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1.
Is there a Role for Oral Triple Therapy in Patients with Acute Coronary Syndromes Without Atrial Fibrillation?
Spinthakis, N, Farag, M, Akhtar, Z, Gorog, DA
Current vascular pharmacology. 2018;(5):427-436
Abstract
BACKGROUND Acute Coronary Syndrome (ACS) patients, despite treatment with Dual Anti- Platelet Therapy (DAPT), have up to 10% risk of recurrent Major Adverse Cardiac Events (MACE) in the short term. METHODS Here we review studies using more potent antithrombotic agent combinations to reduce this risk, namely Triple Therapy (TT) with the addition of an oral anticoagulant, PAR-1 antagonist, or cilostazol to DAPT (mainly aspirin and clopidogrel), and discuss the limitations of trials to date. RESULTS Generally speaking, TT leads to an increase in bleeding. Vorapaxar showed a signal for reducing ischaemic events, but increased intracranial haemorrhage 3-fold in the subacute phase of ACS, although remains an option for secondary prevention beyond the immediate subacute phase, particularly if prasugrel or ticagrelor are not available. Non-Vitamin K Oral Anticoagulants (NOACs) all increased bleeding, with only modest reduction in MACE noted with low dose rivaroxaban. Rivaroxaban can be considered combined with aspirin and clopidogrel in ACS patients at high ischaemic and low bleeding risk, without prior stroke/TIA. The combination of P2Y12 inhibitor and NOAC, without aspirin, looks promising. DAPT may be replaced, not by TT, but by dual therapy comprising a NOAC with a P2Y12 inhibitor. CONCLUSION More potent antithrombotic regimens increase bleeding and should only be considered on an individual basis, after careful risk stratification. Accurate risk stratification of ACS patients, for both ischaemic and bleeding risk, is essential to allow individualised treatment.
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2.
[high on-treatment platelet reactivity in patients with chronic renal failure using acetylsalicylic acid].
Horyniecki, M, Łącka-Gaździk, B, Dworaczek, W, Śnit, M, Łabuz-Roszak, B
Wiadomosci lekarskie (Warsaw, Poland : 1960). 2017;(6 pt 1):1102-1107
Abstract
Cardiovascular diseases (CVD) are the most common cause of mortality in the world. Acetylsalicylic acid (ASA) is a widely used medicine in primary and secondary prevention of cardiovascular diseases. About 1-60% patients taking aspirin have high platelet reactivity (HOPR) despite aspirin treatment. HOPR is significantly more frequent in patients with chronic kidney disease (CKD) and it increases the risk of adverse cardiovascular events in these patients. The cause of HOPR in patients with CKD may be oxidative stress and inflammation. To the risk factors belong diabetes, female sex or decreased HDL cholesterol level.
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3.
Administration of Traditional Chinese Blood Circulation Activating Drugs for Microvascular Complications in Patients with Type 2 Diabetes Mellitus.
He, L, Wang, H, Gu, C, He, X, Zhao, L, Tong, X
Journal of diabetes research. 2016;:1081657
Abstract
Traditional Chinese medicine (TCM) is an important complementary strategy for treating diabetes mellitus (DM) in China. Traditional Chinese blood circulation activating drugs are intended to guide an overall approach to the prevention and treatment of microvascular complications of DM. The core mechanism is related to the protection of the vascular endothelium and the basement membrane. Here, we reviewed the scientific evidence underpinning the use of blood circulation activating drugs to prevent and treat DM-induced microvascular complications, including diabetic nephropathy (DN), diabetic peripheral neuropathy (DPN), and diabetic retinopathy (DR). Furthermore, we summarized the effects and mechanism of TCM on improving blood rheology, inhibiting aggregation of platelet, forming advanced glycation end products (AGEs), regulating oxidative stress, reducing blood fat, and improving lipid metabolism. The paper provides a new theoretical basis for the clinical practice of TCM in the prevention and treatment of DM and its microvascular complications.
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4.
Mechanism of the anti-platelet effect of natural bioactive compounds: role of peroxisome proliferator-activated receptors activation.
Fuentes, E, Fuentes, F, Palomo, I
Platelets. 2014;(7):471-9
Abstract
Platelets are crucial mediators of the acute complications of atherosclerosis causing life-threatening ischemic events throughout plaque development. The inhibition of the platelet function has been used for a long time in an effort to prevent and treat cardiovascular diseases. However, morbidity and mortality figures indicate that current anti-platelet strategies are far from a panacea. In this context, a large number of natural bioactive compounds (NBCs) (polyphenols, terpenoids, alkaloids and fatty acids, among others) have been reported with apparent inhibitory activity on human platelets and each constituent may possess multiple targets. In this sense, the article describes how the mechanism of anti-platelet action by NBCs peroxisome proliferator-activated receptors agonists is mediated by inhibition of protein kinase-α, cyclooxygenase-1, thromboxane A2, cytosolic calcium, and indirect stimulation of protein kinase A (increased in cyclic adenosine monophosphate levels) and protein kinase G (increased in cyclic guanosine monophosphate levels).
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5.
Influence of omega-3 polyunsaturated fatty acid-supplementation on platelet aggregation in humans: a meta-analysis of randomized controlled trials.
Gao, LG, Cao, J, Mao, QX, Lu, XC, Zhou, XL, Fan, L
Atherosclerosis. 2013;(2):328-34
Abstract
OBJECTIVE Increased platelet activity predicts adverse cardiovascular events. The objective was to assess the effects of long-chain omega-3 polyunsaturated fatty acid (n-3 PUFA)-supplementation on platelet aggregation. METHODS AND RESULTS We conducted a meta-analysis of randomized controlled trials identified using PubMed, Embase and the Cochrane Library. Fifteen studies were included. In comparison to placebo using the random-effect model, n-3 PUFA-supplementation significantly reduced adenosine diphosphate-induced platelet aggregation (standard mean difference [SMD] = -1.23 with 95% confidence interval [CI] -2.24 to -0.23, p = 0.02) and platelet aggregation units, determined using the VerifyNow(®) rapid platelet-function assay system (SMD = -6.78 with 95% CI -12.58 to -0.98, p = 0.02). There was a trend toward decreased collagen-induced (SMD = -0.70 with 95% CI -0.72 to 0.33, p = 0.18) and arachidonic acid-induced platelet aggregation (SMD = -0.43 with 95% CI -2.26 to 1.40, p = 0.64) compared with controls; however, statistical significance was not reached. CONCLUSIONS Our meta-analysis demonstrates that n-3 PUFA-supplementation is associated with a significant reduction in platelet aggregation when the participants were at poor health status, but not in healthy persons. High-risk patients with cardiovascular disease and even diabetics may potentially benefit from n-3 PUFAs therapy. However, n-3 PUFAs may not be effective in primary prevention. Larger trials need to be carried out to confirm the present findings.
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6.
Inflammation in atherosclerosis: from pathophysiology to practice.
Libby, P, Ridker, PM, Hansson, GK, ,
Journal of the American College of Cardiology. 2009;(23):2129-38
Abstract
Until recently, most envisaged atherosclerosis as a bland arterial collection of cholesterol, complicated by smooth muscle cell accumulation. According to that concept, endothelial denuding injury led to platelet aggregation and release of platelet factors which would trigger the proliferation of smooth muscle cells in the arterial intima. These cells would then elaborate an extracellular matrix that would entrap lipoproteins, forming the nidus of the atherosclerotic plaque. Beyond the vascular smooth muscle cells long recognized in atherosclerotic lesions, subsequent investigations identified immune cells and mediators at work in atheromata, implicating inflammation in this disease. Multiple independent pathways of evidence now pinpoint inflammation as a key regulatory process that links multiple risk factors for atherosclerosis and its complications with altered arterial biology. Knowledge has burgeoned regarding the operation of both innate and adaptive arms of immunity in atherogenesis, their interplay, and the balance of stimulatory and inhibitory pathways that regulate their participation in atheroma formation and complication. This revolution in our thinking about the pathophysiology of atherosclerosis has now begun to provide clinical insight and practical tools that may aid patient management. This review provides an update of the role of inflammation in atherogenesis and highlights how translation of these advances in basic science promises to change clinical practice.
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7.
Is the effect of antihypertensive drugs on platelet aggregability and fibrinolysis clinically relevant?
Fogari, R, Zoppi, A
American journal of cardiovascular drugs : drugs, devices, and other interventions. 2005;(4):211-23
Abstract
Hypertension is associated with decreased fibrinolytic potential, mainly expressed as elevated plasma plasminogen activator inhibitor type 1 (PAI-1) levels, and increased platelet aggregability, which may account in part for the increased risk of atherosclerosis and its clinical complications in hypertensive patients. The effects of antihypertensive drugs on this prothrombotic state have been investigated and controversial findings have been reported, possibly because of differences in study designs, patients selected, and methodology used. Scarce and conflicting data exist about the effects of diuretics and beta-adrenoceptor antagonists on the fibrinolytic system, whereas ACE inhibitors have generally been reported to improve the fibrinolytic balance by decreasing plasma PAI-1 levels, calcium channel antagonists have been shown to increase tissue plasminogen activator (tPA) activity, and angiotensin II type 1 (AT(1)) receptor antagonists seem to exert neutral effects. beta-Adrenoceptor antagonists, calcium channel antagonists, and AT(1)-receptor antagonists have been reported to exert anti-aggregatory effects on platelets, while contrasting data exist about the influence of ACE inhibitors. Clinical implications of the changes induced by antihypertensive drugs on the fibrinolytic balance and platelet function are still debated. In particular, the question of whether these changes may translate into different degrees of cardiovascular protection in hypertensive patients remains unanswered. While awaiting more information from clinical trials, the choice of antihypertensive drugs, particularly in high-risk patients, should take into account effects beyond their BP-lowering efficacy. Selected agents should have a favorable, or at least neutral, impact on fibrinolytic function and platelet activity.
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8.
Statins, platelet aggregation and coronary heart disease.
Dajani, EZ, Shahwan, TG, Dajani, NE
Journal of the Association for Academic Minority Physicians : the official publication of the Association for Academic Minority Physicians. 2002;(1):27-31
Abstract
It is becoming increasingly recognized that the beneficial effects of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-Co-A) reductase inhibitors (statins) on reducing clinically important cardiovascular events (myocardial infarction and stroke) are not only attributable to their hypocholesterolemic effect but also to non-lipid mechanisms of action. The nonlipid factors may include the stabilization of arterial plaques, endothelial normalization, anti-inflammatory effects and inhibition of platelet thrombus formation. The inhibition of platelet thrombus formation has not been adequately studied in man and the results are often contradictory. It is the objective of this review to discuss the effects of statins on platelet aggregation in the context of relatively new and specific techniques for the measurement of platelet function as reported by Ma and coinvestigators in this issue of JAAMP. Ma et al. examined the effect of pravastatin given for 8 to 12 weeks on platelet function and low density lipoprotein-cholesterol (LDL-C) in 21 Chinese patients with primary hypercholesterolemia. Platelet function was evaluated by adenosine diphosphate (ADP)-induced aggregation, thromboxane B2 (TXB2) and the expression of alpha granule membrane protein-140 (GMP-140). GMP-140 is considered one of the most sensitive indicators of the state of platelet function. As expected, pravastatin treatment significantly reduced LDL-C and inhibited ADP-induced platelet aggregation, TXB2 synthesis and the expression of GMP-140--all such parameters can lead to thrombus formation and subsequent cardiovascular events. Using the test methods of Ma et al., additional dose-response studies with several statins and standard antiplatelet drugs are needed to confirm their effects on platelet aggregation, if any. Furthermore, we need to determine whether the antiplatelet effect of the statins, if present, is independent of their hypocholesterolemic action. The additional studies could provide important clues toward the development of new and specific antithrombotic drugs.
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9.
The effects of drugs used in anaesthesia on platelet membrane receptors and on platelet function.
Kozek-Langenecker, SA
Current drug targets. 2002;(3):247-58
Abstract
Platelet dysfunctions are known origins of perioperative bleeding disorders which are a major concern in the management of surgical patients. Among multiple factors, interactions of drugs used in anaesthesia with platelets have been implicated to aggravate the risk of haemorrhagic complications. This paper reviews in vitro and in vivo studies which have examined the effects of inhalational, intravenous, and local anaesthetics, opioids, and muscle relaxants on platelets. A brief summary of platelet physiology, function tests, and flow cytometric assessment of membrane receptors is included. Although the results of many studies have been conflicting, it appears that halothane, sevoflurane, and propofol inhibit platelet function in a reversible and dose-related manner at concentrations used clinically. Ilalothane affects the intracellular activating second messenger inositol triphosphate, platelet calcium homeostasis, thromboxane A2 formation, and the inhibiting signal transduction pathway including cyclic adenosine monophosphate. The proposed platelet inhibiting mechanism of sevoflurane involves the suppression of thromboxane A2 formation. Propofol appears to cause platelet dysfunctions by inhibiting calcium mobilisation upon agonist stimulation. Nitrous oxide causes a modest suppression of calcium mobilisation. An interaction of local anaesthetics with components in the platelet membrane appears to account for their inhibiting effect, but only at concentrations far higher than that found during clinical use. A clinically relevant antithrombotic effect of regional anaesthesia has been observed, though. Isoflurane, enflurane, desflurane, barbiturates, etomidate, opioids, and muscle relaxants seem to have negligible effects on platelets at therapeutic concentrations. Anaesthetists should be aware of the potential impairment of the coagulation profile by anaesthetic agents.
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10.
Platelet aggregation inhibition with glycoprotein IIb--IIIa inhibitors.
Proimos, G
Journal of thrombosis and thrombolysis. 2001;(2):99-110
Abstract
Inhibitors of the platelet receptor glycoprotein (GP) IIb--IIIa are a novel and potent class of antithrombotic drugs for the management of patients with non-ST-segment elevation acute coronary syndromes (ACS) and those undergoing percutaneous coronary intervention (PCI). Pharmacodynamic studies with three currently approved agents in this class (abciximab [ReoPro, Centocor, Inc., Malvern, Pennsylvania, and Eli Lilly & Company, Indianapolis, Indiana]; eptifibatide [INTEGRILIN, COR Therapeutics, Inc., South San Francisco, California, and Key Pharmaceuticals, Inc., Kenilworth, New Jersey]; and tirofiban HCI [Aggrastat, Merck & Co., Inc., Whitehouse Station, New Jersey]) all sought to identify dosing regimens that would establish and maintain >80 % inhibition of ex vivo platelet aggregation throughout the duration of intravenous infusion. Direct comparison of these prior studies is difficult, however, because the assays used different anticoagulants (sodium citrate [abciximab, tirofiban HCI] or D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone [PPACK] [eptifibatide]) and different concentrations of the platelet agonist adenosine diphosphate (ADP) (5 micromol [tirofiban HCI] or 20 micromol [abciximab, eptifibatide]). More recent work has attempted to overcome these limitations by using similar assay conditions for all GP IIb--IIIa inhibitors. These studies have indicated that the concentrations of all three agents required to provide the targeted effect for platelet inhibition are considerably higher in the presence of an anticoagulant that does not chelate calcium ions (e.g., heparin or PPACK) than in the presence of calcium-chelating anticoagulant (i.e., sodium citrate). Of the three currently approved GP IIb--IIIa inhibitors, eptifibatide is the only agent whose approved dosing is based on an ex vivo platelet aggregation assay that uses such an anticoagulant. Additionally, Kereiakes et al. have recently reported that the high levels of platelet inhibition (>80 %), using PPACK as an anticoagulant and ADP (20 micromol) as an agonist, are more consistently achieved with the approved dosing regimen of eptifibatide. The antiplatelet effect of abciximab showed more interpatient variability, whereas the median inhibition of ex vivo platelet aggregation with the approved dosing regimen for tirofiban HCl was <80 % at almost all time points during drug infusion.