Prevalences widely differ between studies reporting on aspirin resistance .
BACKGROUND The absolute risk of recurrences among patients using aspirin for prevention of cardiovascular events remains high .
Persistent platelet reactivity despite aspirin therapy might explain this in part .
Reported prevalences of this so-called aspirin resistance vary widely , between 0 % and 57 % .
OBJECTIVES The aim of the study was to systematic ally review all available evidence on prevalence of aspirin resistance and to study determinants of reported prevalence .
Assessing aspirin responsiveness in subjects with multiple risk factors for vascular disease with a rapid platelet function analyzer
Aspirin , compared with placebo , reduces the risk of cardiovascular events by 25 % in population s of patients with and without known arterial vascular disease . However , the phenomena of ‘ aspirin resistance ’ that has been described in 5–50 % of this population may critically reduce aspirin 's efficacy . One study has suggested that aspirin-resistant patients have a 3.5 times higher risk of cardiovascular death . Presently , there are no established , simple , broadly used methods determining antiplatelet properties of aspirin , while conventional aggregometry requires special equipment and trained personnel . We sought to determine the validity of an Ultegra analyzer with the novel aspirin-sensitive cartridge before and after one pill of non-enteric coated aspirin ( 325 mg ) in subjects with multiple risk factors for coronary artery disease . One hundred and fifty-four volunteers were enrolled into the multicenter study , but six of them were excluded . Data from 148 participants were analyzed . Platelets were assessed twice at baseline ( pre-aspirin ) , and after 2–30 h ( post-aspirin ) . We employed 5 μmol/l epinephrine-induced conventional aggregometry , and aspirin response units stimulated by propyl gallate with the point-of-care Ultegra analyzer . A single pill of aspirin  reduced platelet-rich plasma aggregation from 72 ± 21 % to 25 ± 10 % , and diminished aspirin reduction units from 647 ± 95 to 436 ± 69 . The overall agreement between the two methods was 87 % with 85 % sensitivity for Ultegra and 88 % for platelet aggregation , respectively . The correlation between the two methods was 0.902 . Timely determination of aspirin resistance represents an indispensable application in current medicine . The Ultegra RPFA-ASA analyzer is a novel , fast method that could be used in clinical practice for monitoring efficacy of aspirin , and for triaging the aspirin-resistant population . The clinical implication s of these data need to be proven in r and omized trials
Prevalences widely differ between studies reporting on aspirin resistance .
BACKGROUND The absolute risk of recurrences among patients using aspirin for prevention of cardiovascular events remains high .
Persistent platelet reactivity despite aspirin therapy might explain this in part .
Reported prevalences of this so-called aspirin resistance vary widely , between 0 % and 57 % .
OBJECTIVES The aim of the study was to systematic ally review all available evidence on prevalence of aspirin resistance and to study determinants of reported prevalence .