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 .
Prospective, observational study of antiplatelet and coagulation biomarkers as predictors of thromboembolic events after implantation of ventricular assist devices
Background Long-term success in ventricular assist device ( VAD ) recipients is limited by thromboembolic events , the prediction of which remains elusive . We evaluated the predictive value of aspirin hyporesponsiveness and markers of coagulation and fibrinolysis . Methods We prospect ively enrolled patients scheduled to undergo VAD implantation between June 2004 and March 2006 . Once before surgery , daily during hospitalization , and weekly after discharge we assessed platelet function , measured prothrombin activation fragment 1.2 ( F1.2 ) and plasminogen activator inhibitor-1 ( PAI-1 ) concentrations , and evaluated  aspirin hyporesponsiveness by whole-blood aggregometry and thromboelastography . All patients received 325 mg oral aspirin daily from at least 7 days before VAD implantation . Follow-up continued until heart transplantation , death or closure of the data base . Results We included 26 patients ( median follow-up 315 days , range 9–833 days ) . In eight ( 31 % ) patients , 14 thromboembolic events occurred at a median of 42 ( interquartile range 26–131 ) days . Only six ( 43 % ) events based on whole-blood aggregometry and one ( 7 % ) based on thromboelastography coincided with aspirin hyporesponsiveness . Within-patient variability was high for both tests ( 59 % and 567 % , respectively ) . Compared with levels before surgery , PAI-1 concentrations were raised for up to 45 days ( P < 0.0001 ) and those of F1.2 for up to 3 days ( P = 0.0001 ) after VAD implantation . PAI-1 and F1.2 levels did not rise significantly further before thromboembolic events . Conclusions Aspirin hyporesponsiveness was not associated with raised risk of future clinical thromboembolic events after VAD implantation . Impaired fibrinolysis , demonstrated by raised PAI-1 concentrations , might , however , indicate a predisposition to such events early after surgery
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 .