Results indicated that some PFTs may have some prognostic utility , i.e. a trend for more clinical events to be associated with groups classified as ' aspirin resistant ' .
Study -level effect sizes were generally small and absolute outcome risk was not substantially different between ' aspirin resistant ' and ' aspirin sensitive ' design ations .
Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification , the economic model found that a test-treat strategy was likely to be cost-effective .
However , neither assumption is currently evidence based .
BACKGROUND The use of aspirin is well established for secondary prevention of cardiovascular disease .
However , a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment .
It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity .
This report aims to investigate whether or not insufficient platelet function inhibition by aspirin ( ' aspirin resistance ' ) , as defined using platelet function tests ( PFTs ) , is linked to the occurrence of adverse clinical outcomes , and further , whether or not patients at risk of future adverse clinical events can be identified through PFTs .
OBJECTIVES To review systematic ally the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT design ation of ' aspirin resistance ' and the risk of adverse clinical outcome ( s ) in patients prescribed aspirin therapy .
To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs .
Variability of non-response to aspirin in patients with peripheral arterial occlusive disease during long-term follow-up
Non-responsiveness to aspirin as detected by laboratory tests may identify patients at high risk for future vascular events . The aim of this prospect i ve study was to evaluate whether non-responsiveness to aspirin  is stable over time . Ninety-eight patients with stable peripheral arterial occlusive disease ( PAOD ) treated with 100 mg/d aspirin were followed over a median timeframe of 17 months . Platelet function tests were performed initially and at follow-up using arachidonic acid-induced light transmittance aggregometry ( LTA ) in native platelet-rich plasma with the Behring Coagulation Timer ® and by measuring the collagen−epinephrine closure time ( CT ) on a Platelet Function Analyzer ( PFA-100 ® ) . When determining platelet function using LTA , four patients ( 4.1 % ) had residual platelet function ( i.e. , MaxAggr ≥78 % ) despite aspirin treatment , whereas , according to the PFA-100 ® results , 12 patients ( 12.2 % ) were identified as non-responders ( i.e. , CT < 192 s ) . Fifty-seven patients who were still under treatment with 100 mg/d aspirin at the time of follow-up provided a second blood sample . Further platelet function tests with the PFA-100 ® system identified a persistent non-responsiveness to aspirin over time in three patients ( 5.3 % ) whereas four ( 7.0 % ) and 15 ( 26.3 % ) patients had changes in response status when platelet function was assessed by LTA and on the PFA-100 ® , respectively . We conclude that true non-responsiveness to aspirin  is a rare phenomenon in stable PAOD patients . Furthermore , we conclude that in a number of patients , aspirin non-responsiveness is not stable over time
Results indicated that some PFTs may have some prognostic utility , i.e. a trend for more clinical events to be associated with groups classified as ' aspirin resistant ' .
Study -level effect sizes were generally small and absolute outcome risk was not substantially different between ' aspirin resistant ' and ' aspirin sensitive ' design ations .
Based on assumptions of PFTs being able to accurately identify patients at high risk of clinical events and such patients benefiting from treatment modification , the economic model found that a test-treat strategy was likely to be cost-effective .
However , neither assumption is currently evidence based .
BACKGROUND The use of aspirin is well established for secondary prevention of cardiovascular disease .
However , a proportion of patients suffer repeat cardiovascular events despite being prescribed aspirin treatment .
It is uncertain whether or not this is due to an inherent inability of aspirin to sufficiently modify platelet activity .
This report aims to investigate whether or not insufficient platelet function inhibition by aspirin ( ' aspirin resistance ' ) , as defined using platelet function tests ( PFTs ) , is linked to the occurrence of adverse clinical outcomes , and further , whether or not patients at risk of future adverse clinical events can be identified through PFTs .
OBJECTIVES To review systematic ally the clinical effectiveness and cost-effectiveness evidence regarding the association between PFT design ation of ' aspirin resistance ' and the risk of adverse clinical outcome ( s ) in patients prescribed aspirin therapy .
To undertake exploratory model-based cost-effectiveness analysis on the use of PFTs .