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 .
Screening for Aspirin Responsiveness After Transient Ischemic Attack and Stroke: Comparison of 2 Point-of-Care Platelet Function Tests With Optical Aggregometry
Background and Purpose — Recent studies suggest that patients who do not respond to aspirin ( ASA ) therapy may be at increased risk of ischemic vascular events . The availability of simple to use point-of-care ( POC ) platelet function tests now potentially allows aspirin nonresponsiveness to be identified in routine clinical practice . However , there are very few data on whether the different tests produce consistent results . We therefore compared 2 POC tests ( PFA-100 device and the Ultegra-RPFA [ RPFA ] ) with conventional light transmission aggregometry ( LTA ) . Methods — Platelet function was assessed by all 3 tests in 100 patients receiving low-dose ASA therapy after transient ischemic attack ( TIA ) or ischemic stroke . Results — The incidence of ASA nonresponsiveness was 17 % by the RPFA and 22 % by the PFA-100 , compared with only 5 % by LTA ( ie , as defined with both arachidonic acid and ADP ) . Agreement between the RPFA and the PFA-100 and arachidonic acid induced LTA was poor ( & kgr;=0.16 , 95 % CI , −0.08 to 0.39 , P=0.11 ; and & kgr;=0.09 −0.12 to 0.30 , P=0.32 , respectively ) . Agreement between the 2 POC tests was also poor ( & kgr;=0.14 , −0.08 to 0.36 , P=0.15 ) . Only 2 % of patients were aspirin nonresponders by all 3 tests . Conclusions — The prevalence of apparent ASA nonresponsiveness was higher with both the POC tests than with LTA . However , agreement between the tests was poor and very few patients were ASA nonresponsive by all 3 tests . Aspirin nonresponsiveness is therefore highly test-specific and large prospect i ve studies will be required to determine the prognostic value of each of the separate tests
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 .