD or OGD/R model. P7C3-A20 administration significantly reduced cerebral infarction in MCAO rats. Moreover, brain NAD levels were elevated both in normal and MCAO mice after P7C3-A20 treatment.

CONCLUSIONS

P7C3-A20 has neuroprotective effect in cerebral ischemia. The study contributes to the development of NAMPT activators against ischemic stroke and expands the horizon of the neuroprotective effect of aminopropyl carbazole chemicals.