No abstract available.
Korea* ; Myocardial Infarction* ; Purinergic P2Y Receptor Antagonists*

Purinergic P2Y Receptor Antagonists ; Consensus ; Cardiovascular System ; Cardiology ; Asia

BACKGROUND AND OBJECTIVES: Increased bleeding rates with standard dose prasugrel have led to increased questions about the effectiveness and safety of the lower maintenance dose. We compared platelet inhibitory efficacy between low dose prasugrel and standard dose clopidogrel in patients on maintenance dose dual antiplatelet therapy. SUBJECTS AND METHODS: Forty-three patients who underwent percutaneous coronary intervention were randomized to receive 75 mg clopidogrel (n=23) or 5 mg prasugrel (n=20). Another 20 patients were allocated to 10 mg prasugrel as a reference comparison group. All patients (weight, > or =60 kg; age, <75 years) had been receiving 100 mg aspirin and 75 mg clopidogrel daily. The platelet function test was performed at baseline and 30 days after randomization. The primary endpoint was P2Y12 reaction unit (PRU) at 30 days between 5 mg prasugrel and 75 mg clopidogrel. RESULTS: No differences in baseline PRU values were observed among the three groups. The prasugrel (5 mg) group had a significantly lower PRU value compared with that of 75 mg clopidogrel (174.6+/-60.2 vs. 223.4+/-72.9, p=0.022) group at 30 days, whereas the 10 mg prasugrel group showed a lower PRU value (71.9+/-34.4) compared with that of the 5 mg prasugrel (p<0.001). The rate of high on-treatment platelet reactivity (PRU >235) was significant lower in the 5 mg prasugrel group than that in the 75 mg clopidogrel group (15.0% vs. 56.5%, p=0.010). CONCLUSION: Prasugrel (5 mg) is more potent antiplatelet therapy than 75 mg clopidogrel in non-low body weight and non-elderly patients on a maintenance dose dual antiplatelet therapy.
Aspirin ; Body Weight ; Hemorrhage ; Humans ; Percutaneous Coronary Intervention* ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists ; Random Allocation ; Prasugrel Hydrochloride

BACKGROUND/AIMS: Platelet counts and characteristics can influence platelet reactivity during antiplatelet therapy. We compared the effects of both platelet count and indices on platelet reactivity between patients who were treated with either clopodogrel or ticagrelor. METHODS: Patients with coronary artery disease who underwent percutaneous coronary intervention were randomly assigned to either the clopidogrel (n = 63) or ticagrelor (n = 65) groups. Platelet count, platelet indices (including mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction), and platelet reactivity were measured before intervention, and 48 hours and 30 days post-intervention. High on-treatment platelet reactivity (HPR) was defined as ≥ 47 unit as assessed by multiple electrode platelet aggregometry. RESULTS: Baseline platelet reactivity was similar between the two groups; however, at 48 hours and 30 days, platelet reactivity was significantly lower in the ticagrelor group than in the clopidogrel group. Platelet count, mean platelet volume, platelet distribution width, platelet large cell ratio, and immature platelet fraction were significantly correlated with platelet reactivity in the clopidogrel group; however, these correlations were attenuated in the ticagrelor group. The use of clopodogrel (hazard ratio [HR] 4.1, 95% confidence interval [CI] 1.4–11.9; p = 0.010) and platelet count (HR 9.7, 95% CI 2.9–32.7; p = 0.001) were independent predictors for 30 day HPR. Platelet count was an independent predictor of HPR in the clopidogrel group but not in the ticagrelor group. CONCLUSIONS: Platelet count and indices are significantly correlated with platelet reactivity. However, antiplatelet treatment with ticagrelor could overcome these associations.
Blood Platelets* ; Coronary Artery Disease ; Electrodes ; Humans ; Mean Platelet Volume ; Percutaneous Coronary Intervention ; Platelet Count* ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists

OBJECTIVE: Dual antiplatelet therapy (DAPT) with aspirin and a P2Y12 receptor inhibitor is the cornerstone of treatment in patients with acute coronary syndromes (ACS) and in those undergoing percutaneous coronary intervention (PCI). In current clinical situation, availability of different oral P2Y12 inhibitors (clopidogrel, prasugrel, and ticagrelor) has enabled physicians to switch among therapies owing to specific clinical scenarios. Although optimum time, loading dose and interval of transition between P2Y12 inhibitors is still controversial and needs further evidence, switching between oral inhibitors frequently occurs in clinical practice for several reasons. DATA SOURCES: This review was based on data in articles published in PubMed up to June 2018, with the following keywords "antiplatelet therapy", "ACS", "PCI", "ticagrelor", and "clopidogrel". STUDY SELECTION: Original articles and critical reviews on de-escalation strategy in ACS patients after PCI were selected. References of the retrieved articles were also screened to search for potentially relevant papers. RESULTS: Safety concerns associated with switching between antiplatelet agents, has prompted the use of clopidogrel for patients with ACS especially after PCI as a de-escalation strategy. Practical considerations for de-escalating therapies in patients with ACS such as reducing dose of P2Y12 inhibitors or shortening duration of DAPT (followed by aspirin or P2Y12 receptor inhibitor monotherapy) as potential options are yet to be standardized and validated. CONCLUSIONS Current review will provide an overview of the pharmacology of common P2Y12 inhibitors, definitions of de-escalation and different de-escalating strategies and its outcomes, along with possible direction to be explored in de-escalation.
Acute Coronary Syndrome ; drug therapy ; therapy ; Aspirin ; therapeutic use ; Diamines ; therapeutic use ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors ; therapeutic use ; Purinergic P2Y Receptor Antagonists ; therapeutic use ; Thiazoles ; therapeutic use

OBJECTIVE: To explore the inhibitory effect of PSB0739 on the formation of semen-derived amyloid fibrils. METHODS: PAP248-286 (440 μmol/L) was incubated with PSB0739 at different concentrations, and at different time points of incubation, aliquots were taken from each sample for Congo red staining to detect the formation of amyloid fibers. The morphology of amyloid fibrils incubated in the presence or absence of PSB0739 was visualized using transmission electron microscope. The effect of PSB0739 on amyloid fibril formation was determined using virus infection assays at different time points, and the surface charges of amyloid fibril incubated with PSB0739 were calculated using a Zeta potentiometer. The cytotoxicity of PSB0739 in Hela cells was determined using MTT assay. The antiviral effect of PSB0738 against HIV- 1 was evaluated by infection assay. RESULTS: PSB0739 inhibited SEVI fibril formation in a dose-dependent manner . At 48 h of incubation, 220 μmol/L of PSB0739 obviously inhibited the formation of amyloid fibrils in 440 μmol/L of SEVI. Transmission electron microscopy revealed that 220 μmol/L PSB0739 prevented PAP248- 286 (440 μmol/L) from forming amyloid fibrils. PSB0739 antagonized SEVI-mediated enhancement of HIV-1 infection, and 1760 μmol/L of PSB0739 completely reversed the positive charge of SEVI ( < 0.05). PSB0739 below the concentration of 62.5 μmol/L showed no obvious cytotoxicity in Hela cells (>0.05). PSB0739 showed a direct anti-HIV activity with an IC of 21.77±5.15 μmol/L. CONCLUSIONS PSB0739 can inhibit the formation of semen-derived amyloid fibrils .
Amyloid ; chemistry ; drug effects ; Anti-HIV Agents ; pharmacology ; Dose-Response Relationship, Drug ; HIV Infections ; drug therapy ; HIV-1 ; drug effects ; HeLa Cells ; Humans ; In Vitro Techniques ; Microscopy, Electron, Transmission ; Purinergic P2Y Receptor Antagonists ; pharmacology ; Semen ; chemistry

To explore novel ADP receptor inhibitors with anti-thrombotic activity, eighteen compounds were synthesized and their structures were confirmed by 1H NMR and MS. The results showed that the activity of compound C1 was superior to ticlopidine in platelet aggregation inhibition tests in vivo and worthy for further investigation. Compounds A4, B2, C4 and C7 possessed moderate platelet aggregation inhibitory activities.
Animals ; Male ; Molecular Structure ; Platelet Aggregation ; drug effects ; Platelet Aggregation Inhibitors ; chemical synthesis ; chemistry ; pharmacology ; Purinergic P2Y Receptor Antagonists ; chemical synthesis ; chemistry ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Thienopyridines ; chemical synthesis ; chemistry ; pharmacology

Acute Coronary Syndrome/drug therapy* ; Aged ; Clopidogrel/therapeutic use* ; Humans ; Percutaneous Coronary Intervention ; Platelet Aggregation Inhibitors/therapeutic use* ; Purinergic P2Y Receptor Antagonists/therapeutic use* ; Ticagrelor/therapeutic use* ; Treatment Outcome

BACKGROUND: Dual therapy with aspirin and clopidogrel has emerged as the gold standard therapy for patients treated with drug-eluting stents (DES). However, there is variability in patients' responses to this antiplatelet therapy, and some patients continue to show ischemic recurrences after therapy. The purpose of the study was to compare the simultaneously obtained results of various platelet-function tests for assessing the prevalence of antiplatelet resistance in coronary artery disease patients undergoing DES therapy. METHODS: A total of 66 patients were administered a loading dose of aspirin, clopidogrel, and cilostazol at least 12 hr before stenting. The results of VerifyNow (Accumetrics, USA), multiplate analyzer (Dynabyte Medical, Germany), and vasodilator-stimulated phosphoprotein/P2Y12 (Biocytex, France) assays were compared with those of light transmission aggregometry (LTA) analysis. RESULTS: The P2Y12 reaction units and P2Y12% inhibition values obtained using the VerifyNow assay showed strong correlation (r) with the results of the LTA analysis. All tests results showed low concordance in defining the antiplatelet resistance in patients, and the degrees of agreement were as follows: 0 for aspirin reaction units; 0.25, P2Y12% inhibition; 0, aspirin-sensitive patients' identification test; 0.21, ADPtest; and 0.14, platelet reactivity index, expressed as the kappa statistics. The prevalence of aspirin and clopidogrel resistances in patients resulted in remarkable variations, from 0% to 22.7% and from 9.1% to 48.5%, respectively. CONCLUSIONS: The clinical usefulness of the different assays for the correct classification of patients in terms of antiplatelet resistance remains unclear. Further studies are required to determine the best method for correlating the occurrences of adverse ischemic events.
Aged ; Aspirin/*administration & dosage ; Coronary Artery Disease/*drug therapy ; Drug Resistance ; Drug Therapy, Combination ; Drug-Eluting Stents ; Female ; Humans ; Male ; Middle Aged ; Platelet Aggregation/drug effects ; Platelet Aggregation Inhibitors/*administration & dosage ; Platelet Function Tests ; Purinergic P2Y Receptor Antagonists/administration & dosage ; Receptors, Purinergic P2Y12/metabolism ; Tetrazoles/administration & dosage ; Ticlopidine/administration & dosage/*analogs & derivatives

INTRODUCTIONTicagrelor is a novel antiplatelet drug developed to reduce atherothrombosis. The PLATO trial compared ticagrelor and aspirin to clopidogrel and aspirin in patients with acute coronary syndromes (ACS). Ticagrelor was found to be superior in the primary composite endpoint of cardiovascular death, myocardial infarction or stroke, without increasing major bleeding events. The current study estimates the lifetime cost-effectiveness of ticagrelor relative to generic clopidogrel from a Singapore public healthcare perspective.

METHODSThis study used a two-part cost-effectiveness model. The first part was a 12-month decision tree (using PLATO trial data) to estimate the rates of major cardiovascular events, healthcare costs and health-related quality of life. The second part was a Markov model estimating lifetime quality-adjusted survival and costs conditional on events during the initial 12 months. Daily drug costs applied were SGD 1.05 (generic clopidogrel) and SGD 6.00 (ticagrelor). Cost per quality-adjusted life years (QALY) was estimated from a Singapore public healthcare perspective using life tables and short-term costs from Singapore, and long-term costs from South Korea. Deterministic and probabilistic sensitivity analyses were performed.

RESULTSTicagrelor was associated with a lifetime QALY gain of 0.13, primarily driven by lower mortality. The resulting incremental cost per QALY gained was SGD 10,136.00. Probabilistic sensitivity analysis indicated that ticagrelor had a > 99% probability of being cost-effective, given the lower recommended WHO willingness-to-pay threshold of one GDP/capita per QALY.

CONCLUSIONBased on PLATO trial data, one-year treatment with ticagrelor versus generic clopidogrel in patients with ACS, relative to WHO reference standards, is cost-effective from a Singapore public healthcare perspective.

Acute Coronary Syndrome ; drug therapy ; economics ; Adenosine ; analogs & derivatives ; economics ; therapeutic use ; Aspirin ; administration & dosage ; Clinical Trials as Topic ; Cost-Benefit Analysis ; Decision Trees ; Drug Costs ; Humans ; Markov Chains ; Platelet Aggregation Inhibitors ; administration & dosage ; economics ; Purinergic P2Y Receptor Antagonists ; administration & dosage ; economics ; Quality-Adjusted Life Years ; Republic of Korea ; Singapore ; Ticlopidine ; administration & dosage ; analogs & derivatives