title: Effect of therapeutic plasma exchange on coagulation parameters in patients on warfarin.
abstract: Therapeutic plasma exchange (TPE) without plasma replacement results in coagulation factor removal. Warfarin decreases the activity of vitamin K dependent coagulation factors. The combined effect of TPE and warfarin on the coagulation system has not been studied. A prospective, observational study was conducted in patients undergoing TPE while on warfarin. One plasma volume TPEs were performed on the COBE Spectra Apheresis System (Terumo BCT, Lakewood, CO) with 5% albumin. International normalized ratio (INR), fibrinogen, and factor II activity were obtained pre and post procedure. Eight patients underwent 121 TPEs that met study criteria with pre and post data. The average pre values were INR 2.09 ± 0.58, fibrinogen 263 ± 76 mg/dl, and factor II 29 ± 16% and the average post values were INR 4.12 ± 1.44, fibrinogen 105 ± 31 mg/dl, and factor II 13 ± 7%. The pre-INR was ≥2.00 for 55% of TPEs. The pre value (Y0 ) predicts the post value (Y) by the following equations Y = -0.54 + 2.21Y0 , Y =12.10 + 0.35Y0, and Y =1.83 + 0.39Y0 for INR, fibrinogen, and factor II respectively. In conclusion, pre procedure laboratory values can predict the post laboratory values for patients on warfarin receiving single plasma volume TPE with albumin replacement. The post-INR is approximately twice the pre-INR. At normal and mildly elevated pre-INR, the effect of TPE on the INR is less marked. A single plasma volume TPE decreases the plasma level by ∼65% for fibrinogen and 60% for factor II.
authors.affiliation: Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota.
authors.forename: Nicole D
authors.initials: ND
authors.lastname: Zantek
authors.forename: Shanna
authors.initials: S
authors.lastname: Morgan
authors.forename: Paul F
authors.initials: PF
authors.lastname: Zantek
authors.forename: David C
authors.initials: DC
authors.lastname: Mair
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Bowman
authors.forename: Agnes
authors.initials: A
authors.lastname: Aysola
mesh_terms: D000328:Adult; D000925:Anticoagulants / Q000627:therapeutic use*; D001777:Blood Coagulation / Q000187:drug effects*; D005260:Female; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D019934:International Normalized Ratio; D008297:Male; D008875:Middle Aged; D010951:Plasma Exchange; D011446:Prospective Studies; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin; D005340:Fibrinogen
keywords: International Normalized Ratio; apheresis; coumadin; factor II; fibrinogen