REGULAR ARTICLE The effect of uremia on platelet contractile force, clot elastic modulus and bleeding time in hemodialysis patients Donald F. Brophy a,b,c, * , Erika J. Martin c,d , Sheryl L. Carr c , Barry Kirschbaum b , Marcus E. Carr Jr. b,c,d a Department of Pharmacy, Virginia Commonwealth University, Richmond, VA, United States b Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, United States c Coagulation Special Studies Laboratory, Virginia Commonwealth University, Richmond, VA, United States d Hemodyne, Inc., Richmond, VA, United States Received 11 November 2005; received in revised form 21 February 2006; accepted 28 February 2006 Available online 21 June 2006 Abstract Introduction: Uremic bleeding frequently occurs in dialysis patients. Although its mechanism is not well characterized, acquired platelet dysfunction has been implicated in its pathogenesis. Skin bleeding time has been used to characterize platelet dysfunction in this population. However, the bleeding time is prone to error. The goal of this study was to compare the bleeding time to the novel platelet function parameters platelet contractile force and clot elastic modulus as well as platelet aggregation studies in controls and patients receiving maintenance hemodialysis. Materials and methods: Forty-five subjects completed this study (25 controls, 20 dialysis). All subjects had the Ivy skin bleeding time procedure performed, as well as the collection of whole blood samples for the determination of platelet contractile force, clot elastic modulus, % von Willebrand Factor antigen, and platelet aggregation studies. Pearson’s correlation determined the relationships between 0049-3848/$ - see front matter D 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.thromres.2006.02.013 Abbreviations: ADP, adenosine diphosphate; BUN, blood urea nitrogen; CEM, clot elastic modulus; CKD, chronic kidney disease; Da, daltons; ESRD, end-stage renal disease; NS, not significant; PCF, platelet contractile force; PPP, platelet poor plasma; PRP, platelet rich plasma; SEM, standard error of the mean; vWF:Ag, von Willebrand factor antigen. * Corresponding author. Virginia Commonwealth University, PO Box 980533, Richmond, VA 23298-0533, United States. Tel.: +1 804 827 1455; fax: +1 804 828 8359. E-mail address: dbrophy@vcu.edu (D.F. Brophy). KEYWORDS Uremia; Platelet contractile force; Clot retraction; Clot elastic modulus; Platelet aggregation; Bleeding time Thrombosis Research (2007) 119, 723 — 729 intl.elsevierhealth.com/journals/thre