Platelet function predicts myocardial damage in patients with acute myocardial infarction

Shexiang Baoxin Pill enriches Lactobacillus to regulate purine metabolism in patients with stable coronary artery disease

BACKGROUND

It has been clinically confirmed that the Shexiang Baoxin Pill (SBP) dramatically reduces the frequency of angina in patients with stable coronary artery disease (SCAD). However, potential therapeutic mechanism of SBP has not been fully explored.

PURPOSE

The study explored the therapeutic mechanism of SBP in the treatment of SCAD patients.

METHODS

We examined the serum metabolic profiles of patients with SCAD following SBP treatment. A rat model of acute myocardial infarction (AMI) was established, and the potential therapeutic mechanism of SBP was explored using metabolomics, transcriptomics, and 16S rRNA sequencing.

RESULTS

SBP decreased inosine production and improved purine metabolic disorders in patients with SCAD and in animal models of AMI. Inosine was implicated as a potential biomarker for SBP efficacy. Furthermore, SBP inhibited the expression of genes involved in purine metabolism, which are closely associated with thrombosis, inflammation, and platelet function. The regulation of purine metabolism by SBP was associated with the enrichment of Lactobacillus. Finally, the effects of SBP on inosine production and vascular function could be transmitted through the transplantation of fecal microbiota.

CONCLUSION

Our study reveals a novel mechanism by which SBP regulates purine metabolism by enriching Lactobacillus to exert cardioprotective effects in patients with SCAD. The data also provide previously undocumented evidence indicating that inosine is a potential biomarker for evaluating the efficacy of SBP in the treatment of SCAD.

Pro-Inflammatory Food, Gut Microbiota, and Cardiovascular and Pancreatic Diseases

Recent studies have shown that a pro-inflammatory diet and dysbiosis, especially a high level of trimethylamine-N-oxide (TMAO), are associated with various adverse health conditions. Cardiovascular diseases and pancreatic diseases are two major morbidities in the modern world. Through this narrative review, we aimed to summarize the association between a pro-inflammatory diet, gut microbiota, and cardiovascular and pancreatic diseases, along with their underlying mechanisms. Our review revealed that TMAO is associated with the development of cardiovascular diseases by promoting platelet aggregation, atherosclerotic plaque formation, and vascular inflammation. TMAO is also associated with the development of acute pancreatitis. The pro-inflammatory diet is associated with an increased risk of pancreatic cancer and cardiovascular diseases through mechanisms that include increasing TMAO levels, activating the lipopolysaccharides cascade, and the direct pro-inflammatory effect of certain nutrients. Meanwhile, an anti-inflammatory diet decreases the risk of cardiovascular diseases and pancreatic cancer.

Proteomic analysis reveals activation of platelet- and fibrosis-related pathways in hearts of ApoE-/- mice exposed to diesel exhaust particles

Air pollution is an environmental risk factor linked to multiple human diseases including cardiovascular diseases (CVDs). While particulate matter (PM) emitted by diesel exhaust damages multiple organ systems, heart disease is one of the most severe pathologies affected by PM. However, the in vivo effects of diesel exhaust particles (DEP) on the heart and the molecular mechanisms of DEP-induced heart dysfunction have not been investigated. In the current study, we attempted to identify the proteomic signatures of heart fibrosis caused by diesel exhaust particles (DEP) in CVDs-prone apolipoprotein E knockout (ApoE-/-) mice model using tandem mass tag (TMT)-based quantitative proteomic analysis. DEP exposure induced mild heart fibrosis in ApoE-/- mice compared with severe heart fibrosis in ApoE-/- mice that were treated with CVDs-inducing peptide, angiotensin II. TMT-based quantitative proteomic analysis of heart tissues between PBS- and DEP-treated ApoE-/- mice revealed significant upregulation of proteins associated with platelet activation and TGFβ-dependent pathways. Our data suggest that DEP exposure could induce heart fibrosis, potentially via platelet-related pathways and TGFβ induction, causing cardiac fibrosis and dysfunction.

Serum trimethylamine N-oxide levels among coronary artery disease and acute coronary syndrome patients: a systematic review and meta-analysis

Background and Aim

Recent studies have linked trimethylamine N-oxide (TMAO) to cardiovascular diseases; our study aimed to analyze the association between coronary artery disease (CAD), acute coronary syndrome (ACS), and TMAO.

Methods

PubMed, Scopus, Embase, and Web of Science were searched using terms such as 'CAD' and 'TMAO'. Only observational controlled studies were included. RevMan software version 5.4 was used for the analysis.

Results

A significant association was found between the CAD group and increased serum TMAO levels compared with the control group (MD=1.16, 95% CI=0.54-1.78, P=0.0003). This association remained significant among acute coronary syndrome patients (MD=0.98, 95% CI=0.73-1.23, P<0.00001) and was also detected among young and old CAD patients (MD=0.35, 95% CI=0.06-0.64, P=0.02 and MD=1.36, 95% CI=0.71-2.01, P<0.0001, respectively). On further analysis of intestinal metabolites, the authors detected an insignificant association between choline, betaine, carnitine, and CAD. According to our sensitivity analysis, TMAO is an acceptable diagnostic marker for CAD (0.721, SE was 0.0816, 95% CI: 0.561-0.881).

Conclusion

TMAO is an acceptable diagnostic marker for CAD, with significantly higher levels among these patients regardless of their age. Other metabolites did not show such an association. The role of serum level TMAO in the early diagnosis of CAD should be further explored.

The effect of ticagrelor on coronary microvascular function after PCI in patients with ACS compared to clopidogrel: A systematic review and meta-analysis

BACKGROUND

The function of coronary microcirculation is an important factor in predicting the prognosis of patients with acute coronary syndrome (ACS) who receive percutaneous coronary intervention (PCI) therapy. Ticagrelor, a type of oral P2Y12 inhibitor, is widely prescribed to ACS patients and can improve prognosis compared to clopidogrel. However, the efficacy of ticagrelor on coronary microcirculation, compared to clopidogrel, remains unclear. The objective of this meta-analysis was to determine the efficacy of ticagrelor on coronary microcirculation.

METHODS

The PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov databases were comprehensively searched to identify studies until November 2022. Data was pooled using the fixed effects model or random effects model based on the level of heterogeneity. Sensitivity analyses were performed to measure the effects of potential confounders.

RESULTS

After screening, 16 trials with a total of 3676 participants were ultimately included in the analysis. The meta-analysis revealed that compared to clopidogrel, patients receiving ticagrelor exhibited a more significant reduction in the IMR (WMD: -6.23, 95% CI: -8.41 to -4.04), a reduction in the cTFC (WMD: -1.88; 95% CI: -3.32 to -0.45), and greater increases in CFR (WMD: 0.38; 95% CI: 0.18 to 0.57), MBG (RR 1.29, 95% CI 1.12 to 1.48), and TIMI (RR 1.03, 95% CI 1.00 to 1.06).

CONCLUSION

Our findings suggest that, compared to clopidogrel, ticagrelor has a significant effect in reducing coronary microcirculatory resistance, enhancing coronary blood flow reserve, and improving myocardial perfusion.

Thyroid hormones and platelet activation in COVID-19 patients

PURPOSE

To retrospectively describe the association between thyroid hormones (TH) and platelet activation, as represented by mean platelet volume (MPV), in a cohort of patients hospitalized for COVID-19 with no known thyroid disease, and to correlate these data with the severity of COVID-19 and the occurrence of death/ARDS (Acute Respiratory Distress Syndrome).

METHODS

103 patients with real-time polymerase chain reaction (RT-PCR) testing-confirmed COVID-19 and hospitalized were enrolled. Serum samples were collected from patients upon admission before starting any treatment. Chi-squared test was used to determine the association between euthyroid sick syndrome (ESS) and COVID-19 severity. Multivariate logistic regression was performed to evaluate the best independent predictors of COVID-19 deaths/ARDS.

RESULTS

39/103 (37.9%) of patients were found to have ESS, and this condition was an independent predictor for the severity of COVID-19 (p = 0.003). Lower TSH and lower FT3/FT4 ratio correlated with higher MPV (p = 0,001 and p = 0.010), with an opposite trend with respect to what has been documented in non-COVID patients. Increasing MPV and lower FT3 significantly increased the risk, in COVID-19 patients, of an adverse outcome of death/ARDS.

CONCLUSION

Increased platelet activation, as represented by increased MPV, has already been reported to correlate with COVID-19 severity, possibly as a consequence of cytokine release. We demonstrated, in a cohort of 103 patients with COVID-19, that MPV is inversely correlated to TH levels, in particular in the case of ESS, where downregulation of TH axis may occur in case of systemic cytokine inflammation and more severe outcomes (death/ARDS). That ESS itself may directly cause platelet activation, as demonstrated by higher MPV in these patients, is an interesting hypothesis which deserves further investigation.

Combination of White Blood Cell Count to Mean Platelet Volume Ratio and Neutrophil-to-Platelet Ratio Predicts Long-Term Adverse Events in Patients with MINOCA

Background

White blood cell count to mean platelet volume ratio (WMR) and neutrophil-to-platelet ratio (NPR) have been demonstrated as prognostic inflammatory biomarkers of the acute coronary syndrome. We aimed to evaluate the prognostic value of WMR and NPR among myocardial infarction with nonobstructive coronary arteries (MINOCA) patients.

Method

A total of 274 MINOCA patients were enrolled. Baseline clinical data, blood cell panel, and biochemical parameters were evaluated. The patients were classified according to the medians of WMR and NPR. The primary endpoint of the present study was major adverse cardiovascular events (MACE). Multivariable Cox regression analysis was used to assess the effect of independent variables of WMR and NPR on the dependent variable (MACE).

Result

The median values of WMR and NPR were 701 and 0.03, respectively. During the median follow-up of 28 months, a total of 58 incidences of MACE occurred. The MACE rate was more frequent in high WMR and high NPR patients. In Kaplan-Meier analysis, the incidence of MACE was higher in WMR>701 and NPR>0.03 (long-rank P = 0.004 and P = 0.002, respectively). The combined high WMR and high NPR showed a significantly higher rate of MACE (long-rank P = 0.001). Cox regression analysis showed that the combined high WMR and high NPR were independent predictors of long-term MACE with the highest hazard ratio (HR, 2.511; 95% CI, 1.271 to 4.960; P = 0.008).

Conclusion

High WMR and NPR separately or in combination were correlated with increased risk of MACE among MINOCA patients, suggesting WMR and NPR may assist as a reliable inflammatory marker in risk prediction of MINOCA patients.

Relationships Among Gut Microbiota, Ischemic Stroke and Its Risk Factors: Based on Research Evidence

Stroke is a highly lethal disease and disabling illness while ischemic stroke accounts for the majority of stroke. It has been found that inflammation plays a key role in the initiation and progression of stroke, and atherosclerotic plaque rupture is considered to be the leading cause of ischemic stroke. Furthermore, chronic inflammatory diseases, such as obesity, type 2 diabetes mellitus (T2DM) and hypertension, are also considered as the high-risk factors for stroke. Recently, the topic on how gut microbiota affects human health has aroused great concern. The initiation and progression of ischemic stroke has been found to have close relation with gut microbiota dysbiosis. Hence, this manuscript briefly summarizes the roles of gut microbiota in ischemic stroke and its related risk factors, and the practicability of preventing and alleviating ischemic stroke by reconstructing gut microbiota.

Can platelet activation result in increased plasma Aβ levels and contribute to the pathogenesis of Alzheimer's disease?

One of the central lesions in the brain of subjects with Alzheimer's disease (AD) is represented by aggregates of β-amyloid (Aβ), a peptide of 40-42 amino acids derived from the amyloid precursor protein (APP). The reasons why Aβ accumulates in the brain of individuals with sporadic forms of AD are unknown. Platelets are the primary source of circulating APP and, upon activation, can secrete significant amounts of Aβ into the blood which can be actively transported to the brain across the blood-brain barrier and promote amyloid deposition. Increased platelet activity can stimulate platelet adhesion to endothelial cells, trigger the recruitment of leukocytes into the vascular wall and cause perivascular inflammation, which can spread inflammation in the brain. Neuroinflammation is fueled by activated microglial cells and reactive astrocytes that release neurotoxic cytokines and chemokines. Platelet activation is also associated with the progression of carotid artery disease resulting in an increased risk of cerebral hypoperfusion which may also contribute to the AD neurodegenerative process. Platelet activation may thus be a pathophysiological mechanism of AD and for the strong link between AD and cerebrovascular diseases. Interfering with platelet activation may represent a promising potential adjunct therapeutic approach for AD.

Crushed/chewed administration of potent P2Y12 inhibitors in ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention: Systematic review and meta-analysis

Crushed or chewed potent P2Y₁₂ inhibitors are commonly used in the hope of bridging the gap of platelet inhibition in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI). The study aimed to investigate the efficacy and safety of this alternative oral administration strategy by performing a meta-analysis of available randomized clinical trials (RCTs). PubMed, Embase, the Cochrane Library and Web of Science medical literature databases were searched for RCTs comparing crushed/chewed vs. integral administration of loading dose potent P2Y₁₂ inhibitors in patients with STEMI undergoing pPCI with no language restrictions from inception to January 20th, 2021. The primary efficacy endpoints of high on treatment platelet reactivity (HPR) and P2Y₁₂ reaction units (PRU) at 1 hour together with safety and additional clinical endpoints were evaluated by pooled odds ratio (OR) or mean differences (MD) with 95% confidence intervals (95% CI). A total of 973 patents in six RCTs were eligible for analysis, while 876 patients present baseline and procedural characteristics. HPR and PRU at 1 hour were significantly reduced in the group receiving crushed/chewed P2Y₁₂ inhibitors compared with integral tablets (OR 0.28, 95% CI 0.16 to 0.49, P < .0001; MD -60.62, 95% CI -97.06 to -24.19, P = .001, respectively). Safety endpoints of major bleeding (OR 0.54, 95% CI 0.11 to 2.73, P = .46) and any bleeding (OR 0.84, 95% CI 0.43 to 1.64, P = .61), as well as additional clinical endpoints of cardiovascular death, myocardial infarction, and stroke were not affected by the oral administration strategy. In STEMI patients undergoing pPCI, crushed or chewed administration of potent P2Y₁₂ inhibitors are associated with enhanced early platelet inhibition and appear to be safe. The clinical profile transformed from this pharmacodynamic benefit need to be determined by further researches.

Acute coronary syndrome is associated with a substantial change in the platelet lipidome

AIMS

Platelets play a key role in the pathophysiology of coronary artery disease (CAD) and patients with enhanced platelet activation are at increased risk to develop adverse cardiovascular events. Beyond reliable cardiovascular risk factors such as dyslipoproteinaemia, significant changes of platelet lipids occur in patients with CAD. In this study, we investigate the platelet lipidome by untargeted liquid chromatography-mass spectrometry, highlighting significant changes between acute coronary syndrome (ACS) and chronic coronary syndrome (CCS) patients. Additionally, we classify the platelet lipidome, spotlighting specific glycerophospholipids as key players in ACS patients. Furthermore, we examine the impact of significantly altered lipids in ACS on platelet-dependent thrombus formation and aggregation.

METHODS AND RESULTS

In this consecutive study, we characterized the platelet lipidome in a CAD cohort (n = 139) and showed significant changes of lipids between patients with ACS and CCS. We found that among 928 lipids, 7 platelet glycerophospholipids were significantly up-regulated in ACS, whereas 25 lipids were down-regulated compared to CCS. The most prominent up-regulated lipid in ACS, PC18:0 (PC 10:0-8:0), promoted platelet activation and ex vivo platelet-dependent thrombus formation.

CONCLUSIONS

Our results reveal that the platelet lipidome is altered in ACS and up-regulated lipids embody primarily glycerophospholipids. Alterations of the platelet lipidome, especially of medium chain lipids, may play a role in the pathophysiology of ACS.

Plasma Exosome Profile in ST-Elevation Myocardial Infarction Patients with and without Out-of-Hospital Cardiac Arrest

The identification of new biomarkers allowing an early and more accurate characterization of patients with ST-segment elevation myocardial infarction (STEMI) is still needed, and exosomes represent an attractive diagnostic tool in this context. However, the characterization of their protein cargo in relation to cardiovascular clinical manifestation is still lacking. To this end, 35 STEMI patients (17 experiencing resuscitated out-of-hospital cardiac arrest (OHCA-STEMI) and 18 uncomplicated) and 32 patients with chronic coronary syndrome (CCS) were enrolled. Plasma exosomes were characterized by the nanoparticle tracking analysis and Western blotting. Exosomes from STEMI patients displayed a higher concentration and size and a greater expression of platelet (GPIIb) and vascular endothelial (VE-cadherin) markers, but a similar amount of cardiac troponin compared to CCS. In addition, a difference in exosome expression of acute-phase proteins (ceruloplasmin, transthyretin and fibronectin) between STEMI and CCS patients was found. GPIIb and brain-associated marker PLP1 accurately discriminated between OHCA and uncomplicated STEMI. In conclusion, the exosome profile of STEMI patients has peculiar features that differentiate it from that of CCS patients, reflecting the pathophysiological mechanisms involved in STEMI. Additionally, the exosome expression of brain- and platelet-specific markers might allow the identification of patients experiencing ischemic brain injury in STEMI.

Identification of potential biomarkers and immune cell infiltration in acute myocardial infarction (AMI) using bioinformatics strategy

Acute myocardial infarction (AMI) was considered a fatal disease resulting in high morbidity and mortality; platelet activation or aggregation plays a critical role in participating in the pathogenesis of AMI. The current study aimed to reveal the underlying mechanisms of platelets in the confrontation of AMI and potential biomarkers that separate AMI from other cardiovascular diseases and healthy people with bioinformatic strategies. Immunity analysis revealed that the neutrophil was significantly decreased in patients with SCAD compared with patients with ST-segment elevation myocardial infarction (STEMI) or healthy controls; monocytes and neutrophils showed potential in distinguishing patients with STEMI from patients with SCAD. Six differentially expressed genes (DEGs) showed great performances in differentiating STEMI patients from SCAD patients with AUC greater than 0.9. Correlation analysis showed that these six DEGs were significantly positively correlated with neutrophils; three genes were negatively correlated with monocytes. Weighted gene co-expression network analysis (WGCNA) found that module ‘royalblue’ had the highest correlation with STEMI; genes in STEMI-related module were enriched in cell–cell interactions, blood vessels’ biological processes, and peroxisome proliferator-activated receptor (PPAR) signaling pathway; four genes (FN1, CD34, LPL, and WWTR1) represented the capability of identifying patients with STEMI from healthy controls and patients with SCAD; two genes (ARG1 and NAMPTL) were considered as novel biomarkers for identifying STEMI from SCAD; FN1 represented the potential as a novel biomarker for STEMI. Our findings indicated that the distribution of neutrophils could be considered as a potential molecular trait for separating patients with STEMI from SCAD.

Assessment of Admission Time Cell Blood Count (CBC) Parameters in Predicting Post-primary Percutaneous Coronary Intervention TIMI Frame Count in Patients with ST-segment Elevation Myocardial Infarction

OBJECTIVES

In this study, we aimed to assess the value of admission time CBC parameters in predicting post-primary PCI corrected TIMI frame count.

BACKGROUND

Recent years have witnessed a large series of studies evaluating different laboratory variables to predict no-reflow phenomenon following primary PCI (PPCI) in patients with STEMI. However, a general agreement about the most reliable predictor of the no-reflow phenomenon is challenging and also intriguing.

METHODS

The current study concluded 208 consecutive patients who underwent primary PCI for ST-Elevation Myocardial Infarction (STEMI) from January 2014 to February 2016. Blood samples were obtained after taking ECG. Complete blood samples were collected and analyzed within 5 minutes from sampling. Post-PCI corrected Thrombolysis in Myocardial Infarction (TIMI) frame count was determined by one interventional cardiologist blinded to patients' clinical data. The correlation between admission time blood parameters and post-primary PCI corrected TIMI frame count in patients with STEMI were assessed.

RESULTS

Corrected TIMI frame count was positively correlated with WBC count (R: 0.18, P-value: <0.01), neutrophil count (R: 0.34, P-value: <0.01), and platelet count (R: 0.23, P-value: <0.01) and negatively correlated with lymphocyte count (R: -0.2, P-value: <0.01). Multiple linear regression results demonstrated that corrected TIMI frame count was positively correlated with neutrophil count (P < 0·001) and platelet count (P < 0·001) and negatively correlated with lymphocyte count (p=0.004).

CONCLUSION

High counts of WBC, neutrophil, and platelet and low count of lymphocyte may be predictors of no-reflow in STEMI patients undergoing PPCI. The clinical significance of such predictive parameters becomes clear as we consider the treatment approach in STEMI patients. Appropriate risk stratification leads to better treatment planning and allocation of resources.

Antithrombotic treatment in primary percutaneous coronary intervention

INTRODUCTION

Despite a timely mechanical reperfusion with primary percutaneous coronary intervention (pPCI) patients presenting with ST-elevation myocardial infarction (STEMI) display an increased risk of adverse cardiovascular events. Several studies have demonstrated that guideline-directed antithrombotic therapy is effective to reduce this risk. However, there is still much to be accomplished to improve antithrombotic therapies in this clinical setting.

AREAS COVERED

This paper reviews current data on antithrombotic therapy in STEMI patients undergoing pPCI.

EXPERT OPINION

Antithrombotic therapy for STEMI patients undergoing pPCI should take into account the variability of thrombotic and bleeding risk in the short and long term. Patients with STEMI profit from the administration of early onset antiplatelet agents and anticoagulation to achieve sufficient and predictable antithrombotic effect at the time of pPCI. Thereafter, antithrombotic therapies should be tailored to individual risk of recurrence over the long term, to avoid excess bleeding, while ensuring adequate secondary ischemic prevention.

Adipsin deficiency does not impact atherosclerosis development in Ldlr-/- mice

Obesity is a potent risk factor for atherosclerotic morbidity and mortality. Cytokines secreted from adipose tissue, namely, adipokines, have been suggested to be actively involved in atherosclerosis. One of the most abundant adipokines, adipsin, is downregulated in obesity. It catalyzes the rate-limiting step of alternative complement activation, which is one of the three complement pathways potentially involved in inflammation in atherosclerosis. Interestingly, adipsin has been identified as a novel biomarker in human coronary artery disease. However, its role in the development of atherosclerosis remains unexplored. We crossed adipsin^-/- mice onto an Ldlr^-/- background [double-knockout (DKO) mice] and induced atherogenesis by high-fat and high-cholesterol feeding. Metabolic profiles were systemically characterized, and atherosclerotic plaques were measured at both aortic root and arch regions. Western blotting was conducted to assess adipsin level and complement activity. The DKO mice exhibited similar sizes of atherosclerotic lesions as Ldlr^-/- control mice at both the aortic root and arch regions. Accordingly, they displayed comparable metabolic parameters, including body weight, insulin sensitivity, and lipid profiles, along with compensated complement activity. Adipsin deficiency does not impact the development of atherosclerosis in Ldlr^-/- mice despite its crucial function in alternative complement activation. Therefore, it is unlikely to play an important role in mediating the risk of atherosclerotic complications in obesity.NEW & NOTEWORTHY Adipsin deficiency does not impact the development of atherosclerosis in Ldlr^-/- mice despite its crucial function in alternative complement activation. Therefore, it is unlikely to play an important role in mediating the risk of atherosclerotic complications in obesity.

Effect of Prehospital Crushed Prasugrel Tablets in Patients With ST-Segment–Elevation Myocardial Infarction Planned for Primary Percutaneous Coronary Intervention

Background:

Early treatment with a potent oral platelet P2Y 12 inhibitor is recommended in patients presenting with ST-segment–elevation myocardial infarction scheduled to undergo primary percutaneous coronary intervention (pPCI). The impact on coronary reperfusion of crushed P2Y 12 inhibitor tablets, which lead to more prompt and potent platelet inhibition, is unknown.

Methods:

We conducted a randomized controlled, multicenter trial in the Netherlands, enrolling patients with ST-segment–elevation myocardial infarction scheduled to undergo pPCI. Patients were randomly allocated to receive in the ambulance, before transfer, a 60-mg loading dose of prasugrel either as crushed or integral tablets. The independent primary end points were thrombolysis in myocardial infarction (TIMI) 3 flow in the infarct-related artery at initial coronary angiography, and complete (≥70%) ST-segment resolution 1 hour after pPCI. The safety end points were TIMI major and Bleeding Academic Research Consortium ≥3 bleedings. Secondary end points included platelet reactivity and ischemic outcomes.

Results:

A total of 727 patients were assigned to either crushed or integral tablets of prasugrel loading dose. The median time from study treatment to wire-crossing during pPCI was 57 (47–70) minutes. The primary end point TIMI 3 flow in the infarct-related artery before pPCI occurred in 31.0% in the crushed group versus 32.7% in the integral group (odds ratio, 0.92 [95% CI, 0.65–1.30], P =0.64). Complete ST-segment resolution 1 hour after pPCI was present in 59.9% in the crushed group versus 57.3% in the integral group (odds ratio, 1.11 [95% CI, 0.78–1.58], P =0.55). Platelet reactivity at the beginning of pPCI, measured as P2Y 12 reactivity unit, differed significantly between groups (crushed, 192 [132–245] versus integral, 227 [184–254], P ≤0.01). TIMI major and Bleeding Academic Research Consortium ≥3 bleeding occurred in 0% in the crushed group versus 0.8% in the integral group, and in 0.3% in the crushed group versus 1.1% in the integral group, respectively. There were no differences observed between groups regarding ischemic events at 30 days.

Conclusions:

Prehospital administration of crushed prasugrel tablets does not improve TIMI 3 flow in the infarct-related artery before pPCI or complete ST-segment resolution 1 h after pPCI in patients presenting with ST-segment–elevation myocardial infarction scheduled for pPCI.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03296540.

Ischemic and Bleeding Events Associated with Thrombocytopenia and Thrombocytosis after Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction

The early and late ischemic and bleeding clinical outcomes according to baseline platelet count after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI) remain unclear. Overall, 10,667 patients from the Cardiovascular Risk and identification of potential high-risk population in AMI (COREA-AMI) I and II registries were classified according to the following universal criteria on baseline platelet counts: (1) moderate to severe thrombocytopenia (platelet < 100 K/μL, n = 101), (2) mild thrombocytopenia (platelet = 100~149 K/μL, n = 631), (3) normal reference (platelet = 150~450 K/μL, n = 9832), and (4) thrombocytosis (platelet > 450 K/μL, n = 103). The primary endpoint was the occurrence of major adverse cardiovascular events (MACE). The secondary outcome was Bleeding Academic Research Consortium (BARC) 2, 3, and 5 bleeding. After adjusting for confounders, the moderate to severe thrombocytopenia (HR, 2.03; 95% CI, 1.49-2.78); p < 0.001), mild thrombocytopenia (HR, 1.15; 95% CI, 1.01-1.34; p = 0.045), and thrombocytosis groups (HR, 1.47; 95% CI, 1.07-2.03; p = 0.019) showed higher 5-year MACE rates than the normal reference. In BARC 2, 3, and 5 bleeding outcomes, the bleedings rates were higher than the normal range in the moderate to severe thrombocytopenia (HR, 2.18; 95% CI, 1.36-3.49; p = 0.001) and mild thrombocytopenia (HR, 1.41; 95% CI, 1.12-1.78; p = 0.004) groups. Patients with AMI had higher 5-year MACE rates after PCI if they had lower- or higher-than-normal platelet counts. Thrombocytopenia revealed higher early and late bleeding rates whereas thrombocytosis showed long-term bleeding trends, although these trends were not statistically significant.

Immunothrombosis and thromboinflammation in host defense and disease

Platelets are increasingly being recognized for playing roles beyond thrombosis and hemostasis. Today we know that they mediate inflammation by direct interactions with innate immune cells or secretion of cytokines/chemokines. Here we review their interactions with neutrophils and monocytes/macrophages in infection and sepsis, stroke, myocardial infarction and venous thromboembolism. We discuss new roles for platelet surface receptors like GPVI or GPIb and also look at platelet contributions to the formation of neutrophil extracellular traps (NETs) as well as to deep vein thrombosis during infection, e.g. in COVID-19 patients.

Whole blood flow cytometry protocol for the assessment of platelet phenotype, function, and cellular interactions

Platelets are a key component of the hemostatic system and their roles in inflammation via interactions with leukocytes have also gained attention in recent years. Changes in platelet phenotype and function can cause bleeding and/or thrombosis and, as such, monitoring platelet-specific changes is crucial to assessing hemostasis in the clinical setting. Currently, available platelet function tests such as platelet aggregometry and thromboelastography require a large volume of blood, which is a major limitation for the pediatric population. Whole blood flow cytometric analysis of platelets is increasingly utilized in recent years, primarily due to the sensitivity of this method, but also because it only requires a small amount of blood with minimal sample manipulation. We have developed a whole blood flow cytometry methodological approach that enables the assessment of platelet phenotype, function, and their interactions with monocytes and neutrophils.

Cangrelor, Tirofiban, and Chewed or Standard Prasugrel Regimens in Patients With ST-Segment-Elevation Myocardial Infarction: Primary Results of the FABOLUS-FASTER Trial

Supplemental Digital Content is available in the text.

Background:

Standard administration of newer oral P2Y₁₂ inhibitors, including prasugrel or ticagrelor, provides suboptimal early inhibition of platelet aggregation (IPA) in patients with ST-segment–elevation myocardial infarction undergoing primary percutaneous coronary intervention. We aimed to investigate the effects of cangrelor, tirofiban, and prasugrel, administered as chewed or integral loading dose, on IPA in patients undergoing primary percutaneous coronary intervention.

Methods:

The FABOLUS-FASTER trial (Facilitation Through Aggrastat or Cangrelor Bolus and Infusion Over Prasugrel: A Multicenter Randomized Open-Label Trial in Patients with ST-Elevation Myocardial Infarction Referred for Primary Percutaneous Intervention) is an investigator-initiated, multicenter, open-label, randomized study. A total of 122 P2Y₁₂-naive patients with ST-segment–elevation myocardial infarction were randomly allocated (1:1:1) to cangrelor (n=40), tirofiban (n=40) (both administered as bolus and 2-hour infusion followed by 60 mg of prasugrel), or 60-mg loading dose of prasugrel (n=42). The latter group underwent an immediate 1:1 subrandomization to chewed (n=21) or integral (n=21) tablets administration. The trial was powered to test 3 hypotheses (noninferiority of cangrelor compared with tirofiban using a noninferiority margin of 9%, superiority of both tirofiban and cangrelor compared with chewed prasugrel, and superiority of chewed prasugrel as compared with integral prasugrel, each with α=0.016 for the primary end point, which was 30-minute IPA at light transmittance aggregometry in response to 20 μmol/L adenosine diphosphate.

Results:

At 30 minutes, cangrelor did not satisfy noninferiority compared with tirofiban, which yielded superior IPA over cangrelor (95.0±8.9 versus 34.1±22.5; P<0.001). Cangrelor or tirofiban were both superior to chewed prasugrel (IPA, 10.5±11.0; P<0.001 for both comparisons), which did not provide higher IPA over integral prasugrel (6.3±11.4; P=0.47), despite yielding higher prasugrel active metabolite concentration (ng/mL; 62.3±82.6 versus 17.1±43.5; P=0.016).

Conclusions:

Cangrelor provided inferior IPA compared with tirofiban; both treatments yielded greater IPA compared with chewed prasugrel, which led to higher active metabolite concentration but not greater IPA compared with integral prasugrel.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02978040; URL: https://www.clinicaltrialsregister.eu; EudraCT 2017-001065-24.

COMPARison of pre-hospital CRUSHed vs. uncrushed Prasugrel tablets in patients with STEMI undergoing primary percutaneous coronary interventions: Rationale and design of the COMPARE CRUSH trial

BACKGROUND

Dual antiplatelet therapy constitutes the cornerstone of medical treatment in patients with ST elevation myocardial infarction (STEMI). However, oral antiplatelet agents, such as prasugrel or ticagrelor, are characterized by slow gastrointestinal drug absorption in the acute phase of STEMI, leading to decreased bioavailability and therefore delayed onset of platelet inhibition. Evidence suggests that administration of crushed tablets of the P2Y₁₂ inhibitor prasugrel improves drug absorption and achieves earlier antiplatelet effects in STEMI patients undergoing primary percutaneous coronary intervention (PCI). However, the clinical implications of these pharmacokinetic and pharmacodynamic findings are unknown.

HYPOTHESIS

The present study is designed to test the hypothesis that patients presenting with STEMI planned for primary PCI will have improved markers of optimal reperfusion and clinical outcomes by prehospital administration of crushed tablets of prasugrel loading dose.

STUDY DESIGN

COMPARE CRUSH (NCT03296540) is a randomized trial in a regionally organized ambulance care setting evaluating the efficacy and safety of pre-hospital loading dose with prasugrel crushed tablets versus integral tablets in approximately 674 patients presenting with STEMI planned for primary PCI. The independent primary endpoints are percentage of patients reaching thrombolysis in myocardial infarction (TIMI) flow grade 3 in the infarct-related artery at initial angiography, or achieving ≥70% ST-segment elevation resolution at 1 hour post-PCI. Secondary clinical endpoints are death, myocardial infarction, revascularization, and stent thrombosis followed up to 1 year. Moreover, the primary safety endpoint is bleeding events assessed at 48 hours.

CONCLUSIONS

The COMPARE CRUSH trial will assess whether prehospital administration of loading dose prasugrel in form of crushed tablets - which is expected to provide faster platelet inhibition compared to standard treatment with integral tablets - results in improved reperfusion and clinical outcomes. RCT# NCT03296540.

Targeting the human microbiome and its metabolite TMAO in cardiovascular prevention and therapy

The human gut microbiota is the most important active part of the intestinal micro-ecosystem. Lifestyle modification, drug intake and nutrition have an impact on the composition of the gut microbiota and its metabolites. This review focuses on the effects of changes in the gut microbiota as well as the important metabolite Trimethylamine-N-oxide (TMAO). Furthermore, relevant therapeutic options to target the human microbiome in patients with cardiovascular disease are presented.

Gut Microbiota-Dependent Marker TMAO in Promoting Cardiovascular Disease: Inflammation Mechanism, Clinical Prognostic, and Potential as a Therapeutic Target

Cardiovascular disease (CVD) is the leading cause of death worldwide, especially in developed countries, and atherosclerosis (AS) is the common pathological basis of many cardiovascular diseases (CVDs) such as coronary heart disease (CHD). The role of the gut microbiota in AS has begun to be appreciated in recent years. Trimethylamine N-oxide (TMAO), an important gut microbe-dependent metabolite, is generated from dietary choline, betaine, and L-carnitine. Multiple studies have suggested a correlation between plasma TMAO levels and the risk of AS. However, the mechanism underlying this relationship is still unclear. In this review, we discuss the TMAO-involved mechanisms of atherosclerotic CVD from the perspective of inflammation, inflammation-related immunity, cholesterol metabolism, and atherothrombosis. We also summarize available clinical studies on the role of TMAO in predicting prognostic outcomes, including major adverse cardiovascular events (MACE), in patients presenting with AS. Finally, since TMAO may be a novel therapeutic target for AS, several therapeutic strategies including drugs, dietary, etc. to lower TMAO levels that are currently being explored are also discussed.

Platelet Function in Aging

Aging is associated with an increased incidence of cardiovascular disease and thrombosis. Platelets play a major role in maintaining hemostasis and in thrombus formation, making them a key player in thrombotic disorders. Whereas it is well-known that platelet aggregability is increased in vascular diseases, the contribution of age-related changes in platelet biology to cardiovascular risk is not well-understood. Several lines of evidence support that platelets from older subjects differ in their function and structure, making platelets more prone to activation and less sensitive to inhibition. These age-related changes could lead to platelet hyperactivity and to the development of a prothrombotic state in advanced age. This review will focus on platelet biochemical modifications during aging and on the mechanisms by which these alterations could lead to thrombotic disease.

Acetylsalicylic acid decreases clotting in combination with enoxaparin during haemodialysis in vitro

BACKGROUND

Anticoagulation is a cornerstone in haemodialysis (HD) therapy to avoid clotting of blood when it comes into contact with the dialysis membrane. Although heparins are usually administered as anticoagulants, they are not always sufficient to maintain adequate HD. We investigated the additional effect of acetylsalicylic acid compared with standard anticoagulation on maintaining adequate flow properties during HD in vitro.

METHODS

We collected blood from 42 healthy volunteers, between 18 and 60 years of age, into bags filled with 1, 1.5 or 2 mg enoxaparin, with (treatment group) or without (control group) 100 mg of aspirin. Blood was evaluated before, during and at the end of each experiment to determine coagulation parameters, whole blood aggregation and thromboelastogram measurements. Transmembrane pressure was recorded as indirect estimate of dialysis patency. The primary endpoint was time to filter clotting.

RESULTS

Addition of acetylsalicylic acid significantly prolonged the time to circuit clotting from 120 (105-150) min to >180 min (120-180) min (P = 0.047) and allowed lowering the enoxaparin concentration from 2 mg per circuit to 1 mg without an increase in clotting. Furthermore, it reduced the transmembrane pressure from 46 to 4 mmHg (P < 0.001) after 4 h of dialysis. Acetylsalicylic acid better preserved the platelet count (128 versus 116 × 10E9/L, P = 0.01) and improved platelet aggregation at the end of the dialysis procedure.

CONCLUSION

Adding acetylsalicylic acid to HD circuits lowered the transmembrane pressure, better preserved platelet function and prolonged the time to circuit clotting, which in sum increases haemodialyser performance and may facilitate a more effective HD.

Flavin monooxygenase 3, the host hepatic enzyme in the metaorganismal trimethylamine N-oxide-generating pathway, modulates platelet responsiveness and thrombosis risk

Essentials Microbe-dependent production of trimethylamine N-oxide (TMAO) contributes to thrombosis risk. The impact of host flavin monooxygenase 3 (FMO3) modulation on platelet function is unknown. Genetic manipulation of FMO3 in mice alters systemic TMAO levels and thrombosis potential. Genetic manipulation of FMO3 is associated with alteration of gut microbial community structure.

SUMMARY

Background Gut microbes play a critical role in the production of trimethylamine N-oxide (TMAO), an atherogenic metabolite that impacts platelet responsiveness and thrombosis potential. Involving both microbe and host enzymatic machinery, TMAO generation utilizes a metaorganismal pathway, beginning with ingestion of trimethylamine (TMA)-containing dietary nutrients such as choline, phosphatidylcholine and carnitine, which are abundant in a Western diet. Gut microbial TMA lyases use these nutrients as substrates to produce TMA, which upon delivery to the liver via the portal circulation, is converted into TMAO by host hepatic flavin monooxygenases (FMOs). Gut microbial production of TMA is rate limiting in the metaorganismal TMAO pathway because hepatic FMO activity is typically in excess. Objectives FMO3 is the major FMO responsible for host generation of TMAO; however, a role for FMO3 in altering platelet responsiveness and thrombosis potential in vivo has not yet been explored. Methods The impact of FMO3 suppression (antisense oligonucleotide-targeting) and overexpression (as transgene) on plasma TMAO levels, platelet responsiveness and thrombosis potential was examined using a murine FeCl3 -induced carotid artery injury model. Cecal microbial composition was examined using 16S analyses. Results Modulation of FMO3 directly impacts systemic TMAO levels, platelet responsiveness and rate of thrombus formation in vivo. Microbial composition analyses reveal taxa whose proportions are associated with both plasma TMAO levels and in vivo thrombosis potential. Conclusions The present studies demonstrate that host hepatic FMO3, the terminal step in the metaorganismal TMAO pathway, participates in diet-dependent and gut microbiota-dependent changes in both platelet responsiveness and thrombosis potential in vivo.

Effect of aspirin treatment on abacavir-associated platelet hyperreactivity in HIV-infected patients

BACKGROUND

Ischemic cardiovascular events are a relevant cause of morbidity and mortality in HIV-infected patients. Use of abacavir (ABC), a nucleoside analog reverse transcriptase inhibitor, has been associated with increased risk of myocardial infarction (MI) and with platelet hyperreactivity. We explored whether low-dose aspirin reduces in vivo platelet activation and platelet hyperreactivity induced by ABC in HIV-infected subjects.

METHODS AND RESULTS

In a randomized, placebo-controlled, cross-over study forty HIV-infected patients with ABC-associated platelet hyperreactivity, defined by a score based on laboratory variables reflecting in vivo platelet activation and ex vivo platelet hyperresponsiveness, were randomized to aspirin 100 mg daily for 15 days with subsequent cross-over to placebo for additional 15 days or placebo for 15 days with subsequent cross-over to aspirin for further 15 days. In vivo and ex vivo platelet activation markers were measured at day 15 and 30. One group of healthy subjects, one of untreated HIV infected-patients and one treated without ABC, were studied concomitantly. Serum TxB₂ and urinary 11-dehydro-TxB₂ were decreased by aspirin in ABC-treated patients, but not as much as in healthy controls. Aspirin therapy reduced significantly platelet hyperreactivity (score: from 9.3, 95% CIs 8.7 to 10.0, to 7.5, 6.9 to 8.0), however without bringing it back to the levels of healthy controls (score: 4.6, 95% CIs 3.6 to 5.6).

CONCLUSION

Aspirin reduces ABC-induced in vivo platelet activation and platelet hyperreactivity in HIV-infected patients, however without normalizing them. Whether the observed reduction of platelet activation is sufficient to prevent cardiovascular events requires a prospective trial.

Amperometric myeloperoxidase immunoassay based on the use of CuPdPt nanowire networks

This research describes a nanowire network-based method for detecting the activity of myeloperoxidase (MPO), a biomarker of acute coronary syndromes (ACS). Trimetallic CuPdPt nanowire networks (CuPdPt NWNWs) were prepared by a one-step chemical reduction method. The metallic precursors quickly form nanowire network structures without the need for additional capping agents or surfactants. This process creates a product with a clean surface. The NWNWs were dropped onto a glassy carbon electrode (GCE) to obtain a sensor with good catalytic activity towards the reduction of hydrogen peroxide (H₂O₂), which was used as an electrochemical probe working at -0.4 V (vs. SCE). It also provided a large surface for further modification. Next, an antibody against MPO was immobilized on the modified GCE via the stable conjunction between Cu, Pt, Pd and amino groups. Upon binding of MPO to the antibody on the GCE, the current response to H₂O₂ was reduced by 35 μA·cm^-2. The immunosensor had a linear response within the 100 fg·mL^-1 to 50 ng·mL^-1 MPO concentration range and a 33 fg·mL^-1 detection limit (at an S/N ratio of 3). The recovery of spiked serum samples ranged from 99.8 to 103.6%. This result suggests that the method can be applied to the quantitation of MPO in human serum samples. Graphical abstract A trimetallic CuPdPt nanowire networks was placed on a glassy cabon electrode (GCE) to design an immunosensor for myeloperoxidase (MPO), a biomarker for the acute coronary syndrome (ACS). Antibody against MPO was immobilized on the network via conjugation between Cu, Pt, Pd and amino groups. Amperometric i-t measurements were conducted to quantify the amount of MPO that binds to the antibody on the surface of the modified GCE.

Third generation P2Y12 antagonists inhibit platelet aggregation more effectively than clopidogrel in a myocardial infarction registry

The current standard of antiplatelet therapy of patients after myocardial infarction includes the P2Y12 receptor antagonists clopidogrel, prasugrel or ticagrelor. This study aimed to compare the antiplatelet effect of clopidogrel, prasugrel and ticagrelor in patients after myocardial infarction. In a single-centre registry the antiplatelet effect of clopidogrel, prasugrel and ticagrelor was investigated by aggregometry in patients after myocardial infarction. To assess the overall capacity of platelet aggregation whole blood was induced with thrombin receptor activating peptide (TRAP; 32 μM). To specifically quantify the effect of P2Y12 antagonists, whole blood was stimulated with 6.4 μM adenosine diphophosphate (ADP). Relative ADP induced aggregation (r-ADP-agg) was defined as the ADP-TRAP ratio to reflect an individual degree of P2Y12-dependent platelet inhibition. Platelet function of 238 patients was analysed [clopidogrel (n=58), prasugrel (n=65), ticagrelor (n=115)]. The r-ADP-agg was 35 ± 14% for patients receiving clopidogrel, 28 ± 10% for patients receiving prasugrel and 26 ± 11% for patients receiving ticagrelor. The r-ADP-agg was significantly lower in patients treated with prasugrel (p=0.0024) or ticagrelor (p<0.0001) compared to clopidogrel. There was no significant difference between patients receiving prasugrel or ticagrelor (p=0.2559). In conclusion, prasugrel and ticagrelor provide a stronger platelet inhibition compared to clopidogrel in patients after myocardial infarction. No significant difference in platelet inhibition was detected between prasugrel and ticagrelor. (registry for patients after Myocardial Infarction Treated with AntiPlatelet agents; DRKS00003146).

The in vitro effect of the new antithrombotic drug candidate ALX-0081 on blood samples of patients undergoing percutaneous coronary intervention

Compound ALX-0081 is a bivalent humanised Nanobody® that binds the A1-domain of von Willebrand factor (VWF) with high affinity. Consequently, it can block the interaction between VWF and its platelet-receptor- glycoprotein Ib, which leads inevitably to formation of arterial thrombi. It was the objective of this study to assess the in vitro effects of ALX-0081 on platelet adhesion and aggregation in coronary artery disease (CAD) patients to determine the optimal concentration of ALX-0081 and the effect of co-medication. We included nine CAD patients, who were scheduled for elective percutaneous coronary intervention (PCI), and 11 healthy volunteers. At admission all patients received aspirin, clopidogrel and heparin. Blood was drawn 24 hours (h) before and 1 h after start of the PCI procedure and was subsequently spiked with different concentrations of ALX-0081 or buffer. The efficacy of ALX-0081 was assessed by in vitro experiments: flow chamber experiments, ristocetin-induced platelet aggregation (RIPA), and the platelet function analyser (PFA-100TM). VWF levels in CAD patients were significantly higher than in healthy controls. During PCI VWF levels did not rise. In all in vitro experiments, ALX-0081 led to complete inhibition of platelet adhesion and aggregation. However, the required effective concentration was higher in patients than in controls and was related to plasma VWF levels. In conclusion, ALX-0081 is able to completely inhibit in vitro platelet adhesion and aggregation in CAD patients scheduled for elective PCI. The efficacy of ALX-0081 is not influenced by PCI or co-medication. However, due to higher VWF levels in CAD patients a higher effective concentration of ALX-0081 was required than in healthy individuals.

The role of SCUBE1 in the pathogenesis of no-reflow phenomenon presenting with ST segment elevation myocardial infarction

Objective:

SCUBE1 [signal peptide-CUB (complement C1r/C1 s)-EGF (epidermal growth factor)-like domain-containing protein 1] might function as a novel platelet-endothelial adhesion molecule and play pathological roles in cardiovascular biology. Acute myocardial infarction is one of the most common causes of death in modern society. The concept of “no reflow” (NR) refers to a state of myocardial tissue hypoperfusion in the presence of a patent epicardial coronary artery. The main mechanisms of this phenomenon are thought to be high platelet activity and much thrombus burden. So, we researched the role of SCUBE1 in the pathogenesis of NR.

Methods:

A total of 142 patients with ST elevation myocardial infarction (STEMI) (n=42 with NR and n=100 without NR) and 50 healthy individuals were prospectively case-control recruited between March 2015 and October 2016 from our outpatient clinics of cardiology department. Patients with STEMI were diagnosed according to American Heart Association (AHA) guideline for the management of STEMI.

Results:

The mean SCUBE1 levels of the control subjects were 34±8.4 ng/mL, the mean SCUBE1 levels of patients with STEMI who were treated successfully with primary percutaneous coronary intervention (PCI) were 51±6.2, and the mean SCUBE1 levels of patients with STEMI who had NR phenomenon after primary PCI procedure were 97.2±8.9 ng/mL.

Conclusion:

In our opinion, SCUBE1 might contribute to NR phenomenon via thrombus activation and aggregation. The pathophysiology of NR phenomenon is unclear. The present study is the first clinical study that demonstrated that serum SCUBE1 level was significantly higher in patients with NR and that serum SCUBE1 was an independent predictor for the presence of NR in our study population.

Platelet Function Testing in Patients with Acute Ischemic Stroke: An Observational Study

BACKGROUND

The measurement of platelet reactivity in patients with stroke undergoing antiplatelet therapies is not commonly performed in clinical practice. We assessed the prevalence of therapy responsiveness in patients with stroke and further investigated differences between patients on prevention therapy at stroke onset and patients naive to antiplatelet medications. We also sought differences in responsiveness between etiological subtypes and correlations between Clopidogrel responsiveness and genetic polymorphisms.

METHODS

A total of 624 stroke patients on antiplatelet therapy were included. Two different groups were identified: "non-naive patients", and "naive patients". Platelet function was measured with multiple electrode aggregometry, and genotyping assays were used to determine CYP2C19 polymorphisms.

RESULTS

Aspirin (ASA) responsiveness was significantly more frequent in naive patients compared with non-naive patients (94.9% versus 82.6%, P < .0010). A better responsiveness to ASA compared with Clopidogrel or combination therapy was found in the entire population (P < .0010), in non-naive patients (P < .0253), and in naive patients (P < .0010). Multivariate analysis revealed a strong effect of Clopidogrel as a possible "risk factor" for unresponsiveness (odds ratio 3.652, P < .0001). No difference between etiological subgroups and no correlations between responsiveness and CYP2C19 polymorphisms were found.

CONCLUSION

In our opinion, platelet function testing could be potentially useful in monitoring the biological effect of antiplatelet agents. A substantial proportion of patients with stroke on ASA were "resistant", and the treatment with Clopidogrel was accompanied by even higher rates of unresponsiveness. Longitudinal studies are needed to assess whether aggregometry might supply individualized prognostic information and whether it can be considered a valid tool for future prevention strategies.

Utility of point of care assessment of platelet reactivity (using the PFA-100®) to aid in diagnosis of stroke

BACKGROUND

Rapid and accurate diagnosis of patients presenting with symptoms of stroke is needed to facilitate the timely delivery of proven effective treatment for patients with acute ischemic stroke (AIS). The aim of this study was to determine whether early assessment of platelet reactivity in patients presenting with symptoms of AIS was associated with a diagnosis of AIS, transient ischemic attack (TIA), or stroke mimic.

METHODS

This prospective study included patients with symptoms of AIS treated at an inner-city emergency department (ED). Blood samples were obtained and assayed for platelet reactivity (quantified by closure time). Patients were grouped by discharge diagnosis into: AIS, TIA, or stroke mimic. Binary logistic regression model was used to predict the association of closure time with the final diagnosis of 1) either AIS or TIA or, 2) stroke mimic.

RESULTS

Of 114 patients enrolled, 32 were diagnosed with AIS, 33 TIA, and 49 were diagnosed as a stroke mimic. There was no significant difference in closure times among patients with a diagnosis of AIS or TIA versus stroke mimic. A history of migraines and history of seizures were independently associated with lower odds of an AIS or TIA diagnosis (OR 0.31, 95% CI 0.10 to 0.94 and OR 0.08, 95% CI 0.01 to 0.88, respectively).

CONCLUSION

Closure time was not found to be a clinically reliable differentiator of patients with a diagnosis of AIS, TIA, or stroke mimic in the ED.

Randomised trial to compare a protective effect of Clopidogrel Versus TIcagrelor on coronary Microvascular injury in ST-segment Elevation myocardial infarction (CV-TIME trial)

AIMS

Ticagrelor has shown greater, more rapid and more consistent platelet inhibition than clopidogrel. However, the superiority of ticagrelor for preventing ischaemic damage in STEMI patients has not been proven. The aim of this trial was to assess whether ticagrelor is superior to clopidogrel in preventing microvascular injury in ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

Patients with STEMI underwent prospective random assignment to receive a loading dose (LD) of clopidogrel 600 mg or ticagrelor 180 mg (1:1 ratio) before primary percutaneous coronary intervention (PCI). As the primary endpoint, the index of microcirculatory resistance (IMR) was measured immediately after primary PCI. The secondary endpoint was the infarct size estimated from the wall motion score index (WMSI). A total of 76 patients were enrolled (clopidogrel group=38, ticagrelor group=38). The IMR in the ticagrelor group was significantly lower than that in the clopidogrel group (22.2±18.0 vs. 34.4±18.8 U, p=0.005). Cardiac enzymes were less elevated in the ticagrelor group than in the clopidogrel group (CK peak; 2,651±1,710 vs. 3,139±2,698 ng/ml, p=0.06). Infarct size, estimated by WMSI, was not different between the ticagrelor and clopidogrel groups at baseline (1.55±0.30 vs. 1.61±0.29, p=0.41) or after three months (1.42±0.33 vs. 1.47±0.33, p=0.57).

CONCLUSIONS

In patients with STEMI treated by primary PCI, a 180 mg LD of ticagrelor might be more effective in reducing microvascular injury than a 600 mg LD of clopidogrel, as demonstrated by IMR immediately after primary PCI.

MEAN PLATELET VOLUME AND PLATELET FUNCTION ANALYSIS IN ACROMEGALIC PATIENTS BEFORE AND AFTER TREATMENT

Objective

Mean platelet volume (MPV) and platelet function analysis have been studied before in acromegaly, but the effect of treatment on both parameters has not been evaluated. We aimed to investigate MPV and platelet function analysis in acromegalic patients after six-months of treatment.

Methods

Forty patients with active acromegaly and 36 healthy subjects were included in the study. Plasma glucose and lipids, fibrinogen, GH, IGF-1 levels, MPV and platelet function analysis were measured. All patients with acromegaly were re-evaluated six months after treatment.

Results

Fasting blood glucose (FBG), GH, IGF-1, fibrinogen levels and MPV values were significantly higher in acromegalic group compared with the control. Platelet function was enhanced significantly (pcol-ADP: 0.002, pcolepinephrine: 0.002). After 6 months of treatment FBG, serum GH, IGF-1, fibrinogen and MPV decreased and collagen/ADP- and collagen/epinephrine-closure times (CT) were increased. Acromegalic patients that were in remission with long-acting SSA after surgery had significantly higher fibrinogen levels and MPV and decreased collagen/epinephrine-CT with respect to the controls (pfibrinogen: 0.001, pMPV: 0.026, pcol-epinephrine: 0.037).

Conclusion

Acromegaly was associated with increased MPV and enhanced platelet activity. Although growth hormone hypersecretion was controlled by surgery and medical treatment, these parameters did not improve - indicating a still increased risk for cardiovascular events.

Platelet microparticle number is associated with the extent of myocardial damage in acute myocardial infarction

INTRODUCTION

Activated platelets generate microparticles. Increased platelet microparticles occur in acute myocardial infarction (AMI) and contribute to intracoronary thrombosis and subsequent myocardial injury. This study aimed to investigate the impact of platelet microparticles on intracoronary thrombosis by assessing the relationship between platelet microparticles and the extent of myocardial damage in AMI.

MATERIAL AND METHODS

This was a cross sectional study. The subjects were patients with acute coronary syndrome (ACS). Forty-one consecutive subjects with ACS admitted to intensive cardiovascular care unit were enrolled. The clinical spectrum of ACS comprised AMI (n = 26), both ST-elevation AMI (STEMI) and non-ST-elevation AMI (NSTEMI), and unstable angina (n = 15). Platelet microparticles were isolated from peripheral venous blood and detected with anti-CD42b-PE by the flow cytometry method. The extent of myocardial damage was determined by measuring the peak level of serial cardiac enzymes within 24 h of admission.

RESULTS

Subjects with AMI had a significantly higher number of platelet microparticles than those with unstable angina (4855 ±4509/µl vs. 2181 ±1923/µl respectively; p = 0.036). Subjects with STEMI had the highest number of platelet microparticles, but no significant difference was detected as compared to those with NSTEMI (5775 ±5680/µl vs. 3601 ±1632/µl). The number of platelet microparticles in AMI was positively associated with the extent of myocardial damage (peak CK-MB: r = 0.408, p = 0.019 and peak GOT: r = 0.384, p = 0.026).

CONCLUSIONS

The number of platelet microparticles was increased in AMI as compared to unstable angina and associated with the extent of myocardial damage.

Gut Microbial Metabolite TMAO Enhances Platelet Hyperreactivity and Thrombosis Risk

Normal platelet function is critical to blood hemostasis and maintenance of a closed circulatory system. Heightened platelet reactivity, however, is associated with cardiometabolic diseases and enhanced potential for thrombotic events. We now show gut microbes, through generation of trimethylamine N-oxide (TMAO), directly contribute to platelet hyperreactivity and enhanced thrombosis potential. Plasma TMAO levels in subjects (n > 4,000) independently predicted incident (3 years) thrombosis (heart attack, stroke) risk. Direct exposure of platelets to TMAO enhanced sub-maximal stimulus-dependent platelet activation from multiple agonists through augmented Ca(2+) release from intracellular stores. Animal model studies employing dietary choline or TMAO, germ-free mice, and microbial transplantation collectively confirm a role for gut microbiota and TMAO in modulating platelet hyperresponsiveness and thrombosis potential and identify microbial taxa associated with plasma TMAO and thrombosis potential. Collectively, the present results reveal a previously unrecognized mechanistic link between specific dietary nutrients, gut microbes, platelet function, and thrombosis risk.

Clinical Significance of Laboratory-determined Aspirin Poor Responsiveness After Primary Percutaneous Coronary Intervention

AIMS

The objective of the present substudy was to examine whether aspirin poor/high responsiveness (APR/AHR) is associated with increased rates of major adverse cardiovascular events (MACE) and serious bleeding after primary percutaneous coronary intervention (PPCI).

METHODS

We analyzed 961 consecutive ST-elevation acute myocardial infarction patients who underwent PPCI between February 2008 and June 2011. Multiplate analyser (Dynabite, Munich, Germany) was used for the assessment of platelet reactivity. APR/AHR were defined as the upper/lower quintiles of ASPI values, determined 24 h after aspirin loading. APR patients were tailored using 300 mg maintenance dose for 30 days. The co-primary end points at 30 days were: MACE (death, non-fatal infarction, ischemia-driven target vessel revascularization and ischemic stroke) and serious bleeding according to the BARC classification.

RESULTS

One hundred and 90 patients were classified as APR, and 193 patients as AHR. At admission, compared with aspirin sensitive patients (ASP), patients with APR had more frequently diabetes, anterior infarction and heart failure, while AHR patients had reduced values of creatine kinase, leukocytes, heart rate and systolic blood pressure. Compared with ASP, the rates of 30-day primary end points did not differ neither in APR group including tailored patients (MACE, adjusted OR 1.02, 95%CI 0.47-2.17; serious bleeding, adjusted OR 1.92, 95%CI 0.79-4.63), nor in patients with AHR (MACE, adjusted OR 1.58, 95%CI 0.71-5.51; serious bleeding, adjusted OR 0.69, 95%CI 0.22-2.12).

CONCLUSIONS

The majority of APR patients were suitable for tailoring. Neither APR including tailored patients nor AHR were associated with adverse 30-day efficacy or safety clinical outcomes.

Coagulation parameters and platelet function analysis in patients with acromegaly

OBJECTIVE

Acromegaly is associated with increased cardiovascular morbidity and mortality. The data about the evaluation of coagulation and fibrinolysis in acromegalic patients are very limited and to our knowledge, platelet function analysis has never been investigated. So, we aimed to investigate the levels of protein C, protein S, fibrinogen, antithrombin 3 and platelet function analysis in patients with acromegaly.

METHODS

Thirty-nine patients with active acromegaly and 35 healthy subjects were included in the study. Plasma glucose and lipid profile, fibrinogen levels, GH and IGF-1 levels and protein C, protein S and antithrombin III activities were measured in all study subjects. Also, platelet function analysis was evaluated with collagen/ADP and collagen-epinephrine-closure times.

RESULTS

Demographic characteristics of the patient and the control were similar. As expected, fasting blood glucose levels and serum GH and IGF-1 levels were significantly higher in the patient group compared with the control group (pglc: 0.002, pGH: 0.006, pIGF-1: 0.001, respectively). But lipid parameters were similar between the two groups. While serum fibrinogen and antithrombin III levels were found to be significantly higher in acromegaly group (p fibrinogen: 0.005 and pantithrombin III: 0.001), protein S and protein C activity values were significantly lower in the patient group (p protein S: 0.001, p protein C: 0.001). Also significantly enhanced platelet function (measured by collagen/ADP- and collagen/epinephrine-closure times) was demonstrated in acromegaly (p col-ADP: 0.002, p col-epinephrine: 0.002). The results did not change, when we excluded six patients with type 2 diabetes in the acromegaly group. There was a negative correlation between serum GH levels and protein S (r: -0.25, p: 0.04)) and protein C (r: -0.26, p: 0.04) values. Likewise, there was a negative correlation between IGF-1 levels and protein C values (r: -0.39, p: 0.002), protein S values (r: -0.39, p: 0.001), collagen/ADP-closure times (r: -0.28, p: 0.02) and collagen/epinephrine-closure times (r:-0.26, p: 0.04). Also, we observed a positive correlation between IGF-1 levels and fibrinogen levels (r: 0.31, p: 0.01).

CONCLUSION

Acromegaly was found to be associated with increased tendency to coagulation and enhanced platelet activity. This hypercoagulable state might increase the risk for cardiovascular and cerebrovascular events in acromegaly.

Effect of Hematologic Parameters on Microvascular Reperfusion in Patients With ST-Segment Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

OBJECTIVES

Despite the significant role of certain hematologic parameters in reperfusion injury, their relationship with microvascular reperfusion remains not well understood. Therefore, our objective was to evaluate the relationship between hematologic parameters at admission and microvascular reperfusion in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (primary PCI).

METHODS

A total of 213patients (mean age: 57.5 ± 11 years) with STEMI were included. Blood samples were obtained from all patients prior to primary PCI. Electrocardiographic recordings were made for the evaluation of ST-segment resolution (STR) before and after primary PCI. Angiographic assessment in the infarct-related artery was performed using the myocardial blush grade (MBG) and thrombolysis in myocardial infarction (TIMI) flow. Patients were categorized into 2 groups as those with impaired microvascular reperfusion (STR <70%, TIMI: 0-1, and MBG: 0-1) and those with normal microvascular reperfusion (STR >70%, TIMI: 2-3, and MBG: 2-3).

RESULTS

Of the overall study group, 139, 105, and 69 patients had an STR of <70%, MBG of 0-1, and TIMI of 0-1, respectively. Demographic parameters in both groups are shown in the tables. Patients with impaired microvascular reperfusion were found to have higher white blood cell (WBC) count, neutrophil count, lymphocyte count, and mean platelet volume (MPV). Neutrophil-lymphocyte ratio and platelet count were similar between the 2 groups. Correlation analysis showed a negative correlation between lymphocyte count and STR (r: -.195, P: .004), lymphocyte count and TIMI flow(r: -.09, P: .14), and lymphocyte count and MBG (r: -.211, P: .002).

CONCLUSION

Our results suggest that higher WBC count and MPV at admission are independent predictors of impaired microvascular perfusion in patients with STEMI. On the other hand, a negative correlation was found between lymphocyte count and impaired microvascular perfusion. Specifically, elevated lymphocyte count seemed to indicate the presence of impaired microvascular reperfusion in patients with STEMI.

Preoperative platelet dysfunction predicts blood product transfusion in children undergoing cardiac surgery

OBJECTIVES

Excessive bleeding can be a problem during or after cardiac surgery. While cardiopulmonary bypass-associated platelet dysfunction is an important inducer of coagulopathy, preoperative platelet dysfunction can also contribute to this bleeding. We investigated the relationship between preoperative platelet dysfunction and transfusion of blood products given to children undergoing cardiac surgery.

METHODS

The platelet function analyser test measures platelet function in vitro by aspirating blood through a small standard hole (creating high shear) in a collagen membrane infused with a platelet agonist. The time taken to form a platelet plug is known as closure time and prolonged closure time (CT) indicates platelet dysfunction. Three hundred and thirty-eight children who had undergone surgery with cardiopulmonary bypass between 2008 and 2012 were included. The volume of red blood cells and fresh-frozen plasma transfused was recorded. The relationship between closure time and transfusion requirements was analysed using linear and logistic regression.

RESULTS

Patients with prolonged closure time had greater odds of getting red blood cells and fresh-frozen plasma transfusions compared with patients with normal closure time (P <0.01). On univariate analysis, age, weight, haematocrit, cardiopulmonary bypass time, Risk Adjustment for Congenital Heart Surgery score and closure time were associated with increased odds of red blood cells and fresh-frozen plasma transfusion in the operation theatre (P <0.05). However, when logistic multivariable regression analysis was applied, only age, cardiopulmonary bypass time and closure time remained as significant predictive factors for transfusion.

CONCLUSIONS

In children who have undergone cardiac surgery, when age and cardiopulmonary bypass time are accounted for, a prolonged preoperative closure time is significantly associated with increased odds of red blood cells and fresh-frozen plasma transfusion in the operation theatre. This may have implications for planning and utilization of blood products.

Reduced platelet hyperreactivity and platelet-monocyte aggregation in HIV-infected individuals receiving a raltegravir-based regimen

OBJECTIVE

Platelets are key cells in atherosclerosis and acute cardiovascular events. Platelet hyperreactivity and increased platelet-monocyte aggregation (PMA) are found in HIV-infected patients and may contribute to the excess cardiovascular risk. The integrase inhibitor raltegravir (RAL) has been associated with better residual viral suppression and reduction in inflammatory and coagulation biomarkers. The aim of our study was to investigate whether RAL-treated patients have reduced platelet reactivity and PMA.

DESIGN AND METHODS

We performed a cross-sectional study involving 80 virologically suppressed adult HIV1-infected patients on a RAL-based (n = 25), nonnucleoside reverse transcriptase inhibitor (NNRTI)-based (n = 30) or a protease inhibitor based (n = 25) regimen and 30 healthy controls. Platelet reactivity was determined by measuring platelet P-selectin expression and the binding of fibrinogen to platelets to stimulation with two concentrations of ADP. PMA was determined by measuring the expression of the platelet marker CD42b on CD14 positive cells.

RESULTS

HIV-infected individuals had higher platelet reactivity and PMA than controls. RAL-treated individuals showed significantly lower P-selectin expression to stimulation with low (P = 0.026 vs. NNRTI and P = 0.005 vs. protease inhibitor group) and high-dose ADP (P = 0.009 vs. NNRTI and P = 0.003 vs. protease inhibitor group). A similar trend for was found for fibrinogen binding, although only the difference in P-selectin expression between RAL and protease inhibitor treated patients reached statistical significance (P = 0.038). PMA was also lower in the RAL group than in the NNRTI (P = 0.037) and protease inhibitor (P = 0.034) groups.

CONCLUSION

Use of a RAL-based regimen was associated with a reduction in persistent HIV-induced platelet hyperreactivity and PMA compared with NNRTI and protease inhibitor based regimen.