Haematologica 2004;89: supplement no. 8 - Supplements ...

140PostersPostersANTIPLATELET THERAPYPO-089HIGH RATE OF NON RESPONDERS TO ASPIRIN AND/ORCLOPIDOGREL TREATMENT IN THE FIRST DAYS FOLLOWINGPERCUTANEOUS CORONARY INTERVENTIONS: AN EX VIVOSTUDYPaniccia R, Tellini I, Costanzo M, Valente S,Lombardi A, Giglioli C, Lazzeri C, Prisco D,Gensini GF, Abbate RDip. Area Critica Medico-Chirurgica, Universitàdegli Studi di Firenze; Dip. del Cuore e dei Vasi,Azienda Ospedaliero-Universitaria Careggi,Florence, ItalyAspirin (ASA) therapy following both acutemyocardial infarction (AMI) and acute coronary syndromes(ACS) has been shown to reduce the relativerisk of recurrent vascular events and death. However,the inhibition of platelet function by ASA is notuniform among patients and this may be relevantfor the occurrence of new ischemic events. Recently,PFA-100 (Dade Behring, Germany) closure time(CT) has been suggested as a possible tool to identifyASA-resistant patients. Aim of this study was toinvestigate the response to ASA+clopidogrel treatmentin 60 patients with AMI or ACS after PCI, byassessing PFA-100 CTs by collagen+epinephrine(CT/EPI) and collagen+ADP (CT/ADP) cartridges. Allpatients were treated with 325 mg ASA once a dayand clopidogrel - 300 mg bolus immediately beforethe procedure followed by 75 mg/day. Citrated bloodsamples were taken 5-36 hrs after the procedure and(in 42/60 patients) also 4-5 days after the PCI. Acontrol group of 101 healthy subjects, who had nottaken any antiplatelet agent for 15 days before bloodsampling, was also studied. ASA and clopidogrelresponders were defined respectively as patients witha CT/EPI and a CT/ADP over the 95th percentile valuein the control group (CT/EPI >203 s and CT/ADP>139 s). Five to 36 hrs after PCI, 14/60 patients(23%) had normal CT/EPI values and 42/60 patients(70%) had normal CT/ADP values. Eighteen out of 60patients (31%) showed both CTs prolonged, whereas13/60 patients (22%) had both CTs in the normalrange. Four to 5 days after PCI, 16/42 patients (38%)had normal CT/EPI values. Ten of these 16 patientshad had prolonged CT/EPI values 5-36 hrs after theprocedure. Thirty-five out of 42 patients (83%) hadnormal CT/ADP values. Eight of these 35 patients hadhad prolonged CT/ADP values 5-36 hrs after the procedure.In conclusion, short-term antiplatelet treatmentwith combination of ASA and clopidogrel doesnot prolong PFA-100 CTs in a relevant proportion ofAMI and ACS patients. If this lack of ex vivo responsivenessto ASA and/or clopidogrel is related to anincreased risk of medium–term cardiovascular complicationsshould be assessed by further studies.PO-090ASPIRIN RESISTANCE IN PATIENTS UNDERGONE CAROTIDENDOARTERIECTOMY AND RE-STENOSIS: PRELIMINARY DATARuzzon E, Randi Ml, Tezza F, Toldo C, Gallo S,Fabris FDept. of Medical and Surgical Sciences, Universityof Padua Medical School, ItalyAspirin antiplatelet effect is not uniform in allpatients. Aspirin resistance occurs in about 30% ofpatients with thromboembolic vascular eventsdespite therapeutic doses of aspirin. We report thedata of 27 patients (6 females and 21 males, meanage 66±9.5 years) who underwent endoarteriectomybecause carotid symptomatic stenosis and treatedwith Aspirin 100 mg/day for at least 6 months. Thepatients were divided in two groups A) patients whoexperienced a re-stenosis B) patients without restenosis.We performed aggregation study with Bornmethod in all patients during Aspirin treatment andin 6 normal subjects matched for sex and age treatedwith low-dose Aspirin for at least 15 days. Aggregationwas considered to be reduced if < 40% withADP and