title: Role of the laboratory in monitoring patients receiving dual antiplatelet therapy.
abstract: BACKGROUND
  The increasing demand for therapeutic monitoring in patients receiving antiplatelet therapy has been paralleled by the development of instruments and tests whose clinical usefulness is still under debate. We devised a laboratory approach to detect patients with antiplatelet resistance at risk to develop thrombotic events.
  
  
  METHODS
  One hundred and eighty patients, under aspirin and clopidogrel after angioplasty and stent implantation, were studied by PFA100(®) with collagen/epinephrine (CoEPI, cutoff 165s) cartridge and by Multiplate(®) using arachidonic acid (ASPItest, pos < 862AUC), ADP (ADPtest, pos < 417AUC), and collagen (COLtest, pos < 607AUC).
  
  
  RESULTS
  Only 67 of 173 patients with ASPI < 862 displayed a prolonged CoEPI and up to 65 patients had normal CoEPI despite ASPI < 300. Patients with ASPI < 300 had significantly lower COL than patients with ASPI > 300. One hundred and thirty-eight patients displaying ADP < 417 had significantly lower COL than those with ADP > 417. Association between COL and ADP remained after ASPI stratification: in patients with suboptimal (ASPI 300-892) or maximal (ASPI < 300) response to aspirin, having ADP < 417 (clopidogrel responsive) increased COL positivity, respectively, from 9.5 to 58.8% and from 47.6 to 82.7%.
  
  
  CONCLUSIONS
  A combination of specific tests may be useful in identifying higher-risk patients with poor compliance or drug resistance who potentially may benefit from therapy change.
authors.affiliation: Clinical Chemistry Unit, Maggiore della Carità Hospital, Novara, Italy. vidali@med.unipmn.it
authors.forename: M
authors.initials: M
authors.lastname: Vidali
authors.forename: R
authors.initials: R
authors.lastname: Rolla
authors.forename: M
authors.initials: M
authors.lastname: Parrella
authors.forename: C
authors.initials: C
authors.lastname: Cassani
authors.forename: M
authors.initials: M
authors.lastname: Manzini
authors.forename: M R
authors.initials: MR
authors.lastname: Portalupi
authors.forename: R
authors.initials: R
authors.lastname: Serino
authors.forename: M D
authors.initials: MD
authors.lastname: Prando
authors.forename: G
authors.initials: G
authors.lastname: Bellomo
authors.forename: P
authors.initials: P
authors.lastname: Pergolini
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty; D001241:Aspirin / Q000627:therapeutic use*; D019411:Clinical Laboratory Techniques / Q000295:instrumentation / Q000379:methods*; D000077144:Clopidogrel; D004351:Drug Resistance; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic / Q000295:instrumentation / Q000379:methods*; D015999:Multivariate Analysis; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D010979:Platelet Function Tests / Q000295:instrumentation / Q000379:methods; D019095:Point-of-Care Systems; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents; D013927:Thrombosis / Q000097:blood / Q000175:diagnosis; D013988:Ticlopidine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D010975:Platelet Aggregation Inhibitors; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin