Sex Difference in the Antiplatelet Effect of Aspirin in Patients with Stroke

Teaching gender medicine can enhance the quality of healthcare

Teaching gender and sex differences is fundamental in medical classes because it has a strong impact in reducing disparity in treatment, in defining effective and personalized therapies that respect the different physiology and pathophysiology of women. Furthermore, it is the prerequisite for the pharmacoequity.

Sex differences in the prognostic role of achieving target doses of heart failure medications: Data from the Swedish Heart Failure Registry

AIMS

Guidelines recommend target doses (TD) of heart failure (HF) with reduced ejection fraction (HFrEF) medications regardless of sex. Differences in pharmacokinetics and pharmacodynamics may explain heterogeneity in treatment response, adverse reactions, and tolerability issues across sexes. The aim of this study was to explore sex-based differences in the association between TD achievement and mortality/morbidity in HFrEF.

METHODS AND RESULTS

Patients with HFrEF and HF duration ≥6 months registered in the Swedish HF Registry between May 2000 and December 2020 (follow-up until December 2021) were analysed. Treatments of interest were renin-angiotensin system inhibitors (RASI) or angiotensin receptor-neprilysin inhibitors (ARNI), and beta-blockers. Multivariable Cox regression models were performed to explore the risk of cardiovascular mortality or hospitalization for HF across dose categories in females versus males. A total of 17 912 patients were analysed (median age 77.0 years, interquartile range [IQR] 70.0-83.0), 29% were female. Over a median follow-up of 1.33 years (IQR 0.29-3.22), for RASI/ARNI there was no significant difference in outcome for females achieving 50-99% versus 100% of TD (hazard ratio 0.92, 95% confidence interval 0.83-1.03), whereas males showed a gradual lowering in risk together with the achievement of higher % of TD (p-interaction = 0.030). For beta-blockers the achievement of TD was associated with the lowest risk of outcome regardless of sex.

CONCLUSIONS

Our findings suggest that females and males might differently benefit from the same dose of RASI/ARNI, and do represent a general call for randomized controlled trials to consider sex-specific up-titration schemes when testing HFrEF treatments in need of up-titration.

Sex differences in antiplatelet therapy: state-of-the art

Antiplatelet therapy is a cornerstone of secondary prevention of cardiovascular diseases (CVDs). However, current guidelines are based on data derived primarily from men, as women are generally underrepresented in trials. Consequently, there are insufficient and inconsistent data on the effect of antiplatelet drugs in women. Sex differences were reported in platelet reactivity, patient management, and clinical outcomes after treatment with aspirin, P2Y₁₂ inhibitor, or dual antiplatelet therapy. To evaluate whether sex-specific antiplatelet therapy is needed, in this review we discuss (i) how sex affects platelet biology and response to antiplatelet agents, (ii) how sex and gender differences translate into clinical challenges and (iii) how the cardiological care in women might be improved. Finally, we highlight the challenges faced in clinical practice regarding the different needs and characteristics of female and male patients with CVD and address issues requiring further investigation.

Gender differences in efficacy and safety of antiplatelet strategies for acute coronary syndromes

INTRODUCTION

Dual antiplatelet therapy (DAPT) represents the cornerstone of secondary prevention in patients presenting with acute coronary syndrome (ACS) and undergoing percutaneous coronary intervention. Despite its undisputed efficacy in reducing thrombotic events, DAPT increases the risk of bleeding, which is associated with higher morbidity and mortality. Novel antiplatelet strategies (i.e. in terms of timing, selection of drugs and their combinations, and modulation strategies) have been tested in randomized trials, suggesting the utility of tailored approaches in selected populations (i.e. patients at high bleeding or ischemic risk). It remains uncertain whether the effect of these strategies is influenced by sex.

AREAS COVERED

This narrative review provides an overview of available evidence surrounding sex differences in the efficacy and safety of antiplatelet strategies for ACS and analyzes the potential reasons behind these findings. Relevant content was searched for in PubMed.

EXPERT OPINION

Significant differences between women and men exist in terms of clinical presentation, pharmacotherapies, interventional management, and prognosis of ACS. However, these observations do not appear to be attributed to different pharmacodynamic effects of antiplatelet therapies between women and men. Unfortunately, a critical issue depends on women being often underrepresented in clinical trials, leading to a substantial lack of sex-specific evidence.

Sexual dimorphism in immune cell responses following stroke

Recent bodies of work in regard to stroke have revealed significant sex differences in terms of risk and outcome. While differences in sex hormones have been the focus of earlier research, the reasons for these differences are much more complex and require further identification. This review covers differences in sex related immune responses with a focus on differences in immune cell composition and function. While females are more susceptible to immune related diseases, they seem to have better outcomes from stroke at the experimental level with reduced pro-inflammatory responses. However, at the clinical level, the picture is much more complex with worse neurological outcomes from stroke. While the use of exogenous sex steroids can replicate some of these findings, it is apparent that many other factors are involved in the modulation of immune responses. As a result, more research is needed to better understand these differences and identify appropriate interventions and risk modification.

Risk of stroke after unilateral or bilateral TKA (simultaneous and staged without discharge) in 327,438 matched patients using data from the National Health Insurance Claims for South Korea

PURPOSE

This study aims to investigate the incidence rate and risk factors of stroke in patients treated with bilateral TKA compared with patients with unilateral TKA.

METHODS

In this retrospective nationwide cohort study, we compared patients undergoing unilateral TKA or bilateral TKA using data from the Korean National Health Insurance claims database between January 1, 2009 and August 31, 2017 and included patients older than 40 years of age who underwent primary TKA by the index date as documented primary diagnosis and first additional diagnosis without a history of stroke during the preceding 1 year. We used matched Cox regression models to compare the incidence rate and risk factors of newly acquired stroke among patients treated with unilateral TKA or bilateral TKA after propensity score (PS) matching.

RESULTS

In the present study, 163,719 patients who received unilateral TKA were matched to 163,719 patients with bilateral TKA based on PS. The risk of stroke during the study period was lower in patients treated with bilateral TKA than in patients with unilateral TKA (adjusted hazard ratio [HR] 0.79). Patients who received bilateral TKA were at decreased risk of stroke when the following variables were present: advanced age (70-79 years, HR 0.76), female sex (HR 0.75), rural area (HR 0.77), small- or medium-sized hospital (HR 0.75), health insurance (HR 0.77), history of hypertension drug use (HR 0.75), congestive heart failure (HR 0.70), connective tissue disease (HR 0.71), diabetes (HR 0.77), and diabetes with complication (HR 0.76).

CONCLUSION

The risk of stroke was lower in patients treated with bilateral TKA than in patients with unilateral TKA. Patients treated with bilateral TKA were at decreased risk of stroke when the following variables were present: age (70-79 years), female sex, health insurance, history of hypertension drug use, and comorbidities, such as congestive heart failure, connective tissue disease, and diabetes.

Sex differences in thrombosis as it affects acute ischemic stroke

Ischemic stroke is a devastating health problem, affecting approximately 800,000 patients in the US every year, making it the leading cause of combined death and disability in the country. Stroke has historically been thought of as predominantly impacting men, however it is becoming increasingly clear that stroke affects women to a greater degree than men. Indeed, women have worse outcomes compared to men following ischemic stroke. Recent clinical advances have shown great promise in acute stroke therapy, with the use of mechanical endovascular thrombectomy (with and without recombinant tissue plasminogen activator; rtPA) greatly improving outcomes. This observation makes it clear that removal of clots and reperfusion, either mechanically or pharmacologically, is critical for improving outcomes of patients following acute ischemic stroke. Despite these promising advances, long-term neurological sequelae persist in the post-stroke population. This review focuses on mechanisms of thrombosis (clot formation) as it pertains to stroke and important sex differences in thrombosis and responses to treatment. Finally, we describe recent data related to new therapeutic approaches to thrombolysis, with a particular focus on von Willebrand Factor (vWF).

Gender medicine: Towards a gender-specific treatment of neuropsychiatric disorders

Sex and gender are increasingly recognized as major influencing factors in disorders across all medical specialties. Even though there is ample evidence of sex and gender differences in neuropsychiatric disorders, a sex and gender-differentiated approach has not yet been sufficiently applied to diagnostics and management. Therefore, there is an urgent need to establish general recommendations and guidelines toward precision and sex/gender medicine, with regard to dosage, tolerability, interactions and side effects, sensitivity of diagnostic tests, and distinct treatment strategies. This chapter illustrates the current knowledge about sex and gender aspects in neuropsychiatric disorders, providing a base not only to assist the clinician in the handling of specific pathologic entities, but also to sensitize medical practitioners to consider sex and gender in clinical decision-making. As such, the chapter is a call to action to physicians and researchers to produce more sex- and gender-stratified evidence, leading to an acceleration of guideline development. Such novel guidelines will provide a base for medical education, of both medical students and specialists, as well as a reference point for practitioners, toward precision medicine.

Prognostic value of mean platelet volume to plateletcrit ratio in patients with osteosarcoma

Objective

The objective of this study was to investigate the prognostic value of preoperative mean platelet volume to plateletcrit (MPV/PCT) ratio in patients with osteosarcoma.

Materials and methods

The retrospective study included 188 consecutive osteosarcoma patients who experienced neoadjuvant chemotherapy and surgical resection of tumor. The relationships between MPV/PCT and clinicopathological characteristics were analyzed. The Kaplan-Meier analysis and Cox regression proportional hazard model were applied to assess the prognostic value of MPV/PCT ratio.

Results

MPV/PCT ratio was found to be significantly associated with platelet count, platelet distribution width, and PCT (all P<0.001). Kaplan-Meier analysis showed that high MPV/PCT ratio (≥43.58) was associated with a prolonged disease-free survival (DFS, P=0.035). The multivariate Cox revealed that only good chemotherapy response was an independent predictor of better DFS in the overall population. However, the stratification analysis showed that a high MPV/PCT ratio (≥43.58) was indicated as an independent prognostic factor for a favorable DFS (HR =0.137, 95%CI =0.029-0.644, P=0.012) in the male osteosarcoma patients but not in female patients.

Conclusion

The high preoperative MPV/PCT ratio may serve as an independent prognostic factor for a favorable prognosis in male osteosarcoma patients. Further studies are needed to confirm the findings.

Sex Differences Do Not Exist in Outcomes among Stroke Patients with Intracranial Atherosclerosis in China: Subgroup Analysis from the Chinese Intracranial Atherosclerosis Study

BACKGROUND

To date, sex difference in outcomes among patients with intracranial atherosclerosis (ICAS) has rarely been discussed in China as well as in the world. This study aimed to estimate the sex difference in outcomes among patients with ICAS in Chinese cerebral ischemia patients.

METHODS

We analyzed 1,335 men and women with ICAS who were enrolled in the Chinese Intracranial Atherosclerosis study. They were followed-up for ischemic stroke recurrence, any cause of death, cerebral vascular events (including transient ischemic attack, ischemic and hemorrhagic stroke), combined end points (including cerebral vascular events, angina or myocardial infarction, pulmonary embolism, peripheral vascular events), and unfavorable outcome (modified Rankin scale score of 3-6) at 1 year.

RESULTS

During the follow-up period, 59 (13.44%) combined end points were documented in women and 107 (11.94%) in men. Of the combined end points, 47 were recurrent ischemic stroke events (14 in women and 33 in men), and 51 other causes of deaths (24 in women and 27 in men). There were 349 unfavorable end points (117 in women and 232 in men). The cumulative probability of death was higher in women, but after adjusting for age, diabetes mellitus, hypertension, family history of stroke, current smoker, heavy drinking, hyperhomocysteinemia, and heart disease, there was no significant difference. There was also a lack of difference in 1-year ischemic stroke recurrence, cerebral vascular events, combined end points, and unfavorable outcome between women and men at 1 year.

CONCLUSIONS

These results suggest no sex difference in outcome among patients with ICAS in Chinese cerebral ischemia patients.

Aspirin for primary prevention of cardiovascular disease events

Aspirin has been used for the prevention and treatment of cardiovascular disease (CVD) for several decades. The efficacy of aspirin for secondary prevention of cardiovascular disease is well established, but the clinical benefit of aspirin for primary prevention of CVD is less clear. The primary literature suggests that aspirin may provide a reduction in CVD events, but the absolute benefit is small and accompanied by an increase in bleeding. For aspirin to be beneficial for an individual patient, the risk of a future CVD event must be large enough to outweigh the risk of bleeding. The estimation of CVD risk is multifaceted and can involve numerous risk scores and assessments of concomitant comorbidities that confer additional CVD risk. Numerous guidelines provide recommendations for the use of aspirin for primary prevention, but they often contradict one another despite being based on the same clinical trials. Additional literature suggests that the presence of comorbidities that increase CVD risk, such as diabetes mellitus, asymptomatic peripheral arterial disease, or chronic kidney disease, does not ensure that aspirin therapy will be beneficial. Ongoing clinical trials may provide additional insight, but until more data are available, an individualized assessment of CVD risk with careful evaluation of risk and benefit should be performed before recommending aspirin therapy for primary prevention of CVD.

Sex differences in antiplatelet response in ischemic stroke

Sex differences exist in the occurrence, treatment and outcome of ischemic stroke. Compared with men, women have more stroke events and are less likely to fully recover from a stroke. Given the rapidly aging population, stroke incidence and mortality among women are projected to substantially rise by 2050. This has important public health consequences. Mitigating the burden of stroke among women will require a fundamental understanding of sex differences and sex-specific issues including cerebrovascular disease pathophysiology, treatment and outcome. An aspect of stroke treatment receiving increasing but insufficient attention involves possible interactions between estrogen levels, antiplatelet drugs and stroke outcome. Emerging evidence suggests that antiplatelet therapy may provide primary stroke protection but not primary myocardial infarction prevention in women, while the opposite may be true among men. Understanding sex-specific issues related to women who experience stroke is critical to clinicians who treat women with antiplatelet medications as part of a secondary stroke prevention regimen; however, the ideal antiplatelet medication, and dose, in women requires further research. In this article we present a conceptual framework for sex differences in antiplatelet treatment response in ischemic stroke, thrombus formation and the mediating role of estrogen, sex differences in antiplatelet treatment response in clinical trials, and sex differences in antiplatelet treatment use in ischemic stroke.

Secondary Stroke Prevention in Women

In a meta-analysis of results from 21 randomized trials comparing antiplatelet therapy with placebo in 18,270 patients with prior stroke or transient ischemic attack, antiplatelet therapy was associated with a 28% relative odds reduction in nonfatal strokes and a 16% reduction in fatal strokes, while another trial for secondary prevention with atorvastastin 80 mg showed a 16% risk reduction in time to first occurrence of stroke (adjusted hazard ratio: 0·84, 95% CI: 0·71–0·99). However, few studies have examined the sex differences regarding the efficacy of these treatments. Specifically, recent studies have reported higher rates of perioperative complications during endarterectomy in women. Nonetheless, to date, the data on the effects of carotid artery stenting in women, coming from diverse studies and meta-analyses, have been limited owing to the small number of female patients examined. Owing to this, the evidence of the benefit for women is unclear. Peculiar pathophysiological aspects of stroke, the higher stroke risk in some specific periods in life (e.g., pregnancy, puerperium and older age) and worse documented stroke outcome in women suggest that sex does matter in stroke management. Thus, future randomized controlled trials need to be sex-balanced, in order to better understand the efficacy of appropriate secondary stroke prevention therapy in women.

A review on sex differences in stroke treatment and outcome

BACKGROUND

Beyond epidemiological differences, it has been controversial whether any important sex differences exist in the treatment of stroke. In this review paper, the following areas are covered: thrombolysis, stroke unit care, secondary prevention, surgical treatment, and rehabilitation. Additionally, symptoms at stroke onset, as well as outcome measures, such as death, dependency, stroke recurrence, quality of life, and depression are reviewed.

METHODS

Search in PubMed, tables-of-contents, review articles, and reference lists after studies that include information about sex differences in stroke care.

RESULTS

Ninety papers are included in this review. Women suffer more from cortical and non-traditional symptoms. Men and women benefit equally from thrombolysis and stroke unit care. Women with cardioembolic strokes may benefit more from anticoagulant therapy. Most studies have not found any tendency towards sexism in the choice of treatment. Post-stroke depression and low quality-of-life seem to be more common among women. Mortality rates are higher among men in some studies, while long-term ADL-dependency seems to be more common among women.

CONCLUSIONS

Sex differences in stroke treatment and outcome are small, with no unequivocal proof of sex discrimination. Women have less favourable functional outcome because of higher age at stroke onset and more severe strokes.

Aspirin resistance: disparities and clinical implications

Abstract Aspirin is one of the most widely prescribed drugs for the prevention of thrombosis in patients with vascular disease. Yet, aspirin is unable to prevent thrombosis in all patients. The term "aspirin resistance" has been used to broadly define the failure of aspirin to prevent a thrombotic event. Whether this is directly related to aspirin itself through biochemical aspirin resistance or treatment failure, or if it is because of aspirin's inability to overcome the thrombogenic aspects of the disease process itself, has not been elucidated. This can have dramatic clinical implications for a variety of vascular disease subsets and is cause for concern, considering the high prevalence of aspirin use for both primary and secondary prevention. Disparities exist in the rates of aspirin resistance among certain patient populations, such as women, patients with diabetes mellitus, and those with heart failure, and across clinical conditions, such as cardiovascular and cerebrovascular disease. Clinical trial data from studies observing resistance have revealed that regardless of study size, dose of aspirin, control for drug interactions and adherence, or assay used to measure platelet function, aspirin resistance is associated with an increased risk for adverse events. Although the evidence is mounting, there has yet to be a consensus on the appropriate clinical response to aspirin resistance.

Improving the quality of care for women with cardiovascular disease: report of a DCRI Think Tank, March 8 to 9, 2007

BACKGROUND

Differences in pathophysiology, diagnosis, and treatment of women with cardiovascular disease compared with men has become a major focus during the past decade. Nevertheless, little attention has focused on improving the quality of healthcare in women compared with other areas of cardiovascular medicine.

METHODS

To address this deficit, Duke University Medical Center convened a national Duke Clinical Research Institute (DCRI) Think Tank meeting, including basic science and clinical researchers, payers, legislators, clinical experts, government regulators, and members of the pharmaceutical and device industries. This report provides an overview of the discussions and proposed solutions.

RESULTS

Discussion concentrated on the development of strategies to improve the quality of health care for women with heart disease. Key components to improve quality care include: (1) enhance the quantity and quality of evidence-based medicine to guide care in women through improvements in trial design, enrollment and retention of women subjects, results analysis and reporting, and better incentives to perform research in women; (2) provide incentives to develop better data in women through mandating changes in the drug and device development and approval processes; (3) incorporate specific recommendations for women into guidelines when data are sufficient; and (4) apply proven sex-based differences in risk stratification, diagnostic testing, and drug usage and dosing in clinical care. Examples of possible strategies are included.

CONCLUSION

The above approach represents a necessary, but not sufficient, platform to improve the overall quality of healthcare in women with cardiovascular disease.

Sex differences in stroke: epidemiology, clinical presentation, medical care, and outcomes

Stroke has a greater effect on women than men because women have more events and are less likely to recover. Age-specific stroke rates are higher in men, but, because of their longer life expectancy and much higher incidence at older ages, women have more stroke events than men. With the exception of subarachnoid haemorrhage, there is little evidence of sex differences in stroke subtype or severity. Although several reports found that women are less likely to receive some in-hospital interventions, most differences disappear after age and comorbidities are accounted for. However, sex disparities persist in the use of thrombolytic treatment (with alteplase) and lipid testing. Functional outcomes and quality of life after stroke are consistently poorer in women, despite adjustment for baseline differences in age, prestroke function, and comorbidities. Here, we comprehensively review the epidemiology, clinical presentation, medical care, and outcomes of stroke in women.

Secondary stroke prevention: inside the vessels and beyond

Cerebral ischaemic stroke is frequently a relapsing, if not chronic, disease. Its incidence is age-dependent, and with the ageing of society the need for effective therapies increases. This review considers current and alternative hypotheses underlying secondary prevention of stroke. Currently, secondary stroke prevention is widely practiced with aspirin (acetylsalicylic acid), a drug that has been in use for more than 100 years. Newer drugs such as ticlopidine and clopidogrel have subsequently been developed, but their efficacy barely surpasses that of aspirin. Other drugs used in secondary stroke prevention include HMG-CoA reductase inhibitors and antihypertensive agents. The endovascular paradigm has shaped the thinking of secondary stroke prevention, and aspirin, ticlopidine and clopidogrel are known as 'platelet inhibitors'; however, their pharmacological and clinical effects are not fully explained within the platelet paradigm. Moreover, in recent years, reduction of stroke incidence has also been observed with HMG-CoA reductase inhibitors, regardless of their lipid-lowering effects. Hence, current understanding needs to be supplemented by considering mechanisms beyond platelet inhibition. Evidence has shown that aspirin, ticlopidine and clopidogrel share neuroprotective properties not explained by the platelet paradigm and that are reminiscent of a preconditioning effect. This neuroprotective mechanism is also shared with HMG-CoA reductase inhibitors.