European Stroke Prevention Study. 2. Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke

Detrimental Roles of Hypoxia-Inducible Factor-1α in Severe Hypoxic Brain Diseases

Hypoxia stabilizes hypoxia-inducible factors (HIFs), facilitating adaptation to hypoxic conditions. Appropriate hypoxia is pivotal for neurovascular regeneration and immune cell mobilization. However, in central nervous system (CNS) injury, prolonged and severe hypoxia harms the brain by triggering neurovascular inflammation, oxidative stress, glial activation, vascular damage, mitochondrial dysfunction, and cell death. Diminished hypoxia in the brain improves cognitive function in individuals with CNS injuries. This review discusses the current evidence regarding the contribution of severe hypoxia to CNS injuries, with an emphasis on HIF-1α-mediated pathways. During severe hypoxia in the CNS, HIF-1α facilitates inflammasome formation, mitochondrial dysfunction, and cell death. This review presents the molecular mechanisms by which HIF-1α is involved in the pathogenesis of CNS injuries, such as stroke, traumatic brain injury, and Alzheimer's disease. Deciphering the molecular mechanisms of HIF-1α will contribute to the development of therapeutic strategies for severe hypoxic brain diseases.

Molecular Mechanisms of Ischemic Stroke: A Review Integrating Clinical Imaging and Therapeutic Perspectives

Ischemic stroke poses a significant global health challenge, necessitating ongoing exploration of its pathophysiology and treatment strategies. This comprehensive review integrates various aspects of ischemic stroke research, emphasizing crucial mechanisms, therapeutic approaches, and the role of clinical imaging in disease management. It discusses the multifaceted role of Netrin-1, highlighting its potential in promoting neurovascular repair and mitigating post-stroke neurological decline. It also examines the impact of blood-brain barrier permeability on stroke outcomes and explores alternative therapeutic targets such as statins and sphingosine-1-phosphate signaling. Neurocardiology investigations underscore the contribution of cardiac factors to post-stroke mortality, emphasizing the importance of understanding the brain-heart axis for targeted interventions. Additionally, the review advocates for early reperfusion and neuroprotective agents to counter-time-dependent excitotoxicity and inflammation, aiming to preserve tissue viability. Advanced imaging techniques, including DWI, PI, and MR angiography, are discussed for their role in evaluating ischemic penumbra evolution and guiding therapeutic decisions. By integrating molecular insights with imaging modalities, this interdisciplinary approach enhances our understanding of ischemic stroke and offers promising avenues for future research and clinical interventions to improve patient outcomes.

Hemorrhage induced by antithrombotic agents: new insights from a real-world pharmacovigilance study

BACKGROUND

Hemorrhage represents the most common and serious side effect of antithrombotic agents. Many studies have compared the risk of bleeding between different antithrombotic agents, but analysis of time-to-onset for hemorrhage induced by these drugs is yet sparse.

METHODS

We conducted a retrospective study based on the adverse drug reaction reports on antithrombotic agents collected by the Henan Adverse Drug Reaction Monitoring Center. We assessed the reporting odds ratio to determine the disproportionate reporting signals for bleeding and the Weibull shape parameter was used to evaluate the time-to-onset data.

RESULTS

In the signal detection, crude low molecular weight heparin-hemorrhage was found as a positive signal. The hemorrhage for most antithrombotic agents was random failure profiles. In particular, the hazard of hemorrhage decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

CONCLUSION

We found that the risk of bleeding in patients taking Crude low molecular weight heparins was significantly higher compared to other antithrombotic agents, but with a small magnificence, which may be attributed to the severely irrational use of this medication under improper management. Statistics in days, results showed that the risk of bleeding decreased over time for warfarin and clopidogrel and increased for alteplase, nadroparin, and dipyridamole.

Dual Antiplatelet Therapy for the Acute Management and Long-term Secondary Prevention of Ischemic Stroke and Transient Ischemic Attack, An Updated Review

To improve the efficacy over antiplatelet monotherapy, dual antiplatelet therapy (DAPT) has been increasingly adopted in the management of non-cardioembolic stroke. For minor ischemic stroke and high-risk transient ischemic attack, the aspirin-clopidogrel combination is now recommended for acute short-term treatment, whereas aspirin-ticagrelor combination may be considered in selected patients, especially those with resistance to clopidogrel. For long-term stroke prevention, aspirin-dipyridamole combination has been used as an alternative to antiplatelet monotherapy, and aspirin or clopidogrel combined with cilostazole may be prescribed for added protection in high-risk patients. In this paper, we review the development of DAPT from a historical perspective and describe the findings from major clinical trials published up until the end of 2023. Using the 2021 American Heart Association guideline for secondary stroke prevention as a basis for our recommendations, we further discuss areas of controversy and more recent developments to provide an updated review for clinicians to consider in their daily practice.

Effect of an herbal medicine, Chunghyul-dan, on prevention of recurrence in patients with ischemic stroke: A retrospective cohort study

Research indicates that Chunghyul-dan (CHD), a herbal medicine, has an inhibitory effect on stroke recurrence in small vessel disease. Recent studies have suggested that CHD might also act on large arteries. This study aimed to verify the preventive effect of CHD on strokes of all the Trial of Org 10172 in Acute Stroke Treatment (TOAST) causative classifications. We retrospectively analyzed 2 years of medical records of patients with ischemic stroke treated with CHD, 600 mg once daily, in combination with antiplatelet or anticoagulant agents. The prevalence of stroke recurrence in 2 years was analyzed. Stroke recurrence was defined as new neurological symptoms with corresponding brain imaging results. Nine of the 202 patients (4.46%) had recurrent ischemic stroke. Four occurred within 180 days, 3 between 180 and 365 days, and 2 between 365 and 730 days. All had only 1 recurrence. The recurrence rates were 1.12%, 5%, and 5.48% for small vessel occlusion, cardioembolism, and large vessel atherosclerosis, respectively. There were no adverse effects. These results suggest that CHD could inhibit ischemic stroke recurrence of all TOAST causative categories. A randomized controlled trial is needed to confirm this hypothesis.

The Critical Role of Equilibrative Nucleoside Transporter-2 in Modulating Cerebral Damage and Vascular Dysfunction in Mice with Brain Ischemia-Reperfusion

BACKGROUND

Cerebral vascular protection is critical for stroke treatment. Adenosine modulates vascular flow and exhibits neuroprotective effects, in which brain extracellular concentration of adenosine is dramatically increased during ischemic events and ischemia-reperfusion. Since the equilibrative nucleoside transporter-2 (Ent2) is important in regulating brain adenosine homeostasis, the present study aimed to investigate the role of Ent2 in mice with cerebral ischemia-reperfusion.

METHODS

Cerebral ischemia-reperfusion injury was examined in mice with transient middle cerebral artery occlusion (tMCAO) for 90 minutes, followed by 24-hour reperfusion. Infarct volume, brain edema, neuroinflammation, microvascular structure, regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (CMRO2), and the production of reactive oxygen species (ROS) were examined following the reperfusion.

RESULTS

Ent2 deletion reduced the infarct volume, brain edema, and neuroinflammation in mice with cerebral ischemia-reperfusion. tMCAO-induced disruption of brain microvessels was ameliorated in Ent2-/- mice, with a reduced expression of matrix metalloproteinases-9 and aquaporin-4 proteins. Following the reperfusion, the rCBF of the wild-type (WT) mice was quickly restored to the baseline, whereas, in Ent2-/- mice, rCBF was slowly recovered initially, but was then higher than that in the WT mice at the later phase of reperfusion. The improved CMRO2 and reduced ROS level support the beneficial effects caused by the changes in the rCBF of Ent2-/- mice. Further studies showed that the protective effects of Ent2 deletion in mice with tMCAO involve adenosine receptor A2AR.

CONCLUSIONS

Ent2 plays a critical role in modulating cerebral collateral circulation and ameliorating pathological events of brain ischemia and reperfusion injury.

The machine learning methods to analyze the using strategy of antiplatelet drugs in ischaemic stroke patients with gastrointestinal haemorrhage

BACKGROUND

For ischaemic stroke patients with gastrointestinal haemorrhage, stopping antiplatelet drugs or reducing the dose of antiplatelet drugs was a conventional clinical therapy method. But not a study to prove which way was better. And the machinery learning methods could help to obtain which way more suit for some patients.

METHODS

Data from consecutive ischaemic stroke patients with gastrointestinal haemorrhage were prospectively collected. The outcome was a recurrent stroke rate, haemorrhage events, mortality and favourable functional outcome (FFO). We analysed the data using conventional logistic regression methods and a supervised machine learning model. We used unsupervised machine learning to group and analyse data characters.

RESULTS

The patients of stopping antiplatelet drugs had a lower rate of bleeding events (p = 0.125), mortality (p = 0.008), rate of recurrence of stroke (p = 0.161) and distribution of severe patients (mRS 3-6) (p = 0.056). For Logistic regression, stopping antiplatelet drugs (OR = 2.826, p = 0.030) was related to lower mortality. The stopping antiplatelet drugs in the supervised machine learning model related to mortality (AUC = 0.95) and FFO (AUC = 0.82). For group by unsupervised machine learning, the patients of better prognosis had more male (p < 0.001), younger (p < 0.001), had lower NIHSS score (p < 0.001); and had a higher value of serum lipid level (p < 0.001).

CONCLUSIONS

For ischemic stroke patients with gastrointestinal haemorrhage, stopping antiplatelet drugs had a better prognosis. Patients who were younger, male, with lesser NIHSS scores at admission, with the fewest history of a medical, higher value of diastolic blood pressure, platelet, blood lipid and lower INR could have a better prognosis.

Antithrombotic Therapy for Primary and Secondary Prevention of Ischemic Stroke: JACC State-of-the-Art Review

Stroke is a devastating condition with significant morbidity and mortality worldwide. Antithrombotic therapy plays a crucial role in both primary and secondary prevention of stroke events. Single or dual antiplatelet therapy is generally preferred in cases of large-artery atherosclerosis and small-vessel disease, whereas anticoagulation is recommended in conditions of blood stasis or hypercoagulable states that mostly result in red thrombi. However, the benefit of antithrombotic therapies must be weighed against the increased risk of bleeding, which can pose significant challenges in the pharmacological management of this condition. This review provides a comprehensive summary of the currently available evidence on antithrombotic therapy for ischemic stroke and outlines an updated therapeutic algorithm to support physicians in tailoring the strategy to the individual patient and the underlying mechanism of stroke.

Genotype-guided dual antiplatelet therapy in cerebrovascular disease: assessing the risk and benefits for ethnic populations

INTRODUCTION

Cerebrovascular disease is a leading cause of morbidity and mortality in the world and antiplatelet therapy is a main pharmacologic means of secondary prevention. Clinical information has accumulated about benefit of dual antiplatelet therapy in certain clinical scenarios, genetic causes of antiplatelet resistance and its effect on clinical outcomes, and ethnic and geographic distributions of genetic polymorphisms.

AREAS COVERED

This review covers literature related to the pharmacogenomics of antiplatelet agents with a focus on ethnic variability, antiplatelet resistance, and dual antiplatelet therapy in cerebrovascular disease.

EXPERT OPINION

Selecting patients for dual antiplatelet therapy and specific agents require consideration of multiple factors. Ethnic factors should be considered in certain circumstances, but additional research is needed to determine the generalizability of the findings.

Antithrombotic therapy in antiphospholipid syndrome with arterial thrombosis: a systematic review and network meta-analysis

Introduction

The optimal secondary thromboprophylactic strategies for patients with antiphospholipid syndrome (APS) and arterial thrombosis remain controversial. This study aimed to evaluate the comparative efficacy and safety of various antithrombotic strategies in APS with arterial thrombosis.

Methods

A comprehensive literature search was conducted using OVID MEDLINE, EMBASE, Web of Science, and the Cochrane Controlled Register of Trials (CENTRAL) from inception until 30 September 2022, with no language restrictions. The inclusion criteria for eligible studies were as follows: inclusion of APS patients with arterial thrombosis, treatment with either antiplatelet agents, warfarin, direct oral anticoagulants (DOACs), or a combination of these therapies, and reporting of recurrent thrombotic events.

Results

We conducted a frequentist random-effects network meta-analysis (NMA) involving 13 studies with a total of 719 participants, comprising six randomized and seven non-randomized studies. In comparison to single antiplatelet therapy (SAPT), the combined use of antiplatelet and warfarin demonstrated a significant reduction in the risk of recurrent overall thrombosis, with a risk ratio (RR) of 0.41 (95% CI 0.20 to 0.85). Dual antiplatelet therapy (DAPT) showed a lower risk of recurrent arterial thrombosis compared to SAPT although the difference did not reach statistical significance, with an RR of 0.29 (95% CI 0.08 to 1.07). DOAC was associated with a significant increase in the risk of recurrent arterial thrombosis, with an RR of 4.06 (95% CI 1.33 to 12.40) when compared to SAPT. There was no significant difference in major bleeding among various antithrombotic strategies.

Discussion

Based on this NMA, the combination of warfarin and antiplatelet therapy appears to be an effective approach in preventing recurrent overall thrombosis in APS patients with a history of arterial thrombosis. While DAPT may also show promise in preventing recurrent arterial thrombosis, further studies are needed to confirm its efficacy. Conversely, the use of DOACs was found to significantly increase the risk of recurrent arterial thrombosis.

Contemporary Antiplatelet and Anticoagulant Therapies for Secondary Stroke Prevention: A Narrative Review of Current Literature and Guidelines

PURPOSE OF REVIEW

Stroke is a leading cause of death and disability worldwide. The annual incidence of new or recurrent stroke is approximately 795,000 cases per year in the United States, of which 87% are ischemic in nature. In addition to the management of modifiable high-risk factors to reduce the risk of recurrent stroke, antithrombotic agents (antiplatelets and anticoagulants) play an important role in secondary stroke prevention. This review will discuss the published literature on the use of antiplatelets and anticoagulants in secondary prevention of acute ischemic stroke and transient ischemic attack (TIA), including their pharmacology, efficacy, and adverse effects. We will also highlight the role of dual antiplatelet therapy (DAPT) in secondary stroke prevention, along with supporting literature.

RECENT FINDINGS

Single antiplatelet therapy (SAPT) with aspirin or clopidogrel reduces the risk of recurrent ischemic stroke in patients with non-cardioembolic ischemic stroke or TIA. However, as shown in recent trials, short-term DAPT with aspirin and clopidogrel or ticagrelor for 21-30 days is more effective than SAPT in patients with minor acute non-cardioembolic stroke or high-risk TIA. Although short-term DAPT is highly effective in preventing recurrent stroke, a more prolonged course can increase bleeding risks without additional benefit. DAPT for 90 days, followed by aspirin monotherapy for patients with large vessel intracranial atherosclerotic disease, is suitable for secondary stroke prevention. However, patients need to be monitored for both minor (e.g., bruising) and major (e.g., intracranial) bleeding complications. Conversely, oral warfarin and newer direct oral anticoagulant (DOACs) such as dabigatran, rivaroxaban, apixaban, and edoxaban are the agents of choice for secondary stroke prevention in patients with non-valvular cardioembolic strokes. DOACs may be preferred over warfarin due to decreased bleeding risks, including ICH, lack of need for international normalized ratio monitoring, no dietary restrictions, and limited drug-drug interactions. The choice between different antiplatelets and anticoagulants for prevention of ischemic stroke depends on the underlying stroke mechanism, cytochrome P450 2C19 polymorphisms, bleeding risk profile, compliance, drug tolerance, and drug resistance. Physicians must carefully weigh each patient's relative benefits and bleeding risks before initiating an antiplatelet/anticoagulant treatment regimen. Further studies are warranted to study the optimal duration of DAPT in symptomatic intracranial atherosclerosis since the benefit is most pronounced in the short term while the bleeding risk remains high during the extended duration of therapy.

A randomized controlled trial to evaluate outcomes with Aggrenox in patients with SARS-CoV-2 infection

BACKGROUND

Coronavirus disease 2019 (COVID-19) is an immunoinflammatory and hypercoagulable state that contributes to respiratory distress, multi-organ dysfunction, and mortality. Dipyridamole, by increasing extracellular adenosine, has been postulated to be protective for COVID-19 patients through its immunosuppressive, anti-inflammatory, anti-coagulant, vasodilatory, and anti-viral actions. Likewise, low-dose aspirin has also demonstrated protective effects for COVID-19 patients. This study evaluated the effect of these two drugs formulated together as Aggrenox in hospitalized COVID-19 patients.

METHODS

In an open-label, single site randomized controlled trial (RCT), hospitalized COVID-19 patients were assigned to adjunctive Aggrenox (Dipyridamole ER 200mg/ Aspirin 25mg orally/enterally) with standard of care treatment compared to standard of care treatment alone. Primary endpoint was illness severity according to changes on the eight-point COVID ordinal scale, with levels of 1 to 8 where higher scores represent worse illness. Secondary endpoints included all-cause mortality and respiratory failure. Outcomes were measured through days 14, 28, and/or hospital discharge.

RESULTS

From October 1, 2020 to April 30, 2021, a total of 98 patients, who had a median [IQR] age of 57 [47, 62] years and were 53.1% (n = 52) female, were randomized equally between study groups (n = 49 Aggrenox plus standard of care versus n = 49 standard of care alone). No clinically significant differences were found between those who received adjunctive Aggrenox and the control group in terms of illness severity (COVID ordinal scale) at days 14 and 28. The overall mortality through day 28 was 6.1% (3 patients, n = 49) in the Aggrenox group and 10.2% (5 patients, n = 49) in the control group (OR [95% CI]: 0.40 [0.04, 4.01], p = 0.44). Respiratory failure through day 28 occurred in 4 (8.3%, n = 48) patients in the Aggrenox group and 7 (14.6%, n = 48) patients in the standard of care group (OR [95% CI]: 0.21 [0.02, 2.56], p = 0.22). A larger decrease in the platelet count and blood glucose levels, and larger increase in creatinine and sodium levels within the first 7 days of hospital admission were each independent predictors of 28-day mortality (p < 0.05).

CONCLUSION

In this study of hospitalized patients with COVID-19, while the outcomes of COVID illness severity, odds of mortality, and chance of respiratory failure were better in the Aggrenox group compared to standard of care alone, the data did not reach statistical significance to support the standard use of adjuvant Aggrenox in such patients.

Surgical Pharmacy for Optimizing Medication Therapy Management Services within Enhanced Recovery after Surgery (ERAS(®)) Programs

Drug-related problems (DRPs) are common among surgical patients, especially older patients with polypharmacy and underlying diseases. DRPs can potentially lead to morbidity, mortality, and increased treatment costs. The enhanced recovery after surgery (ERAS) system has shown great advantages in managing surgical patients. Medication therapy management for surgical patients (established as "surgical pharmacy" by Guangdong Province Pharmaceutical Association (GDPA)) is an important part of the ERAS system. Improper medication therapy management can lead to serious consequences and even death. In order to reduce DRPs further, and promote the rapid recovery of surgical patients, the need for pharmacists in the ERAS program is even more pressing. However, the medication therapy management services of surgical pharmacy and how surgical pharmacists should participate in ERAS programs are still unclear worldwide. Therefore, this article reviews the main perioperative medical management strategies and precautions from several aspects, including antimicrobial agents, antithrombotic agents, pain medication, nutritional therapy, blood glucose monitoring, blood pressure treatment, fluid management, treatment of nausea and vomiting, and management of postoperative delirium. Additionally, the way surgical pharmacists participate in perioperative medication management, and the relevant medication pathways are explored for optimizing medication therapy management services within the ERAS programs. This study will greatly assist surgical pharmacists' work, contributing to surgeons accepting that pharmacists have an important role in the multidisciplinary team, benefitting medical workers in treating, counseling, and advocating for their patients, and further improving the effectiveness, safety and economy of medication therapy for patients and promoting patient recovery.

Antiplatelet therapy for secondary prevention of lacunar stroke: a systematic review and network meta-analysis

PURPOSE

To comprehensively compare the efficacy of different antiplatelet therapies for secondary prevention of lacunar stroke (LS).

METHODS

The relevant studies were identified by searching PubMed, EMBASE, Web of Science, and Cochrane Collaboration Database up to May 2022. Cardiovascular and cerebrovascular events were chosen to evaluate the efficacy of antiplatelet therapy for secondary prevention. Loop-specific approach and node-splitting analysis were used to evaluate consistency and inconsistency, respectively. The value of the surface under the cumulative ranking (SUCRA) was calculated and ranked. Funnel-plot symmetry was used to evaluate publication bias. The meta-analysis was performed by using STATA 16.0.

RESULTS

Thirteen studies with a total of 33,011 subjects were included in this network meta-analysis. Compared with placebo, aspirin, clopidogrel, cilostazol, ticlopidine, aspirin plus dipyridamole, and aspirin plus clopidogrel were associated with reducing cardiovascular and cerebrovascular events. The SUCRA estimated relative ranking of treatments showed that cilostazol may be the most effective (RR 0.56, 95% CI 0.42-0.74, SUCRA 95.8). No significant inconsistency or publication bias was found in the study.

CONCLUSIONS

This meta-analysis suggests that cilostazol may be a priority option for secondary prevention of patients with LS. These findings still need further study in the future.

Motor sequela of adult and pediatric stroke: Imminent losses and ultimate gains

Stroke is the leading cause of neurological disability in the United States and worldwide. Remarkable advances have been made over the past 20 years in acute vascular treatments to reduce infarct size and improve neurological outcome. Substantially less progress has been made in the understanding and clinical approaches to neurological recovery after stroke. This chapter reviews the epidemiology, bedside examination, localization approaches, and classification of stroke, with an emphasis on motor stroke presentations and management, and promising research approaches to enhancing motor aspects of stroke recovery.

Potential Inhibitors of SARS-CoV-2 Main Protease (M(pro)) Identified from the Library of FDA-Approved Drugs Using Molecular Docking Studies

The Corona Virus Infectious Disease-2019 (COVID-19) outbreak originated at Wuhan, China, in December 2019. It has already spread rapidly and caused more than 6.5 million deaths worldwide. Its causal agent is a beta-coronavirus named SARS-CoV-2. Many efforts have already been made to develop new vaccines and drugs against these viruses, but over time, it has changed its molecular nature and evolved into more lethal variants, such as Delta and Omicron. These will lead us to target its more-conserved proteins. The sequences' BLAST and crystal structure of the main protease M^pro suggest a high sequence and structural conservation. M^pro is responsible for the proteolytic maturation of the polyprotein essential for the viral replication and transcription, which makes it an important drug target. Discovery of new drug molecules may take years before getting to the clinics. So, considering urgency, we performed molecular docking studies using FDA-approved drugs to identify molecules that could potentially bind to the substrate-binding site and inhibit SARS-CoV-2's main protease (M^pro). We used the Glide module in the Schrödinger software suite to perform molecular docking studies, followed by MM-GBSA-based energy calculations to score the hit molecules. Molecular docking and manual analysis suggest that several drugs may bind and potentially inhibit M^pro. We also performed molecular simulations studies for selected compounds to evaluate protein-drug interactions. Considering bioavailability, lesser toxicity, and route of administration, some of the top-ranked drugs, including lumefantrine (antimalarial), dipyridamole (coronary vasodilator), dihydroergotamine (used for treating migraine), hexoprenaline (anti asthmatic), riboflavin (vitamin B2), and pantethine (vitamin B5) may be taken forward for further in vitro and in vivo experiments to investigate their therapeutic potential.

Navigating Antiplatelet Treatment Options for Stroke: Evidence-Based and Pragmatic Strategies

PURPOSE OF REVIEW

The benefit of using antiplatelet monotherapy in acute ischemic stroke and secondary stroke prevention is well established. In the last few years, several large randomized trials showed that the use of short-term dual antiplatelet therapy in particular stroke subtypes may reduce the risk of recurrent ischemic events. The aim of this article is to provide a critical analysis of the current evidence and recommendations for the use of antiplatelet agents for stroke prevention.

RECENT FINDINGS

Long-term therapy with aspirin, clopidogrel, or aspirin plus extended-release dipyridamole is recommended for secondary stroke prevention in patients with noncardioembolic ischemic stroke. Short-term dual antiplatelet therapy with aspirin and clopidogrel is superior to antiplatelet monotherapy in secondary stroke prevention when used in patients with mild noncardioembolic stroke or high-risk transient ischemic attack. Dual therapy, however, is associated with an increased risk of major bleeding, particularly when the treatment is extended for greater than 30 days. Similarly, aspirin plus ticagrelor is superior to aspirin monotherapy for the prevention of recurrent ischemic stroke, although this combination is associated with a higher risk of hemorrhagic complications when compared to other dual antiplatelet regimens. Among patients who carry CYP2C19 genetic polymorphisms associated with a slow bioactivation of clopidogrel, short-term treatment with aspirin plus ticagrelor is superior to aspirin plus clopidogrel for the reduction of recurrent stroke; however, the use of ticagrelor is associated with a higher risk of any bleeding. In patients with symptomatic intracranial stenosis, aggressive medical management in addition to dual antiplatelet therapy up to 90 days is recommended. Antiplatelet therapy has an essential role in the management of ischemic stroke. The specific antiplatelet regimen should be individualized based on the stroke characteristics, time from symptom onset, and patient-specific predisposition to develop hemorrhagic complications.

Antiplatelets and Vascular Dementia: A Systematic Review

Vascular dementia (VD) is a neurocognitive disorder whose precise definition is still up for debate. VD generally refers to dementia that is primarily caused by cerebrovascular disease or impaired cerebral blood flow. It is a subset of vascular cognitive impairment, a class of diseases that relate any cerebrovascular injury as a causal or correlating factor for cognitive decline, most commonly seen in the elderly. Patients who present with both cognitive impairment and clinical or radiologic indications of cerebrovascular pathology should have vascular risk factors, particularly hypertension, examined and treated. While these strategies may be more effective at avoiding dementia than at ameliorating it, there is a compelling case for intensive secondary stroke prevention in these patients. Repeated stroke is related to an increased chance of cognitive decline, and poststroke dementia is connected with an increased risk of death. In general, most physicians follow recommendations for secondary stroke prevention in patients with VD, which can be accomplished by the use of antithrombotic medicines such as antiplatelets (aspirin, clopidogrel, ticlopidine, cilostazol, etc.). In individuals with a high risk of atherosclerosis and those with documented symptomatic cerebrovascular illness, antiplatelets treatment lowers the risk of stroke. While this therapy strategy of prevention and rigorous risk management has a compelling justification, there is only limited and indirect data to support it. The following systematic review examines the role of antiplatelets in the management of vascular dementia in published clinical trials and studies and comments on the current evidence available to support their use and highlights the need for further study.

Antiplatelet treatment for acute secondary prevention of non-cardioembolic minor stroke / transient ischaemic attack: an update for the acute physician

Acute stroke is the leading cause of disability in the UK and a leading cause of mortality worldwide. The majority of patients with ischaemic stroke present with minor deficits or transient ischaemic attack (TIA), and are often first seen by patient-facing clinicians. Urgent evaluation and treatment are important as many patients are at high risk of major vascular events and death within hours to days after the index event. This narrative review summarises the evidence on four antiplatelet treatments for non-cardioembolic stroke prevention: aspirin, clopidogrel, dipyridamole and ticagrelor. Each of these drugs has a unique mechanism and has been tested as a single agent or in combination. Aspirin, when given early is beneficial and short-term treatment with aspirin and clopidogrel has been shown to be more effective in high-risk TIA / minor stroke. This review concludes by highlighting gaps in evidence, including scope for future trials that could potentially change clinical practice.

European Stroke Organisation (ESO) guideline on pharmacological interventions for long-term secondary prevention after ischaemic stroke or transient ischaemic attack

Recurrent stroke affects 9% to 15% of people within 1 year. This European Stroke Organisation (ESO) guideline provides evidence-based recommendations on pharmacological management of blood pressure (BP), diabetes mellitus, lipid levels and antiplatelet therapy for the prevention of recurrent stroke and other important outcomes in people with ischaemic stroke or transient ischaemic attack (TIA). It does not cover interventions for specific causes of stroke, including anticoagulation for cardioembolic stroke, which are addressed in other guidelines. This guideline was developed through ESO standard operating procedures and the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology. The working group identified clinical questions, selected outcomes, performed systematic reviews, with meta-analyses where appropriate, and made evidence-based recommendations, with expert consensus statements where evidence was insufficient to support a recommendation. To reduce the long-term risk of recurrent stroke or other important outcomes after ischaemic stroke or TIA, we recommend: BP lowering treatment to a target of <130/80 mmHg, except in subgroups at increased risk of harm; HMGCoA-reductase inhibitors (statins) and targeting a low density lipoprotein level of <1.8 mmol/l (70 mg/dl); avoidance of dual antiplatelet therapy with aspirin and clopidogrel after the first 90 days; to not give direct oral anticoagulant drugs (DOACs) for embolic stroke of undetermined source and to consider pioglitazone in people with diabetes or insulin resistance, after careful consideration of potential risks. In addition to the evidence-based recommendations, all or the majority of working group members supported: out-of-office BP monitoring; use of combination treatment for BP control; consideration of ezetimibe or PCSK9 inhibitors when lipid targets are not achieved; consideration of use of low-dose DOACs in addition to an antiplatelet in selected groups of people with coronary or peripheral artery disease and aiming for an HbA1c level of <53 mmol/mol (7%) in people with diabetes mellitus. These guidelines aim to standardise long-term pharmacological treatment to reduce the burden of recurrent stroke in Europe.

Physiologically based modelling of the antiplatelet effect of aspirin: A tool to characterize drug responsiveness and inform precision dosing

A computational approach involving mathematical modeling and in silico experiments was used to characterize the determinants of extent and duration of platelet cyclooxygenase (COX)-1 inhibition by aspirin and design precision dosing in patients with accelerated platelet turnover or reduced drug bioavailability. To this purpose, a recently developed physiologically-based pharmacokinetics (PK) and pharmacodynamics (PD) model of low-dose aspirin in regenerating platelets and megakaryocytes, was used to predict the main features and determinants of platelet COX-1 inhibition. The response to different aspirin regimens in healthy subjects and in pathological conditions associated with alterations in aspirin PK (i.e., severely obese subjects) or PD (i.e., essential thrombocytemya patients), were simulated. A model sensitivity analysis was performed to identify the main processes influencing COX-1 dynamics. In silico experiments and sensitivity analyses indicated a major role for megakaryocytes and platelet turnover in determining the extent and duration of COX-1 inhibition by once-daily, low-dose aspirin. They also showed the superiority of reducing the dosing interval vs increasing the once-daily dose in conditions of increased platelet turnover, while suggested specific dose adjustments in conditions of possible reduction in drug bioavailability. In conclusion, the consistency of our model-based findings with experimental data from studies in healthy subjects and patients with essential thrombocythemia supports the potential of our approach for describing the determinants of platelet inhibition by aspirin and informing precision dosing which may guide personalized antithrombotic therapy in different patient populations, especially in those under-represented in clinical trials or in those associated with poor feasibility.

The role of CYP2C19 genotyping to guide antiplatelet therapy following ischemic stroke or transient ischemic attack

Introduction

Clopidogrel is an antiplatelet agent recommended for secondary prevention of ischemic stroke (IS) and transient ischemic attack (TIA). Conversion of clopidogrel to its active metabolite by hepatic cytochrome P450-2C19 (CYP2C19) is essential for the inhibition of the P2Y12 receptor and subsequent platelet aggregation to prevent thrombotic events. CYP2C19 is highly polymorphic, with over 30 loss of function (LoF) alleles. This review considers whether there is sufficient data to support genotype guided antiplatelet therapy after stroke.

Areas covered

A systematic literature review retrieved articles, which describe the interaction between CYP2C19 genotype and clinical outcomes following IS or TIA when treated with clopidogrel. The review documents efforts to identify optimal antiplatelet regimens and explores the value genotype guided antiplatelet therapy. The work outlines the contemporary understanding of clopidogrel metabolism and appraises evidence linking CYP2C19 LoF variants with attenuated platelet inhibition and poorer outcomes.

Expert opinion

There is good evidence that CYP2C19 LoF allele carriers of Han-Chinese ancestry have increased risk for further vascular events following TIA or IS when treated with clopidogrel. The evidence base is less certain in other populations. The expansion of pharmacogenetics into routine clinical practice will facilitate further research and help tailor other aspects of secondary prevention.

Comparison of Outcomes of Ischemic Stroke Initially Imaged With Cranial Computed Tomography Alone vs Computed Tomography Plus Magnetic Resonance Imaging

IMPORTANCE

Patients with acute ischemic stroke often undergo magnetic resonance imaging (MRI) in addition to computed tomography (CT), but its association with clinical outcomes is uncertain.

OBJECTIVE

To assess whether clinical outcomes of patients with acute ischemic stroke with initial CT alone were noninferior to those with additional MRI.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective observational propensity score-matched cohort study of clinical outcomes at discharge and 1 year for patients hospitalized with acute ischemic stroke was conducted at an academic medical center between January 2015 and December 2017. Data collection from an electronic medical record system performed from May 2020 through January 2022 was not completely blinded. Noninferiority margins were based on the designs of previous randomized clinical trials of ischemic stroke treatments. Statistical analysis was performed in January 2022. Participants were adults hospitalized with acute ischemic stroke with admission diagnosis based on CT. Exclusion criteria were primarily missing data. From 508 eligible patients, all 123 cases with additional MRI were propensity-score matched to 123 controls without.

EXPOSURE

MRI after initial diagnosis.

MAIN OUTCOMES AND MEASURES

Death or dependence at hospital discharge (modified Rankin Scale score of 3-6) and stroke or death occurring in survivors within 1 year after discharge.

RESULTS

Among 246 participants, the median age was 68 years (IQR, 58-78.8 years) and 131 (53.0%) were men. Death or dependence at discharge occurred more often in patients with additional MRI (59 of 123 [48.0%]) than in those with CT alone (52 of 123 [42.3%]; absolute difference, 5.7%; 95% CI, -6.7% to 18.1%), meeting the -7.50% criterion for noninferiority. Stroke or death within 1 year after discharge determined for 225 of 235 (96%) survivors occurred more often in patients with additional MRI (22 of 113 [19.5%]) than in those with CT alone (14 of 112 [12.5%]; relative risk, 1.14; 95% CI, 0.86-1.50), meeting the 0.725 relative risk criterion for noninferiority.

CONCLUSIONS AND RELEVANCE

This propensity score-matched cohort study of patients hospitalized with acute ischemic stroke found that a diagnostic imaging strategy of initial CT alone was noninferior to initial CT plus additional MRI with regard to clinical outcomes at discharge and at 1 year. Further research is needed to determine which patients hospitalized with acute ischemic stroke benefit from MRI.

P2Y12 inhibitors plus aspirin for acute treatment and secondary prevention in minor stroke and high-risk transient ischemic attack: A systematic review and meta-analysis

BACKGROUND

Aspirin is a cornerstone of preventive treatment for stroke recurrence, but during the last few years the role of dual antiplatelet therapy (DAPT) is much more emerging.

OBJECTIVE

This systematic review aimed to compare early use of P2Y12 inhibitors (clopidogrel/ticagrelor) plus aspirin to aspirin alone for acute treatment and secondary prevention in acute non-cardioembolic minor ischemic stroke or TIA.

METHODS

A systematic search on MEDLINE and EMBASE was performed. Treatment effects were estimated with RRs and 95% CI. We used RevMan 5.4 for data analyses. We assessed methodological quality of selected studies according to Rob2 tools and quality of evidence with GRADE approach.

RESULTS

Four RCTs were included, enrolling 21,459 patients. Compared to aspirin alone, DAPT was superior in reducing stroke recurrence (RR 0.74, 95% CI 0.67-0.82, P <0.00001, absolute risk difference by 2%, NNT 50) and disabling stroke defined as mRS>2 (RR 0.84, 95% CI 0.75-0.95, P = 0.004), with no impact on all causes of mortality (RR 1.30, 95% CI 0.90-1.89, P = 0.16). An increased risk of major bleeding was emerged (RR 2.54, 95% CI 1.65-3.92, P <0.0001, absolute risk difference by 0,4%, NNH 250), in particular with ticagrelor, but there was no correlation between therapy duration and bleeding risk, as appeared from one-month (RR 3.06, 95% CI 1.64 to 5.69) and three-month (RR 2.09, 95% CI 1.18 to 3.69) follow-up analysis.

CONCLUSIONS

Early administration of P2Y12 inhibitors plus aspirin in patients with acute non-cardioembolic minor ischemic stroke or TIA reduced the incidence of ischemic stroke recurrence, impacting more significantly than the increased bleeding risk and influencing patients' quality of life by reducing disabling stroke.

Antiplatelet Therapy in Atherothrombotic Diseases: Similarities and Differences Across Guidelines

Antiplatelet therapy, mainly consisting of aspirin and P2Y₁₂ receptor antagonists, is the cornerstone of the pharmacological treatment and prevention of atherothrombotic diseases. Its use, especially in secondary cardiovascular prevention, has significantly improved patient clinical outcomes in the last decades. Primary safety endpoint (i.e., bleeding complications) remain a major drawback of antiplatelet drugs. National and international societies have published and regularly updated guidelines for antiplatelet therapy aiming to provide clinicians with practical recommendations for a better handling of these drugs in various clinical settings. Many recommendations find common ground between international guidelines, but certain strategies vary across the countries, particularly with regard to the choice of molecules, dosage, and treatment duration. In this review, we detail and discuss the main antiplatelet therapy indications in the light of the different published guidelines and the significant number of recently published clinical trials and meta-analyses and highlight the areas that deserve further investigation in order to improve antiplatelet therapy in patients with atherothrombotic diseases.

Investigational drugs for ischemic stroke: what's in the clinical development pipeline for acute phase and prevention?

INTRODUCTION

Stroke is a leading cause of disability and mortality and its burden expected to increase. The only approved drug for acute ischemic stroke is the intravenous thrombolytic alteplase. The risk of bleeding complications is one of the reasons for the undertreatment of eligible patients. Numerous drugs are currently being developed to improve safety-efficacy.

AREAS COVERED

We reviewed literature from January 1^st, 2000, to 15^th January 2022 for the development and testing of novel drugs with the aim of targeting treatment at prevention of ischemic stroke: PubMed, MEDLINE, Google Scholar, and ClinicalTrial.gov.

EXPERT OPINION

The pathophysiology of ischemic stroke involves multiple pathways causing cerebral artery obstruction and brain tissue ischemia. Data suggest that tenecteplase is a more promising fibrinolytic agent with a superior efficacy-safety profile, compared to the currently approved alteplase. Current guidelines consider a short-term cycle of mannitol or hypertonic saline to be advisable in patients with space-occupying hemispheric infarction. Regarding primary and secondary prevention, research is primarily focused on identifying mechanisms to improve the safety-efficacy profile using a "hemostasis-sparing" approach. Further evaluation on those agents that have already shown promise for their risk/benefit profiles, would benefit greatly a neurologist's capacity to successfully prevent and treat ischemic stroke patients.

Contemporary antiplatelet therapy for secondary stroke prevention: a narrative review of current literature and guidelines

Antiplatelet therapy is one of the mainstays for secondary stroke prevention. This narrative review aimed to highlight the current evidence and recommendations of antiplatelet therapy for stroke prevention.We conducted advanced literature search for antiplatelet therapy. Landmark studies and randomised controlled trials evaluating antiplatelet therapy for secondary stroke prevention are reviewed. Results from Cochrane systematic review, pooled data analysis and meta-analysis are discussed.Single-antiplatelet therapy (SAPT) with aspirin, aspirin/extended-release dipyridamole or clopidogrel reduces the risk of recurrent ischaemic stroke in patients with non-cardioembolic ischaemic stroke or transient ischaemic attack (TIA). Dual-antiplatelet therapy (DAPT) with aspirin and clopidogrel or ticagrelor for 21-30 days is more effective than SAPT in patients with minor acute noncardioembolic ischaemic stroke or high-risk TIA. Prolonged use of DAPT is associated with higher risk of haemorrhage without reduction in stroke recurrence than SAPT. Compared with placebo, aspirin reduces the relative risk of recurrent stroke by approximately 22%. Aspirin/dipyridamole and cilostazol are superior to aspirin but associated with significant side effects. Cilostazol or ticagrelor might be more effective than aspirin or clopidogrel in patients with intracranial stenosis.SAPT is indicated for secondary stroke prevention in patients with non-cardioembolic ischaemic stroke or TIA. DAPT with aspirin and clopidogrel or ticagrelor for 21-30 days followed by SAPT is recommended for patients with minor acute noncardioembolic stroke or high-risk TIA. Selection of appropriate antiplatelet therapy should also be based on compliance, drug tolerance or resistance.

Antiplatelet Use in Ischemic Stroke

Objective:

A literature review of antiplatelet agents for primary and secondary stroke prevention, including mechanism of action, cost, and reasons for lack of benefit.

Data sources:

Articles were gathered from MEDLINE, Cochrane Reviews, and PubMed databases (1980-2021). Abstracts from scientific meetings were considered. Search terms included ischemic stroke, aspirin, clopidogrel, dipyridamole, ticagrelor, cilostazol, prasugrel, glycoprotein IIb/IIIa inhibitors.

Study selection and data extraction:

English-language original and review articles were evaluated. Guidelines from multiple countries were reviewed. Articles were evaluated independently by 2 authors.

Data synthesis:

An abundance of evidence supports aspirin and clopidogrel use for secondary stroke prevention. In the acute phase (first 21 days postinitial stroke), these medications have higher efficacy for preventing further stroke when combined, but long-term combination therapy is associated with higher hemorrhage rates. Antiplatelet treatment failure is influenced by poor adherence and genetic polymorphisms. Antiplatelet agents such as cilostazol may provide extra benefit over clopidogrel and aspirin, in certain racial groups, but further research in more diverse ethnic populations is needed.

Relevance to patient care and clinical practice:

This review presents the data available on the use of different antiplatelet agents poststroke. Dual therapy, recurrence after initiation of secondary preventative therapy, and areas for future research are discussed.

Conclusions:

Although good evidence exists for the use of certain antiplatelet agents postischemic stroke, there are considerable opportunities for future research to investigate personalized therapies. These include screening patients for platelet polymorphisms that confer antiplatelet resistance and for randomized trials including more racially diverse populations.

Effects of Dose Titration on Dipyridamole-Induced Headache: A Randomized, Double-Blind Clinical Trial

PURPOSE

The aim of this study is to investigate the effect of gradual dipyridamole titration and the incidence of dipyridamole-induced headache in patients with ischemic stroke or transient ischemic attack (TIA).

METHODS

A randomized, double-blind, double-placebo, parallel group, phase 4 clinical trial (KCT0005457) was conducted between July 1, 2019, and February 25, 2020, at 15 medical centers in South Korea. The study included patients aged >19 years diagnosed with a noncardioembolic ischemic stroke or TIA within the previous 3 weeks. The participants were randomized 1:1:1 to receive Adinox® (aspirin 25 mg/dipyridamole 200 mg) and aspirin (100 mg) once daily for the first 2 weeks followed by Adinox® twice daily for 2 weeks (titration group), Adinox® twice daily for 4 weeks (standard group), and aspirin 100 mg once daily for 4 weeks (control group). The primary endpoint was incidence of headache over 4 weeks. The key secondary endpoint was mean cumulative headache.

RESULTS

Ninety-six patients were randomized into the titration (n = 31), standard (n = 32), and control (n = 33) groups. The titration and standard groups (74.1% vs. 74.2%, respectively) showed no difference in the primary endpoint. However, the mean cumulated headache was significantly lower in the titration group than in the standard group (0.31 ± 0.46 vs. 0.58 ± 0.51, p = 0.023). Further, adverse drug reactions were more common in the standard group than in the titration group (28.1% vs. 9.7%, respectively, p = 0.054), although not significantly different.

CONCLUSION

The titration strategy was effective in lowering the incidence of cumulative dipyridamole-induced headache.

Antiplatelet therapy in cardiovascular disease: current status and future directions

Antiplatelet medications remain a cornerstone of therapy for atherosclerotic cardiovascular and cerebrovascular diseases. In primary prevention (patients with cardiovascular risk factors but no documented events, symptoms or angiographic disease), there is little evidence of benefit of any antiplatelet therapy, and such therapy carries the risk of excess bleeding. Where there is documented disease (secondary prevention), stable patients benefit from long-term antiplatelet monotherapy, aspirin being first choice in those with coronary heart disease and clopidogrel in those with cerebrovascular disease; moreover, recent evidence shows that low-dose rivaroxaban in combination with aspirin confers added benefit, in patients with stable cardiovascular and peripheral arterial disease. In patients with acute cerebrovascular disease, aspirin combined with clopidogrel reduces subsequent risk, while in acute coronary syndrome, dual antiplatelet therapy comprising aspirin and a P2Y₁₂ inhibitor (clopidogrel, prasugrel or ticagrelor) confers greater protection than aspirin monotherapy, with prasugrel and ticagrelor offering greater antiplatelet efficacy with faster onset of action than clopidogrel. Although greater antiplatelet efficacy is advantageous in preventing thrombotic events, this must be tempered by increased risk of bleeding which may be a particular issue in certain patient groups, as will be discussed. We will also discuss possible future approaches to personalisation of antiplatelet therapy.

A Nomogram for Individualized Prediction of Calf Muscular Vein Thrombosis in Stroke Patients During Rehabilitation: A Retrospective Study

Objectives: To develop a nomogram for predicting calf muscle veins thrombosis (CMVT) in stroke patients during rehabilitation. Methods: We enrolled 360 stroke patients from the Rehabilitation Medicine Center from December 2015 to February 2019. Of the participants, 123 were included in the CMVT group and 237 in the no CMVT group. The least absolute shrinkage and selection operator (LASSO) regression model was applied to optimize feature selection for the model. Multivariable logistic regression analysis was applied to construct a predictive model. Performance and clinical utility of the nomogram were generated using the Harrell's concordance index, calibration curve, and decision curve analysis (DCA). Results: Age, Brunnstrom stage (lower extremity), D-dimer, and antiplatelet therapy were associated with the occurrence of CMVT. The prediction nomogram showed satisfactory performance with a concordance index of 0.718 (95% CI: 0.663-0.773) in internal verification. The Hosmer-Lemeshow test, P = .217, suggested that the model was of goodness-of-fit. In addition, the DCA demonstrated that the CMVT nomogram had a good clinical net benefit. Conclusions: We developed a nomogram that could help clinicians identify high-risk groups of CMVT in stroke patients during rehabilitation for early intervention.

Neutrophils and Platelets: Immune Soldiers Fighting Together in Stroke Pathophysiology

Neutrophils and platelets exhibit a diverse repertoire of functions in thromboinflammatory conditions such as stroke. Most cerebral ischemic events result from longstanding chronic inflammation secondary to underlying pathogenic conditions, e.g., hypertension, diabetes mellitus, obstructive sleep apnea, coronary artery disease, atrial fibrillation, morbid obesity, dyslipidemia, and sickle cell disease. Neutrophils can enable, as well as resolve, cerebrovascular inflammation via many effector functions including neutrophil extracellular traps, serine proteases and reactive oxygen species, and pro-resolving endogenous molecules such as Annexin A1. Like neutrophils, platelets also engage in pro- as well as anti-inflammatory roles in regulating cerebrovascular inflammation. These anucleated cells are at the core of stroke pathogenesis and can trigger an ischemic event via adherence to the hypoxic cerebral endothelial cells culminating in aggregation and clot formation. In this article, we review and highlight the evolving role of neutrophils and platelets in ischemic stroke and discuss ongoing preclinical and clinical strategies that may produce viable therapeutics for prevention and management of stroke.

Antithrombotic Therapy in the Prevention of Stroke

OVERVIEW

Ischemic stroke is a leading cause of death and disability throughout the world. Antithrombotic therapy, which includes both antiplatelet and anticoagulant agents, is a primary medication of choice for the secondary prevention of stroke. However, the choices vary with the need to incorporate evolving, newer information into the clinical scenario. There is also the need to factor in co-morbid medical conditions as well as the cost ramifications for a particular patient as well as compliance with the regimen. Pertinent Updates: In the acute setting, dual antiplatelet therapy from three weeks to up to three months has become recognized as a reasonable approach for patients with either minor stroke or transient ischemic attack or those with symptoms associated with higher-grade intracranial stenosis. This approach is favored for non-cardioembolic stroke as a cardiogenic mechanism tends to be best managed with attention to the cardiac condition as well as anticoagulant therapy. Risk stratification for recurrent stroke is important in weighing potential risk versus benefits. For example, prolonged dual antiplatelet therapy, with a combination such as aspirin and clopidogrel or aspirin and ticagrelor, tends to have negation of the potential clinical benefit of stroke prevention, over time, by the enhanced bleeding risk. Anticoagulant choices are now impacted by newer agents, initially identified as novel oral anticoagulants (NOACs), which also became associated with "non-vitamin K" agents as they are no longer considered novel. Alternatively, they are now often identified as direct oral anticoagulants (DOACs). They tend to be viewed as superior or non-inferior to warfarin with the caveat that warfarin is still viewed as the agent of choice for stroke prevention in patients with mechanical heart valves.

CONCLUSION

Based upon cumulative information from multiple clinical trials of secondary prevention of stroke, there is an increasing array of approaches in an effort to provide optimal management. Antithrombotic therapy, including in combination with anticoagulant therapy, continues to evolve with the general caveat that "one size does not fit all". In view of this, we desire to provide an evidence-based approach for the prevention of stroke with antithrombotic agents.

Ischemic Stroke

This concise review of the epidemiology, pathophysiology, evaluation, acute management, and prevention of ischemic stroke targets internists, family practitioners, and emergency physicians who manage patient with stroke.

Design of a randomised, double-blind, crossover, placebo-controlled trial of effects of sildenafil on cerebrovascular function in small vessel disease: Oxford haemodynamic adaptation to reduce pulsatility trial (OxHARP)

Background

Cerebral small vessel disease (SVD) is associated with increased cerebrovascular pulsatility, endothelial dysfunction, and impaired vascular reactivity. Vasodilating phosphodiesterase inhibitors may improve cardiovascular pulsatility and reactivity, and potentially reduce progression of SVD.

Hypothesis: Sildenafil, a PDE5 inhibitor, will reduce cerebrovascular pulsatility and increase cerebrovascular reactivity compared to placebo, and is non-inferior to cilostazol, a PDE3 inhibitor.

Methods

OxHARP is a randomised, double-blind, crossover trial of sildenafil 50 mg thrice daily, cilostazol 100 mg twice daily and placebo in 75 patients with mild to moderate small vessel disease and a previous lacunar or cryptogenic stroke or TIA. Participants undergo a physiological assessment at baseline and on each treatment, including transcranial Doppler ultrasound (TCD, DWL DopplerBox) to assess cerebrovascular pulsatility and reactivity to 4–6% carbon dioxide. In up to 60 patients, cerebrovascular pulsatility, perfusion and reactivity will also be assessed by MRI.

Outcome measures

The primary outcome is difference in middle cerebral artery pulsatility (Gosling’s Pulsatility Index, PI) after 3 weeks of sildenafil versus placebo. Secondary outcomes including non-inferiority of sildenafil vs cilostazol in effects on PI, percentage increase in MCA blood flow velocity and BOLD-fMRI response during inhalation of 4–6% carbon dioxide.

Discussion

Reduction in cerebral pulsatility and increased cerebrovascular reactivity during treatment with sildenafil would indicate potential benefit to prevent progression of SVD, suggesting a need for trials with clinical outcomes.

Trial Registration OxHARP is registered with ClinicalTrials.org, NCT03855332

Challenges in setting Permitted Daily Exposure (PDE) Limits for pharmaceuticals: A review

BACKGROUND

When more than one drug is manufactured at a shared facility or equipment in pharmaceutical manufacturing, the potential carry-over of the retained residue of existing drug product on product contact parts of the equipment to the next product can be a source of cross contamination. Permitted daily exposure (PDE) is derived based on the complete nonclinical and clinical data available and is a dose that is unlikely to cause adverse effects if an individual is exposed, by any route, at or below this dose every day over a lifetime.

OBJECTIVE

The objective was to present a comprehensive review of available scientific knowledge for derivation of PDE.

METHODS

PubMed and ScienceDirect databases were searched using keywords "PDE" and "pharmaceuticals" and all the relevant literature up to March 2021 was reviewed. We have also calculated PDEs for Tobramycin (CAS No. 32986-56-4) and Acetyl Salicylic Acid (ASA, CAS No. 50-78-2).

RESULTS

This research will be useful for scientists working in the PDE domain. The given examples emphasize the importance of use of human data in calculating PDE.

CONCLUSION

The duty of the risk assessor entrusted with setting PDEs is to derive a data driven, scientifically justified value that is safe for patients, while avoiding unjustified conservativeness that puts unnecessary burden on manufacturing.

Detection of Fraud in a Clinical Trial Using Unsupervised Statistical Monitoring

BACKGROUND

A central statistical assessment of the quality of data collected in clinical trials can improve the quality and efficiency of sponsor oversight of clinical investigations.

MATERIAL AND METHODS

The database of a large randomized clinical trial with known fraud was reanalyzed with a view to identifying, using only statistical monitoring techniques, the center where fraud had been confirmed. The analysis was conducted with an unsupervised statistical monitoring software using mixed-effects statistical models. The statistical analyst was unaware of the location, nature, and extent of the fraud.

RESULTS

Five centers were detected as atypical, including the center with known fraud (which was ranked 2). An incremental analysis showed that the center with known fraud could have been detected after only 25% of its data had been reported.

CONCLUSION

An unsupervised approach to central monitoring, using mixed-effects statistical models, is effective at detecting centers with fraud or other data anomalies in clinical trials.

Use of dipyridamole is associated with lower risk of lymphoid neoplasms: a propensity score-matched cohort study

The anti-cancer potential of dipyridamole has been suggested from experiments, but evidence from population-based studies is still lacking. We aimed to explore if dipyridamole use was related to a lower risk of lymphoid neoplasms. We identified individuals with prescription of aspirin after diagnosis of ischaemic cerebrovascular disease since 2006 by linking several Swedish registers. In these aspirin users, those with dipyridamole prescription were further identified as the study group and patients without dipyridamole were randomly selected as reference group with 1:1 ratio using a propensity score-matching approach. After a median of 6·67 years of follow-up, a total of 46 patients with dipyridamole use developed lymphoid neoplasms with an incidence rate of 0·49 per 1 000 person-years, while the rate in the matched group was 0·74 per 1 000 person-years. As compared to non-users, dipyridamole users were associated with a significantly decreased risk of lymphoid neoplasms [hazard ratio (HR) = 0·65; 95% confidence interval (CI) = 0·43-0·98]. Specifically, the reduced risk was observed for non-Hodgkin lymphomas (HR = 0·64; 95% CI = 0·42-0·94), especially B-cell lymphomas (HR = 0·56; 95% CI = 0·35-0·88). Dipyridamole use was related to a lower risk of lymphoid neoplasms, indicating a clinical potential of dipyridamole to be an adjunct anti-tumour agent against lymphoid neoplasms.

A Clinical Update on Antiplatelet Therapy in Secondary Prevention of Ischemic Stroke

PURPOSE OF REVIEW

Antiplatelet therapy remains the standard of care in secondary stroke prevention for non-cardioembolic ischemic stroke and transient ischemic attack. We aim to examine the use of antiplatelet agents in secondary prevention through highlighting relevant clinical trials and meta-analyses as well as providing commentary regarding our practice.

RECENT FINDINGS

In the POINT and CHANCE trials, dual antiplatelet therapy reduced recurrent stroke compared to aspirin monotherapy. Sub-analyses of these trials suggest that genetic polymorphisms could play a role in diminishing the effectiveness of clopidogrel. Similarly, THALES demonstrated better outcomes with ticagrelor-aspirin combination therapy over aspirin monotherapy. Combination antiplatelet therapy with aspirin and the P2Y12 inhibitors, clopidogrel and ticagrelor, reduced stroke recurrence in those presenting with mild ischemic stroke or high risk TIA. Genetic polymorphisms may play a role in determining the appropriate regimen. Questions remain regarding the optimal duration of combination antiplatelet therapy for various stroke etiologies.

Meta-Analysis of Usefulness of Antiplatelet Therapy in Ischemic Stroke or Transient Ischemic Attack

The efficacy of early administration of dual antiplatelet therapy (DAPT) for secondary prevention after acute ischemic stroke or transient ischemic attack (TIA) is uncertain. This systematic review and meta-analysis compares the safety and efficacy of early administration (<24 hours) of DAPT (using either clopidogrel or ticagrelor with aspirin) versus single antiplatelet therapy (SAPT; aspirin alone) in acute non-cardioembolic ischemic stroke or TIA, incorporating data from large randomized controlled trials. Published trials fulfilling our criteria were identified from an electronic search of MEDLINE, with key words including: "clopidogrel or ticagrelor", "aspirin", "ischemic stroke", "transient ischemic attack", and "randomized controlled trial". Included were 3 randomized controlled trials of 21,067 patients assessing early administration (<24 hours from symptom onset) of DAPT versus SAPT in non-cardioembolic acute ischemic stroke or TIA. Our efficacy outcomes were ischemic stroke and all-cause mortality. Our safety outcome was severe bleeding. We performed a meta-analysis to pool results with a hierarchical Bayesian random-effects model. Dual antiplatelet therapy significantly reduced the risk of ischemic stroke (hazard ratio [HR], 0.73; 95% credible interval [CrI]: 0.54, 0.97), while increasing the risk of severe bleeding (HR, 2.48; 95% CrI: 1.07, 5.26). There was a non-significant numerical trend toward increased mortality with DAPT (HR, 1.29; 95% CrI: 0.73, 2.23). These observations were robust under the sensitivity analysis. In the present systematic review and meta-analysis of randomized controlled trials, DAPT reduced the risk of ischemic stroke at the cost of an increase in severe bleeding. Additional trials examining the ideal timing of DAPT administration are needed to thoroughly investigate the role, if any, of routine DAPT in patients with non-cardioembolic ischemic stroke or high-risk TIA.

Oral antithrombotic therapy for the prevention of recurrent cerebrovascular events

Stroke is frequently a disabling and even life-threatening condition that has an ischemic cause in most cases. Transient ischemic attack (TIA) is a lower-risk condition that still exposes to the risk of future major cardiovascular events. The causes of stroke can be classified as cardioembolic disease, large vessel disease, small vessel disease, undetermined, or others. Cardioembolic disease and atherothrombosis of large arteries are the most common underlying processes of ischemic stroke and TIA. Therefore, antithrombotic therapy is a central strategy in the pharmacological management of these patients. However, because antithrombotic therapy provides ischemic protection at the price of increased bleeding, defining the fine balance between efficacy and safety is a clinical challenge. Numerous trials have recently defined the current indications to the use of anticoagulant and antiplatelet therapy in patients with various subtypes of ischemic stroke or TIA. In this review, we provide an updated appraisal of the currently available evidence on the use of various oral antithrombotic agents for prevention of recurrent events after an ischemic stroke or TIA.