Determinants of reduced antiplatelet effect of aspirin in patients with stable coronary artery disease

10. Cardiovascular Disease and Risk Management: Standards of Care in Diabetes-2024

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, an interprofessional expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Comparative Effectiveness of Aspirin Dosing in Cardiovascular Disease and Diabetes Mellitus: A Subgroup Analysis of the ADAPTABLE Trial

OBJECTIVE

Patients with diabetes mellitus (DM) and concomitant atherosclerotic cardiovascular disease (ASCVD) must be on the most effective dose of aspirin to mitigate risk of future adverse cardiovascular events.

RESEARCH DESIGN AND METHODS

ADAPTABLE, an open-label, pragmatic study, randomized patients with stable, chronic ASCVD to 81 mg or 325 mg of daily aspirin. The effects of aspirin dosing was assessed on the primary effectiveness outcome, a composite of all-cause death, hospitalization for myocardial infarction, or hospitalization for stroke, and the primary safety outcome of hospitalization for major bleeding. In this prespecified analysis, we used Cox proportional hazards models to compare aspirin dosing in patients with and without DM for the primary effectiveness and safety outcome.

RESULTS

Of 15,076 patients, 5,676 (39%) had DM of whom 2,820 (49.7%) were assigned to 81 mg aspirin and 2,856 (50.3%) to 325 mg aspirin. Patients with versus without DM had higher rates of the composite cardiovascular outcome (9.6% vs. 5.9%; P < 0.001) and bleeding events (0.78% vs. 0.50%; P < 0.001). When comparing 81 mg vs. 325 mg of aspirin, patients with DM had no difference in the primary effectiveness outcome (9.3% vs. 10.0%; hazard ratio [HR] 0.98 [95% CI 0.83-1.16]; P = 0.265) or safety outcome (0.87% vs. 0.69%; subdistribution HR 1.25 [95% CI 0.72-2.16]; P = 0.772).

CONCLUSIONS

This study confirms the inherently higher risk of patients with DM irrespective of aspirin dosing. Our findings suggest that a higher dose of aspirin yields no added clinical benefit, even in a more vulnerable population.

10. Cardiovascular Disease and Risk Management: Standards of Care in Diabetes-2023

The American Diabetes Association (ADA) "Standards of Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations and a full list of Professional Practice Committee members, please refer to Introduction and Methodology. Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Platelet inhibition by low-dose aspirin is not influenced by body mass or weight

Aspirin's clinical efficacy may be influenced by body weight and mass. Although inadequate platelet inhibition by aspirin is suggested as responsible, evidence for this in non-diabetic patients is sparse. We investigated the influence of body weight and mass on aspirin's inhibition of platelet aggregation in healthy adults without diabetes. Cohort one (NYU, n = 84) had light transmission aggregometry (LTA) of platelet-rich plasma to submaximal adenosine diphosphate (ADP) and arachidonic acid (AA) before and following 1 week of daily 81 mg non-enteric coated aspirin. Subjects in the validation cohort (Duke, n = 66) were randomized to 81 mg or 325 mg non-enteric coated aspirin for 4 weeks, immediately followed by 4 weeks of the other dose, with LTA to submaximal collagen, ADP, and AA before and after each dosage period. Body mass index (BMI) range was 18.0-57.5 kg/m2 and 25% were obese. Inhibition of platelet aggregation was similar irrespective of BMI, body weight and aspirin dose. There was no correlation between platelet aggregation before or after aspirin with BMI or body weight. Our data demonstrate that aspirin produces potent inhibition of direct and indirect COX1-mediated platelet aggregation in healthy adults without diabetes regardless of body weight or mass - suggesting that other mechanisms explain lower preventive efficacy of low-dose aspirin with increasing body weight/mass.

Factors Associated with Aspirin Resistance in Hong Kong Chinese Patients with Stable Coronary Heart Disease Using the Multiplate® Analyzer and Serum Thromboxane B2

Introduction: Aspirin resistance may be associated with various conditions. We measured serum thromboxane B2 (TXB2) and platelet function using the Multiplate® Analyzer with arachidonic acid (ASPI) in patients on long term aspirin therapy to identify aspirin resistance and associated factors. Materials and Methods: Chinese patients with stable coronary heart disease had samples for serum TXB2 and ASPI measurement taken before and 1 h after taking a morning dose of 80 mg aspirin. Results: In 266 patients with mean age 66.6 ± 10.7 years, 17% were female and 55% were current or previous smokers. TXB2 and ASPI measurements were significantly higher before the dose than at 1 h post dose, with 46% of subjects having high ASPI values (AUC > 300 AU*min) pre dose compared with 27% at 1 h post dose. TXB2 and ASPI measures of platelet aggregation showed weak correlations, which were only significant before the dose (r = 0.219, p = 0.001). Increased ASPI measurements were associated with white blood cell (WBC) count, haematocrit, platelet count and heart rate at 24 h post dose but only with WBC count, smoking history and heart rate at 1 h post dose. Diabetes was not associated with reduced platelet response to aspirin. The WBC count associated with aspirin resistance was over 6.55 × 109/L by receiver operating characteristic analysis. Conclusions: The antiplatelet response to aspirin was reduced in a large proportion of patients. Patients with higher WBC count within the normal range appear to be at increased risk of aspirin resistance. Higher or more frequent doses of aspirin may be needed in many patients.

Effects of DPP4 Inhibitor in Platelet Reactivity and Other Cardiac Risk Markers in Patients with Type 2 Diabetes and Acute Myocardial Infarction

Background: The management of acute myocardial infarction (AMI) presents several challenges in patients with diabetes, among them the higher rate of recurrent thrombotic events, hyperglycemia and risk of subsequent heart failure (HF). The objective of our study was to evaluate effects of DPP-4 inhibitors (DPP-4i) on platelet reactivity (main objective) and cardiac risk markers. Methods: We performed a single-center double-blind randomized trial. A total of 70 patients with type 2 diabetes (T2DM) with AMI Killip ≤2 on dual-antiplatelet therapy (aspirin plus clopidogrel) were randomized to receive sitagliptin 100 mg or saxagliptin 5 mg daily or matching placebo. Platelet reactivity was assessed at baseline, 4 days (primary endpoint) and 30 days (secondary endpoint) after randomization, using VerifyNow Aspirin™ assay, expressed as aspirin reaction units (ARUs); B-type natriuretic peptide (BNP) in pg/mL was assessed at baseline and 30 days after (secondary endpoint). Results: Mean age was 62.6 ± 8.8 years, 45 (64.3%) male, and 52 (74.3%) of patients presented with ST-segment elevation MI. For primary endpoint, there were no differences in mean platelet reactivity (p = 0.51) between the DPP-4i (8.00 {−65.00; 63.00}) and placebo (−14.00 {−77.00; 52.00}) groups, as well in mean BNP levels (p = 0.14) between DPP-4i (−36.00 {−110.00; 15.00}) and placebo (−13.00 {−50.00; 27.00}). There was no difference between groups in cardiac adverse events. Conclusions: DPP4 inhibitor did not reduce platelet aggregation among patients with type 2 diabetes hospitalized with AMI. Moreover, the use of DPP-4i did not show an increase in BNP levels or in the incidence of cardiac adverse events. These findings suggests that DPP-4i could be an option for management of T2DM patients with acute MI.

Platelet Aggregation Before Aspirin Initiation in Pediatric Patients With Congenital Heart Disease at High Risk of Thrombosis

Background

Aspirin following unfractionated heparin is the most common anticoagulation strategy for pediatric patients who experienced cardiac surgery at high risk of thrombosis. The platelet aggregation test is the golden method to evaluate the aspirin effect on platelet function. However, the platelet aggregation basal status before postoperative aspirin initiation and the related clinical influencing factors hasn't been investigated systemically in this population.

Methods

In a prospective cohort of 247 children, arachidonic acid-induced platelet aggregation (PAG-AA) was measured by means of light transmission aggregometry (LTA) before the first dose of aspirin after cardiac surgical procedure and the perioperative variables were also collected. Distribution of this population's PAG-AA basal status was described. Univariate and multivariate logistic regression analysis were performed to identify the main influencing factors of PAG-AA.

Results

The median time of aspirin administration was 2 (1–27) days after surgery and the corresponding median value of basal PAG-AA was 20.70% (1.28–86.49%), with 67.6% population under 55% and 47.8% population under 20%. Patients undergoing cardiopulmonary bypass (CPB) had a significantly lower basal PAG-AA than those without (30.63 ± 27.35 vs. 57.91 ± 27.58, p = 0.013). While patients whose test done within 3 days after CPB had a significantly lower PAG-AA than those out of 3 days (25.61 ± 25.59 vs. 48.59 ± 26.45, p = 0.001). Univariate analysis implied that the influencing factors of the basal PAG-AA including CPB use, test time point, cyanosis, and platelet count. Multivariate regression analysis indicated that only CPB use, test time point, and platelet count were the main independent influencing factors for the basal PAG-AA.

Conclusion

The majority of children have impaired basal platelet aggregometry responses before postoperative aspirin initiation. The main influencing factors are CPB use, test time point, and platelet count. To establish the platelet aggregometry baseline prior to commencement of aspirin therapy, testing should be performed 3 days later following the procedure when effect of CPB is basically over.

10. Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2022

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc22-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc22-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Use of 3D Printing for the Development of Biodegradable Antiplatelet Materials for Cardiovascular Applications

Small-diameter synthetic vascular grafts are required for surgical bypass grafting when there is a lack of suitable autologous vessels due to different reasons, such as previous operations. Thrombosis is the main cause of failure of small-diameter synthetic vascular grafts when used for this revascularization technique. Therefore, the development of biodegradable vascular grafts capable of providing a localized and sustained antithrombotic drug release mark a major step forward in the fight against cardiovascular diseases, which are the leading cause of death globally. The present paper describes the use of an extrusion-based 3D printing technology for the production of biodegradable antiplatelet tubular grafts for cardiovascular applications. For this purpose, acetylsalicylic acid (ASA) was chosen as a model molecule due to its antiplatelet activity. Poly(caprolactone) and ASA were combined for the fabrication and characterization of ASA-loaded tubular grafts. Moreover, rifampicin (RIF) was added to the formulation containing the higher ASA loading, as a model molecule that can be used to prevent vascular prosthesis infections. The produced tubular grafts were fully characterized through multiple techniques and the last step was to evaluate their drug release, antiplatelet and antimicrobial activity and cytocompatibility. The results suggested that these materials were capable of providing a sustained ASA release for periods of up to 2 weeks. Tubular grafts containing 10% (w/w) of ASA showed lower platelet adhesion onto the surface than the blank and grafts containing 5% (w/w) of ASA. Moreover, tubular grafts scaffolds containing 1% (w/w) of RIF were capable of inhibiting the growth of Staphylococcus aureus. Finally, the evaluation of the cytocompatibility of the scaffold samples revealed that the incorporation of ASA or RIF into the composition did not compromise cell viability and proliferation at short incubation periods (24 h).

Contemporary Clinical Use of Aspirin: Mechanisms of Action, Current Concepts, Unresolved Questions, and Future Perspectives

The ability of aspirin to inhibit platelet aggregation has positioned this agent within the most frequently used drugs worldwide. The aim of this article is to review the contemporary clinical use of aspirin and also to discuss unresolved issues not yet translated into clinical practice. Results from several clinical trials have led to strong guideline recommendations for aspirin use in the acute management and secondary prevention of cardiovascular disease. On the contrary, guidelines regarding aspirin use as primary prevention of cardiovascular disease are almost conservative, supported by recent trials reporting that the bleeding risk outweighs the potential benefits in most patients. In pregnancy, aspirin has proved efficient in preventing preeclampsia and small-for-gestational-age births in women at high risk, and is hence widely recommended in clinical guidelines. Despite the vast amount of clinical data on aspirin, several unresolved questions remain. Randomized trials have reported that aspirin reduces the risk of recurrent venous thromboembolism, but the clinical relevance remains limited, because direct oral anticoagulants are more effective. Laboratory studies suggest that a twice-daily dosing regimen or evening intake may lead to more efficient platelet inhibition, and the potential clinical benefit of such strategies is currently being explored in ongoing clinical trials. Enteric-coated formulations of aspirin are frequently used, but it remains unclear if they are safer and as efficient as plain aspirin. In the future, aspirin use after percutaneous coronary interventions might not be mandatory in patients who also need anticoagulant therapy, as several trials support shorter aspirin duration strategies. On the other hand, new treatment indications for aspirin will likely arise, as there is growing evidence that aspirin may reduce the risk of colorectal cancer and other types of cancer.

MicroRNA as Biomarkers for Platelet Function and Maturity in Patients with Cardiovascular Disease

Patients with cardiovascular disease (CVD) are at increased risk of suffering myocardial infarction. Platelets are key players in thrombus formation and, therefore, antiplatelet therapy is crucial in the treatment and prevention of CVD. MicroRNAs (miRs) may hold the potential as biomarkers for platelet function and maturity. This systematic review was conducted using the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). To identify studies investigating the association between miRs and platelet function and maturity in patients with CVD, PubMed and Embase were searched on October 13 and December 13, 2020 without time boundaries. Risk of bias was evaluated using a standardized quality assessment tool. Of the 16 included studies, 6 studies were rated "good" and 10 studies were rated "fair." In total, 45 miRs correlated significantly with platelet function or maturity (rho ranging from -0.68 to 0.38, all p < 0.05) or differed significantly between patients with high platelet reactivity and patients with low platelet reactivity (p-values ranging from 0.0001 to 0.05). Only four miRs were investigated in more than two studies, namely miR-223, miR-126, miR-21 and miR-150. Only one study reported on the association between miRs and platelet maturity. In conclusion, a total of 45 miRs were associated with platelet function or maturity in patients with CVD, with miR-223 and miR-126 being the most frequently investigated. However, the majority of the miRs were only investigated in one study. More data are needed on the potential use of miRs as biomarkers for platelet function and maturity in CVD patients.

10. Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2021

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc21-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc21-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Fibrin Clot Formation and Lysis in Plasma

Disturbance in the balance between fibrin formation and fibrinolysis can lead to either bleeding or thrombosis; however, our current routine coagulation assays are not sensitive to altered fibrinolysis. The clot formation and lysis assay is a dynamic plasma-based analysis that assesses the patient’s capacity for fibrin formation and fibrinolysis by adding an activator of coagulation as well as fibrinolysis to plasma and measuring ex vivo fibrin clot formation and breakdown over time. This assay provides detailed information on the fibrinolytic activity but is currently used for research only, as the assay is prone to inter-laboratory variation and as it demands experienced laboratory technicians as well as specialized personnel to validate and interpret the results. Here, we describe a protocol for the clot formation and lysis assay used at our research laboratory.

Genetic Variation in PEAR1, Cardiovascular Outcomes and Effects of Aspirin in a Healthy Elderly Population

The platelet endothelial aggregation receptor-1 (PEAR1) rs12041331 variant has been identified as a genetic determinant of platelet aggregation in response to antiplatelet therapies, including aspirin. However, association with atherothrombotic cardiovascular events is less clear, with limited evidence from large trials. Here, we tested association of rs12041331 with cardiovascular events and aspirin use in a randomized trial population of healthy older individuals. We undertook post hoc analysis of 13,547 participants of the ASPirin in Reducing Events in the Elderly (ASPREE) trial, median age 74 years. Participants had no previous diagnosis of atherothrombotic cardiovascular disease at enrollment, and were randomized to either 100 mg daily low-dose aspirin or placebo for median 4.7 years follow-up. We used Cox proportional hazard regression to model the relationship between rs12041331 and the ASPREE primary cardiovascular disease (CVD) end point, and composites of major adverse cardiovascular events (MACE) and ischemic stroke (STROKE); and bleeding events; major hemorrhage (MHEM) and intracranial bleeding (ICB). We performed whole-population analysis using additive and dominant inheritance models, then stratified by treatment group. Interaction effects between genotypes and treatment group were examined. We observed no statistically significant association (P < 0.05) in the population, or by treatment group, between rs12041331 and cardiovascular or bleeding events in either model. We also found no significant interaction effects between rs12041331-A and treatment group, for CVD (P = 0.65), MACE (P = 0.32), STROKE (P = 0.56), MHEM (P = 0.59), or ICB (P = 0.56). The genetic variant PEAR1 rs12041331 is not associated with cardiovascular events in response to low-dose aspirin in a healthy elderly population.

The ABO Locus is Associated with Increased Fibrin Network Formation in Patients with Stable Coronary Artery Disease

BACKGROUND

 The ABO locus has been associated with increased risk of myocardial infarction (MI) in patients with coronary artery disease (CAD), but the underlying mechanisms are unknown. As altered fibrin clot structure has been demonstrated to predict MI in CAD patients, we examined the association between the ABO risk variant and fibrin clot properties, and investigated the effects of other CAD-associated risk variants.

METHODS

 We included 773 stable CAD patients. Patients were genotyped for 45 genome-wide CAD risk variants, including rs495828 at the ABO locus. We used a genetic risk score (GRS) for CAD calculated as the weighted sum of the number of risk alleles based on all 45 variants. Fibrin clot properties were evaluated using a turbidimetric assay. We studied clot maximum absorbance, a measure of clot density and fiber thickness, together with clot lysis time, an indicator of fibrinolysis potential.

RESULTS

 The rs495828 risk allele was present in 13.2% of patients and associated with higher clot maximum absorbance (adjusted effect size per risk allele: 1.05 [1.01 - 1.09], p = 0.01) but not with clot lysis time (p = 0.97). The rs12936587 (p = 0.04), rs4773144 (p = 0.02), and rs501120 (p = 0.04) were associated with clot lysis time; however, after Bonferroni correction, no significant associations were found between any of the remaining 44 CAD-associated variants and fibrin clot properties. The GRS was not associated with fibrin clot properties (p-values > 0.05).

CONCLUSION

 The ABO risk allele was associated with a more compact fibrin network in stable CAD patients, which may represent a mechanism for increased MI risk in ABO risk variant carriers.

Antiplatelet therapies in diabetes

Cardiovascular complications remain the main cause of mortality and morbidity in diabetes. This is related to advanced vascular pathology in this population, together with an enhanced thrombotic environment. The increased risk in thrombosis is secondary to platelet hyper-reactivity and increased levels and/or altered activity of coagulation factors. The current review is focused on the role of antiplatelet agents in modulating the thrombotic milieu in diabetes and improving vascular outcome in this high-risk population. We review the latest evidence for the use of aspirin in primary vascular prevention together with long-term treatment with this agent for secondary prevention. We also discuss the effects of the various P2Y₁₂ inhibitors, including clopidogrel, prasugrel and ticagrelor, on both short- and long-term secondary vascular prevention. Moreover, we briefly review antiplatelet therapies in special groups of people including those intolerant to aspirin, individuals with peripheral vascular disease and those with cerebrovascular pathology. The overall aim of this review is to provide the healthcare professional with a pragmatic guide for the management of thrombotic risk using established antiplatelet therapies to improve vascular outcome in persons with diabetes.

10. Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2020

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes the ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee (https://doi.org/10.2337/dc20-SPPC), are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction (https://doi.org/10.2337/dc20-SINT). Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Aspirin for primary prevention of cardiovascular disease: a meta-analysis with a particular focus on subgroups

BACKGROUND

The role of aspirin in primary prevention of cardiovascular disease (CVD) remains unclear. We aimed to investigate the benefit-risk ratio of aspirin for primary prevention of CVD with a particular focus on subgroups.

METHODS

Randomized controlled trials comparing the effects of aspirin for primary prevention of CVD versus control and including at least 1000 patients were eligible for this meta-analysis. The primary efficacy outcome was all-cause mortality. Secondary outcomes included cardiovascular mortality, major adverse cardiovascular events (MACE), myocardial infarction, ischemic stroke, and net clinical benefit. The primary safety outcome was major bleeding. Subgroup analyses involving sex, concomitant statin treatment, diabetes, and smoking were performed.

RESULTS

Thirteen randomized controlled trials comprising 164,225 patients were included. The risk of all-cause and cardiovascular mortality was similar for aspirin and control groups (RR 0.98; 95% CI, 0.93-1.02; RR 0.99; 95% CI, 0.90-1.08; respectively). Aspirin reduced the relative risk (RRR) of major adverse cardiovascular events (MACE) by 9% (RR 0.91; 95% CI, 0.86-0.95), myocardial infarction by 14% (RR 0.86; 95% CI, 0.77-0.95), and ischemic stroke by 10% (RR 0.90; 95% CI, 0.82-0.99), but was associated with a 46% relative risk increase of major bleeding events (RR 1.46; 95% CI, 1.30-1.64) compared with controls. Aspirin use did not translate into a net clinical benefit adjusted for event-associated mortality risk (mean 0.034%; 95% CI, - 0.18 to 0.25%). There was an interaction for aspirin effect in three patient subgroups: (i) in patients under statin treatment, aspirin was associated with a 12% RRR of MACE (RR 0.88; 95% CI, 0.80-0.96), and this effect was lacking in the no-statin group; (ii) in non-smokers, aspirin was associated with a 10% RRR of MACE (RR 0.90; 95% CI, 0.82-0.99), and this effect was not present in smokers; and (iii) in males, aspirin use resulted in a 11% RRR of MACE (RR 0.89; 95% CI, 0.83-0.95), with a non-significant effect in females.

CONCLUSIONS

Aspirin use does not reduce all-cause or cardiovascular mortality and results in an insufficient benefit-risk ratio for CVD primary prevention. Non-smokers, patients treated with statins, and males had the greatest risk reduction of MACE across subgroups.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019118474.

Aspirin & clopidogrel non-responsiveness & its association with genetic polymorphisms in patients with myocardial infarction

Background & objectives:

Cytochrome P450, P2Y12, cyclooxygenase-1 (COX1) and glycoprotein V1 (GPVI) gene polymorphisms are known to affect patient responsiveness towards aspirin and clopidogrel dual antiplatelet therapy (DAPT). The present study was undertaken to identify aspirin and clopidogrel non-responsiveness and its association with genetic polymorphism in patients with myocardial infarction (MI).

Methods:

A total of 207 MI patients who were on DAPT, were included. The DAPT non-responsiveness was determined by light transmittance aggregometry using arachidonic acid and adenosine diphosphate and high platelet reactivity by collagen. Platelet activation biomarkers, thromboxane B₂ (TxB₂) and soluble CD40 ligand (sCD40L) were measured in plasma. Patient compliance was checked by estimating drug and its metabolite levels (aspirin and clopidogrel) in plasma using liquid chromatography-mass spectrometry/mass spectrometry. Genomic DNA was extracted, amplified by polymerase chain reaction and subsequently sequenced to identify CYP450, P2Y12, COX1 and GPVI gene polymorphisms.

Results:

Of the 207 patients, 32 were non-responders. The DAPT non-responsiveness was found in 15.5 per cent patients. The non-responsiveness showed a significant and an independent association with gender [odds ratio (OR)=0.18, 95% confidence interval (CI)=0.01-0.78, P=0.023], TxB₂ (OR=1.00, 95% CI=1.00-1.01, P=0.013), CYP2C19*2 G>A (OR=3.33, 95% CI=1.04-10.69, P=0.044) and GPVI T>C (OR=0.23, 95% CI=0.08-0.67, P=0.007) after adjusting the demographic, clinical and genetic confounding factors when assessed between non-responder and responder compliant patients.

Interpretation & conclusions:

The study showed a significant association of genetic polymorphisms (CYP2C19*2 G>A and GPVI T>C) with DAPT non-responsiveness in MI patients. The findings of this study need further validation in a large cohort of patients with clinical follow up.

Aspirin has potential benefits for primary prevention of cardiovascular outcomes in diabetes: updated literature-based and individual participant data meta-analyses of randomized controlled trials

Background

The clinical benefit of aspirin for the primary prevention of cardiovascular disease (CVD) in diabetes remains uncertain. To evaluate the efficacy and safety of aspirin for the primary prevention of cardiovascular outcomes and all-cause mortality events in people with diabetes, we conducted an updated meta-analysis of published randomised controlled trials (RCTs) and a pooled analysis of individual participant data (IPD) from three trials.

Methods

Randomised controlled trials of aspirin compared with placebo (or no treatment) in participants with diabetes with no known CVD were identified from MEDLINE, Embase, Cochrane Library, and manual search of bibliographies to January 2019. Relative risks with 95% confidence intervals were used as the summary measures of associations.

Results

We included 12 RCTs based on 34,227 participants with a median treatment duration of 5.0 years. Comparing aspirin use with no aspirin, there was a significant reduction in risk of major adverse cardiovascular events (MACE)0.89 (0.83–0.95), with a number needed to treat (NNT)of 95 (95% CI 61 to 208) to prevent one MACE over 5 years average follow-up. Evidence was lacking of heterogeneity and publication bias among contributing trials for MACE. Aspirin use had no effect on other endpoints including all-cause mortality; however, there was a significant reduction in stroke for aspirin dosage ≤ 100 mg/day 0.75 (0.59–0.95). There were no significant effects of aspirin use on major bleeding and other bleeding events, though some of the estimates were imprecise. Pooled IPD from the three trials (2306 participants) showed no significant evidence of an effect of aspirin on any of the outcomes evaluated; however, aspirin reduced the risk of MACE in non-smokers 0.70 (0.51–0.96) with a NNT of 33 (95% CI 20 to 246) to prevent one MACE.

Conclusions

Aspirin has potential benefits in cardiovascular primary prevention in diabetes. The use of low dose aspirin may need to be individualised and based on each individual’s baseline CVD and bleeding risk.

Systematic review registration PROSPERO: CRD42019122326

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0875-4) contains supplementary material, which is available to authorized users.

Increased bodyweight and inadequate response to aspirin in individuals with coronary artery disease

Recent reports have suggested that aspirin effect might be influenced by bodyweight, with decreased efficacy in heavier individuals. We investigated the influence of bodyweight on aspirin pharmacodynamics in two independent datasets of patients taking non-enteric coated aspirin 100 mg QD for coronary artery disease (CAD). In the first dataset, 368 patients had their platelet aggregation assessed using VerifyNow Aspirin and measured in Aspirin Reaction Units (ARU). In the second dataset, 70 patients had serum thromboxane B2 (TXB2) dosage assessed by an ELISA assay and measured in pg/mL. Platelet aggregation was independently associated with bodyweight, with 8.41 (95% CI 1.86-14.97; adjusted p-value = 0.012) increase in ARU for every 10 kg. Furthermore, the rate of non-response to aspirin (defined as ARU ≥ 550) was significantly associated with increased bodyweight (adjusted p-value = 0.007), with OR = 1.23 (95% CI 1.06-1.42) for every 10 kg. Similar results were found considering body mass index (in kg/m²), with 15.5 (95% CI 5.0 to 25.9; adjusted p-value = 0.004) increase in ARU for every 10 kg and non-response OR = 1.43 (95% CI 1.13 to 1.81, adjusted p-value = 0.003) for every 5 kg/m². Moreover, serum TXB2 was higher in patients weighting more than 70 kg (222.6 ± 62.9 versus 194.9 ± 61.9 pg/mL; adjusted p-value = 0.018). In two different datasets of patients with CAD on non-enteric coated aspirin 100 mg QD, increased bodyweight was independently associated with impaired response to aspirin.

10. Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2019

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

Neutrophil gelatinase-associated lipocalin (NGAL) and cardiovascular events in patients with stable coronary artery disease

Inflammation is an important mediator in the pathogenesis of atherosclerosis. Neutrophil gelatinase-associated lipocalin (NGAL) is a small glycoprotein secreted by neutrophils. NGAL regulates the activity of matrix metalloproteinase-9, which plays a role in plaque instability. It has therefore been hypothesised that NGAL may modulate inflammation and promote the development and progression of atherosclerosis. Our aim was to assess the predictive value of plasma NGAL in a prospective cohort study of 876 high-risk patients with stable coronary artery disease (CAD). NGAL levels were measured using the NGAL Test^TM from BioPorto Diagnostics. Clinical follow-up was performed after a median of 3.1 years. The endpoint was a combination of non-fatal acute myocardial infarction (MI), cardiovascular death (CVD), or ischaemic stroke. The NGAL concentration was (median [25;75%]: 64.3 µg/L [51.3;81.4]). The area under the receiver operating characteristic curve (AUC) was 0.56 (95% confidence interval (CI): 0.49;0.64) for the diagnosis of the composite endpoint and 0.66 (95% CI: 0.56;0.75) after adding NGAL to high-sensitive C-reactive protein (hs-CRP), leucocyte count, interleukin-6 (IL-6), calprotectin, age, sex, body mass index (BMI), diabetes mellitus, smoking and creatinine. However, the AUC for hs-CRP, leucocyte count, IL-6, calprotectin, age, sex, BMI, diabetes mellitus, smoking and creatinine without NGAL was similar at 0.66 (95% CI: 0.56;0.76). NGAL alone had no predictive value with respect to the composite endpoint of non-fatal AMI, ischaemic stroke, or CVD in stable CAD patients. NGAL did not add any predictive value to the endpoint compared with existing inflammatory biomarkers and cardiovascular risk factors.

9. Cardiovascular Disease and Risk Management: Standards of Medical Care in Diabetes-2018

The American Diabetes Association (ADA) "Standards of Medical Care in Diabetes" includes ADA's current clinical practice recommendations and is intended to provide the components of diabetes care, general treatment goals and guidelines, and tools to evaluate quality of care. Members of the ADA Professional Practice Committee, a multidisciplinary expert committee, are responsible for updating the Standards of Care annually, or more frequently as warranted. For a detailed description of ADA standards, statements, and reports, as well as the evidence-grading system for ADA's clinical practice recommendations, please refer to the Standards of Care Introduction Readers who wish to comment on the Standards of Care are invited to do so at professional.diabetes.org/SOC.

The influence of low-grade inflammation on platelets in patients with stable coronary artery disease

Inflammation is likely to be involved in all stages of atherosclerosis. Numerous inflammatory biomarkers are currently being studied, and even subtle increases in inflammatory biomarkers have been associated with increased risk of cardiovascular events in patients with coronary artery disease (CAD). Low-grade inflammation may influence both platelet production and platelet activation potentially leading to enhanced platelet aggregation. Thrombopoietin is considered the primary regulator of platelet production, but it likely acts in conjunction with numerous cytokines, of which many have altered levels in CAD. Previous studies have shown that high-sensitive C-reactive protein (CRP) independently predicts increased platelet aggregation in stable CAD patients. Increased levels of CRP, fibrinogen, interleukin-6, stromal cell-derived factor-1, CXC motif ligand 16, macrophage migration inhibitory factor, RANTES, calprotectin, and copeptin have been associated with increased risk of cardiovascular events in CAD patients. Additionally, some of these inflammatory markers have been associated with enhanced platelet activation and aggregation. However, CRP and other inflammatory markers provide only limited additional predictive value to classical risk factors such as smoking, blood pressure, and cholesterol levels. Existing data do not clarify whether inflammation simply accompanies CAD and increased production and aggregation of platelets, or whether a causal relationship exists. In this review, we provide a comprehensive overview of inflammatory markers in stable CAD with particular emphasis on platelet production, activation, and aggregation in CAD patients.

Reduced Antiplatelet Effect of Aspirin Does Not Predict Cardiovascular Events in Patients With Stable Coronary Artery Disease

Background

Increased platelet aggregation during antiplatelet therapy may predict cardiovascular events in patients with coronary artery disease. The majority of these patients receive aspirin monotherapy. We aimed to investigate whether high platelet‐aggregation levels predict cardiovascular events in stable coronary artery disease patients treated with aspirin.

Methods and Results

We included 900 stable coronary artery disease patients with either previous myocardial infarction, type 2 diabetes mellitus, or both. All patients received single antithrombotic therapy with 75 mg aspirin daily. Platelet aggregation was evaluated 1 hour after aspirin intake using the VerifyNow Aspirin Assay (Accriva Diagnostics) and Multiplate Analyzer (Roche; agonists: arachidonic acid and collagen). Adherence to aspirin was confirmed by serum thromboxane B₂. The primary end point was the composite of nonfatal myocardial infarction, ischemic stroke, and cardiovascular death. At 3‐year follow‐up, 78 primary end points were registered. The primary end point did not occur more frequently in patients with high platelet‐aggregation levels (first versus fourth quartile) assessed by VerifyNow (hazard ratio: 0.5 [95% CI, 0.3–1.1], P=0.08) or Multiplate using arachidonic acid (hazard ratio: 1.0 [95% CI, 0.5–2.1], P=0.92) or collagen (hazard ratio: 1.4 [95% CI, 0.7–2.8], P=0.38). Similar results were found for the composite secondary end point (nonfatal myocardial infarction, ischemic stroke, stent thrombosis, and all‐cause death) and the single end points. Thromboxane B₂ levels did not predict any end points. Renal insufficiency was the only clinical risk factor predicting the primary and secondary end points.

Conclusions

This study is the largest to investigate platelet aggregation in stable coronary artery disease patients receiving aspirin as single antithrombotic therapy. We found that high platelet‐aggregation levels did not predict cardiovascular events.

Coronary artery disease-associated genetic variants and biomarkers of inflammation

INTRODUCTION

Genetic constitution and inflammation both contribute to development of coronary artery disease (CAD). Several CAD-associated single-nucleotide polymorphisms (SNPs) have recently been identified, but their functions are largely unknown. We investigated the associations between CAD-associated SNPs and five CAD-related inflammatory biomarkers.

METHODS

We genotyped 45 CAD-associated SNPs in 701 stable CAD patients in whom levels of high-sensitivity C-reactive protein (hsRCP), interleukin-6, calprotectin, fibrinogen and complement component 3 levels had previously been measured. A genetic risk score was calculated to assess the combined risk associated with all the genetic variants. A multiple linear regression model was used to assess associations between the genetic risk score, single SNPs, and the five inflammatory biomarkers.

RESULTS

The minor allele (G) (CAD risk allele) of rs2075650 (TOMM40/APOE) was associated with lower levels of high-sensitivity C-reactive protein (effect per risk allele: -0.37 mg/l [95%CI -0.56 to -0.18 mg/l]). The inflammatory markers tested showed no association with the remaining 44 SNPs or with the genetic risk score.

CONCLUSIONS

In stable CAD patients, the risk allele of a common CAD-associated marker at the TOMM40/APOE locus was associated with lower hsCRP levels. No other genetic variants or the combined effect of all variants were associated with the five inflammatory biomarkers.

Whole Blood Platelet Aggregation Test and Prediction of Hemostatic Difficulty After Tooth Extraction in Patients Receiving Antiplatelet Therapy

When patients on antiplatelet therapy (APT) require minor invasive surgery, APT is usually continued to limit the risk of thrombosis. However, the possibility of hemostatic difficulties necessitates the monitoring of platelet aggregation to prevent unexpected bleeding. We examined whether whole blood aggregometry as a point-of-care testing (POCT) could be useful as a tool for predicting hemostatic difficulties. Sixty-five patients receiving APT and 15 patients who were not receiving APT were enrolled in the present study; all patients were scheduled to undergo a tooth extraction. Whole blood samples were obtained and were examined using multiple electrode aggregometry. The aggregometry was performed using arachidonic acid (AA), adenosine diphosphate (ADP), and thrombin receptor activating peptide. Hemostatic difficulty was defined as a need for more than 10 minutes of compression to achieve hemostasis. The AA test results were significantly lower in patients treated with aspirin (control: 97.7 [29.0] U, aspirin: 14.5 [7.2] U, P < .001). The ADP test results were also significantly lower in patients treated with a P2Y₁₂ inhibitor (control: 77.7 [21.7] U, P2Y₁₂ inhibitor: 37.3 [20.4] U, P < .01). Six of the examined cases exhibited hemostatic difficulties. The cutoff values for the prediction of hemostatic difficulty were 16.5 U for the AA test (sensitivity, 0.833; specificity, 0.508) and 21 U for the ADP test (sensitivity, 0.847; specificity, 0.500). Our study showed that whole blood aggregometry was useful as a POCT for the prediction of hemostatic difficulties after tooth extraction in patients receiving APT.

Thrombopoietin and platelet aggregation in patients with stable coronary artery disease

Thrombopoietin (TPO) may facilitate platelet activation and aggregation. However, data on the impact of TPO on platelet aggregation in patients with stable coronary artery disease (CAD) are scarce. We aimed to investigate associations between TPO and platelet aggregation and activation in patients with stable coronary artery disease (CAD). We studied 900 stable CAD patients. Serum TPO was assessed by ELISA. Platelet aggregation was evaluated using the Multiplate Analyzer (agonists: arachidonic acid [AA] and collagen) and the VerifyNow Aspirin Assay. Platelet activation was evaluated by soluble (s)P-selectin. Cyclooxygenase-1 inhibition was evaluated by serum thromboxane B₂ (TXB₂). We found that TPO correlated weakly with platelet aggregation evaluated by Multiplate using AA (r = -0.09, p = 0.01) and collagen as agonists (r = -0.03, p = 0.43) and by VerifyNow (r = 0.07, p = 0.03). We found no correlation between TPO and sP-selectin (r = -0.01, p = 0.70). Independent predictors of AA-induced platelet aggregation by Multiplate included high levels of sP-selectin and serum TXB₂, high platelet count, increasing age and body mass index, female sex, and active smoking. Independent predictors of TPO included low AA-induced platelet aggregation by Multiplate, high levels of hs-CRP, active smoking, and high platelet aggregation evaluated by VerifyNow. In conclusion, TPO levels did not correlate with platelet activation and only weak associations were found between TPO and platelet aggregation, suggesting that TPO did not substantially facilitate platelet aggregation in stable CAD patients.

Effects of Aspirin on Endothelial Function and Hypertension

PURPOSE OF REVIEW

Endothelial dysfunction is intimately related to the development of various cardiovascular diseases, including hypertension, and is often used as a target for pharmacological treatment. The scope of this review is to assess effects of aspirin on endothelial function and their clinical implication in arterial hypertension.

RECENT FINDINGS

Emerging data indicate the role of platelets in the development of vascular inflammation due to the release of proinflammatory mediators, for example, triggered largely by thromboxane. Vascular inflammation further promotes oxidative stress, diminished synthesis of vasodilators, proaggregatory and procoagulant state. These changes translate into vasoconstriction, impaired circulation and thrombotic complications. Aspirin inhibits thromboxane synthesis, abolishes platelets activation and acetylates enzymes switching them to the synthesis of anti-inflammatory substances. Aspirin pleiotropic effects have not been fully elucidated yet. In secondary prevention studies, the decrease in cardiovascular events with aspirin outweighs bleeding risks, but this is not the case in primary prevention settings. Ongoing trials will provide more evidence on whether to expand the use of aspirin or stay within current recommendations.