@article{7333a6e5a02a481fa9298400ac2b9992,
title = "Variable responsiveness to clopidogrel and aspirin among patients with acute coronary syndrome as assessed by platelet function tests",
abstract = "Unresponsiveness to clopidogrel or aspirin has been reported in patients with acute coronary syndrome (ACS). Platelet aggregometry (PA) and the Impact-R [Cone and Plate(let) Analyzer (CPA) technology, measuring whole blood platelet adhesion under flow conditions] were compared in detecting laboratory unresponsiveness to clopidogrel and aspirin among ACS patients. Platelet-rich plasma (PRP) samples were evaluated in 404 patients by PA using adenosine diphosphate (ADP) and arachidonic acid (AA) and whole blood samples by the Impact-R ADP- and AA-response tests. The first cohort (n = 114) was assayed by PA on days 1 and 4 of the onset of ACS. A patient with relative decrease of ≤ 10% in ADP-induced maximal platelet aggregation after clopidogrel treatment was defined as laboratory non-responding (NR) patient to clopidogrel. This relative value correlated well with an absolute value of ADP-induced aggregation ≥ 70%. A patient with an absolute value of AA-induced maximal aggregation ≥ 60% was defined as laboratory NR patient to aspirin. The second cohort (n = 290) was tested on day 4 by both systems and results analyzed by receiver operating characteristic curve. The following cut-off values of the Impact-R surface coverage were obtained: ≤ 2.8% and ≤ 3.4% for clopidogrel and aspirin NR patients, respectively. The incidence of NR patients to clopidogrel and aspirin, according to the two methods was 27% and 22%, respectively. Impact-R compared to PA in detecting clopidogrel and aspirin NR patients revealed: 79% and 82% agreement, 71% and 73% sensitivity, 83% and 86% specificity, respectively. In conclusion, the Impact-R and PA results demonstrated high degree of similarity.",
keywords = "Acute coronary syndrome, Aspirin, Clopidogrel, Impact-R, Platelet aggregometer, Platelets",
author = "Boris Shenkman and Shlomi Matetzky and Paul Fefer and Hanoch Hod and Yulia Einav and Aharon Lubetsky and David Varon and Naphtali Savion",
note = "Funding Information: The authors thank S. Kotev-Emeth for technical assistance. The study was partially supported by DiaMed (Cresier, Switzerland). ",
year = "2008",
doi = "10.1016/j.thromres.2007.10.018",
language = "אנגלית",
volume = "122",
pages = "336--345",
journal = "Thrombosis Research",
issn = "0049-3848",
publisher = "Elsevier Ltd.",
number = "3",
}