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 .
Earlier application of loading doses of aspirin and clopidogrel decreases rate of recurrent cardiovascular ischemic events for patients undergoing percutaneous coronary intervention.
BACKGROUND Aspirin and clopidogrel resistance plays a significant role in the development of cardiovascular ischemic events for ninety patients undergoing percutaneous coronary intervention . Recent studies have indicated that increasing the dose of antiplatelet drugs maybe a potent method to improve the inhibition of platelet aggregation . METHODS  Thrombelastograph ( TEG ) determinations were used to evaluate the effect of antiplatelet therapy . According to the results , 90 patients were divided into three groups and given different doses of aspirin and clopidogrel . Thirty patients with both an inhibition rate of  aspirin > 50 % and an inhibition rate of clopidogrel > 50 % were defined as the control group . Sixty patients with an inhibition rate for aspirin < 50 % and an inhibition rate for clopidogrel < 50 % were defined as the resistance group . Patients in resistance group were r and omly assigned to be given a routine dose ( 100 mg aspirin plus 75 mg clopidogrel per day , which we called a resistance plus routine dose group , R + R ) and a loading dose ( 200 mg aspirin and 150 mg clopidogrel per day , which we called resistance plus loading dose group , R + L ) of antiplatelet therapy . A 12-month follow-up was observed to examine the change of inhibition rate of antiplatelet therapy and to estimate the relationship between inhibition rate and the occurrence of cardiovascular ischemic events . RESULTS After 6 months of antiplatelet therapy , the inhibition rate of aspirin  in the R + L group increased from ( 31.4 ± 3.7)% to ( 68.6 ± 7.1)% , which was significantly higher than that in R + R group , ( 51.9 ± 8.2)% ( P < 0.01 ) . The inhibition rate of clopidogrel  in the R + L group increased from ( 22.1 ± 3.8)% to ( 60.2 ± 7.4)% , which was significantly higher than in the R + R group , ( 45.9 ± 4.3)% ( P < 0.01 ) . The occurrence rates of cardiovascular ischemic events , stent thrombosis , recurrent unstable angina and myocardial infa rct ion in the R + R group were 20 % , 36 % and 17 % , respectively . Occurrence was significantly increased compared with that in the control group , 3 % , 10 % and 1 % , respectively ( P < 0.01 ) . In contrast , the occurrence rates in the R + L group ( 10 % , 23 % and 6 % , respectively ) were attenuated compared with those in the R + R group ( P < 0.01 ) , although still higher than in the control group ( P < 0.01 ) . CONCLUSIONS Almost all of the cardiovascular ischemic events occurred in the first six months after percutaneous coronary intervention . According to the result of TEG determinations , earlier application of a loading dose of aspirin and clopidogrel can decrease the rate of recurrent cardiovascular ischemic events
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 .