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 .
Long-term clinical outcome based on aspirin and clopidogrel responsiveness status after elective percutaneous coronary intervention: a 3T/2R (tailoring treatment with tirofiban in patients showing resistance to aspirin and/or resistance to clopidogrel) trial substudy.
OBJECTIVES The purpose of this study was to investigate the long-term outcome after elective percutaneous coronary intervention in low-risk patients screened for aspirin and /or clopidogrel responsiveness in the 3T/2R ( Tailoring Treatment With Tirofiban in Patients Showing Resistance to Aspirin and /or Resistance to Clopidogrel ) trial . BACKGROUND The impact of aspirin and /or clopidogrel poor response on long-term outcome is debated . METHODS  Aspirin and clopidogrel response was measured with the VerifyNow system aspirin and P2Y12 assays .  After percutaneous coronary intervention ( PCI ) , death , stroke , and myocardial infa rct ion were assessed up to 1 year . RESULTS Overall , 1,277 patients were screened , and 826 ( 65 % ) were treated with PCI . In all , 124 patients were found to be aspirin  poor responders , and there were 179 clopidogrel poor responders ( totally , 278 poor responders ) . The 1-year end point was significantly higher in poor responders as compared to full responders ( 15.8 % vs. 8.6 % , p=0.002 ) , which is principally due to more myocardial infa rct ion occurrence . At multivariable analysis , clopidogrel poor response emerged as an independent predictor ( hazard ratio : 1.15 , 95 % confidence interval : 1.03 to 1.28 ) . Receiver-operator characteristic analysis identifies≤23 of percentage of platelet inhibition and ≥208 of P2Y12 reactivity units as optimal cut offs to predict 1-year end point . Excluding periprocedural events , also peri-PCI myocardial infa rct ion , which is strongly related to aspirin/clopidogrel poor response , was an independent predictor ( hazard ratio : 1.25 , 95 % confidence interval : 1.14 to 1.37 ) . Glycoprotein IIb/IIIa inhibitor administration reduces this risk in poor responders ( 21.2 % vs. 34.7 % , p=0.02 ) , but not in full responders ( 6.3 % vs. 6.5 % , p=0.8 ) . CONCLUSIONS Poor response to clopidogrel  is an independent predictor of periprocedural myocardial infa rct ion and worse 1-year outcome in low-risk patients undergoing PCI , whereas poor response to aspirin failed to predict a worse outcome . Contrary to what was observed in poor responders , glycoprotein IIb/IIa inhibitor therapy failed to provide a benefit in aspirin and /or clopidogrel full responders
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 .