title: Platelet function after cessation of chronic clopidogrel therapy.
abstract: Surgeons increasingly encounter patients on clopidogrel therapy who are preparing to undergo surgery. The goal of this study was to examine the change in platelet function after the common clinical scenario of discontinuing chronic clopidogrel therapy in those patients preparing to  undergo an elective surgery, and the time course of platelet function recovery after clopidogrel discontinuation. Patients on clopidogrel therapy scheduled for an elective surgical procedure had their platelet function tested using a VerifyNow P2Y12 device (Accumetrics, San Diego, CA). Platelet  inhibition was evaluated at baseline before clopidogrel discontinuation, and subsequently studied every other day in the week before their scheduled procedure. Mean platelet inhibition was 32.1 per cent on Day 0 (before clopidogrel discontinuation), decreasing to 3.7 per cent on Day 4. Platelet  inhibition decreased significantly after discontinuation of clopidogrel in a time-dependent manner (P = 0.011), although a considerable interindividual variability of P2Y12 reaction units values was observed over the study period. Patients on concomitant proton pump inhibitors and clopidogrel  demonstrated a decreased effect of clopidogrel. In conclusion, individual platelet function monitoring may assist the surgeon in perioperative decision-making in patients receiving clopidogrel therapy preparing to undergo elective surgery.
authors.affiliation: Department of Surgery, Beaumont Health System, Royal Oak, Michigan 48073, USA. pperaki1@hfhs.org
authors.forename: Peter G
authors.initials: PG
authors.lastname: Perakis
authors.forename: Tahir
authors.initials: T
authors.lastname: Yunus
authors.forename: Graham
authors.initials: G
authors.lastname: Long
authors.forename: Zulfiqar F
authors.initials: ZF
authors.lastname: Cheema
authors.forename: Robert
authors.initials: R
authors.lastname: Hammond
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Shanley
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000187:drug effects*; D000077144:Clopidogrel; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D008297:Male; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D010979:Platelet Function Tests; D011446:Prospective Studies; D054328:Proton Pump Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D012307:Risk Factors; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
chemical_list: D010975:Platelet Aggregation Inhibitors; D054328:Proton Pump Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine