Changes in von Willebrand factor and ADAMTS-13 in patients following arthroplasty

Abstract

The glycoprotein, von Willebrand factor (VWF) is a carrier protein for factor VIII. When bound to platelets and the extracellular matrix, it promotes aggregation or adhesion of platelets to areas of vascular damage. A disintegrin and metalloproteinase with thrombospondin motif, member 13 (ADAMTS13) cleaves between the tyr1605 and met1606 residues in the central A2 domain of VWF decreasing its activity. The levels of ADAMTS13 and VWF are positively correlated with the risk of developing thrombosis and inversely correlated with the risk of bleeding. A total of 93 patients were observed, who underwent total hip arthroplasty or total knee arthroplasty. Blood samples were collected preoperatively and on postoperative days (PODs) 1, 2, 3, 5 and 7. Plasma levels of the ADAMTS13 antigen were determined using western blotting. The proteolytic activity was validated with the FRETS-VWF73 assay. VWF:Ag and VWF:RCo activity were measured using an enzyme-linked immunosorbent assay. Prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), antithrombin III and plasma fibrinogen levels were measured on a Sysmex® CA500 system with corresponding reagents. D-dimer levels were measured on a STA-R fully automated coagulation analyzer. The results demonstrated that, the levels of VWF antigen and activity in the patient increased from postoperative day (POD) 1. By contrast, the level of the ADAMTS13 antigen and its activity in the patients decreased significantly. Starting on POD1, fibrinogen and D-dimer levels increased. No significant changes were observed in PT, APTT and TT. It was concluded that the ADAMTS13 and VWF levels exhibited a marked association with thrombosis risk. The levels of ADAMTS13 and VWF may be potentially useful as markers for predicting thrombotic complications following arthroplasty and inhibiting the activity of VWF may be a novel prophylaxis to reduce postoperative deep venous thrombosis and pulmonary embolism.