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 .
Aspirin non-responsiveness as measured by PFA-100 in patients with coronary artery disease.
INTRODUCTION The purpose of the present study was to study the concept of aspirin resistance or non-responsiveness by investigating the response to long-term aspirin therapy in patients with a former acute myocardial infa rct ion ( AMI ) . MATERIAL S AND METHODS Patients with an AMI ( n=202 ) r and omly assigned to aspirin 160 mg/day ( n=71 ) , aspirin 75 mg/day and warfarin ( INR 2.0 - 2.5 ) ( n=58 ) or warfarin ( INR 2.8  - 4.2 ) ( n=73 ) were evaluated by the PFA-100(R ) , biochemical variables and clinical events after a mean treatment period of 4 years . RESULTS The limit for being an aspirin non-responder was defined as the 95th percentile value in the warfarin alone group ( 196 s ) with the epinephrine cartridge . In patients on aspirin alone 25/71 ( 35 % ) were non-responders and on the combination 23/58 ( 40 % ) . With the adenosine diphosphate ( ADP ) cartridge only minor differences were found . The levels of thromboxane B(2 ) in both aspirin groups , in responders as well as in non-responders , were extremely low compared to the warfarin alone group . Evaluating both aspirin groups together ( n=129 ) , the levels of soluble P-selectin were significantly higher in non-responders as compared to responders ( p=0.012 ) . During the observation period of 4 years with limited number of events , there was a tendency for higher event rates in non-responders as compared to responders ( 36 % vs. 24 % , p=0.28 ) . CONCLUSIONS In our evaluation of the PFA-100(R ) a considerable number of post-AMI patients seemed to be non-responders to long-term aspirin therapy in doses of 75 and 160 mg/day . Circulating levels of P-selectin were higher in the non-responders . A tendency to higher incidence of clinical events among non-responders was observed
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 .