Von Willebrand factor and mitral valve prolapse.

The levels of von Willebrand factor (vWF:Ag) were measured in 27 patients with mitral valve prolapse (MVP) and compared to 27 age matched controls. Decreased levels of vWF:Ag (less than 80%) were found in 59% (16/27) of those with MVP compared to only 7% (2/27) of the controls (p less than 0.001). Mean vWF: Ag levels were also significantly lower in those with MVP (68 +/- 30% versus 100 +/- 23%, p less than 0.001). In those with MVP and congestive heart failure secondary to rupture chordae tendineae, however, the mean level of vWF: Ag was not significantly different from control values (95 +/- 32). There was an increased incidence of recurrent nose bleeds in those with MVP and low levels of vWF:Ag. We conclude that there is a relationship between MVP and low levels of vWF:Ag which may explain the increased incidence of epistaxis in such patients. Increased release of vWF:Ag in those with MVP and concomitant congestive heart failure may account for the normal levels found in this subgroup.