Antiplatelet Agents

Author(s):  
Eelco F. M. Wijdicks ◽  
Sarah L. Clark

Antiplatelet agents are commonly used in vascular medicine and cardiology, but also in the pharmacologic management of patients with ischemic stroke. Aspirin alone remains the mainstay of therapy for secondary stroke prevention. Several landmark studies for the optimal duration and dose of antiplatelet therapy in stroke prevention are discussed. Dual antiplatelet therapy is needed after carotid artery stenting. Situations where antiplatelet agents also come into play are endovascular procedures associated with procedure-related thrombi. Antiplatelet agents have different mechanisms of action, and each will be discussed. Testing of platelet function and the issue of antiplatelet resistance and discontinuation of antiplatelet agents before procedures will be discussed in this Chapter.

2019 ◽  
Vol 14 (3) ◽  
pp. 220-222 ◽  
Author(s):  
Anthony S Kim ◽  
J Donald Easton

Stroke symptoms can be unsettling, even when symptoms resolve, but focusing on stroke prevention can be empowering provided that effective interventions for appropriate patient populations are available. Current options include interventions for symptomatic carotid artery stenosis, anticoagulation for atrial fibrillation, high-dose statins, new oral anticoagulants, new developments in atrial fibrillation detection, and new therapeutics are in development. For antiplatelet therapy, aspirin monotherapy is effective but dual antiplatelet therapy with the combination of aspirin and clopidogrel increases hemorrhage risks over the long term that outweigh potential benefits. In the short term though, both the Clopidogrel in High-Risk Patients with Acute Nondisabling Cerebrovascular Events (CHANCE) and Platelet-Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) trials have shown a benefit of short-term dual-antiplatelet therapy, though the increased major hemorrhage risk seen in POINT could justify applying dual-antiplatelet therapy to just the first 21 days. Furthermore, since clopidogrel is a prodrug that must be metabolized to have antiplatelet activity, it is not surprising that the treatment effect in CHANCE was limited to patients who were not carriers of loss-of-function alleles for clopidogrel metabolism. Ticagrelor, an antiplatelet agent which failed to meet its primary endpoint as monotherapy compared to aspirin in the Acute Stroke or Transient Ischaemic Attack Treated with Aspirin or Ticagrelor and Patient Outcomes (SOCRATES) trial, is currently being tested as combination therapy with aspirin compared to aspirin alone in Acute Stroke or Transient Ischaemic Attack Treated With Ticagrelor and ASA for Prevention of Stroke and Death (THALES). These developments along with improvements to the infrastructure to perform rapid evaluations and to apply intensive secondary stroke prevention interventions hold continued promise for the future.


2009 ◽  
Vol 1 ◽  
pp. CMT.S2208
Author(s):  
Howard S. Kirshner

This review considers treatments of proved efficacy in secondary stroke prevention, with an emphasis on antiplatelet therapy. Most strokes could be prevented, if readily available lifestyle and risk factor modifications could be applied to everyone. In secondary stroke prevention, the same lifestyle and risk factor modifications are also important, along with anticoagulation for patients with cardiac sources of embolus, carotid procedures for patients with significant internal carotid artery stenosis, and antiplatelet therapy. For patients with noncardioembolic ischemic strokes, FDA-approved antiplatelet agents are recommended and preferred over anticoagulants. ASA, clopidogrel, and ASA + ER-DP are recognized as accepted first-line options for secondary prevention of noncardioembolic ischemic stroke. Combined antiplatelet therapy with ASA + clopidogrel has not been shown to carry benefit greater than risk in stroke or TIA patients. Aspirin and extended release dipyridamole appeared to carry a greater benefit over aspirin alone in individual studies, leading to a recommendation of this agent in the AHA guidelines, but the recently completed PRoFESS trial showed no difference in efficacy between clopidogrel and aspirin with extended release dipyridamole, and clopidogrel had better tolerability and reduced bleeding risk.


Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Muhammad Umer ◽  
Kateryna Kurako ◽  
Nestor Galvez-Jimenez ◽  
Efrain Salgado

Objective: To assess the impact of antiplatelet therapy for secondary stroke prevention in patients with suboptimally controlled treatable cerebrovascular risk factors per guidelines. Results: Of the 1755 patients, 219 (12.47%) patients had a second stroke event between November 2006-December 2012. Mean age of this group of patients was 66.4 years old with male predominance (M:F=1.5:1). 192 (88%) patients were on antiplatelet therapy at the time of the second stroke. 27 (12 %) were not on antiplatelet therapy. Of the total cohort, treatable risk factors were poorly controlled in 130 (59%) patients: 121 (55%) hypertension; 78 (36%) hyperlipidemia, 44 (20%) diabetes. Antiplatelet agents included aspirin, clopidogrel alone or in combination with aspirin, and extended-release dipyridamole. The data showed no significant difference among antiplatelet agents for secondary stroke prevention (p<0.05). Stroke classification was as follows: 162 (74%) ischemic and 57 (26%) hemorrhagic. Categories of ischemic stroke were as follows: large-artery atherosclerosis 40 (18%), small vessel disease 45 (21%), cardioembolic 42 (19%), 35 (16%) cryptogenic / stroke of undetermined etiology. Of the 192 patients on antiplatelet therapy with stroke, 116 (60%) had poorly controlled risk factors. Conclusions: This study suggests that the use of antiplatelet therapy, regardless of which agent, for secondary stroke prevention may not be important or beneficial in the absence of optimal treatable cerebrovascular risk factor control. Further studies are needed to support this finding including further analysis of our data to assess risk factor control in those patients on antiplatelet therapy who did not suffer a second stroke during the period of surveillance


2020 ◽  
Vol 61 (3) ◽  
Author(s):  
Enrico M. Marone ◽  
Luigi F. Rinaldi ◽  
Simona Chierico ◽  
Giulia Marazzi ◽  
Piernicola Palmieri ◽  
...  

2018 ◽  
Vol 72 (17) ◽  
pp. 2086-2087 ◽  
Author(s):  
Sorin J. Brener ◽  
Patrick W. Serruys ◽  
Marie-Claude Morice ◽  
Roxana Mehran ◽  
Arie Pieter Kappetein ◽  
...  

2016 ◽  
Vol 6 (1) ◽  
pp. 38-46
Author(s):  
NS Neki

Antiplatelet agents are mainly used in the prevention and management of atherothrombotic complications. Dual antiplatelet therapy, combining aspirin and clopidogrel, is the standard care for patients having acute coronary syndromes or undergoing percutaneous coronary intervention according to the current ACC/AHA and ESC guidelines. But in spite of administration of dual antiplatelet therapy, some patients develop recurrent cardiovascular ischemic events especially stent thrombosis which is a serious clinical problem. Antiplatelet response to clopidogrel varies widely among patients based on ex vivo platelet function measurements. Clopidogrel is an effective inhibitor of platelet activation and aggregation due to its selective and irreversible blockade of the P2Y12 receptor. Patients who display little attenuation of platelet reactivity with clopidogrel therapy are labeled as low or nonresponders or clopidogrel resistant. The mechanism of clopidogrel resistance remains incompletely defined but there are certain clinical, cellular and genetic factors including polymorphisms responsible for therapeutic failure. Currently there is no standardized or widely accepted definition of clopidogrel resistance. The future may soon be realised in the routine measurement of platelet activity in the same way that blood pressure, cholesterol and blood sugar are followed to help guide the therapy, thus improving the care for millions of people. This review focuses on the methods used to identify patients with clopidogrel resistance, the underlying mechanisms, metabolism, clinical significance and current therapeutic strategies to overcome clopidogrel resistance.J Enam Med Col 2016; 6(1): 38-46


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