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 .
Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy
Background —Postoperative thromboembolic stroke affects 2 % to 3 % of patients undergoing carotid endarterectomy ( CEA ) and is preceded by 1 to 2 hours of increasing cerebral embolization . Previous work has demonstrated that high rates of postoperative embolization are associated with increased platelet reactivity to adenosine 5′-diphosphate ( ADP ) . Our hypothesis was that preoperative administration of the platelet ADP antagonist clopidogrel could reduce postoperative embolization . Methods and Results —One hundred CEA patients on routine aspirin therapy ( 150 mg ) were r and omized to 75 mg clopidogrel ( n=46 ) or placebo ( n=54 ) the night before surgery . Platelet response to ADP was assessed by whole-blood flow cytometry . The number of emboli detected by transcranial Doppler within 3 hours of CEA was independently quantified . Time taken from flow restoration to skin closure was used as an indirect measure of the time to secure hemostasis . In comparison with placebo , clopidogrel produced a small ( 8.8 % ) but significant reduction in the platelet response to ADP ( P < 0.05 ) while conferring a 10-fold reduction in the relative risk of those patients having > 20 emboli in the postoperative period ( odds ratio , 10.23 ; 95 % CI , 1.3 to 83.3 ; P = 0.01 , Fisher ’s exact test ) . However , in the clopidogrel-treated patients , the time from flow restoration to skin closure ( an indirect marker of hemostasis ) was significantly increased ( P = 0.04 , Fisher ’s exact test ) , although there was no increase in bleeding complications or blood transfusions . Conclusions —This is the first study to show that a CEA patient ’s postoperative thromboembolic potential can be significantly reduced by targeted preoperative antiplatelet therapy without increasing the risk of bleeding complications
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 .