Postmenopausal women have an increased maximal platelet reactivity compared to men despite dual antiplatelet therapy

Being Overweight or Obese Is Associated with an Increased Platelet Reactivity Despite Dual Antiplatelet Therapy with Aspirin and Clopidogrel

PURPOSE

Obese patients exhibit an overall increased platelet reactivity and a reduced sensitivity to antiplatelet therapy. The aim of this study is to evaluate the platelet reactivity measured by impedance aggregometry in overweight and obese patients and chronic coronary syndrome (CCS) that were treated with dual antiplatelet therapy (DAPT).

METHODS

Platelet aggregation was assessed by impedance aggregometry in patients with CCS receiving DAPT (aspirin plus clopidogrel). We compared the platelet reactivity in patients with a normal weight versus overweight or obese patients. Furthermore, the correlation between the body mass index (BMI) and adenosine diphosphate- (ADP-) or thrombin receptor-activating peptide- (TRAP-) dependent platelet aggregation was analyzed.

RESULTS

64 patients were included in the study of which 35.9% were patients with normal weight. A higher ADP- and TRAP-dependent platelet reactivity was observed in overweight and obese patients (ADP: median 27 units (U) [IQR 13-39.5] vs. 7 U [6-15], p < 0.001 and TRAP: 97 U [73-118.5] vs. 85 U [36-103], p = 0.035). Significant positive correlations were observed between agonist-induced platelet reactivity and BMI.

CONCLUSION

Despite the use of DAPT, a higher platelet reactivity was found in overweight and obese patients with CCS. If these patients will benefit from treatment with more potent platelet inhibitors, it needs to be evaluated in future clinical trials.

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.

Gender-differences in antithrombotic therapy across the spectrum of ischemic heart disease: Time to tackle the Yentl syndrome?

The incidence and clinical presentation of ischemic heart disease (IHD), as well as thrombotic and bleeding risks, appear to differ between genders. Compared with men, women feature an increased thrombotic risk, probably related to an increased platelet reactivity, higher level of coagulation factors, and sex-associated unique cardiovascular risk factors, such as pregnancy-related (i.e., pre-eclampsia and gestational diabetes), gynecological disorders (i.e., polycystic ovary syndrome, early menopause) and autoimmune or systemic inflammatory diseases. At the same time, women are also at increased risk of bleeding, due to inappropriate dosing of antithrombotic agents, smaller blood vessels, lower body weight and comorbidities, such as diabetes and chronic kidney disease. Pharmacological strategies focused on the personalization of antithrombotic treatment may, therefore, be particularly appealing in women in light of their higher bleeding and ischemic risks. Paradoxically, although women represent a large proportion of cardiovascular patients in our practice, adequate high-quality clinical trial data on women remain scarce and inadequate to guide decision-making processes. As a result, IHD in women tends to be understudied, underdiagnosed and undertreated, a phenomenon known as a "Yentl syndrome." It is, therefore, compelling for the scientific community to embark on dedicated clinical trials to address underrepresentation of women and to acquire evidence-based knowledge in the personalization of antithrombotic therapy in women.

Sex-Related Differences in Platelet Aggregation: A Literature Review Supplemented with Local Data from a Group of Generally Healthy Individuals

The process of platelet aggregation is often influenced by several factors including sex and age. A literature review confirmed the existence of sex-related differences in platelet aggregation. Although 68 out of 78 papers found such differences, there are still some controversies regarding these differences, which can be due to multiple factors (age, trigger, concomitant disease, sample handling, etc.). These outcomes are discussed in line with novel results obtained from a local study, in which blood samples from a total of 53 overall healthy women and men with ages ranging from 20 to 66 years were collected. Aggregation was induced with seven different triggers (ristocetin, thrombin receptor activating peptide 6 [TRAP-6], arachidonic acid [AA], platelet-activating factor 16 [PAF-16], ADP, collagen, or thromboxane A₂ analog U-46619) ex vivo. In addition, three FDA-approved antiplatelet drugs (vorapaxar, ticagrelor, or acetylsalicylic acid [ASA]) were also tested. In general, women had higher aggregation responses to some agonists (ADP, TRAP), as well as lower benefit from inhibitors (ASA, vorapaxar). The aggregatory responses to AA and TRAP decreased with age in both sexes, while responses to ADP, U-46619, and PAF were affected by age only in women. In conclusion, more studies are needed to decipher the biological importance of sex-related differences in platelet aggregation in part to enable personalized antiplatelet treatment.

Supplementation with omega-3 or omega-6 fatty acids attenuates platelet reactivity in postmenopausal women

Postmenopausal women are at increased risk for a cardiovascular event due to platelet hyperactivity. There is evidence suggesting that ω-3 polyunsaturated fatty acids (PUFAs) and ω-6 PUFAs have cardioprotective effects in these women. However, a mechanistic understanding of how these fatty acids regulate platelet function is unknown. In this study, we supplemented postmenopausal women with fish oil (ω-3 fatty acids) or evening primrose oil (ω-6 fatty acids) and investigated the effects on their platelet activity. The effects of fatty acid supplementation on platelet aggregation, dense granule secretion, and activation of integrin αIIbβ3 at basal levels and in response to agonist were tested in postmenopausal women following a supplementation and washout period. Supplementation with fish oil or primrose oil attenuated the thrombin receptor PAR4-induced platelet aggregation. Supplementation with ω-3 or ω-6 fatty acids decreased platelet dense granule secretion and attenuated basal levels of integrin αIIbβ3 activation. Interestingly, after the washout period following supplementation with primrose oil, platelet aggregation was similarly attenuated. Additionally, for either treatment, the observed protective effects post-supplementation on platelet dense granule secretion and basal levels of integrin activation were sustained after the washout period, suggesting a long-term shift in platelet reactivity due to fatty acid supplementation. These findings begin to elucidate the underlying mechanistic effects of ω-3 and ω-6 fatty acids on platelet reactivity in postmenopausal women. Hence, this study supports the beneficial effects of fish oil or primrose oil supplementation as a therapeutic intervention to reduce the risk of thrombotic events in postmenopausal women. https://clinicaltrials.gov/ct2/show/NCT02629497.

Sex and gender in cardiovascular medicine: presentation and outcomes of acute coronary syndrome

Although health disparities in women presenting with acute coronary syndrome (ACS) have received growing attention in recent years, clinical outcomes from ACS are still worse for women than for men. Women continue to experience higher patient and system delays and receive less aggressive invasive treatment and pharmacotherapies. Gender- and sex-specific variables that contribute to ACS vulnerability remain largely unknown. Notwithstanding the sex differences in baseline coronary anatomy and function, women and men are treated the same based on guidelines that were established from experimental and clinical trial data over-representing the male population. Importantly, younger women have a particularly unfavourable prognosis and a plethora of unanswered questions remains in this younger population. The present review summarizes contemporary evidence for gender and sex differences in vascular biology, clinical presentation, and outcomes of ACS. We further discuss potential mechanisms and non-traditional risk conditions modulating the course of disease in women and men, such as unrecognized psychosocial factors, sex-specific vascular and neural stress responses, and the potential impact of epigenetic modifications.

Sex differences in platelet reactivity in patients with myocardial infarction treated with triple antiplatelet therapy - results from assessing platelet activity in coronary heart disease (APACHE)

)Several earlier studies have reported increased risk of bleeding in women with myocardial infarction, (MI) compared to men. The reasons for the observed difference are incompletely understood, but one suggested explanation has been excess dosing of antithrombotic drugs in women. The aim of this prospective observational study was to assess sex differences in platelet activity in patients treated with three different platelet inhibitors. We recruited 125 patients (37 women and 88 men) with MI, scheduled for coronary angiography. All patients received clopidogrel and aspirin. A subgroup of patients received glycoprotein (GP) IIb/IIIa-inhibitor. Platelet aggregation in whole blood was assessed at several time points, using impedance aggregometry. Soluble P-selectin was measured 3 days after admission. There were no significant differences between women and men in baseline features or comorbidities except higher frequency of diabetes, lower hemoglobin value, and lower estimated glomerular filtration rate, in women on admission. We observed significantly more in-hospital bleeding events in women compared to men (18.9% vs. 6.8%, p = .04). There were no differences in platelet aggregation using three different agonists, reflecting treatment effect of GPIIb/IIIa-inhibitors, clopidogrel, and aspirin, 6-8 hours, 3 days, 7-9 days, or 6 months after loading dose. Moreover, there was no significant difference in soluble P-selectin. The main finding of this study was a consistent lack of difference between the sexes in platelet aggregation, using three different agonists at several time-points. Our results do not support excess dosing of anti-platelet drugs as a major explanation for increased bleeding risk in women.

Sex differences in vascular reactivity of coronary artery bypass graft conduits

Females have increase in-hospital mortality and poorer outcomes following coronary artery bypass grafting (CABG). Biological differences in the reactivity of the graft conduits to circulating catecholamine may contribute to this sex difference. This study examined sex differences in the vasoconstrictor responses of internal mammary artery (IMA) and saphenous vein (SV) conduits to phenylephrine (PE) and endothelin-1 (ET-1). Functional IMA and SV were obtained from 78 male and 50 female patients undergoing CABG (67.7 ± 11 and 69 ± 10 years, respectively) and subjected to the following experimental conditions. (1) Concentration response curves for PE and ET-1 were generated in an intact IMA and SV and endothelium denuded IMA segments, (2) in the presence of the nitric oxide synthase inhibitor (L-NAME) or the cyclooxygenase inhibitor (indomethacin) in an endothelium-intact IMA and (3) the activity state (abundance and phosphorylation) of the α1-adrenergic receptor was investigated using Phos-tag™ western blot analysis. (1) Compared to male, female IMA and SV were hypersensitive to PE but not ET-1 (p < 0.05). The female IMA hypersensitivity response to PE was abolished following endothelial denudation, (2) persisted in the presence of L-NAME but was abolished in the presence of indomethacin and (3) there was no sex differences in the abundance and phosphorylation of the α1-adrenergic receptor in IMA. Female IMA and SV graft conduits are hypersensitive to α1-adrenergic stimuli. This endothelial cyclooxygenase pathway-mediated hypersensitivity may produce excessive IMA and SV graft constriction in females administered catecholamines and could contribute to their poorer CABG outcomes.

Mechanisms Responsible for Serotonin Vascular Reactivity Sex Differences in the Internal Mammary Artery

Background

The increased adverse cardiac events in women undergoing coronary artery bypass grafting are multifactorial and may include clinical, psychosocial, and biological factors. Potential contributing biological factors could include vascular hyperreactivity of the internal mammary artery (IMA) to endogenous vasoconstrictors in women, resulting in a predilection to myocardial ischemia. This study evaluated sex differences in serotonin and thromboxane A₂ dependent vasoconstriction in human isolated IMA, with the mechanistic role of (1) the endothelium, (2) nitric oxide (NO), (3) prostaglandins, and (4) receptor activity investigated for any observed sex difference.

Methods and Results

Viable isolated human IMA segments were obtained from 116 patients (44 women [mean age, 66.8±12.2 years] and 72 men [mean age, 66.6±10.4 years]) undergoing coronary artery bypass grafting. Cumulative concentration‐response curves for serotonin and thromboxane A₂ mimetic, U46619, were determined and revealed an increased sensitivity to serotonin but not U46619 in women. This sex difference to serotonin was further assessed by the following: (1) endothelial denudation, (2) endothelial NO synthase inhibition and NO quantification using electron paramagnetic resonance, (3) cyclooxygenase inhibition and prostaglandin metabolite quantification using mass spectrometry, and (4) quantification of receptor activity status. The female hyperreactivity to serotonin was (1) abolished by endothelial denudation; (2) unaffected by NO synthase inhibition, with no difference in electron paramagnetic resonance–assessed NO levels; (3) abolished by cyclooxygenase inhibition (quantification of prostaglandins in IMA revealed a trend towards reduced 6‐keto prostaglandin F1α in female IMA; P=0.08); and (4) unrelated to receptor activity.

Conclusions

These data indicate that female IMAs are hyperreactive to serotonin but not U46619, with the former attributable to an endothelium‐dependent cyclooxygenase pathway.

Reprint of: Proteomics in cardiovascular diseases: Unveiling sex and gender differences in the era of precision medicine

Cardiovascular diseases (CVDs) represent the most important cause of mortality in women and in men. Contrary to the long-standing notion that the effects of the major risk factors on CVD outcomes are the same in both sexes, recent evidence recognizes new, potentially independent, sex/gender-related risk factors for CVDs, and sex/gender-differences in the clinical presentation of CVDs have been demonstrated. Furthermore, some therapeutic options may not be equally effective and safe in men and women. In this context, proteomics offers an extremely useful and versatile analytical platform for biomedical researches that expand from the screening of early diagnostic and prognostic biomarkers to the investigation of the molecular mechanisms underlying CDVs. In this review, we summarized the current applications of proteomics in the cardiovascular field, with emphasis on sex and gender-related differences in CVDs.

SIGNIFICANCE

Increasing evidence supports the profound effect of sex and gender on cardiovascular physio-pathology and the response to drugs. A clear understanding of the mechanisms underlying sexual dimorphisms in CVDs would not only improve our knowledge of the etiology of these diseases, but could also inform health policy makers and guideline committees in tailoring specific interventions for the prevention, treatment and management of CVDs in both men and women.

Proteomics in cardiovascular diseases: Unveiling sex and gender differences in the era of precision medicine

Cardiovascular diseases (CVDs) represent the most important cause of mortality in women and in men. Contrary to the long-standing notion that the effects of the major risk factors on CVD outcomes are the same in both sexes, recent evidence recognizes new, potentially independent, sex/gender-related risk factors for CVDs, and sex/gender-differences in the clinical presentation of CVDs have been demonstrated. Furthermore, some therapeutic options may not be equally effective and safe in men and women. In this context, proteomics offers an extremely useful and versatile analytical platform for biomedical researches that expand from the screening of early diagnostic and prognostic biomarkers to the investigation of the molecular mechanisms underlying CDVs. In this review, we summarized the current applications of proteomics in the cardiovascular field, with emphasis on sex and gender-related differences in CVDs.

SIGNIFICANCE

Increasing evidence supports the profound effect of sex and gender on cardiovascular physio-pathology and the response to drugs. A clear understanding of the mechanisms underlying sexual dimorphisms in CVDs would not only improve our knowledge of the etiology of these diseases, but could also inform health policy makers and guideline committees in tailoring specific interventions for the prevention, treatment and management of CVDs in both men and women.

Gender Differences in Associations Between Intraprocedural Thrombotic Events During Percutaneous Coronary Intervention and Adverse Outcomes

Women are frequently reported to have increased morbidity after presentation with acute coronary syndromes and myocardial infarction; however, whether a greater thrombotic tendency contributes to gender differences in clinical outcomes of urgent percutaneous coronary intervention is unknown. Intraprocedural Thrombotic Events (IPTEs) are defined as new or increasing thrombus, abrupt vessel closure, no reflow or slow reflow, or distal embolization at any time during percutaneous coronary intervention. IPTEs were evaluated in this pooled analysis of 6,591 patients with stent implantation and blinded quantitative coronary angiography (QCA) analysis, from the ACUITY and HORIZONS-AMI trials. We compared major adverse cardiac events (MACE) at in-hospital, 30-day, and 1-year follow-up and major bleeding at 30 days according to gender and the presence or absence of IPTE. IPTE was identified in 507 patients (7.7%), with 119 of 1,744 (6.8%) occurring in women and 388 of 4,847 (8.0%) in men (p = 0.12). IPTE, but not gender, was independently associated with MACE at in-hospital and 30-day follow-up. At 1-year follow-up, the adjusted hazard of MACE was higher in women and in patients with IPTE; however, the risk of MACE associated with IPTE was similar among women and men. There was no significant interaction between IPTE and gender for 1-year MACE or 30-day bleeding. IPTE predicted major bleeding only in women. In conclusion, in acute coronary syndromes, women have increased risk of adverse outcome at 1 year. IPTEs are common, occur at similar frequency, and are associated with similar degree of increased MACE in both genders at short- and long-term follow-up. Higher thrombotic propensity does not offer a mechanistic explanation for the worse outcomes noted in women.

Influence of race and sex on thrombogenicity in a large cohort of coronary artery disease patients

Background

It is uncertain whether sex and race affect thrombogenicity in patients with coronary artery disease. We evaluated the effects of sex and race on thrombogenicity in patients with coronary artery disease treated with aspirin.

Methods and Results

Patients on aspirin therapy for 1 week or longer with known or suspected coronary artery disease undergoing nonurgent cardiac catheterization (n=1172), of whom 924 were on aspirin and clopidogrel therapy, were studied. The primary end point was thrombin‐induced platelet‐fibrin clot strength (MA_KH) measured by thrombelastography. Secondary end points included coagulation index, a measure of overall coagulation; G, another measure of clot strength; and maximal platelet aggregation. Women had greater MA_KH, G, and coagulation index than men, both with and without clopidogrel therapy (with clopidogrel: 68.3±6 versus 65.8±6 mm, P<0.0001; 11.4±3 versus 9.5±4 dyne/cm², P<0.0001; and 0.12±3 versus −0.7±3, P=0.003, respectively). Platelet aggregation (induced by ADP, thrombin receptor activating peptide, or collagen) did not differ between sexes. Black patients had greater MA_KH and G than white patients (with clopidogrel: 67.8±7 versus 66.4±6 mm, P=0.005; 11±4 versus 10±3 dyne/cm², P=0.02, respectively). Black women had the highest MA_KH levels. By multivariate analysis, sex, race, diabetes, platelet count, and hemoglobin level were independently associated with MA_KH. Sex, but not race, was also associated with the frequency of MA_KH ≥72 mm (a threshold related to ischemic event occurrence in patients undergoing coronary intervention).

Conclusions

Sex and race independently influence platelet‐fibrin clot strength. Black women appear to have the highest thrombogenicity profile, potentially conferring a high‐risk phenotype for thrombotic event occurrence.

Response to antiplatelet therapy and platelet reactivity to thrombin receptor activating peptide-6 in cardiovascular interventions: Differences between peripheral and coronary angioplasty

BACKGROUND

The long-term prognosis of patients with peripheral arterial disease (PAD) is significantly worse than the prognosis of coronary artery disease (CAD) patients. Detrimental platelet activation could contribute to the increased rate of adverse cardiovascular events in PAD. We therefore investigated whether response to antiplatelet therapy and thrombin inducible platelet activation differ between patients with best medical therapy undergoing angioplasty and stenting for symptomatic PAD (n = 166) or CAD (n = 104).

METHODS

Adenosine diphosphate (ADP), arachidonic acid (AA) and thrombin receptor activating peptide (TRAP)-6 inducible platelet reactivity was measured by multiple electrode aggregometry (MEA). Platelet surface expression of P-selectin and activated glycoprotein IIb/IIIa (GPIIb/IIIa) in response to ADP, AA, and TRAP-6, and the formation of monocyte-platelet aggregates (MPA) in response to ADP and TRAP-6 were assessed by flow cytometry.

RESULTS

Patients with PAD had significantly higher platelet reactivity in response to ADP and AA by MEA compared to CAD patients. Likewise, the expression of P-selectin and GPIIb/IIIa following stimulation with ADP and AA, and MPA formation in response to ADP were significantly higher in PAD patients than in CAD patients. In response to TRAP-6, patients with PAD showed a significantly increased platelet aggregation by MEA, higher expression of activated GPIIb/IIIa, and more pronounced formation of MPA than CAD patients.

CONCLUSION

Following angioplasty and stenting, PAD patients exhibit a significantly diminished response to dual antiplatelet therapy and an increased susceptibility to TRAP-6 inducible platelet activation compared to CAD patients.