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 .
Pharmacodynamic Effects of Different Aspirin Dosing Regimens in Type 2 Diabetes Mellitus Patients With Coronary Artery Disease
Background — Patients with type 2 diabetes mellitus ( T2DM ) have reduced aspirin-induced pharmacodynamic effects . This may be attributed to increased platelet turnover rates result ing in an increased proportion of non – aspirin-inhibited platelets during the daily dosing interval . The hypothesis of this study was that an increase in the frequency of drug administration [ twice daily ( bid ) versus once daily ( od ) ] may provide more effective platelet inhibition in T2DM patients . Methods and Results — T2DM patients with stable coronary artery disease were prospect ively recruited . Patients modified their aspirin regimen on a weekly basis according to the following scheme : 81 mg/od , 81 mg/bid , 162 mg/od , 162 mg/bid , and 325 mg/od . Pharmacodynamic assessment s included light-transmittance aggregometry after arachidonic acid , collagen and adenosine diphosphate stimuli ; VerifyNow-Aspirin assay ; and serum thromboxane B2 ( TXB2 ) levels .  Twenty patients were analyzed . All patients were sensitive and compliant to aspirin irrespective of dose , as assessed by arachidonic acid – induced aggregation . When aspirin was administered once daily , there was no significant effect on platelet reactivity by increasing the once-daily dosing using aspirin-sensitive assays ( collagen-induced aggregation and VerifyNow-Aspirin ) . An increase in aspirin dose by means of a second daily administration was associated with a significant reduction in platelet reactivity assessed by collagen-induced aggregation and VerifyNow-Aspirin between 81 mg/od and 81 mg/bid ( P<0.05 for both assays ) and between 81 mg/od and 162 mg/bid ( P<0.05 for both assays ) . There was no impact of aspirin dosing regimens on adenosine diphosphate – induced aggregation . A dose-dependent effect of aspirin was observed on serum TXB2 levels ( P=0.003 ) . Conclusions — Aspirin dosing regimens are associated with different pharmacodynamic effects in platelets from T2DM patients and stable coronary artery disease , with a twice-daily , low-dose aspirin administration result ing in greater platelet inhibition than once-daily administration as assessed by aspirin-sensitive assays and a dose-dependent effect on serum TXB2 levels . The clinical implication s of a modified aspirin regimen tailored to T2DM patients warrant further investigation . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT01201785
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 .