title: Clopidogrel pretreatment in primary percutaneous coronary intervention: prevalence of high on-treatment platelet reactivity and impact on preprocedural patency of the infarct-related artery.
abstract: To date, there is limited data on levels of platelet inhibition achieved in patients with ST-elevation myocardial infarction (STEMI) who are loaded with clopidogrel and aspirin (ASA) prior to undergoing primary percutaneous coronary intervention (P-PCI). The aim of this investigation was to evaluate the percentage of STEMI patients with high on-treatment platelet reactivity (HPR) to clopidogrel at the time of initiating P-PCI and its association with the initial patency of the infarct-related artery (IRA). This prospective pharmacodynamic study included 50 STEMI patients, previously naïve to oral antiplatelet agents, who received 500-mg ASA and 600-mg clopidogrel loading doses prior to P-PCI. Platelet function assessment was performed at the beginning of the procedure using various assays, including VerifyNow™ system (primary endpoint), light transmission aggregometry and multiple electrode aggregometry. The percentage of patients with suboptimal response to clopidogrel and ASA assessed with the VerifyNow™ system was 88.0% and 28.6%, respectively. Similar results were obtained with the other assays used. A higher percentage of patients with initial patency of the IRA was observed among those patients without HPR compared with those with HPR to clopidogrel (66.7% vs 15.9%; p=0.013), while no differences were observed regarding postprocedural angiographic or electrocardiographic outcomes. In conclusion, this study shows that a high percentage of STEMI patients have inadequate levels of clopidogrel-induced and, to a lesser extent, aspirin-mediated platelet inhibition when starting a P-PCI procedure, and suggests that a poor response to clopidogrel might be associated with impaired initial TIMI flow in the IRA.
authors.affiliation: Director of Cardiovascular Research Lab, Heart Diseases Institute, Bellvitge University Hospital - IDIBELL, Feixa Llarga s/n. CP 08907, L'Hospitalet de Llobregat, Barcelona, Spain. jlferreiro@bellvitgehospital.cat
authors.forename: José Luis
authors.initials: JL
authors.lastname: Ferreiro
authors.forename: Sílvia
authors.initials: S
authors.lastname: Homs
authors.forename: Javier
authors.initials: J
authors.lastname: Berdejo
authors.forename: Gerard
authors.initials: G
authors.lastname: Roura
authors.forename: Josep
authors.initials: J
authors.lastname: Gómez-Lara
authors.forename: Rafael
authors.initials: R
authors.lastname: Romaguera
authors.forename: Luis
authors.initials: L
authors.lastname: Teruel
authors.forename: Guillermo
authors.initials: G
authors.lastname: Sánchez-Elvira
authors.forename: Ana Lucrecia
authors.initials: AL
authors.lastname: Marcano
authors.forename: Joan Antoni
authors.initials: JA
authors.lastname: Gómez-Hospital
authors.forename: Dominick J
authors.initials: DJ
authors.lastname: Angiolillo
authors.forename: Ángel
authors.initials: Á
authors.lastname: Cequier
mesh_terms: D001158:Arteries / Q000473:pathology* / Q000601:surgery; D000077144:Clopidogrel; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000628:therapy*; D062645:Percutaneous Coronary Intervention / Q000379:methods*; D015539:Platelet Activation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D011300:Preoperative Care; D015995:Prevalence; D011446:Prospective Studies; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D014654:Vascular Patency / Q000187:drug effects
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine