Association of platelet aggregation with lipid levels in the Japanese population: the Suita study

The Influence of Non-High-Density Lipoprotein Cholesterol on the Efficacy of Genotype-Guided Dual Antiplatelet Therapy in Preventing Stroke Recurrence

BACKGROUND AND PURPOSE

Non-high-density lipoprotein cholesterol (non-HDL-C), which represents the total cholesterol content of all pro-atherogenic lipoproteins, has recently been included as a new target for lipid-lowering therapy in high-risk atherosclerotic patients in multiple guidelines. Herein, we aimed to explore the relationship between non-HDL-C level and the efficacy and safety of ticagrelor-aspirin versus clopidogrel-aspirin in preventing stroke recurrence.

METHODS

This study comprised a post hoc analysis of the CHANCE-2 (Ticagrelor or Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events II) trial, from which 5,901 patients with complete data on non-HDL-C were included and categorized by median non-HDL-C levels, using a cutoff of 3.5 mmol/L. The primary efficacy and safety outcomes were recurrent stroke and severe or moderate bleeding within 90 days.

RESULTS

Ticagrelor-aspirin significantly reduced the risk of recurrent stroke in patients with low non-HDL-C (71 [4.8%] vs. 119 [7.7%]; adjusted hazard ratio [HR] 0.54; 95% confidence interval [CI], 0.40-0.74), but not in those with high non-HDL-C (107 [7.3%] vs. 108 [7.6%]; adjusted HR, 0.88; 95% CI, 0.67-1.16), compared with clopidogrel-aspirin (P for interaction=0.010). When analyzed as a continuous variable, the benefit of ticagrelor-aspirin for recurrent stroke decreased as non-HDL-C levels increased. No significant differences in the treatment assignments across the non-HDL-C groups were observed in terms of the rate of severe or moderate bleeding (5 [0.3%] vs. 8 [0.5%] in the low non-HDL-C group; 4 [0.3%] vs. 2 [0.1%] in the high non-HDL-C group; P for interaction=0.425).

CONCLUSION

CHANCE-2 participants with low non-HDL-C levels received more clinical benefit from ticagrelor-aspirin versus clopidogrel-aspirin compared to those with high non-HDL-C, following minor ischemic stroke or transient ischemic attack.

The association between platelet reactivity and lipoprotein levels in Framingham Heart Study participants

BACKGROUND

Hypertriglyceridemia is an independent risk factor for major adverse cardiovascular events, though the mechanisms linking triglycerides and platelet function with thrombosis, remain elusive. The aim of this study was to assess the association between platelet function and triglyceride levels.

METHODS

We included participants from the Framingham Heart Study Third Generation cohort, OMNI, and New Offspring Spouse cohort who attended the third examination cycle (2016-2019). Eligible participants were categorized into four triglyceride subgroups.

RESULTS

The study comprised a total of 1897 (55.53 %) participants with normal TG levels; 883 (25.85 %) participants with high-normal TGs; 378 (11.07 %) with borderline high TGs; and 258 (7.55 %) participants with hypertriglyceridemia. After adjusting for age, sex, alcohol consumption, aspirin, statin and P2Y₁₂ inhibitors, the levels of ADP-induced platelet aggregation were inversely associated with total cholesterol levels (P < 0.0001). Platelet disaggregation was associated with low-density lipoprotein and high-density lipoprotein cholesterol levels (P < 0.0001). Lastly, in a shear-stress chamber assay mimicking arterial flow velocities, TG levels in the normal-high group were associated with increased levels of collagen-dependent thrombogenicity (β = 24.16, SE = 6.65, P < 0.0001).

CONCLUSION

Triglyceride levels are associated with altered platelet activation and aggregation. Furthermore, increased platelet-driven thrombogenicity is directly associated with triglyceride levels after adjusting for medications and other covariates.

Independent association of Lp(a) with platelet reactivity in subjects without statins or antiplatelet agents

The physiological effect of Lp(a) on platelet activity is unclear. Previous studies explored the relationship between Lp(a) and platelet aggregation in patients taking statins and antiplatelet agents, but few was conducted in individuals without the bias of those drugs that either influence Lp(a) or platelet activity. The aim of this study was to assess the relationship between Lp(a) levels and platelet aggregation in subjects not taking statins or antiplatelet drugs. A hospital-based cross-sectional study was conducted to investigate the independent contribution of Lp(a) to platelet activity by controlling the effects of potential confounding factors including lipoprotein-associated phospholipase A2 [Lp-PLA2]. Blood samples were collected from 92 subjects without statins or antiplatelet agents from the Second Xiangya Hospital. The univariate correlation analysis showed a significant correlation between AA-induced average aggregation rate [AAR] and ApoB (r = 0.324, P = 0.002), ApoA1 (r = 0.252, P = 0.015), Lp(a) (r = 0.370, P < 0.001), Lp-PLA2 (r = 0.233, P = 0.025) and platelet counts [PLT] (r = 0.389, P < 0.001). Multivariate regression analysis suggested that Lp(a) contributed independently to AA-induced average aggregation rate (β = 0.023, P = 0.027) after controlling for the effects of ApoB, Lp-PLA2 and platelet counts. Lp(a) is positively associated with platelet aggregation independent of Lp-PLA2, which may partly account for the atherothrombotic effect of Lp(a).

Hyperlipidemia and Platelet Parameters: Two Sides of the Same Coin

Introduction: Hyperlipidemia is a disorder in which lipid and cholesterol levels in the blood are elevated. Diabetes, coronary heart disease, obesity, and hypertension are commonly linked to hyperlipidemia. Despite this, hyperlipidemia is a widely neglected illness, owing to its asymptomatic nature, ignorance of aberrant lipid profiles on screening, and economic issues in poor countries such as India. Platelets have been shown to have a role in the thrombus consequences of atheromatous damage in hyperlipidemic individuals by initiating and propagating atherosclerotic plaques. Platelets with bigger diameters are thought to be more metabolically, enzymatically, and functionally agile than platelets with lower sizes. In steady-state operation, these bigger platelets release more thromboxane B2 than regular platelets. Platelets with bigger sizes are more hemostatically active and hence have a higher chance of forming a thrombus and thromboembolism. The aim of this study was to compare the values of key platelet parameters and platelet function in hyperlipidemic patients with normal age and sex-matched controls.

Material and methods: A total of 100 individuals were included in this study, with 68 cases of hyperlipidemia and 32 controls having normal lipid profiles. Platelet volume indices (PVI) such as platelet count (PC), mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR), plateletcrit (PCT), and platelet function (platelet aggregation with adenosine diphosphate, ADP) were compared between hyperlipidemia patients and age sex-matched controls with normal lipid profiles.

Results: The cases had a statistically significant higher mean MPV (10.55 ± 1.81), PDW (14.93 ± 2.82), and P-LCR (30.97 ± 11.74) compared to mean MPV (9.35 ± 1.85), PDW (13.10 ± 2.60), and P-LCR (25.13 ± 12.23) of controls (p-value < 0.05). No significant difference was observed between the study group and control group with respect to mean PC and PCT (p-value > 0.05). In this study, there was a statistically significant increase noted in platelet aggregation percentage in hyperlipidemic patients than in the control group (42.03 ± 25.28 vs 31.25 ± 15.11) (p-value < 0.05).

Conclusion: To conclude, platelet parameters are a significant, easy, and cost-effective method for predicting future acute episodes in hyperlipidemic patients that should be utilized more widely. To avoid vascular events, these individuals may require higher antiplatelet dosages and more rigorous hyperlipidemia therapy.

Association of lipoprotein(a) with platelet aggregation and thrombogenicity in patients undergoing percutaneous coronary intervention

This study aimed to evaluate the association of lipoprotein(a) levels with platelet aggregation and thrombogenicity in patients undergoing percutaneous coronary intervention (PCI), and to investigate the ischemic outcome on this population. Lipoprotein(a) and modified thrombelastography were measured in 6601 consecutive patients underwent PCI on dual antiplatelet therapy. Cox proportional regression analysis was applied to illustrate the ischemic events in a 2-year follow up. The mean levels of lipoprotein(a) were 29.0 mg/dl. Patients with higher lipoprotein(a) levels had significantly accelerated fibrin generation (lower K time and bigger α angle) and greater clot strength (higher maximum amplitude (MA)) than patients with lower lipoprotein(a) levels (P < .001). Moreover, the higher lipoprotein(a) group also exhibited significantly higher adenosine diphosphate (ADP) induced platelet aggregation (MA_ADP) by thrombelastography platelet mapping assay than lower lipoprotein(a) group. Cox regression analyzes revealed that patients with higher lipoprotein(a) levels had a 16% higher risk of major adverse cardiovascular and cerebrovascular events (HR 1.159, 95%CI: 1.005-1.337, P = .042) compared with patients with lower lipoprotein(a) levels. This association persisted after adjustment for a broad spectrum of risk factors (HR 1.174, 95%CI: 1.017-1.355, P = .028). High plasma lipoprotein(a) levels were associated with increased platelet aggregation and ischemic events in patients underwent PCI. Lipoprotein(a) might indicate the need for prolonged antiplatelet therapy.

Cardiovascular events occur independently of high on-aspirin platelet reactivity and residual COX-1 activity in stable cardiovascular patients

Several studies have indicated that approximately 25 % of patients treated with aspirin exhibit high on-treatment platelet reactivity (HTPR), which is potentially associated with cardiovascular events (CVEs). However, this association is still controversial, since the mechanisms by which HTPR contributes to CVEs remain unclear and a no standardised definition of HTPR has been established. To determine whether HTPR is associated with CVE recurrence and what type of assay would best predict CVE recurrence, we conducted a multicentre prospective cohort study of 592 stable cardiovascular outpatients treated with aspirin monotherapy for secondary prevention. Their HTPR was determined by arachidonic acid- or collagen-induced aggregation assays using two different agonist concentrations. Residual cyclooxygenase (COX)-1 activity was assessed by measuring serum thromboxane (TX)B2 or urinary 11-dehydro TXB2. Shear-induced platelet thrombus formation was also examined. We followed all patients for two years to evaluate how these seven indexes were related to the recurrence of CVEs (cerebral infarction, transient ischaemic attack, myocardial infarction, unstable angina, revascularisation, other arterial thrombosis, or cardiovascular death). Of 583 patients eligible for the analysis, CVEs occurred in 69 (11.8 %). A Cox regression model identified several classical risk factors associated with CVEs. However, neither HTPR nor high residual COX-1 activity was significantly associated with CVEs, even by applying cut-off values suggested in previous reports or a receiver-operating characteristic analysis. In conclusion, recurrence of CVEs occurred independently of HTPR and residual COX-1 activity. Thus, our findings do not support the use of platelet or COX-1 functional testing for predicting clinical outcomes in stable cardiovascular patients.

Risk of New-Onset Dyslipidemia After Laparoscopic Adrenalectomy in Patients with Primary Aldosteronism

BACKGROUND

Many patients with primary aldosteronism (PA) show a significant decline in kidney function after adrenalectomy. Thus, PA patients who undergo surgery are at greater risk of both postoperative renal damage and new-onset metabolic events associated with renal insufficiency. The aim of this study was to explore postoperative changes in serum lipid levels and to identify risk factors associated with postoperative new-onset dyslipidemia in PA patients.

METHODS

The records of 57 Japanese patients who underwent unilateral laparoscopic adrenalectomy for PA were retrospectively surveyed. Clinical and biochemical data were evaluated at baseline and 12 months after surgery. Preoperative and postoperative estimated glomerular filtration (eGFR) and serum lipid profile, including triglycerides, high-density lipoprotein (HDL)-cholesterol and low-density lipoprotein (LDL)-cholesterol levels, were compared. Furthermore, uni- and multivariate analyses were performed to determine the predictors for postoperative new-onset dyslipidemia.

RESULTS

A significant decrease in eGFR and deterioration of serum lipid levels was identified postoperatively in most patients. Of the 39 patients without pre-existing dyslipidemia, 18 developed new-onset dyslipidemia postoperatively. Multivariate analysis identified preoperative lower eGFR and higher body mass index as independent predictors for new-onset dyslipidemia after surgery. On univariate analyses, additional factors associated with new-onset dyslipidemia included older age, male sex, higher LDL-cholesterol, and higher LDL/HDL ratio.

CONCLUSIONS

PA patients had a higher risk of postoperative new-onset or progressive dyslipidemia. Clinicians should pay attention to not only follow-up of renal impairment but also total management of new-onset metabolic events associated with renal insufficiency in PA patients.

Cardiovascular correlates of platelet count and volume in the Framingham Heart Study

PURPOSE

Platelet count and volume are inexpensive, routinely assayed biomarkers associated with cardiovascular health, but specific relationships among platelet indices, cardiovascular risk factors, and disease warrant further investigation. The purpose of this study was to understand associations among platelet count, volume, and 20 cardiovascular health-related variables in the Framingham Heart Study (FHS).

METHODS

Cross-sectional analyses were performed on platelet count and volume associations with cardiovascular health indicators in three FHS cohorts (original n = 964, offspring n = 2699, and third generation n = 2419) using multivariate linear regression analysis. Time-to-event analysis was used for cardiovascular disease-related event incidences using Kaplan-Meier plots and Cox proportional hazards regression adjusted for age and sex.

RESULTS

Results were concordant with the hypothesis that higher platelet counts are associated with less favorable cardiovascular risk profiles, although mean platelet volume associations were weaker. In our analysis, increased platelet count across FHS cohorts was consistently associated with smoking, triglycerides, low-density lipoprotein, and total cholesterol levels. Some associations with platelet count appeared sex dependent.

CONCLUSIONS

Significant associations of common blood platelet measurements are observed with sex and cardiovascular risk factors, namely smoking and lipids. Research is warranted to confirm these relationships in other cohorts, evaluate differences by ethnicity, and examine longitudinal effects on disease risk.

Antiplatelet resistance and the role of associated variables in stable patients treated with stenting

Introduction

Nowadays, clopidogrel and acetylsalicylic acid (ASA) have become routinely applied therapies in percutaneous coronary interventions (PCI) with stenting.

Aim

Numerous variables can interfere with antiplatelet responsiveness, so we aimed to investigate the role of different variables associated with ASA or clopidogrel resistance in stable coronary artery disease.

Material and methods

A total of 207 patients undergoing elective PCI were included in the analysis. All patients received a loading dose of clopidogrel and ASA during PCI procedure and followed by dual antiplatelet therapy. Clopidogrel and ASA resistance were measured by impedance aggregometry method.

Results

Of the patients, 19.8% had clopidogrel resistance, 18.8% had ASA resistance, 9.2% had both clopidogrel and ASA resistance, and 71.5% were responsive to both drugs. In multivariate analysis, platelet count, angiotensin receptor blocker (ARB) use, and ASA resistance were independent variables associated with clopidogrel resistance, and clopidogrel resistance was the only variable associated with ASA resistance. In differentiating whether clopidogrel resistance exists or not, optimum ASA aggregometry response cut-off values were specified, and in differentiating whether ASA resistance exists or not, optimum clopidogrel aggregometry response cut-off values were specified.

Conclusions

In this study, there was a higher incidence of low responsiveness to ASA when there was a low response to clopidogrel, and vice versa. Angiotensin receptor blocker use, platelet count, and ASA resistance were independent variables associated with clopidogrel resistance. Clopidogrel resistance was the only independent variable associated with ASA resistance. Angiotensin receptor blocker use seems to an independent risk factor for clopidogrel resistance in this study, but this result needs to be verified in other studies.

Relationship between serum cholesterol and indices of erythrocytes and platelets in the US population

Whereas dyslipidemia has been associated with leukocytosis, the relationship between serum cholesterol and other hematopoietic lineages is poorly defined. Erythrocytes and platelets, anucleate cells relegated to nonspecific diffusional exchange of cholesterol with serum, have been proposed to have a distinct relationship to cholesterol from leukocytes. We examined the relationship between serum cholesterol and circulating erythrocyte/platelet indices in 4,469 adult participants of the National Health and Nutrition Examination Survey (NHANES) 2005-2006. In linear regression analyses, serum non-high density lipoprotein-cholesterol (non-HDL-C) was positively associated with mean erythrocyte number, hematocrit, hemoglobin concentration, platelet count, and platelet crit independently of age, gender, race/ethnicity, smoking, body mass index, serum folate, and C-reactive protein. The magnitude of the relationship was most marked for platelets, with lowest versus highest non-HDL-C quartile subjects having geometric mean platelet counts of 258,000/μl versus 281,000/μl, respectively (adjusted model, P < 0.001 for trend). These associations persisted in a sensitivity analysis excluding several conditions that affect erythrocyte/platelet and/or serum cholesterol levels, and were also noted in an independent analysis of 5,318 participants from NHANES 2007-2008. As non-HDL-C, erythrocytes, and platelets all impact cardiovascular disease risk, there is a need for advancing understanding of the underlying interactions that govern levels of these three blood components.

Prevalence of and risk factors for aspirin resistance in elderly patients with coronary artery disease

Objective

To assess the prevalence of and related risk factors for aspirin resistance in elderly patients with coronary artery disease (CAD).

Methods

Two hundred and forty-six elderly patients (75.9 ± 7.4 years) with CAD who received daily aspirin therapy (≥ 75 mg) over one month were recruited. The effect of aspirin was assessed using light transmission aggregometry (LTA) and thrombelastography platelet mapping assay (TEG). Aspirin resistance was defined as ≥ 20% arachidonic acid (AA)-induced aggregation and ≥ 70% adenosine diphosphate (ADP)-induced aggregation in the LTA assay. An aspirin semi-responder was defined as meeting one (but not both) of the criteria described above. Based on the results of TEG, aspirin resistance was defined as ≥ 50% aggregation induced by AA.

Results

As determined by LTA, 23 (9.3%) of the elderly CAD patients were resistant to aspirin therapy; 91 (37.0%) were semi-responders. As determined by TEG, 61 patients (24.8%) were aspirin resistant. Of the 61 patients who were aspirin resistant by TEG, 19 were aspirin resistant according to LTA results. Twenty-four of 91 semi-responders by LTA were aspirin resistant by TEG. Multivariate logistic regression analysis revealed that elevated fasting serum glucose level (Odds ratio: 1.517; 95% CI: 1.176–1.957; P = 0.001) was a significant risk factor for aspirin resistance as determined by TEG.

Conclusions

A significant number of elderly patients with CAD are resistant to aspirin therapy. Fasting blood glucose level is closely associated with aspirin resistance in elderly CAD patients.