title: Platelet reactivity in patients and recurrent events post-stenting: results of the PREPARE POST-STENTING Study.
abstract: OBJECTIVE
  We investigated the relation of high ex vivo platelet reactivity, rapid fibrin generation, and high thrombin-induced clot strength to postdischarge ischemic events in patients undergoing percutaneous coronary intervention (PCI).
  
  
  BACKGROUND
  High platelet reactivity and rapid fibrin generation may affect the incidence of ischemic events after PCI. However, limited data is available to link these ex vivo markers to the occurrence of events.
  
  
  METHODS
  We measured platelet reactivity to adenosine diphosphate (ADP) by light transmittance aggregometry (LTA) in patients undergoing PCI (n = 192). Clot strength, a measure of thrombin-induced fibrin and platelet interactions, and the time to initial fibrin generation, a marker of thrombin activity, were measured by thrombelastography. The relation of these measurements to ischemic event occurrence was prospectively examined over six months.
  
  
  RESULTS
  A total of 100% and 84% of patients were on aspirin and clopidogrel therapy, respectively, at the time of the initial event. Posttreatment ADP-induced aggregation by LTA (63 +/- 12% vs. 56 +/- 15%, p = 0.02) and clot strength (MA) were higher (74 +/- 5 mm vs. 65 +/- 4 mm, p < 0.001) and time to initial fibrin generation was shorter (4.3 +/- 1.3 min vs. 5.9 +/- 1.5 min, p < 0.001) in patients with events (n = 38). The event rates in the highest quartiles of LTA and MA were 32% and 58%, respectively.
  
  
  CONCLUSIONS
  High platelet reactivity and clot strength, and rapid fibrin formation are novel risk factors for ischemic events after PCI. Clot strength is more predictive than ADP-induced platelet aggregation and may explain the occurrence of events despite treatment with cyclooxygenase-1 and P2Y12 inhibitors.
authors.affiliation: Sinai Center for Thrombosis Research, Baltimore, Maryland 21215, USA. pgurbel@lifebridgehealth.org
authors.forename: Paul A
authors.initials: PA
authors.lastname: Gurbel
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Bliden
authors.forename: Kirk
authors.initials: K
authors.lastname: Guyer
authors.forename: Peter W
authors.initials: PW
authors.lastname: Cho
authors.forename: Kazi A
authors.initials: KA
authors.lastname: Zaman
authors.forename: Rolf P
authors.initials: RP
authors.lastname: Kreutz
authors.forename: Ashwani K
authors.initials: AK
authors.lastname: Bassi
authors.forename: Udaya S
authors.initials: US
authors.lastname: Tantry
mesh_terms: D015906:Angioplasty, Balloon, Coronary; D023903:Coronary Restenosis / Q000097:blood* / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015539:Platelet Activation; D011446:Prospective Studies; D012008:Recurrence; D015607:Stents