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Purpose: Platelets are key mediators in cardiovascular disease (CVD). Low cardiorespiratory fitness (CRF) is a risk factor for CVD. The purpose of our study was to assess if CRF associates with platelet function. Methods: Platelet assays and cardiopulmonary exercise testing were conducted in the Framingham Heart Study (N = 3014). Linear mixed effects models estimated associations between CRF (assessed by peak oxygen uptake [V̇O2]) and multiple platelet reactivity assays. Models were adjusted for multiple medications, risk factors, relatedness, and prevalent CVD. Results: Nineteen associations passed the significance threshold in the fully adjusted models, all indicating higher CRF associated with decreased platelet reactivity. Significant traits spanned multiple platelet agonists. Strongest associations were observed in multiplate whole blood testing after TRAP-6 (e.g., velocity, beta = -0.563, 95% CI = -0.735 to -0.391, P = 1.38E-10), ADP (e.g., velocity, beta = -0.514, 95% CI = -0.681 to -0348, P = 1.41E-09), collagen (e.g., velocity, beta = -0.387, 95% CI = -0.549 to -0.224, P = 3.01E-06), ristocetin (e.g., AUC, beta = -0.365, 95% CI = -0.522 to -0.208, P = 5.17E-06) and arachidonic acid stimulation of platelets (e.g., velocity, beta = -0.298, 95% CI = -0.435 to -0.162, P = 3.39E-04), and light transmission aggregometry (LTA) after ristocetin stimulation (e.g., max aggregation, beta = -0.362, 95% CI = -0.540 to -0.184, P = 6.64E-05). One trait passed significance threshold in the aspirin subsample (LTA ristocetin primary slope, beta = -0.733, 95% CI = -1.134 to -0.333, P = 3.30E-04) and another in a model including von Willebrand Factor levels as a covariate (U46619, a thromboxane receptor mimetic, AUC in the Optimul assay, beta = -0.36, 95% CI = -0.551 to -0.168, P = 2.35E-04). No strong interactions were observed between the associations and sex, age, or body mass index in formal interaction analyses. Conclusions: Our findings build on past work that shows CRF to be associated with reduced CVD by suggesting decreased platelet reactivity may play a mechanistic role. We found significant associations with multiple platelet agonists, indicating higher CRF may globally inhibit platelets; however, given multiple strong associations after TRAP-6 and ADP stimulation, PAR-1 and purinergic signaling may be most heavily involved. This is notable because each of these receptor pathways are tied to anticoagulant (DOAC/thrombin inhibitors) and antiplatelet therapies (P2Y12/PAR1/PAR4 inhibitors) for CVD prevention. [ABSTRACT FROM AUTHOR]

Patients with critical illness often display variable hypo- and hypercoagulable sequalae requiring intense monitoring and anticoagulation pharmacotherapy to prevent or treat inappropriate clot formation. It is imperative to understand the various stages of the clotting cascade and where each pharmacotherapy agent exerts its therapeutic effect. Common coagulation tests are utilized to monitor the areas of the clotting cascade and the effects that anticoagulant pharmacotherapy exhibits. Many novel coagulation tests are also in development. The purpose of this narrative review is to evaluate commonly utilized coagulation tests that monitor anticoagulation while in the intensive care unit. [ABSTRACT FROM AUTHOR]

Background: Although artificial and non-nutritive sweeteners are widely used and generally recognized as safe by the US and European Union regulatory agencies, there have been no clinical trials to assess either long-term cardiovascular disease risks or short-term cardiovascular disease-relevant phenotypes. Recent studies report that fasting plasma levels of erythritol, a commonly used sweetener, are clinically associated with heightened incident cardiovascular disease risks and enhance thrombosis potential in vitro and in animal models. Effects of dietary erythritol on thrombosis phenotypes in humans have not been examined., Methods: Using a prospective interventional study design, we tested the impact of erythritol or glucose consumption on multiple indices of stimulus-dependent platelet responsiveness in healthy volunteers (n=10 per group). Erythritol plasma levels were quantified with liquid chromatography tandem mass spectrometry. Platelet function at baseline and following erythritol or glucose ingestion was assessed via both aggregometry and analysis of granule markers released., Results: Dietary erythritol (30 g), but not glucose (30 g), lead to a >1000-fold increase in erythritol plasma concentration (6480 [5930-7300] versus 3.75 [3.35-3.87] μmol/L; P <0.0001) and exhibited acute enhancement of stimulus-dependent aggregation responses in all subjects, agonists, and doses examined. Erythritol ingestion also enhanced stimulus-dependent release of the platelet dense granule marker serotonin ( P <0.0001 for TRAP6 [thrombin activator peptide 6] and P =0.004 for ADP) and the platelet α-granule marker CXCL4 (C-X-C motif ligand-4; P <0.0001 for TRAP6 and P =0.06 for ADP). In contrast, glucose ingestion triggered no significant increases in stimulus-dependent release of either serotonin or CXCL4., Conclusions: Ingestion of a typical quantity of the non-nutritive sweetener erythritol, but not glucose, enhances platelet reactivity in healthy volunteers, raising concerns that erythritol consumption may enhance thrombosis potential. Combined with recent large-scale clinical observational studies and mechanistic cell-based and animal model studies, the present findings suggest that discussion of whether erythritol should be reevaluated as a food additive with the Generally Recognized as Safe designation is warranted., Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04731363., Competing Interests: S.L. Hazen and Z. Wang report being named as coinventors on pending and issued patents held by the Cleveland Clinic relating to cardiovascular diagnostics and therapeutics, all unrelated to the subject and contents of this article. S.L. Hazen and Z. Wang also report having received royalty payments for inventions or discoveries related to cardiovascular diagnostics or therapeutics from Procter & Gamble and Cleveland HeartLab, Inc, a fully owned subsidiary of Quest Diagnostics. S.L. Hazen is a paid consultant at Zehna Therapeutics, has received research funds from Zehna Therapeutics, and is eligible to receive royalty payments for inventions or discoveries related to cardiovascular diagnostics and therapeutics from Zehna Therapeutics. W.H.W. Tang reports being a consult at Sequana Medical A.G., Cardiol Therapeutics, Zehna Therapeutics, Genomics plc, Boston Scientific, WhiteSwell, Bristol Myers Squibb, Intellia Therapeutics, Alexion Pharmaceuticals, Alleviant Medical, CardiaTec Biosciences, Salubris Biotherapeutics, BioCardia, and has received honoraria from American Board of Internal Medicine, Belvoir Media Group, and Springer Nature. The other authors report no conflicts.

Objective: The aim of this prospective study was to (1) objectively quantify the impact of sex on platelet function in patients with peripheral artery disease (PAD) taking antiplatelet and anticoagulant medications and (2) to develop and test a personalized, iterative algorithm that personalizes thromboprophylaxis that incorporates platelet function testing., Background: Women with PAD have worse outcomes as compared with their male counterparts despite having lower risk factors. This health disparity may be mitigated by personalizing thromboprophylaxis regimens., Methods: Patients undergoing revascularization were enrolled. Serial thromboelastography (TEG) and TEG with platelet mapping (TEG-PM) were performed up to 6 months postoperatively to determine objective coagulation profiles. In a subset of patients, the Antiplatelet Coagulation Exactness (ACE) algorithm was implemented, where patients were iteratively evaluated with TEG and given antiplatelet medications to maintain platelet inhibition at >29%. Statistical analysis was performed using unpaired t test, analysis of variance, and Fisher exact test., Results: One hundred eighty-one patients met the study criteria. Fifty-eight (32%) patients were females and 123 (68%) were males. In the Aspirin cohort, females showed significantly greater clot strength as maximum amplitude - arachidonic acid (MA AA ) and significantly lower platelet inhibition than males: (37.26 vs 32.38, P <0.01) and (52.95% vs 61.65%, P <0.05), respectively. In the Clopidogrel cohort, females showed higher Maximum Amplitude - Adenosine Diphosphate (MA ADP ) (42.58 vs 40.35, P = not significant [NS]) compared with males. Females on dual antiplatelet therapy had higher MA ADP (39.74 vs 35.07, P =NS) and lower platelet inhibition (45.25% vs 54.99%, P= NS) than males. The incidence of thrombosis of the revascularized segment, defined as thrombotic event, was objectively identified on an arterial duplex. Women showed significantly higher thrombotic events than men (22.95% vs 10.57%, P< 0.05) on the same medication. In our pilot study, implementation of the ACE algorithm led to a significant decrease in the thrombosis rate (3%), including nonthrombotic events for females, versus the historic thrombotic rate (22%) from our institution., Conclusions: Women with PAD exhibited higher platelet reactivity, clot strength, and reduced platelet inhibition in response to antiplatelet therapy. The use of the ACE algorithm to tailor antiplatelet medication in patients with PAD post-revascularization, resulted in a significant decrease in thrombotic event rates. This may serve as an opportune way to mitigate outcome sex-specific disparities caused by inadequate thromboprophylaxis in women., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Cangrelor may be used as a bridge when temporary interruption of dual antiplatelet therapy is necessary. However, the optimal dose and monitoring of cangrelor in patients remains unknown, especially in the setting of mechanical circulatory support (MCS). We conducted an observational, single-center, retrospective cohort study of patients who had percutaneous coronary intervention within 3 months and received cangrelor while admitted to any intensive care unit. The primary outcome was the incidence of any major adverse cardiovascular event. Secondary outcomes included VerifyNow platelet reactivity units (PRUs) measured while on cangrelor and any bleeding events while on cangrelor. A total of 92 patients were included. The most common reason for cangrelor use was in the periprocedural setting, with or without MCS (42%-45%), followed by NPO status (26%-28%) and MCS alone (22%-24%). The primary outcome of major adverse cardiovascular event occurred in 1 patient (1.1%). Of 92 patients, 77% had a P2Y12 level collected within 24 hours, and 89% of the cohort was able to achieve the goal P2Y12 PRU of <194. The median P2Y12 value within 24 hours of cangrelor initation was 115 PRU (40-168 PRU). We observed a bleed event rate of 23% (21/92). We found a standardized protocol of cangrelor dosing in critically ill patients who received a drug-eluting stent in the past 3 months to be successful in achieving a goal P2Y12 PRU. Although the optimal PRU remains unknown, cardiovascular clinicians may monitor these levels to help guide decisions regarding cangrelor management. Future randomized controlled trials should evaluate the optimal PRU threshold to balance risks of ischemia and bleeding., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Cilostazol as an adjunct to dual antiplatelet therapy (DAPT) postcoronary stenting may further reduce vascular occlusion risks. The aim of this study was to assess the impact of cilostazol on high residual platelet reactivity (HRPR) in patients undergoing drug-eluting coronary stent implantation., Methods: In a randomized, open-label, single-center, prospective study, the degree of platelet inhibition by cilostazol 100 mg twice daily was assessed on top of conventional DAPT compared with standard clopidogrel and low-dose aspirin combination in poststent patients with HRPR. HRPR was defined as P2Y12 units (PRU) > 240 as measured by the VerifyNow P2Y12 assay. In addition, the platelet activity was assessed by light transmittance aggregometry (LTA) and Multiplate electrode analyzer (MEA)., Results: The total of 148 patients were screened, and HRPR was observed in 64 (43.2%). Those were randomized for DAPT versus triple therapy (TAPT). After 30 days, TAPT group exhibited significantly lower rate of HRPR when assessed by all 3 devices (VerifyNow: 40.0 vs. 66.7% P = 0.04, LTA: 6.7 vs. 30.0% P = 0.02, MEA: 10.0 vs. 30.0% P = 0.05 L all vs. DAPT). Also, higher absolute mean difference in TAPT versus DAPT group after 30 days (VerifyNow: 71.3 ± 38.2 vs. 24.6 ± 40.2 P < 0.001, LTA: 23.9 ± 15.1 vs. 9.4 ± 11.8 P < 0.001, MEA: 9.3 ± 12.9 vs. 2.4 ± 17.3 P = 0.08) was observed., Conclusions: Cilostazol in addition to standard DAPT reduces the incidence of HRPR and diminishes further platelet activity in poststent patients. Whether this favorable laboratory finding will affect clinical outcomes requires an adequately powered randomized trial., Competing Interests: The authors have no conflicts of interest to declare., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Bleeding and transfusion, common challenges in cardiac surgery, are influenced by comorbidity, the complexity of surgery, hypothermia, and the specifics of cardiopulmonary bypass inducing hemodilution, thrombin generation, fibrinolysis, and platelet dysfunction.1-4 Nearly 11% of patients with acute coronary syndromes undergo coronary artery surgery during dual antiplatelet therapy.5 Although preoperative P2Y12 receptor inhibitor therapy may reduce ischemic events, late preoperative exposure to P2Y12 receptor inhibitors increases the risk of surgery-associated bleeding and reoperation for bleeding.2,6-8. [ABSTRACT FROM AUTHOR]

Background: The platelet inhibitory effects induced by oral P2Y12 receptor antagonists are delayed in patients with ST-segment-elevation myocardial infarction undergoing primary percutaneous coronary intervention (P-PCI). In turn, this leads to a gap in platelet inhibition, exposing patients to an increased risk of early thrombotic complications and underscoring the need to define strategies associated with more effective platelet inhibition in the peri-primary percutaneous coronary intervention period. Cangrelor is an intravenous P2Y12 inhibitor with prompt and potent antiplatelet effects. However, to date, there are limited data on the effects of cangrelor used in combination with ticagrelor in patients undergoing primary percutaneous coronary intervention. Moreover, questions have emerged on the potential for drug-drug interactions during the transition from cangrelor to oral P2Y12 inhibitors.Methods: This was a prospective, randomized, double-blind, placebo-controlled pharmacodynamic study conducted in patients undergoing primary percutaneous coronary intervention (n=50) who were randomized to treatment with either cangrelor or matching placebo (bolus followed by 2-hour infusion). All patients received ticagrelor 180-mg loading dose administered as crushed tablets at the time of cangrelor/placebo bolus administration. Pharmacodynamic analyses were performed at 8 time points. Pharmacodynamic effects were measured as P2Y12 reaction units by VerifyNow and platelet reactivity index by vasodilator-stimulated phosphoprotein.Results: Compared with placebo, cangrelor was associated with reduced P2Y12 reaction units as early as 5 minutes after bolus, which persisted during the entire duration of drug infusion, including at 30 minutes (63 [32-93] versus 214 [183-245]; mean difference, 152 [95% CI, 108-195]; P<0·001; primary end point). Parallel findings were shown with platelet reactivity index. Accordingly, high on-treatment platelet reactivity rates were reduced with cangrelor. After discontinuation of cangrelor/placebo infusion, there were no differences in levels of platelet reactivity between groups, ruling out a drug-drug interaction when cangrelor and ticagrelor are concomitantly administered.Conclusions: In patients undergoing primary percutaneous coronary intervention, cangrelor is an effective strategy to bridge the gap in platelet inhibition associated with the use of oral P2Y12 inhibition induced by ticagrelor. Ticagrelor can be administered as a crushed formulation concomitantly with cangrelor without any apparent drug-drug interaction. The clinical implications of these pharmacodynamic findings warrant investigation in an adequately powered clinical trial.Clinical Trial Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT03247738. [ABSTRACT FROM AUTHOR]

Keywords: blood platelets; fentanyl; pharmacology; ticagrelor EN blood platelets fentanyl pharmacology ticagrelor 2479 2481 3 12/23/20 20201222 NES 201222 Platelet inhibition induced by oral P2Y SB 12 sb receptor antagonists is delayed in patients with ST-segment elevation myocardial infarction (STEMI).[1] Morphine further reduces absorption, delays action onset, and decreases antiplatelet effects of oral P2Y SB 12 sb receptor inhibitors among patients with STEMI.[1],[2] The differential effects of fentanyl versus morphine on pharmacodynamic and pharmacokinetic profiles of potent oral P2Y SB 12 sb receptor inhibitors in patients with STEMI have not been reported to date. Effect of intravenous fentanyl on ticagrelor absorption and platelet inhibition among patients undergoing percutaneous coronary intervention: the PACIFY randomized clinical trial (Platelet Aggregation With Ticagrelor Inhibition and Fentanyl). [Extracted from the article]

Up to 11% of patients presenting with acute coronary syndromes undergo coronary artery bypass grafting. Guidelines largely recommend a one-size-fits-all preoperative discontinuation period for P2Y12 receptor blockers to avoid bleeding. These recommendations do not account for highly variable pharmacodynamic responsiveness and for variable recovery of platelet reactivity following discontinuation of P2Y12 receptor blockers. Several observational studies have demonstrated that an objective measurement of platelet function among these patients may reduce the waiting period while mitigating the risk of bleeding. Based on these findings, 2 recent guidelines included a Class IIa and IIb recommendation for platelet function testing in patients undergoing cardiac surgery. The following review article describes the rationale for discontinuation of dual antiplatelet therapy before cardiac surgery and the limitations with this approach, available platelet function assays to assess pharmacodynamic effects, and the association between platelet inhibition and other clinical factors with surgery-related bleeding. The information will assist the reader in determining which patients undergoing cardiac surgery might benefit from preoperative platelet function monitoring. [ABSTRACT FROM AUTHOR]

Background: Patients undergoing percutaneous coronary intervention react differently to antiplatelet drugs. Those with low responsiveness to clopidogrel have a higher risk of cardiac ischemic events. The goal of this study is to conduct a head-to-head comparison of the safety and effectiveness of intensified antiplatelet therapies (either double-dose clopidogrel [DOUBLE] or adjunctive cilostazol [TRIPLE]) and conventional strategy (STANDARD) in patients after percutaneous coronary intervention.Methods: In this single-center, randomized, controlled trial, we used thromboelastography, a platelet function test, to select 1078 patients undergoing percutaneous coronary intervention at high thrombotic risk and compared the intensified antiplatelet therapies with standard antiplatelet therapy. The primary outcome was the incidence of major adverse cardiac and cerebrovascular events at 18 months after percutaneous coronary intervention, defined as a composite of all-cause death, myocardial infarction, target vessel revascularization, or stroke. Bleeding Academic Research Consortium defined bleeding complications (types 1, 2, 3, or 5) were the safety end points.Results: The primary end point occurred in 52 patients (14.4%) in the STANDARD group, 38 patients (10.6%) in the DOUBLE group, and 30 patients (8.5%) in the TRIPLE group (hazard ratio, 0.720; 95% confidence interval, 0.474-1.094, DOUBLE versus STANDARD; hazard ratio, 0.550; 95% confidence interval, 0.349-0.866, TRIPLE versus STANDARD). No significant difference in the rates of major bleeding (Bleeding Academic Research Consortium grade≥3) was found in the DOUBLE group (3.34% versus 1.93% in STANDARD, P=0.133) and the TRIPLE group (2.53% versus 1.93% in STANDARD, P=0.240). The rate of Bleeding Academic Research Consortium-defined minor bleeding increased in the DOUBLE group (27.4% versus 20.3% in STANDARD, P=0.031), but not in the TRIPLE group (23.6% versus 20.3% in STANDARD, P=0.146).Conclusions: In patients with low responsiveness to clopidogrel, as measured by thromboelastography, the intensified antiplatelet strategies with adjunctive use of cilostazol significantly improved the clinical outcomes without increasing the risk of major bleeding. Decreased trend of negative outcomes could be observed in patients with double dosage of clopidogrel, but the difference was not significant.Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01779401. [ABSTRACT FROM AUTHOR]

Purpose: Low cardiorespiratory fitness (CRF) represents a major risk factor for atherosclerosis, and platelets play a key role in the development of this chronic inflammatory disease. Therefore, the purpose of this study was to assess the relationship between CRF and platelet function. Methods: CRF and different aspects of platelet function were assessed in healthy, young, nonsmoking women. Results were compared between groups of low (LF), medium (MF) and high CRF (HF). Measurements were repeated in group LF after a supervised endurance training program lasting two menstrual cycles and obtained results were compared with groups MF and HF. CRF was quantified by maximal oxygen consumption (...O2max) determined by an incremental treadmill exercise test. ...O2max criteria for groups were (mL⋅min-1⋅kg-1 bodyweight): LF < 45, MF 45-55, HF > 55. Platelet activation state and platelet reactivity were assessed by basal and agonist-induced surface expression of CD62P and CD40L as well as the intraplatelet amount of reactive oxygen species. Results: In group LF, basal platelet activation as well as agonist-induced platelet reactivity were increased compared with groups MF and HF. Between groups MF and HF parameters of platelet function were roughly equal despite a pronounced difference regarding CRF. Exercise training improved CRF in group LF and aligned platelet function to levels observed in groups MF and HF, although CRF still markedly differed. Conclusions: Low levels of CRF favor a proinflammatory platelet phenotype. A relatively low dose of exercise is sufficient to normalize platelet function, whereas superior levels of physical activity and CRF do not provide any further substantial benefit, but also no appreciable adverse effects. [ABSTRACT FROM AUTHOR]

Background: Management of ticagrelor-induced bleeding is challenging, as no antidote is currently available. Platelet transfusion, usually proposed to reverse antiplatelet drugs, has been suggested to be ineffective but few data are available.Objective: To assess the efficacy of platelet supplementation to restore platelet aggregation inhibited by ticagrelor.Design: In vitro study.Setting: Blood samples were obtained from the French Blood Bank Institute.Participants: Healthy blood donors.Interventions: Whole blood from healthy donors was spiked with ticagrelor or aspirin (used as a positive control).Main Outcome Measures: Platelet aggregation was investigated with impedance aggregometry on whole blood [expressed in ohms (V)] and light transmission aggregometry (expressed in %) on platelet-rich plasma using ADP or arachidonic acid as agonists for ticagrelor or aspirin, respectively. Platelet supplementation was defined as the addition of washed platelet suspension increasing at least 60% of whole blood platelet count.Results: Ticagrelor (3.25 mM) inhibited ADP-induced platelet aggregation compared with control either in whole blood (2 vs. 13 V, P < 0.05) or in platelet-rich plasma (15 vs. 75% P < 0.05). Aspirin (25 mM) inhibited arachidonic acid-induced aggregation (1 vs. 7.5 V, P < 0.05 in whole blood and 5 vs. 77.5%, P = 0.01 in platelet-rich plasma). Platelet supplementation completely restored arachidonic acid-induced platelet aggregation in whole blood (10 vs. 1 V, P = 0.008) and platelet-rich plasma (73 vs. 5%, P < 0.01) in aspirin-treated samples, whereas it failed to correct ADP-induced aggregation (2 vs. 2 V in whole blood and 13.5 vs. 15% in platelet-rich plasma, P > 0.05) in ticagrelor-treated samples. We also report a case of a ticagrelor-treated patient in whom platelet transfusion failed to restore ADP-induced platelet aggregation.Conclusion: Platelet supplementation restored platelet aggregation in aspirin-spiked but not in ticagrelor-spiked samples. These results do not support the use of platelet transfusion to reverse the effects of ticagrelor. [ABSTRACT FROM AUTHOR]

Abstract: Platelet function test (PFT) is universally used to assess platelet reactivity to antiplatelet drugs in patients after percutaneous coronary intervention (PCI). However, it remains controversial whether individualized antiplatelet therapy guided by PFT can improve the prognosis in patients after PCI. This meta-analysis was conducted to explore the efficacy and safety of individualized antiplatelet therapy guided by PFT in patients after PCI. Studies that compared PFT-guided antiplatelet therapy with standard antiplatelet therapy were researched. The risks of major adverse cardiovascular and cerebrovascular events (MACCE) and major bleeding events were assessed. Pooled odds ratios (ORs) with 95% CIs were obtained. Finally, a total of 16,835 patients from 22 studies met the criteria and were included in the meta-analysis. Compared with standard antiplatelet therapy, individualized antiplatelet therapy guided by PFT significantly decreased the risk of MACCE (OR: 0.58, 95% CI: 0.43-0.77) in patients after PCI. There was no significant difference in major bleeding events (OR: 0.85, 95% CI: 0.70-1.05, P = 0.13). This study identified that PFT-guided individualized antiplatelet therapy could reduce the incidence of MACCE without increasing the risk of hemorrhage in patients after PCI., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background--Allogenic platelet transfusions (PT) are administered to treat excessive bleeding in patients on P2Y12 receptor inhibitors (RI). We assessed the effect of ex vivo and in vivo PT on platelet activation and aggregation in patients on dual antiplatelet therapy. Methods and Results--In the Antagonize P2Y12 Treatment Inhibitors by Transfusion of Platelets in an Urgent or Delayed Timing After Acute Coronary Syndrome or Percutaneous Coronary Intervention Presentation-Acute Coronary Syndrome (APTITUDE-ACS) study, patients presenting with acute coronary syndrome or for elective percutaneous coronary intervention, receiving loading doses of clopidogrel (600 mg, n=13 or 900 mg, n=12), prasugrel 60 mg (n=10), or ticagrelor 180 mg (n=10) were included. PT was performed ex vivo by mixing platelet-rich plasma from blood sampling performed at baseline in increasing proportions with platelet-rich plasma sampled 4 hours after loading dose. The percentage restoration of residual platelet aggregation achieved with 80% proportion PT (residual platelet aggregation 80% PT mix/ residual platelet aggregation baselinex100) significantly decreased with increasing potency of P2Y12 RI (83.9±11%, 73±14%, 66.3±15%, 40.9±19% for clopidogrel 600 mg, clopidogrel 900 mg, prasugrel, and ticagrelor, respectively; P for trend <0.0001). In the APTITUDE-Coronary Artery Bypass Graft (APTITUDE-CABG) study, vasodilator-stimulated phosphoprotein-platelet reactivity index, a specific marker of the P2Y12 RI drug-effect, was assessed before and after in vivo PT administered for excessive bleeding in patients undergoing cardiac surgery while on a maintenance dose of aspirin and clopidogrel (n=45), prasugrel (n=6), or ticagrelor (n=3). When compared with baseline, there was a significant relative increase of 23.1% in platelet activation after PT transfusion (42.2±23.6% versus 56.6±18.2%; P=0.0008). Conclusions--PT restores platelet reactivity in patients with acute coronary syndrome/percutaneous coronary intervention and in patients undergoing cardiac surgery on P2Y12 RI while bleeding with a less effect with increasing potency of P2Y12 inhibition. Clinical Trial Registration--URL: http://www.recherche-biomedicale.sante.gouv.fr/pro/comites/coordonnees.htm and http://www.cnil.fr/. Unique identifiers: No. 301111 and No. 1547216v0. [ABSTRACT FROM AUTHOR]

Background--The burden of coronary artery disease (CAD) is high in blacks, highlighting the need for clinical research of antiplatelet agents in this population. We sought to evaluate platelet reactivity during loading and maintenance dosing of ticagrelor versus clopidogrel, and the pharmacokinetic profile of ticagrelor and its metabolite AR-C124910XX, in black patients with stable CAD taking low-dose aspirin (acetylsalicylic acid). Methods and Results--In a multicenter, randomized, open-label, crossover study, 34 blacks with stable CAD receiving acetylsalicylic acid 75 to 100 mg/d were randomized to clopidogrel (600 mg, then 75 mg QD for 7-9 days) or ticagrelor (180 mg, then 90 mg BID for 7-9 days). After washout 10 to 14 days, patients switched regimens. The primary end point was platelet reactivity 2 hours post loading dose (P2Y12 reactivity units [PRU] measured by the VerifyNow assay). Least-squares mean PRU at 2 hours post loading dose was lower with ticagrelor (27.6) versus clopidogrel (211.2); least-squares mean difference was -183.6 (95% confidence interval, -213.9 to -153.3; P<0.001). At all time points, the least-squares mean PRU was significantly lower, and the percent reduction in PRU from baseline was statistically greater, with ticagrelor versus clopidogrel. At 2 hours post dose, the prevalence of high on-treatment platelet reactivity (=208 PRU) was lower with ticagrelor (0%) than with clopidogrel (57.1%). Pharmacokinetic profiles of ticagrelor and AR-C124910XX were consistent with previous reports in stable CAD populations. Conclusions--In black patients with stable CAD receiving low-dose acetylsalicylic acid, ticagrelor provided a faster onset and greater degree of platelet inhibition than clopidogrel. [ABSTRACT FROM AUTHOR]

Fentanyl is a potent opiate commonly administered during cardiac catheterization procedures in North America. The question of whether fentanyl could have adverse consequences in patients undergoing percutaneous coronary intervention (PCI) is raised by recent research demonstrating that intravenous morphine significantly delays the absorption of oral P2Y12 platelet inhibitors. The presumed mechanism is slowed gastric emptying. The single-center Platelet Aggregation with tiCagrelor Inhibition and FentanYl (PACIFY) trial randomized adults undergoing clinically-indicated elective coronary angiography to receive the procedure with or without intravenous fentanyl (NCT02683707). The study was approved by the Johns Hopkins Medicine Institutional Review Board and all participants provided written informed consent. Eligible adults had not received P2Y12 inhibitors for 14 days prior to enrollment. Other exclusion criteria included: pre-procedural treatment with oral anticoagulants or opiates; platelet count <100,000/mm3; and impaired renal or hepatic function. All participants received subcutaneous lidocaine and intravenous midazolam at the start of the catheterization procedure and as needed thereafter. Doses of all drugs were at the discretion of treating providers. Patients and outcomes assessors were blinded, treating providers were not. Participants who required PCI received an oral dose of 180 mg of ticagrelor at the conclusion of diagnostic angiography. [ABSTRACT FROM AUTHOR]

Background--Individualizing antiplatelet therapy after platelet function testing did not improve outcome after coronary stenting in the Assessment by a Double Randomization of a Conventional Antiplatelet Strategy Versus a Monitoring- Guided Strategy for Drug-Eluting Stent Implantation and of Treatment Interruption Versus Continuation One Year After Stenting (ARCTIC) study. Whether results are different during the phase of secondary prevention starting after hospital discharge, when periprocedural events have been excluded, is unknown. Methods and Results--In ARCTIC, 2440 patients were randomized before coronary stenting to a strategy of platelet function monitoring (VerifyNow P2Y12/aspirin point-of-care assay) with drug adjustment in suboptimal responders to antiplatelet therapy or to a conventional strategy without monitoring and without drug or dose changes. We performed a landmark analysis starting at the time of hospital discharge evaluating the primary end point of death, myocardial infarction, stent thrombosis, stroke, or urgent revascularization through 1 year. After discharge, the primary end point occurred in 8.6% of patients in the monitoring arm and 7.9% in the conventional arm (hazard ratio, 1.105; 95% confidence interval, 0.835-1.461; P=0.48). Stent thrombosis or urgent revascularization occurred in 4.4% and 4.5% in the monitoring and conventional arms, respectively (P=0.99). There was no difference for any of the other ischemic end points. Major bleeding event rates were 1.8% in the monitoring arm and 2.8% in the conventional arm (P=0.11), whereas major or minor bleeding event rates were 2.3% and 3.4%, respectively (P=0.10). Conclusions--Detection of platelet hyper-reactivity by platelet function testing in patients undergoing coronary stenting with further therapeutic adjustment does not reduce ischemic recurrences after intervention. On-treatment platelet hyperreactivity cannot be considered as a risk factor requiring intervention for secondary prevention after percutaneous coronary revascularization. [ABSTRACT FROM AUTHOR]

In the CHAMPION platelet substudy, 11% of the patients receiving cangrelor+clopidogrel were nonresponders to VerifyNow test by using platelet reactivity unit >235 U cutoff.[2] An even greater nonresponder proportion would have been observed with a cutoff of >208.[5] Moreover, 6.3% of the patients were nonresponders at LTA with ADP 20- g despite using late rather then maximal platelet aggregation. We thank Drs Angiolillo, Bhatt, and Stone for commenting on our trial.[1] Our findings integrate, more than contradict, the results of the CHAMPION program (Cangrelor versus Standard Therapy to Achieve Optimal Management of Platelet Inhibition), where cangrelor was superior to clopidogrel for the inhibition of platelet aggregation (IPA) and prevention of ischemic events.[2] Clopidogrel does not provide IPA within the first hour or even longer among ST-segment-elevation myocardial infarction.[3] Prasugrel and ticagrelor are also associated with delayed IPA in ST-segment-elevation myocardial infarction.[4] Our study confirmed the superiority on IPA of cangrelor over prasugrel, either taken as integral or chewed tablets and supports the need for parenteral agents. 2012; 34:, 44-55. doi: 10.1007/s11239-012-0737-3 3 Biscaglia S, Tebaldi M, Vranckx P, Campo G, Valgimigli M. Effects of pre-hospital clopidogrel administration on early and late residual platelet reactivity in ST-segment elevation myocardial infarction patients undergoing primary intervention. [Extracted from the article]

Adding a prasugrel loading dose (LD) to a clopidogrel LD could be desirable because clopidogrel may fail to provide adequate levels of platelet inhibition in patients with acute coronary syndrome undergoing percutaneous coronary intervention.The pharmacodynamic response of prasugrel 60 mg LD alone was compared with prasugrel 60 mg or 30 mg added 24 hours to clopidogrel 600 mg in Transferring from Clopidogrel Loading Dose to Prasugrel Loading Dose in Acute Coronary Syndrome Patients study—a multicenter, randomized, double-blind, double-dummy, 3-arm, parallel, active-comparator controlled study. Two hundred eighty-two patients were randomized to 3 LD strategies: placebo plus prasugrel 60 mg, clopidogrel 600 mg plus prasugrel 60 mg, or clopidogrel 600 mg plus prasugrel 30 mg. Platelet function was assessed using VerifyNow P2Y12 Reaction Units (PRU) immediately before prasugrel LD, and 2, 6, 24, and 72 hours after prasugrel LD in 149 patients with evaluable platelet function studies. At 6 hours after the prasugrel 60 mg LD, the least squares mean (95% confidence interval) difference between placebo/prasugrel 60 mg and clopidogrel 600 mg/prasugrel 60 mg (primary outcome) was 22.2 (-11.0 to 55.5; P=0.19; least squares mean PRU 57.9 versus 35.6, respectively). For clopidogrel 600 mg/prasugrel 30 mg (least squares mean PRU, 53.9), the difference was 3.9 (-28.2 to 36.1; P=0.81) versus placebo/prasugrel 60 mg. No significant differences in PRU were observed at any time point across the 3 groups. There were few bleeding events observed regardless of treatment.Platelet reactivity with prasugrel 60 mg LD added to clopidogrel 600 mg LD was not significantly different compared with prasugrel 60 mg LD alone in acute coronary syndrome patients undergoing percutaneous coronary intervention.URL: http://www.clinicaltrials.gov. Unique identifier: NCT01115738. [ABSTRACT FROM AUTHOR]

Dual antiplatelet therapy with aspirin and clopidogrel is widely used in patients with coronary stents. High residual platelet reactivity (high RPR) after dual antiplatelet therapy is associated with increased cardiovascular events. Endothelial function could affect platelet reactivity in vivo. We hypothesized that endothelial dysfunction could be associated with high RPR after dual antiplatelet therapy in patients with stable coronary artery disease.We screened patients with stable coronary artery disease for cytochrome P450 (CYP) 2C19 genotypes and enrolled 103 patients who lacked CYP2C19∗2 or ∗3 loss-of-function allele to minimize the effect of this gene on high RPR. All patients received aspirin (100 mg/d) and clopidogrel (75 mg/d for long-term treatment or a loading dose of 300 mg) before the following tests. Platelet aggregability was assessed as P2Y12 reaction unit using the VerifyNow System. High RPR was defined as P2Y12 reaction unit ≥230. Peripheral endothelial function was expressed as reactive hyperemia index using reactive hyperemia peripheral arterial tonometry. Fifty-three patients exhibited high RPR. High RPR patients were significantly older, had higher levels of B-type natriuretic peptide, and were predominantly hypertensive compared with non-high RPR patients. Reactive hyperemia index was significantly lower in high RPR patients (0.46±0.15) compared with non-high RPR patients (0.61±0.18; P<0.001). Linear regression analysis demonstrated significant negative correlation between reactive hyperemia index and P2Y12 reaction unit (r=-0.32; P=0.001). Multivariable logistic regression analysis identified reactive hyperemia index as an independent and significant determinant of high RPR (odds ratio, 0.55; 95% confidence interval, 0.39-0.78; P=0.001).In patients with stable coronary artery disease, endothelial function was significantly impaired in high RPR patients. Endothelial dysfunction is independently correlated with high RPR after dual antiplatelet therapy.URL: http://www.umin.ac.jp/ctr. Unique identifier: UMIN000008239. [ABSTRACT FROM AUTHOR]

The article presents an analysis on the relations between pharcodynamics and CYP2C19 genotype in patients treated with ticagrelor and clopidrogrel cardiovascular drugs. It is stated that in Platelet Inhibition and Patient Outcomes (PLATO) trial, ticagrelor reduced the rate of cardiovascular death and myocardial infarction in patients with acute coronary syndrome (ACS). The Influence of CYP2C19 on platelet function is also discussed.

B Methods: b This retrospective cohort study included patients on dual antiplatelet therapy after carotid stenting from July 2016 through June 2020. B Introduction: b Carotid stenting reduces the risk of cerebrovascular events in carotid artery stenosis, however there is a risk of ischemic complications after placement. [Extracted from the article]

The article comments on a landmark analysis of the Double Randomization of a Monitoring Adjusted Antiplatelet Treatment Versus a Common Antiplatelet Treatment for DES Implantation, and an Interruption Versus Continuation of Double Antiplatelet Therapy, One Year After Stenting (ARCTIC) study. Topics discussed include the ex vivo measures of platelet inhibition and the commonly selected strategies after hospital discharge. Also noted are the limitations to ex vivo platelet function test platform.

Background and Purpose: This study tests whether patients with unruptured intracranial aneurysm who underwent stent placement benefitted from platelet function monitoring-guided adjustment of antiplatelet therapy., Methods: We conducted a randomized, open-label, parallel group, assessor-blinded trial. Patients with unruptured intracranial aneurysm who underwent stent placement were assigned in a 1:1 ratio to receive either drug adjustment (patients who had high on-treatment platelet reactivity to antiplatelet therapy on the basis of platelet function monitoring [monitoring group]) or conventional therapy (without monitoring and drug adjustment [conventional group]). The second monitoring was performed 14 days after randomization in patients with drug adjustment. The primary outcome was the composite frequency of ischemic stroke, transient ischemic attack, stent thrombosis, urgent revascularization, and cerebrovascular death within 7 days after stent implantation. The safety outcome was the composite frequency of major, minor, or minimal bleeding within 1 month after stent implantation., Results: In total, 314 patients were included (n=157 per group). The primary combined outcome occurred in 19 patients (12.1%) in the conventional group and 8 patients (5.1%) in the monitoring group (hazard ratio, 0.39 [95% CI, 0.17-0.92]; P =0.03). Ischemic stroke occurred at a lower frequency in the monitoring group compared with that in the conventional group (4.5% versus 12.1%; hazard ratio, 0.34 [95% CI, 0.14-0.83]; P =0.01), which drove the overall primary combined outcome. The safety outcome occurred in the monitoring group (7.0%) and in the conventional group (1.9%; hazard ratio, 3.87 [95% CI, 1.06-14.14]; P =0.03). A significant difference was observed in the frequency of minor or minimal bleeding events between the two groups (monitoring group versus conventional group, 6.4% versus 1.3%; P =0.02) but not in the frequency of major bleeding events between the two groups., Conclusions: Platelet function monitoring-guided antiplatelet therapy reduces thromboembolic events in patients with unruptured intracranial aneurysm after stent placement, significantly enhancing minor or minimal bleeding events but not major bleeding events. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03989557.

Abstract: The aim of our study is to assess the impact of anemia, chronic kidney disease, and diabetes mellitus on platelet reactivity (PR) in patients with severe aortic stenosis, both at baseline and after transcatheter aortic valve implantation (TAVI). This study is a prespecified subanalysis of the REAC-TAVI prospective, multicenter trial that included patients pretreated with aspirin + clopidogrel before TAVI. PR was measured at baseline and at 5 different time points after TAVI with the VerifyNow assay (Accriva Diagnostics, San Diego, CA), over a 3-month follow-up period. Patients with high PR (HPR) at baseline, before TAVI (n = 48) were randomized to aspirin + clopidogrel or aspirin + ticagrelor for 3 months, whereas those with normal PR (NPR) (n = 20) were continued on aspirin + clopidogrel. A "raiser response" in PR was defined as an increase in PR units >20% of baseline after TAVI. Patients with HPR before TAVI presented concomitant anemia and chronic kidney disease more frequently than their counterparts with NPR. Anemia and higher body mass index were independently associated with HPR to clopidogrel at baseline. Moreover, anemic patients with baseline HPR who were continued on clopidogrel presented higher PR after TAVI than patients with HPR switched to ticagrelor. All patients with baseline NPR presented a "raiser response" after TAVI, which was nonexistent among patients with HPR managed with ticagrelor. In summary, anemia seems as a relevant factor associated with baseline HPR and higher PR after TAVI in patients with baseline HPR randomized to clopidogrel, whereas ticagrelor proved more effective than clopidogrel at attaining sustained reductions in PR during follow-up, regardless of baseline comorbidities., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Although recent studies described platelet reactivity (PR) changes in days after transcatheter aortic valve implantation (TAVI), precise time course and duration of these changes have not been fully investigated. The aim of this study was to investigate PR pattern during and after TAVI in multiple time points. Study included 40 consecutive patients undergoing TAVI. All patients underwent the procedure on dual antiplatelet therapy. PR was measured in 7 time points: before induction of anesthesia (T1), after heparin administration (T2), 10 minutes after initial valve implantation (T3), at the end of procedure (T4), and on 3rd, 6th, and 30th postoperative day (T5-T7). PR was measured using impedance aggregometer using 3 different platelet aggregation agonists (arachidonic acid in ASPItest, adenosine diphosphate in ADPtest and thrombin receptor activating peptide 6 in TRAPtest). All patients underwent successful TAVI procedure. Mean PR on T1 was 22.9 ± 23.0 U for ASPItest, 40.5 ± 23.7 U for ADPtest and 91.7 ± 32.5 U for TRAPtest. There was no significant difference in PR on T2. On T3, significant reduction of PR in all 3 tests was observed [ASPI 10.4 ± 11.6 U (P = 0.001), ADP 24.2 ± 14.1 U (P < 0.001) and TRAP 69.3 ± 26.6 U (P < 0.001)]. PR nadir for all tests was reached on T5, with subsequent PR incline. PR values in all tests returned to baseline levels on T7. Our results show that successful TAVI procedure induces transient decrease in PR regardless of the platelet activation pathway., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: The combination of pharmaceutical lipid excipients with aspirin in a novel liquid oral formulation (Vazalore) limits gastrointestinal toxicity of aspirin. This study was performed to determine whether the lipid excipients influence the pharmacodynamic effects of aspirin and whether the excipients directly affect platelet function. The pharmacodynamic effects of aspirin were assessed over a range of concentrations designed to exert limited to maximal inhibition of cyclooxygenase-1 (COX1) necessary for thromboxane A2 production. Platelet aggregation induced by arachidonic acid and assessed with the use of light transmission aggregometry was used as a direct measure of the inhibition of COX1 by aspirin. Flow cytometry was used to assess the direct effect of excipients on platelet function. Twice the ratio of lipid excipient to aspirin used in the formulation of the novel oral agent was used. Blood was taken from 20 healthy subjects and anticoagulated with trisodium citrate (3.2%, 1:10 vol/vol). Aspirin and excipients were added in vitro and incubated for 10 minutes before performance of light transmission aggregometry and flow cytometry. The excipients did not limit the pharmacodynamic effects of aspirin. When the extent of inhibition of platelet aggregation was limited, the excipients tended to enhance pharmacodynamic effects. The excipients did not activate platelets in the absence of agonist and did not alter activation of platelets in response to adenosine diphosphate, arachidonic acid, thrombin, or convulxin (a collagen mimetic). Lipid excipients used in an oral formulation of aspirin do not impair the pharmacodynamic effects of aspirin and do not alter platelet function., Competing Interests: E. N. Deliargyris and J. Prats are consultants to PLx Pharma, Inc. D. J. Schneider was the principle investigator on a grant supporting this study. The remaining author reports no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

The author reflects on a study done on ticagrelor, a reversible binding P2Y12 receptor antagonist. It says that in the Study of Platelet Inhibition and Patient Outcomes (PLATO) on patients with acute coronary syndromes it was discovered to be more effective than clopidogrel. An overview of the comparison between ticagrelor and clopidogrel to show which is more superior regardless of CYPAC19 genotype is offered.

Background: Exercise test (ET) may have adverse effects on platelet function and induce acute thrombotic events in patients with coronary artery disease (CAD). The aim of this study is to investigate the platelet function and evaluate the risk of thrombotic events in CAD patients during ET., Methods: Pubmed, Embase, Cochrane Library, and Web of Science were searched for a systematic review from initiation to October 2019. The inclusion criteria were controlled clinical trails as study design; investigating platelet function in CAD patients during ET; with ET carried out by treadmill or bicycle ergometer; written in English. Included articles were screened based on title/abstract and full-text review by 2 independent reviewers. Platelet aggregation (PA), platelet surface expression of CD62p and PAC-1, plasma levels of platelet factor 4 (PF4) and beta-thromboglobulin (β-TG) were evaluated before and after ET., Results: Eighteen articles were included out of the 427 references initially identified. In most of the studies included ET was terminated because of limited symptoms. Prior to ET, no difference in platelet aggregation was observed in CAD patients compared with healthy controls in majority of the studies, with or without the treatment with Aspirin. Dual anti-platelet therapy suppressed adenosine diphosphate (ADP)-induced platelet aggregation at rest. After ET, platelet aggregation, the serum levels of β-thromboglobulin were found unchanged in majority of studies and platelet factor-4 were found unchanged in half of studies. The expression of platelet surface markers were elevated by ET in a few study., Conclusion: Symptom-limited exercise test did not affect platelet function in patients with coronary artery disease; however exercise to higher intensity may induce platelet activation., Competing Interests: The authors have no conflicts of interests to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Our previous study demonstrated the types of platelet dysfunction varied at early stage (∼3 h) in trauma-induced coagulopathy (TIC) caused by different types of injuries. And arachidonic acid (AA)-dependent pathway inhibition in platelet seemed to be specific for TIC caused by multiple injury (MI). The aim of this research was to further study AA-dependent pathway inhibition in platelets in a rat model of TIC caused by MI and to explore its potential mechanisms., Methods: Sprague-Dawley rat model of TIC caused by MI was established. We used thrombelastography with platelet mapping as a measure of platelet function to assess the inhibitory extent of AA-dependent activation pathway. Flow cytometry was used to determine the expression of activation-dependent granular protein P-selectin (CD62P). In addition, the plasma levels of 6-Keto-prostaglandin F1 alpha (6-Keto-PGF1α), Prostaglandin E2, and Thromboxane B2 were assessed by enzyme-linked immuno sorbent assay., Results: The inhibition rate of AA-dependent pathway after injury was significantly higher than that of control. The maximum amplitude decreased in the MI group, compared with that of control. The percentage of CD62P expression in the MI group was remarkably lower than that of control after AA treatment. The plasma concentrations of 6-Keto-PGF1α and PGE2 increased in the MI group., Conclusion: Platelets inhibition was observed in TIC caused by MI at early stage after injury, which might be partially attributed to AA-dependent activation pathway dysfunction. The increase of plasma Prostacyclin and PGE2 levels may contribute to the inhibition process., Competing Interests: The authors report no conflicts of interest., (Copyright © 2020 by the Shock Society.)

Aims: Chronic kidney disease (CKD) is associated with increased thrombotic events and seems to influence platelet reactivity. Conflicting results have been published on platelet response in CKD patients with stable coronary artery disease. The aim of our study was to investigate the impact of CKD on platelet aggregation in acute coronary syndrome (ACS) patients receiving dual antiplatelet therapy, included the more potent P2Y12 inhibitors., Methods: We enrolled 206 patients with ACS, divided in two groups, according to the presence or the absence of moderate/severe CKD. Platelet aggregation was performed with light transmission aggregometry and results are expressed as percentage of maximum platelet aggregation. High residual platelet reactivity (HRPR) was defined as maximum platelet aggregation more than 59%., Results: Patients with CKD [estimate glomerular filtration rate (eGFR) < 60 ml/min/1.73 m, n = 28] were prevalent older, diabetic, had previous coronary revascularization. In these patients, platelet aggregation was significantly higher than in those with eGFR ≥ 60 ml/min/1.73 m (ADP 10 μmol/l: 28.46 ± 26.19 vs. 16.64 ± 12.79, P < 0.001; ADP 20 μmol/l: 30.07 ± 25.89 vs. 17.46 ± 12.82, P < 0.001). HRPR was observed in 4.4% of patients, with higher prevalence in those with eGFR less than 60 ml/min/1.73 m [21.4 vs. 1.7%, P < 0.001, odds ratio (OR) [95% confidence interval (CI)] = 15.91 (3.71-68.17), P < 0.001]. At multivariate analysis, after correction for baseline confounders, eGFR [adjusted OR (95% CI) = 0.95 (0.91-0.98), P = 0.007], together with the use of clopidogrel [adjusted OR (95% CI) = 23.59 (4.01-138.82), P < 0.001], emerged as determinants of HRPR., Conclusion: In patients with ACS receiving dual antiplatelet therapy, CKD is associated with an increasing ADP-induced platelet aggregation and higher prevalence of HRPR, which is mainly correlated to clopidogrel use.

Bleeding and coagulation management are essential aspects in the management of neonates and children undergoing cardiac surgery. The use of point-of-care tests (POCTs) in a pediatric setting is not as widely used as in the adult setting. This systematic review aims to summarize the evidence showed by the literature regarding the use of POCTs in children undergoing cardiac surgery. We included all studies examining the pediatric population (<18 years old) undergoing cardiac surgery in which the coagulation profile was assessed with POCTs. Three electronic databases (PubMed, Embase, and the Cochrane Controlled Clinical Trials register) were searched. Tests involved were heparin effect tests, viscoelastic tests, and platelet function tests. Due to the wide heterogeneity of the patients and tests studied, a formal meta-analysis was impossible, and the results are therefore presented through a systematic review. Eighty articles were found, of which 47 are presented in this review. At present, literature data are too weak to define POCTs as a "gold standard" for the treatment of perioperative bleeding in pediatric cardiac surgery. Nevertheless, introduction of POCTs into postoperative algorithms has shown to improve bleeding management, patient outcome, and cost efficiency.

Objective: The aim of this study was to explore the individual effects of the CYP2C19 G681A polymorphism and omeprazole use and their interaction on clopidogrel responsiveness in acute coronary syndrome (ACS). The CYP2C19 G681A polymorphism and omeprazole use were both known for retarding the effects of clopidogrel under broad cardiovascular conditions; however, data from ACS patients were limited., Methods: We conducted a cross-sectional study of 102 ACS patients who received clopidogrel before percutaneous coronary intervention. The platelet function was assessed by a Platelet Function Analyzer-200, in which clopidogrel hyporesponsiveness was defined as a closure time (CT) of ≤ 106 s. The CYP2C19 G681A polymorphism was investigated using the PCR-RFLP technique. Statistical analysis was performed by using χ test, Student's t-test, binary logistic regression, and receiver-operating characteristic (ROC) curve., Results: Carriages of the CYP2C19 681A allele and omeprazole use were present in 47.1 and 37.3% patients, respectively. The mean CT ± SD was 103.1 ± 1.7 s and the prevalence of clopidogrel hyporesponsiveness was 66.7%. The CT was significantly shorter in carriages of the 681A allele compared with the 681G allele (P = 0.002), but had no significant difference in patients with vs. without omeprazole use (P = 0.467). The ROC analysis of an effect on clopidogrel hyporesponsiveness of CYP2C19 G681A alone and combination with omeprazole use had area under the curve values of 0.654 and 0.672, respectively., Conclusion: In ACS patients, the effect of the CYP2C19 G681A polymorphism on clopidogrel responsiveness, but not omeprazole use, is strong. However, a combination of both factors enhances clopidogrel hyporesponsiveness.

High on-treatment platelet reactivity (HTPR) was suggested to be better correlated with recurrent ischemic events as compared with gene polymorphism, whereas most of the results were from white populations with acute coronary disease. The evidence is relatively limited regarding HTPR and its genetic determinants in predicting clinical outcomes of stroke among Chinese-Han patients.A prospective study including 131 Chinese-Han stroke patients treated with clopidogrel was analyzed. Platelet function was assessed by light transmission aggregometry (LTA)- adenosine diphosphate (ADP) method. HTPR was defined as 5 μM ADP induced platelet aggregation > 46%. CYP2C19 and P2Y12 genotype were detected using the PCR-RFLP method. The difference in the occurrence of the primary endpoint was analyzed according to platelet function and genetic status.Sixty-three (48.1%) subjects displayed HTPR after administering clopidogrel for 1 week. The prevalence of HTPR was significantly higher in CYP2C19 loss-of-function (LOF) alleles (2, 3) carriers vs wild-type homozygotes (71.7% vs 32.1%, P < .01), and logistic regression analysis showed that carriers of CYP2C19 LOF alleles were an independent risk factor of HTPR. Survival analysis indicated that patients with HTPR had an increased risk of primary endpoints (20.6% vs 7.3%, P = .04), whereas the presence of CYP2C19 LOF alleles or P2Y12 H2 haplotype did not increase the incidence of ischemic events. Cox regression analysis demonstrated that HTPR was an independent predictor of the primary composite endpoint (HR, 3.1; 95% CI, 1.07-8.99; P = .04).We identified a high prevalence of clopidogrel-HTPR in a cohort of Chinese-Han patients with acute ischemic stroke, and patients with HTPR may have an increased risk of recurrent ischemic stroke events. CYP2C19 LOF alleles are associated with HTPR but not with stroke prognosis. Further clinical trials with large samples are needed to confirm these findings.

Rivaroxaban is a direct oral anti-factor Xa anticoagulant. It has recently been suggested that rivaroxaban may affect platelet function in vitro; however, little is known about the clinical impact of this likely antiplatelet effect and whether this probable phenomenon is dose-dependent. Our aim was to determine whether rivaroxaban at 4 different doses inhibits direct platelet aggregation. We included adult patients of both sexes and who were allocated to one of the following groups depending on the prescribed daily dose of rivaroxaban: 5, 10, 15, and 20 mg. In 80 patients (20 patients/group), the percentage of platelet aggregation was determined by means of platelet aggregometry tests before and after rivaroxaban use. Basal samples were obtained before starting rivaroxaban and 1 month after treatment, both 2 and 24 hours after the last dose of the drug (12 hours after in the case of rivaroxaban 5 mg). We used 5 platelet agonists: adenosine diphosphate, epinephrine, arachidonic acid, collagen, and thrombin. There were no significant changes in the percentage of platelet aggregation before and after rivaroxaban use independently of the dose administered and the agonist used. Our results have clearly shown that rivaroxaban, even at a high dose, does not directly affect platelet aggregation.

Supplemental Digital Content is available in the text. Background: Smoking is a potent risk factor for coronary artery disease; however, prior studies describe increased platelet inhibition with clopidogrel among smokers, and some studies report improved outcomes among smokers, a finding described as the smoker's paradox. This study assessed the relationship between platelet reactivity and clinical outcomes after percutaneous coronary interventions among current smokers and nonsmokers. Methods: ADAPT-DES (Assessment of Dual Antiplatelet Therapy With Drug-Eluting Stents) was a prospective, multicenter registry of patients treated with coronary drug-eluting stents. Platelet reactivity was assessed by the VerifyNow point-of-care assay; high on-treatment platelet reactivity (HPR) was defined as P2Y12 reaction units >208. A propensity-adjusted multivariable analysis was performed to determine the relationship between current smoking, platelet reactivity, and subsequent adverse events. Results: Among 8582 patients, 22.6% were active smokers at the time of their percutaneous coronary intervention procedure. Current smokers were younger and had fewer comorbidities compared with nonsmokers. Current smokers had lower mean P2Y12 reaction units and lower rates of HPR compared with nonsmokers. Current smokers had similar rates of adverse events compared with nonsmokers. HPR was associated with higher rates of adverse events for both smokers and nonsmokers; however, there was evidence of interaction between smoking status and the effect of HPR. Smokers with HPR had significantly higher rates of stent thrombosis. Adverse event rates were highest among current smokers with HPR. Conclusions: Current smoking was associated with lower P2Y12 reaction units and lower rates of HPR on average; however, the combination of current smoking and HPR was associated with high rates of stent thrombosis. Clinical Trial Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00638794. [ABSTRACT FROM AUTHOR]

Vicagrel is a new antiplatelet pro-drug based on clopidogrel sulfur lactone metabolites. The purpose of the study was to evaluate the safety, tolerability, and pharmacodynamics (PD) of vicagrel in healthy Chinese subjects.This study was designed as a single-center, randomized, double-blind, placebo-controlled, single oral ascending dose study. Fifty nine subjects were assigned to 6 vicagrel dose cohorts (5, 10, 20, 40, 60, and 75 mg), and 8 subjects were assigned to 75 mg clopidogrel. Within each vicagrel dose cohort, the 10 subjects (9 in the 75 mg cohort) were randomized 4:1 to receive vicagrel or placebo. Platelet function was assessed using VerifyNow P2Y12. ΔP2Y12 reaction units (ΔPRU) and percent inhibition platelet aggregation (%IPA) were used to evaluate the PD of vicagrel.Although the number of adverse events (AEs) increased with vicagrel dose, none were considered serious, suggesting that vicagrel is safe and well-tolerated. The ΔPRU and %IPA patterns suggest that inhibition of ADP-induced platelet aggregation increased in a dose-dependent manner across the 10 to 40 mg dose range. The inhibitory effect was nearly complete at 4 hours (mean %IPA 87.9%-93.0%, mean ΔPRU 206.6-240.0) for doses of 40 to 75 mg of vicagrel. In contrast, for 5 mg vicagrel and 75 mg clopidogrel, there were no measurable effects on platelet aggregation throughout the study.The results suggest that vicagrel at 40 to 75 mg inhibits ADP-induced platelet aggregation, with a fast onset of action and significantly greater potency than clopidogrel. These findings indicate that vicagrel may be a highly effective and well-tolerated antiplatelet agent.