Multiple studies have shown a correlation between high on-treatment platelet reactivity (HPR) and ischemic complications after percutaneous coronary interventions (PCI); however, the role of platelet reactivity testing in order to adjust clopidogrel dose is debated. We sought to determine whether a strategy incorporating platelet reactivity testing with the Multiplate analyzer ...

Background: Diverse pharmacological effects of anti-platelet thienopyridines due to individual differences in metabolism have been reported. However, an association between on-treatment platelet reactivity and adverse ischemic events after drug-eluting stent (DES) implantation in Japanese patients has not been fully elucidated. Methods and Results: A total of 450 consecutive patients on ...

Despite certain clinical benefit in using clopidogrel in patients undergoing percutaneous coronary intervention (PCI), some patients do not attain adequate antiplatelet effects. In this study, the authors investigated the response to clopidogrel in Iranian patients after PCI. Patients who were candidates for elective PCI were enrolled in this study. All ...

OBJECTIVEType 1 diabetes is associated with increased platelet reactivity. We investigated whether α-lipoic acid (ALA) has any effect on platelet reactivity in these patients.RESEARCH DESIGN AND METHODSWe randomly assigned 51 type 1 diabetic patients to ALA (600 mg once daily) or placebo for 5 weeks. Platelet reactivity was evaluated by ...

OBJECTIVES: To investigate the impact of genotypes on the basis of the loss-of-function variant CYP2C19*2 and the gain-of-function variant CYP2C19*17 on on-treatment platelet reactivity and on the occurrence of Thrombolysis in Myocardial Infarction (TIMI) major bleedings in 820 clopidogrel-treated patients who underwent elective coronary stenting. METHODS: On-treatment platelet reactivity was ...

OBJECTIVE: Platelets have an important role in the pathogenesis of atherothrombosis. It has been shown that platelet size measured by mean platelet volume (MPV), correlates with their reactivity and is still regarded as an easy, useful tool for indirect monitoring of platelet activity in different situations. Coronary artery calcification (CAC) ...

Clopidogrel has been used to prevent recurrent ischemic events after acute coronary syndrome and/or coronary stent implantation. An impaired platelet response to this drug (residual high platelet reactivity) has been identified as a risk factor for recurrent ischemic events. The platelet response to clopidogrel is highly heritable (73%) suggesting a ...

BACKGROUND: Previous studies demonstrated that patients with PIA have a smaller infarct and better in-hospital outcome after acute myocardial infarction, than those without angina. This protective effects has been attributed to ischemic preconditioning (PC), to earlier reperfusion after fibrinolysis or its better collateral circulation development. In this study we aimed ...

BACKGROUND: CD40 ligand (CD40L) is expressed on the surface of activated platelets and activated T lymphocytes. Circulating soluble CD40 ligand (sCD40L) is formed from these molecules proteolytically. Fetuin-A is a potent antiinflammatory cytokine. AIM OF THE STUDY: In this study, we aim to investigate sCD40L levels to determine whether there ...

Although there is considerable variability of platelet reactivity among patients treated with clopidogrel, little is known about inter-individual differences and possible role of proton pump inhibitors (PPIs) after prasugrel. We defined the extent of inter-patient variability, and evaluated the impact of PPI interaction in prasugrel-treated patients with acute coronary syndrome ...

Objective: The efficacy of clopidogrel therapy in patients with an acute coronary syndrome (ACS) has been established using the clopidogrel hydrogen sulfate (CHS) formulation. In this study we compared the antiplatelet effectiveness of a generic clopidogrel salt, clopidogrel besylate (CB), with the original CHS in patients with an ACS. Research ...

OBJECTIVE: Platelet aggregation plays a major role in vascular mortality. Individuals with psoriatic arthritis (PsA) are highly predisposed to vascular mortality. We evaluated the correlation between disease activity and platelet aggregation in individuals with PsA. METHODS: Individuals with PsA receiving tumor necrosis factor-α (TNF-α) blockers (n = 114) and healthy ...

BACKGROUND: The antiplatelet effect of clopidogrel has been linked to cytochrome P450 2C19 (CYP2C19) carrier status. The presence of loss of function and gain of function variants were found to have a gene-dose effect on clopidogrel metabolism. However, genotyping is only one aspect of predicting response to clopidogrel and several ...

Platelet dysfunction contributes to the increased risk of thromboischemic complications after percutaneous coronary intervention (PCI), particularly in type 2 diabetes. Little is known about the effects of glycemic control on platelet reactivity. We assessed adenosine diphosphate-induced platelet aggregation and flow cytometric expression of P-selectin in 90 patients (56 diabetic and ...

In healthy pediatric subjects normal count platelet ranges between 250,000 μL and 450,000 μL. An elevated platelet count greater than 2 SD defines a condition of thrombocytosis. On a clinical level, thrombocytosis is classified "mild" at a platelet count between >500,000 μL and <700,000 μL; "moderate" at a platelet count ...

Clopidogrel is an important antiplatelet agent, but a considerable variability in the biological effect of the drug has been observed. Additionally, patients with insufficient platelet reactivity inhibition following a loading dose (LD) of clopidogrel have a poor outcome. The mechanisms of variability are dependent on genetic polymorphisms of enzymes involved ...

INTRODUCTION AND OBJECTIVES: CYP2C19*2 and CYP2C19*17 alleles appear to contribute to heterogeneous clopidogrel metabolism. The aims of the present study were to assess the phenotype-genotype relationship of CYP2C19*2 and *17 allele carriage and to explore the clinical impact of those polymorphisms at 6-month follow-up of an acute event in an ...

Early clustering of adverse cardiovascular events after abrupt cessation of clopidogrel has been reported in patients with acute coronary syndromes. A platelet rebound phenomenon may contribute to this increased thrombotic risk and a gradual drug tapering may attenuate this proposed platelet effect. Accordingly, we aimed to assess the effect of ...

BACKGROUND: The antiplatelet effect of clopidogrel is subject to considerable inter-individual variations. In vitro high on-treatment residual platelet reactivity (HRPR) has been linked to cytochrome P450 (CYP) 2C19*2 carriage, and both were significantly associated with the occurrence of adverse events after coronary stenting. It has been shown that besides CYP2C19, ...

Chronic kidney disease (CKD) is a factor of low response to clopidogrel. We sought to assess the functional impact of cilostazol in CKD patients with undergoing hemodialysis. Seventy-four patients with CKD undergoing hemodialysis and percutaneous coronary intervention were enrolled. Patients were randomly assigned to receive clopidogrel (75 mg/d [group 1, ...

AimsThe aim of this study was to compare on-thienopyridine platelet reactivity of elderly patients (≥75 years) vs. younger patients (<75 years). Elderly patients represent a growing and challenging segment of the coronary population for whom the effect of dual antiplatelet therapy on platelet inhibition has not been specifically addressed.Methods and ...

Background. Numerous reports on the kinetics of leukemic cells during early treatment of childhood acute lymphoblastic leukemia in association with therapeutic outcome have been published. In contrast, little is known about the prognostic relevance of normal blood counts in this setting. Design and Design and Methods. Normal hematopoiesis during and ...

ABSTRACT: BACKGROUND: To report a case of disseminated fusariosis with endogenous endophthalmitis in a patient with acute lymphoblastic leukemia. Transfusion-associated immune modulation secondary to platelet transfusion could play an important role in the pathophysiology of this case. Case Presentation A 9 year-old male with acute lymphoblastic leukemia complicated by pancytopenia ...

The purpose of the study was to systematically evaluate the significance of platelet reactivity on clopidogrel treatment on adverse cardiovascular events using a collaborative meta-analysis using patient-level data for the VerifyNow P2Y12 assay (Accumetrics, San Diego, California). Clinical evidence has been controversial regarding the influence of clopidogrel on treatment platelet ...

Previous studies have suggested that women do not accrue equal therapeutic benefit from antiplatelet medication as compared with men. The physiological mechanism and clinical implications behind this gender disparity have yet to be established. On-treatment platelet reactivity was determined in 717 men and 234 women on dual antiplatelet therapy, undergoing ...

Previous studies showed that esomeprazole does not interfere significantly with the platelet inhibitory effect of clopidogrel. It is unknown whether famotidine, a histamine 2 receptor antagonist, interacts with clopidogrel. This double-blind, randomized study aimed to compare the influence of esomeprazole and famotidine on the platelet inhibitory effect of clopidogrel. Patients ...

Transfusion-related acute lung injury (TRALI), a form of noncardiogenic pulmonary edema that develops during or within 6 h after a blood transfusion, is the most frequent cause of transfusion-associated death in the United States. Because development of TRALI is associated with donor antibodies (Abs) reactive with recipient major histocompatibility complex ...

AIMS - Although adjunctive cilostazol to dual antiplatelet therapy can reduce the risks of clinical events after percutaneous coronary intervention (PCI), whether genetic polymorphism can influence the pharmacodynamics of this regimen has not been evaluated. METHODS - PCI-treated 127 patients taking triple antiplatelet therapy (≥ 1 month) were enrolled. Platelet ...

Background: The paraoxonase activity of the enzyme paraoxonase-1 (PON-1) associated with high-density lipoprotein (HDL) may significantly influence clopidogrel's antiplatelet and clinical efficacy due to its involvement in the clopidogrel biotransformation to the pharmacologically active thiol metabolite. We evaluated the possible relationships of HDL levels as well as PON-1 activities and ...

The addition of clopidogrel to aspirin for patients undergoing percutaneous coronary intervention (PCI) had significantly reduced cardiovascular events. However, despite dual antiplatelet therapy ischaemic events still occur, especially stent thrombosis, which is associated with a high mortality rate. Inter-individual response to clopidogrel is highly variable. It was shown that 4-46% ...

Background: High on clopidogrel treatment platelet reactivity (HTPR) is frequent in patients on hemodialysis (HD). Objectives: The primary aim of the study was to determine the antiplatelet effects of prasugrel versus high-dose clopidogrel in patients on HD with HTPR. Patients/Methods: We performed a prospective, single-center, single-blinded, investigator-initiated, randomized, crossover study to compare platelet ...

Background. Current or recent use of abacavir for treating human immunodeficiency virus type 1 (HIV-1) infection has been associated with increased rates of myocardial infarction (MI). Given the role of platelet aggregation in thrombus formation in MI and the reversible nature of the abacavir association, we hypothesized that patients treated with ...

OBJECTIVE: The aim of this study is to evaluate the relationship between acute exacerbations and the mean platelet volume (MPV) trend in children with cystic fibrosis (CF), to predict the exacerbations. METHODS: A total of 46 children with CF and 37 healthy children were enrolled in the study. White blood ...

Combined inhibition of platelet aggregation is essential to prevent recurrent ischemic episodes in patients with acute coronary syndromes and after percutaneous coronary interventions (PCIs). In combination with aspirin, the ADP receptor antagonist clopidogrel is used widespread for this purpose; however, platelet reactivity after clopidogrel differs substantially between patients and high ...

Mean platelet volume (MPV) is an indicator of platelet activation. We investigated the acute effect of passive smoking on MPV in healthy volunteers. Healthy nonsmoker volunteers (n = 90) spent 120 minutes in a smoke-free room. Then they were exposed to passive smoking in 3 groups consisting of 30 volunteers ...

High residual platelet reactivity (HRPR) in patients receiving clopidogrel has been associated with high risk of ischemic events after percutaneous coronary intervention (PCI). To test the hypothesis that HRPR after clopidogrel loading is an independent prognostic marker of risk of long-term thrombotic events in patients with acute coronary syndromes (ACS) ...

Background: Severe thrombocytopenia is a major risk factor for haemorrhage, and yet platelet function and bleeding risk at low platelet counts are poorly understood because of limitations of platelet function testing at very low platelet counts. Objectives: To examine and compare platelet function in severely thrombocytopenic patients with acute myeloid ...

Background: High on-treatment platelet reactivity is an established risk factor for adverse cardiac events in patients taking clopidogrel following percutaneous coronary intervention (PCI). Methods: Two hundred patients underwent platelet reactivity testing with VerifyNow P2Y12, vasodilator-stimulated phosphoprotein phosphorylation (VASP), and light transmission aggregometry (LTA) with both 5 and 20 μM of ...

BACKGROUND: Experimental data suggest that the use of cryoablation in pulmonary vein isolation (PVI) is associated with less cell damage and less thrombus formation compared to radiofrequency (RF) energy. OBJECTIVES: We hypothesized that cryoablation significantly reduces markers of cell damage, platelet activation, and inflammation in patients undergoing pulmonary vein isolation ...

Aims: Although there is an increased cardiovascular risk in the immediate weeks following bereavement, the mechanism is not well understood. The aim of this study was to determine whether inflammatory and thrombotic changes were present in acute bereavement. Methods and results: Eighty bereaved spouses or parents were prospectively studied within ...

High on-treatment platelet reactivity (HTPR) is present in a substantial percentage of patients on chronic clopidogrel treatment and may have prognostic implications. Strategies to optimize platelet inhibition in such patients are not clear. We performed a prospective, single-center, single-blinded, investigator-initiated randomized, crossover study of platelet inhibition by prasugrel 10 mg/day ...

We report dysmegakaryopoiesis in a case of familial platelet disorder with predisposition to acute myeloid leukemia (familial platelet disorder/acute myeloid leukemia phenotype Mendelian Inheritance in Man number 601 399). Slight reduction of the number of megakaryocytes with high nucleocytoplasmic ratio, strongly basophilic cytoplasm and poorly lobulated nuclei are suggestive of ...

The aim of the present study was to investigate the impact of a adjusted clopidogrel loading dose (LD) according to platelet reactivity index in carriers of ABCB1 mutant allele undergoing percutaneous coronary intervention (PCI). All patients met the inclusion criteria were recruited in the present study. Platelet reactivity was measured ...

The precise mechanisms leading to platelet-targeted autoimmunity in immune thrombocytopenia (ITP) are not known. Cellular checkpoints normally regulate immunological self-reactivity during the development of B and T cells through cell deletion, receptor editing, induction of anergy, and extrinsic cellular suppression. When these checkpoints fail, tolerance to self-antigens may be lost. ...

Specific data about the clopidogrel response in elderly patients are lacking. The present study was performed to compare the platelet reactivity and clopidogrel response between patients aged >75 years and <75 years undergoing percutaneous coronary intervention for non-ST-segment elevation acute coronary syndrome. A total of 689 patients were enrolled, including ...

Platelet activation and aggregation are key events in the pathophysiological process of thrombosis, and vascular occlusions. Antiplatelet therapy has proven to be crucial for managing patients with acute coronary syndromes, coronary artery disease and in patients undergoing percutaneous coronary interventions. However, residual platelet reactivity on antiplatelet treatment confers a five-fold ...

Aims We previously reported that C-reactive protein (CRP) bioactivity on thrombogenesis was based on loss of its pentameric symmetry (pCRP), resulting in formation of monomeric CRP (mCRP). Our purpose was to provide mechanistic information on the direct effects of CRP isoforms on platelet activation and provide a CRP dissociation mechanism ...

Eur J Clin Invest 2011 ABSTRACT: Background  The GRAVITAS trial showed that 150 mg clopidogrel did not improve outcome in patients with high on-clopidogrel platelet reactivity (HPR) screened by the VerifyNow assay. We aimed to determine the impact of 150 mg clopidogrel in stable angina patients with HPR identified with conventional aggregometry ...

Aims: Decreased platelet responsiveness to acetylsalicylic acid (ASA) reported previously in diabetic patients could be attributed to patient-based, clinical, genetic, and cellular factors. The objective of this study was to investigate the effect of genomic polymorphism on the platelet reactivity in diabetic patients treated with ASA. Methods and results: Study cohort consisted ...

Pharmacodynamic studies reported an amplified on-clopidogrel platelet inhibition in smokers potentially caused by an increased metabolic drug activation via induction of cytochrome P450 1A2. The aims of this analysis were to evaluate the impact of smoking on the antiplatelet effect of clopidogrel and prasugrel and to test the potential interaction ...