This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A total of 20 heart failure patients will undergo vascular testing (dependent and independent vasodilation) to assess the longitudinal affects of cardiac transplantation and LVAD support on the peripheral circulation. The 20 subjects will be separated into 2 groups of 10: those who received LVAD support prior to cardiac transplantation and those who did not. Approximately eight vascular tests will be conducted on each participant, lasting 45 to 60 minutes each. The first vascular measure will take place in the GCRC prior to cardiac transplantation. Due to unknown cardiac transplant wait times, this test will be repeated every three months until cardiac transplantation has taken place. One week post cardiac transplantation, a vascular test will be conducted bed side (Fairview Hospital) with the mobile ultrasound. Six more vascular tests will be conducted at the GCRC on a monthly basis with the final test taking place 6 months post-transplant. At the time of cardiac transplantation, a cardiac muscle biopsy will be taken from the apex of the explanted heart to compare the quality of myocardial proteins with the changes seen in endothelial function following cardiac transplantation. This pilot study will examine the time course for improvements in endothelial function, helping pinpoint which month post-transplant is optimal for measuring vascular changes.