This study is a prospective, single-center Phase II trial of Neumega (rhIL-11) in adults with type 1 VWD undergoing elective surgery or major dental procedure. It is anticipated that 10 subjects who meet eligibility criteria will enroll and complete the study. The specific objectives are to determine the efficacy and safety or rhIL-11 during and after elective surgery, and to determine the mechanism of the hemostatic response of rhIL-11.