Acquired and reversible von Willebrand disease with high shear stress aortic valve stenosis

Background. Severe aortic valve stenosis is relatively more prevalent in patients with repeated bleeding episodes. The goal of the present study was to determine the effect of aortic valve replacement on von Willebrand factor levels in patients with aortic stenosis. Methods. Von Willebrand factor levels were assessed by using immunoblotting electrophoresis techniques before and 1 month after surgery in 29 consecutive patients with severe aortic valve stenosis. Results. Eight of 29 patients reported episodes of bleeding, including three episodes of major bleeding, in the 6 months before surgery. None of the patients were receiving anticoagulation therapy. Although there was no difference in platelet count before and after surgery, von Willebrand factor levels were significantly greater at 1 month after surgery (p = 0.05) when compared with preoperative values. Further, von Willebrand factor levels were significantly lower in patients with aortic valve prosthesis mismatch than in those patients without this phenomenon (p < 0.05). Electrophoresis experiments showed a deficit in large multimers of von Willebrand factor preoperatively but not postoperatively, except for in those patients with aortic valve prosthesis mismatch. Conclusions. In conclusion, valve replacement can result in increases in von Willebrand factor in patients with aortic valve stenosis.