title: Prognostic significance of post-clopidogrel platelet reactivity assessed by a point-of-care assay on thrombotic events after drug-eluting stent implantation.
abstract: OBJECTIVE
  The aim of this study was to determine whether platelet reactivity on clopidogrel therapy, as measured by a point-of-care platelet function assay, is associated with thrombotic events after percutaneous coronary intervention (PCI) with drug-eluting stents (DESs).
  
  
  RESULTS
  Platelet reactivity on clopidogrel (post-treatment reactivity) was measured with the VerifyNow P2Y12 assay (Accumetrics Inc., San Diego, CA, USA) in 380 patients undergoing PCI with sirolimus-eluting stents. Receiver-operating characteristic curve analysis was used to derive the optimal cut-off value for post-treatment reactivity in predicting 6 month out-of-hospital cardiovascular (CV) death, non-fatal MI, or stent thrombosis. The mean post-treatment reactivity was 184 +/- 85 PRU (P2Y12 reaction units). The optimal cut-off for the combined endpoint was a post-treatment reactivity > or =235 PRU [area under the curve 0.711 (95% confidence interval 0.529-0.893), P = 0.03], which was similar to the threshold of the upper tertile (231 PRU). Patients with post-treatment reactivity greater than the cut-off value had significantly higher rates of CV death (2.8 vs. 0%, P = 0.04), stent thrombosis (4.6 vs. 0%, P = 0.004), and the combined endpoint (6.5 vs. 1.0%, P = 0.008).
  
  
  CONCLUSIONS
  High post-treatment platelet reactivity measured with a point-of-care platelet function assay is associated with post-discharge events after PCI with DES, including stent thrombosis. Investigation of alternative clopidogrel dosing regimens to reduce ischaemic events in high-risk patients identified by this assay is warranted.
authors.affiliation: Division of Cardiovascular Diseases, Scripps Clinic, 10666 North Torrey Pines Road, Maildrop S1056, La Jolla, CA 92037, USA. price.matthew@scrippshealth.org
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Price
authors.forename: Sarah
authors.initials: S
authors.lastname: Endemann
authors.forename: Raghava R
authors.initials: RR
authors.lastname: Gollapudi
authors.forename: Rafael
authors.initials: R
authors.lastname: Valencia
authors.forename: Curtiss T
authors.initials: CT
authors.lastname: Stinis
authors.forename: Justin P
authors.initials: JP
authors.lastname: Levisay
authors.forename: Alissa
authors.initials: A
authors.lastname: Ernst
authors.forename: Neil S
authors.initials: NS
authors.lastname: Sawhney
authors.forename: Richard A
authors.initials: RA
authors.lastname: Schatz
authors.forename: Paul S
authors.initials: PS
authors.lastname: Teirstein
mesh_terms: D000368:Aged; D015906:Angioplasty, Balloon, Coronary / Q000379:methods*; D000077144:Clopidogrel; D023921:Coronary Stenosis / Q000401:mortality / Q000628:therapy*; D003328:Coronary Thrombosis / Q000517:prevention & control*; D054855:Drug-Eluting Stents; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D019095:Point-of-Care Systems; D011379:Prognosis; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine