Most studies indicated that low on-treatment platelet reactivity ( LTPR ) , as measured by several platelet function tests , and the carriage of CYP2C19 * 17 allele were independent risk factors for bleeding .
A bleeding score also proved to be helpful in identifying patients at risk .
Several patient characteristics were also identified as independent predictors of bleeding , such as older age , female sex and renal failure .
Patients with coronary artery disease are usually treated with dual antiplatelet therapy ( DAPT ) after percutaneous coronary intervention .
Patients on DAPT are at risk of both ischaemic and bleeding events .
Although side-lined for a long time , real-life studies have shown that both the incidence and the associated morbidity and mortality of out-of-hospital bleeding are high .
This indicates that prevention of ( post-interventional ) bleeding is as important as prevention of ischaemia .
For this purpose it is crucial to reliably identify patients with a high bleeding risk .
In order to postulate an algorithm , which could help identifying these patients , we performed a systematic review to determine the value of previously proposed prognostic modalities for bleeding .
Phenotyping vs. genotyping for prediction of clopidogrel efficacy and safety: the PEGASUS-PCI study.
BACKGROUND Prognostic values of genotyping and phenotyping for assessment of clopidogrel responsiveness have been shown in independent studies . OBJECTIVES To compare different assays for prediction of events during long-term follow-up . METHODS In this prospect i ve cohort study polymorphisms of CYP2C19 * 2 and CYP2C19 * 17 alleles , vasodilator-stimulated phosphoprotein phosphorylation ( VASP ) assay , multiple electrode aggregometry ( MEA ) , cone and platelet analyser ( CPA ) and platelet function analyser ( PFA-100 ) were performed in 416 patients undergoing percutaneous coronary intervention .  The rates of events were recorded during a 12-month follow-up . RESULTS Platelet aggregation by MEA predicted stent thrombosis ( 2.4 % ) better ( c-index = 0.90 ; P < 0.001 ; sensitivity = 90 % ; specificity = 83 % ) than the VASP assay , CPA or PFA-100 ( c-index < 0.70 ; P > 0.05 ; sensitivity < 70 % ; specificity < 70 % for all ) or even the CYP2C19 * 2 polymorphism ( c-index < 0.56 ; P > 0.05 ; sensitivity = 30 % ; specificity = 71 % ) . Survival analysis indicated that patients classified as poor responders by MEA had a substantially higher risk of developing stent thrombosis or MACE than clopidogrel responders ( 12.5 % vs. 0.3 % , P < 0.001 , and 18.5 % vs. 11.3 % , P = 0.022 , respectively ) , whereas poor metabolizers ( CYP2C19 * 1/*2 or * 2/*2 carriers ) were not at increased risks ( stent thrombosis , 2.7 % vs. 2.5 % , P > 0.05 ; MACE , 13.5 % vs. 12.1 % , P = 0.556 ) . The incidence of major bleedings ( 2.6 % ) was numerically higher in patients with an enhanced vs. poor response to clopidogrel assessed by MEA ( 4 % vs. 0 % ) or in ultra-metabolizers vs. regular metabolizers ( CYP2C19 * 17/*17 vs. CYP2C19 * 1/*1 ; 9.5 % vs. 2 % ) . The classification tree analysis demonstrated that acute coronary syndrome at hospitalization and diabetes mellitus were the best discriminators for clopidogrel responder status . CONCLUSIONS Phenotyping of platelet response to clopidogrel was a better predictor of stent thrombosis than genotyping
Most studies indicated that low on-treatment platelet reactivity ( LTPR ) , as measured by several platelet function tests , and the carriage of CYP2C19 * 17 allele were independent risk factors for bleeding .
A bleeding score also proved to be helpful in identifying patients at risk .
Several patient characteristics were also identified as independent predictors of bleeding , such as older age , female sex and renal failure .
Patients with coronary artery disease are usually treated with dual antiplatelet therapy ( DAPT ) after percutaneous coronary intervention .
Patients on DAPT are at risk of both ischaemic and bleeding events .
Although side-lined for a long time , real-life studies have shown that both the incidence and the associated morbidity and mortality of out-of-hospital bleeding are high .
This indicates that prevention of ( post-interventional ) bleeding is as important as prevention of ischaemia .
For this purpose it is crucial to reliably identify patients with a high bleeding risk .
In order to postulate an algorithm , which could help identifying these patients , we performed a systematic review to determine the value of previously proposed prognostic modalities for bleeding .