title: Comparison of the CoaguChek XS handheld coagulation analyzer and conventional laboratory methods measuring international normalised ratio (INR) values during the time to therapeutic range after mechanical valve surgery.
abstract: OBJECTIVE
  To compare the international normalised ratio (INR) value of patients evaluated using the CoaguChek XS versus conventional laboratory methods, in the period after open-heart surgery for mechanical valve replacement until a therapeutic range is achieved using vitamin K antagonists (VKA) together with low molecular weight heparin (LMWH).
  
  
  METHODS
  One hundred and five patients undergoing open-heart surgery for mechanical valve replacement were enrolled. Blood samples were collected from patients before surgery, and on the second and fifth postoperative days, simultaneously for both the point of care device and conventional laboratory techniques. Patients were administered VKA together with LMWH at therapeutic doses (enoxaparin 100 IU/kg twice daily) subcutaneously, until an effective range was achieved on approximately the fifth day after surgery.
  
  
  RESULTS
  The mean INR values using the CoaguChek XS preoperatively and on the second and fifth days postoperatively were 1.20 (SD ± 0.09), 1.82 (SD ± 0.45), and 2.55 (SD ± 0.55), respectively. Corresponding results obtained using conventional laboratory techniques were 1.18 (SD ± 0.1), 1.81 (SD ± 0.43), and 2.51 (SD ± 0.58). The correlation coefficient was r = 0.77 preoperatively, r = 0.981 on postoperative day 2, and r = 0.983 on postoperative day 5.
  
  
  CONCLUSIONS
  Results using the CoaguChek XS Handheld Coagulation Analyzer correlated strongly with conventional laboratory methods, in the bridging period between open-heart surgery for mechanical valve replacement and the achievement of a therapeutic range on warfarin and LMWH.
authors.affiliation: Cardiovascular Surgery Clinic, Türkiye Yüksek İhtisas Education and Research Hospital, Ankara, Turkey.
authors.forename: Hasmet
authors.initials: H
authors.lastname: Bardakci
authors.forename: Garip
authors.initials: G
authors.lastname: Altıntaş
authors.forename: Omer Faruk
authors.initials: OF
authors.lastname: Çiçek
authors.forename: Umit
authors.initials: U
authors.lastname: Kervan
authors.forename: Sevinc
authors.initials: S
authors.lastname: Yilmaz
authors.forename: Sadi
authors.initials: S
authors.lastname: Kaplan
authors.forename: Cemal Levent
authors.initials: CL
authors.lastname: Birincioglu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D017984:Enoxaparin / Q000008:administration & dosage; D005260:Female; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D019934:International Normalized Ratio / Q000295:instrumentation*; D007431:Intraoperative Complications / Q000097:blood*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014812:Vitamin K / Q000037:antagonists & inhibitors*; D014859:Warfarin / Q000008:administration & dosage*
chemical_list: D000925:Anticoagulants; D017984:Enoxaparin; D014812:Vitamin K; D014859:Warfarin