Mitral regurgitation is associated with similar loss of von Willebrand factor large multimers, but less anemia as compared to aortic stenosis

Background Various cardiovascular diseases cause acquired von Willebrand syndrome (AVWS), which is characterized by a decrease in high molecular weight (large) von Willebrand factor (VWF) multimers. Mitral regurgitation (MR) has been reported as a cause of AVWS. However, much remains unclear about AVWS associated with MR. Objectives To evaluate VWF multimers in MR patients and examine their impact on clinical characteristics. Methods Moderate or severe MR patients (n=84) were enrolled. VWF parameters such as the VWF large multimer index (VWF-LMI), a quantitative value that represents the amount of VWF large multimers, and clinical data were prospectively analyzed. Results At baseline, the mean hemoglobin level was 12.9 ± 1.9 g/dL and 58 patients (69.0%) showed loss of VWF large multimers defined as VWF-LMI < 80%. VWF-LMI in patients with degenerative MR exhibited lower than those with functional MR. VWF-LMI appeared to be restored the day after mitral valve intervention and the improvement was maintained 1 month after the intervention. Seven patients (8.3%) had a history of bleeding, 6 (7.1%) of whom had gastrointestinal bleeding. Gastrointestinal endoscopy was performed in 23 patients (27.4%) to investigate overt gastrointestinal bleeding, anemia, etc. Angiodysplasia was detected in 2 of the 23 patients (8.7%). Conclusion Moderate or severe MR is frequently associated with loss of VWF large multimers and degenerative MR may cause more severe loss compared to functional MR. Mitral valve intervention corrects the loss of VWF large multimers. Gastrointestinal bleeding may be relatively less frequent and hemoglobin level remains stable in MR patients.