title: The PFA-100 detects sub-optimal antiplatelet responses in patients on aspirin.
abstract: Although it is suspected that some patients with acute coronary syndromes (ACS) could have a sub-optimal response to aspirin (SASAR), currently a fixed dose of ASA is long-term used in all individuals. This study was designed to determine SASAR and whether a SASAR is a predictor for recurrence of ischemic events in patients on low-dose ASA with a previous ACS. One hundred patients taking ASA 100 mg/day were assessed at 1 and 6 months after a first ACS. SASAR was initially defined as a failure of the ASA treatment to significantly prolong the closure time in the Platelet Function Analyzer (PFA-100). SASAR in these samples was reconfirmed by conventional aggregometry. TXB2 levels were determined in plasma. At one month 49 patients showed SASAR in the PFA-100; only 25 of them showed SASAR by conventional aggregometry. At six months, 39 of 81 patients showed SASAR by PFA-100, but conventional aggregometry detected SASAR in only 12 of the 39 patients. TXB2 levels were significantly higher in patients with SASAR. Five patients with SASAR, by both tests, died during follow-up (p = 0.013). The PFA-100 detected a high rate of SASAR in patients with ACS. This instrument could be used to screen for suboptimal response to the antiplatelet action of ASA. Whether persistence of SASAR could relate to a higher risk of recurrence and how adjusting the dose of ASA could reduce the rate of SASAR are issues that deserve further investigations.
authors.affiliation: Cardiovascular Institute, University of Barcelona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Sambola
authors.forename: M
authors.initials: M
authors.lastname: Heras
authors.forename: G
authors.initials: G
authors.lastname: Escolar
authors.forename: M
authors.initials: M
authors.lastname: Lozano
authors.forename: M
authors.initials: M
authors.lastname: Pino
authors.forename: T
authors.initials: T
authors.lastname: Martorell
authors.forename: M
authors.initials: M
authors.lastname: Torra
authors.forename: G
authors.initials: G
authors.lastname: Sanz
mesh_terms: D001241:Aspirin / Q000008:administration & dosage*; D016022:Case-Control Studies; D003327:Coronary Disease / Q000097:blood* / Q000188:drug therapy; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D010979:Platelet Function Tests / Q000295:instrumentation*; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin