Effects of aspirin and clopidogrel in healthy men measured by platelet aggregation and PFA-100

Madsen, Esben Hjorth; Schmidt, Erik Berg; Maurer‐Spurej, Elisabeth; Kristensen, Søren Risom

doi:10.1080/09537100801989857

Cited by 26 publications

(19 citation statements)

References 29 publications

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“…The restriction of LTA analysis guided by PFA reduced the number of LTA results in the analysis, which might be considered a shortcoming of this study. However, we examined our assumption that high PFA-results would be coupled with low LTA-AA results by measuring LTA-AA in all group 2 patients at day 14, as well as random LTA-AA analyses were performed among patients with PFA results above 166 s. In this way, 130 pairs of PFA and LTA-AA results were found to be in agreement with our assumption, whereas none were in disagreement with the assumption, which is also supported by previous observations [24]. The information gained from additional LTA-AA results would therefore have been limited.…”

Section: Strengths and Limitations Of The Studysupporting

confidence: 88%

“…Blood samples were prepared as previously described [24]. PRP was stimulated with arachidonic acid (AA) 1.5 mmol/l (LTAAA), ADP 5.0 mmol/l (LTA ADP 5:max ) and, in the clopidogrel substudy, 20.0 mmol/l of ADP (LTAADP 20:max ) (both from Bio/Data Corporation, Horsham, PA, USA) under continuous stirring (1000 rpm).…”

Section: Light Transmission Aggregometrymentioning

confidence: 99%

“…In particular, we wanted to investigate the reproducibility of results, i.e. whether the classification would vary at different time points, which previous results indicated [24]. Furthermore, in a subgroup of 43 consecutive PAD patients, the occurrence of clopidogrel low-response (CLR) by LTA and IA was investigated.…”

Section: Introductionmentioning

confidence: 98%

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Platelet response to aspirin and clopidogrel in patients with peripheral atherosclerosis

Madsen

GEHR²,

Johannesen³

et al. 2011

Platelets

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Aspirin and clopidogrel are important drugs in the secondary prevention of ischemic events. A considerable individual variation in platelet response to these drugs has, however, been reported, and high residual platelet reactivity despite treatment may be an independent risk factor for ischemic events. Most studies have been undertaken in patients with coronary heart disease, but patients with peripheral artery disease (PAD) may exhibit greater residual platelet reactivity, possibly because of platelet activation by a larger area of diseased endothelium. It is yet unsettled which method that best measures platelet reactivity and an eventual lack of response to aspirin. Several instruments are promoted to measure platelet response and low-response to platelet inhibitors, but it is questionable if they measure this in comparable ways. We studied the comparability of three tests of platelet reactivity for the assessment of low-response to aspirin and clopidogrel in patients with PAD. In 263 patients, platelet function was assessed twice, 3 months apart, by the Platelet Function Analyzer-100 (PFA), light transmission aggregometry (LTA), and whole blood impedance aggregometry (IA). In a subgroup of 43 patients, we studied the effect of a single dose of 600 mg clopidogrel on platelet function. Low-response to aspirin assessed by analyses targeting cyclooxygenase-1 activity (LTA, IA) was rare (≤ 8.1%). With the PFA, we found 17% with low response at both visits, and 60% who were consistently responsive, whereas 23% were categorized differently at the two visits. Low response to clopidogrel, occurred in 0-23%, depending on the method and the criteria used. A low-response to aspirin, defined by lack of COX-1 inhibition, is a rare phenomenon whereas high residual platelet reactivity as determined by PFA may be a rather frequent finding but is not consistent over time in all patients. A low-response to clopidogrel depends very much on the method and definition used.

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Section: Strengths and Limitations Of The Studysupporting

confidence: 88%

Section: Light Transmission Aggregometrymentioning

confidence: 99%

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Platelet response to aspirin and clopidogrel in patients with peripheral atherosclerosis

Madsen

GEHR²,

Johannesen³

et al. 2011

Platelets

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“…This finding suggests that this test detects too many patients with ALR, because LTA-AA values did not increase in these patients, confirming a low cyclooxygenase 1 activity. Of note is that we obtained our results during dual antiplatelet therapy, which should stabilize platelet function more than aspirin alone, because clopidogrel also inhibits AA-stimulated aggregation to some extent (32 ).…”

Section: Monitoring the Aspirin Responsementioning

confidence: 69%

Long-Term Aspirin and Clopidogrel Response Evaluated by Light Transmission Aggregometry, VerifyNow, and Thrombelastography in Patients Undergoing Percutaneous Coronary Intervention

Madsen

Saw

Kristensen³

et al. 2010

Clinical Chemistry

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“…Posteriorly, the need to evaluate platelet function led to the development of technologies such as the PFA-100, a precise, convenient and reliable method that assesses platelet function globally and automatically in citrated whole blood (8,9). However, this system does not detect the effect of certain antiplatelet drugs upon platelet function (10)(11)(12). A recent introduction on the market has been the mentioned Multiplate System® analyzer, which uses different tests to generate reliable information on platelet function and on the effects of antiplatelet treatment.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of bleeding risk and measurement methods in dental patients

Cañigral

Silvestre²,

Cañigral³

et al. 2010

Med Oral

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Objective: The present study explores bleeding manifestations in routine dental surgical procedures, evaluates the influence of antithrombotic drugs upon bleeding risk, and validates the efficiency of a clinical method for the measurement of bleeding. Material and method: A prospective observational study was made involving a cohort of 99 patients in the setting of normal clinical practice, with the added conduction of prior hematological tests including baseline hemostasis and platelet function, based on a new method (Multiplate System®). For evaluation of the bleeding manifestations, a clinical method was selected that evaluates bleeding on the basis of its duration and the hemostatic measures needed to resolve the problem. Results: Almost one-third of the patients (27.3%) were receiving treatment with oral antiplatelet drugs, while 19.2% received oral anticoagulants and 9% received combined therapy with acetylsalicylic acid plus clopidogrel. In turn, an 8% incidence of moderate bleeding episodes was detected correlated to the ASPI platelet function test and to advanced patient age. Conclusion: The incorporation of platelet function tests increases the safety of oral surgery in elderly patients subjected to antiplatelet treatment, particularly with acetylsalicylic acid and clopidogrel.

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Effects of aspirin and clopidogrel in healthy men measured by platelet aggregation and PFA-100

Cited by 26 publications

References 29 publications

Platelet response to aspirin and clopidogrel in patients with peripheral atherosclerosis

Platelet response to aspirin and clopidogrel in patients with peripheral atherosclerosis

Long-Term Aspirin and Clopidogrel Response Evaluated by Light Transmission Aggregometry, VerifyNow, and Thrombelastography in Patients Undergoing Percutaneous Coronary Intervention

Evaluation of bleeding risk and measurement methods in dental patients

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