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 .
Guidance of anticoagulation after intracoronary implantation of Palmaz-Schatz stents by monitoring prothrombin and prothrombin fragment 1 + 2.
The primary objective of this study was to apply a sophisticated coagulation monitoring system including estimation of the concentration of  prothrombin fragment 1 + 2 ( PTF 1 + 2 ) and the activity of prothrombin ( coagulation factor II or FII ) to cases of stent implantation and to compare the results with those of st and ard coagulation tests . The secondary objective was to detect the incidence after stenting of subacute thrombosis ( SAT ) and bleeding complications in these patients and to compare the results with those of a group of patients with stent implantation in whom coagulation was monitored exclusively by st and ard tests .  SAT several days after coronary stenting occurs in up to 20 % despite aggressive intravenous and overlapping oral anticoagulation . According to a prospect i ve study protocol 120 consecutive patients with implantation of 155 Palmaz-Schatz stents  underwent coagulation monitoring including single daily estimation of the  concentration of PTF1 + 2 ( target range < 0.5 nmol/L ) and of  FII activity  ( 15 % to 35 % ) in addition to the st and ard tests of thrombin time ( TT ) , partial thromboplastin time ( aPTT ) , international normalized ratio ( INR ) , antithrombin III ( ATIII ) , and fibrinogen . Adjustment of heparin and phenprocoumon dosages in this study group was based only on the results of PTF1 + 2 and FII measurements . A control group consisted of 53 patients with implantation of 64 stents who were matched for baseline , angiographic , and procedure-related characteristics . After stenting , anticoagulation was monitored by estimation of TT ( target range > 70 seconds ) , aPTT ( > 70 seconds ) , INR ( 3.0 to 4.5 ) , AT III ( > 80 % ) , and fibrinogen ( < 450 mg/dl ) in this control group . There was a weak correlation between PTF1 + 2 and aPTT ( r = 0.337 ; PTF1 + 2 = -0.00169aPTT + 0.491 ) and PTF1 + 2 and TT ( r = 0.328 ; PTF1 + 2 = -0.00142TT + 0.494 ) . A better correlation was found between FII and INR ( r = 0.983 ; FII = -23.8 INR + 134 ) . Stable oral anticoagulation was maintained 2.8 + /- 0.9 days later according to an FII concentration of < 35 % compared with an INR > 3 . The incidence of SAT was 3.3 % with 3.0 % for elective versus 3.8 % for nonelective stenting . The sensitivity , specificity , and accuracy of the PTF1 + 2 test were 100 % , 88 % , and 88 % , respectively . In the control group the incidence of SAT was 17 % , with 16.1 % for elective versus 18 % for nonelective stenting . Major bleeding complications occurred in 10 % ( study group ) and in 11.3 % ( control group ) of patients ( no statistical difference ) . ( ABSTRACT TRUNCATED AT 400 WORDS
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 .