Congestive heart failure affects 5 million people in the United States, and over 60,000 are diagnosed with end-stage heart failure. Treatment options for these individuals are extremely limited. Because of a limited supply of donor organs, fewer than 3,000 people receive heart transplants each year. LVADs are battery-operated devices that can act as a temporary solution until a donor heart becomes available. Upon being surgically implanted into a weakened heart, the LVAD mechanically pumps blood from the heart to the rest of the body. There are, however, serious risks associated with LVADs, including infection, blood clots, and stroke. Early removal of the LVAD may be possible by injecting stem cells to regenerate new heart cells and improve heart function. The purpose of this study is to compare the safety and effectiveness of two types of bone marrow cells -- bone marrow mononuclear cells (BMCs) and immunoselected CD34+ hematopoietic stem cells -- in improving heart function in individuals with end-stage heart failure.~This study will enroll individuals undergoing surgery to receive an LVAD. Participants will be randomly assigned to one of following three groups:~Group 1 (n=30): participants will undergo intramyocardial injection of bone marrow mononuclear cells (BMCs) during LVAD implantation~Group 2 (n=30): participants will undergo intramyocardial injection of immunoselected CD34+ hematopoietic stem cells during LVAD implantation~Group 3 (n=15): participants will undergo LVAD implantation~Prior to LVAD implantation, participants in Groups 1 and 2 will have a sample of bone marrow removed. Following LVAD implantation, study visits will occur at Days 45 and 90, and then every 60 days thereafter until participants receive a heart transplant. At each visit, participants will undergo a LVAD wean procedure, during which the mechanical pump of the LVAD will be gradually turned off, and the LVAD will be operated with a hand pump. The length of time that a participant tolerates the wean procedure will be evaluated. Heart size and function, blood flow, and nerve function will also be assessed. Some participants will undergo a 6-minute walk test. At the time of heart transplant surgery, the LVAD will be removed, and heart cell regeneration and heart function will be evaluated.
Heart failure is a condition in which the heart is unable to pump enough blood to the body's other organs. A heart transplant may be necessary for some individuals with end-stage heart failure. Left ventricular assist devices (LVADs) can assist the heart in pumping blood, and are commonly used until a donor heart becomes available. Bone marrow cells injected into the heart may improve heart function and may lead to earlier LVAD removal. The purpose of this study is to evaluate the safety and effectiveness of injected bone marrow cells in improving heart function in individuals with LVADs who are awaiting heart transplants.