We propose a high risk/high impact study to develop an innovative circulatory support strategy using an implantable pump for the treatment of single functional ventricle. The most common form, hypoplastic left heart syndrome, in which the left ventricle fails to form in a way that is ever functional, is the leading cause of death from all birth defects in the first year of life. Currently, surgical repair is performed with three separate operations. In the first operation, blood flow to the lungs must be derived from a systemic-to-pulmonary arterial shunt to overcome the potentially elevated newborn pulmonary vascular resistance. The shunt, however, makes this procedure notorious for instability and mortality. In the second and third operations, the shunt is disconnected, and blood flow to the lungs is accomplished by connecting the vena cava to the pulmonary arteries. Stability and survival are greatly improved. Unfortunately, the second and third procedures cannot be safely performed in the newborn due to the unsolved obstacle of achieving passive blood flow through the reactive pulmonary circulation. We propose a unique application of a blood pump to temporarily augment flow from the great veins through the lungs until the potential for reactivity resolves. This process normally occurs most rapidly by 2 weeks and is nearly complete at 8 weeks of life. The problematic shunt is avoided, and the newborn pulmonary vessels are perfused by a low-pressure, high-volume flow from a systemic venous source similar to normal right ventricular hemodynamics. We hypothesize that under these conditions, the neonatal pulmonary arteries will mature normally. Once the transitional pulmonary vasculature has remodeled sufficiently to permit a systemic venous source to perfuse the lungs passively, the pump can be safely removed. We further hypothesize that the neonate will tolerate the systemic venous pressure elevation required to permit passive venous flow through the lungs. Using a newborn animal model of univentricular circulation, we will test these hypotheses through the following specific aim: To transition an assisted univentricular circulation (cavopulmonary pump + systemic ventricle) to an unassisted univentricular circulation in which the lungs are perfused by passive vena caval flow alone. We have generated pilot data which support feasibility of this innovative technique using currently available technology. We expect that successful completion of this approach will convert the current high risk three-stage surgical strategy to a much safer single-stage paradigm of newborn Fontan palliation of single ventricle cardiac disease.
| Rodefeld, Mark D; Frankel, Steven H; Giridharan, Guruprasad A (2011) Cavopulmonary assist: (em)powering the univentricular fontan circulation. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 14:45-54 |
| Myers, Cynthia D; Ballman, Kimberly; Riegle, Lindsay E et al. (2010) Mechanisms of systemic adaptation to univentricular Fontan conversion. J Thorac Cardiovasc Surg 140:850-6, 856.e1-6 |
| Rodefeld, Mark D; Coats, Brandon; Fisher, Travis et al. (2010) Cavopulmonary assist for the univentricular Fontan circulation: von Kármán viscous impeller pump. J Thorac Cardiovasc Surg 140:529-36 |
| Throckmorton, Amy L; Ballman, Kimberly K; Myers, Cynthia D et al. (2008) Performance of a 3-bladed propeller pump to provide cavopulmonary assist in the failing Fontan circulation. Ann Thorac Surg 86:1343-7 |
| Throckmorton, Amy L; Ballman, Kimberly K; Myers, Cynthia D et al. (2007) Mechanical cavopulmonary assist for the univentricular Fontan circulation using a novel folding propeller blood pump. ASAIO J 53:734-41 |
| Myers, Cynthia D; Mattix, Kelly; Presson Jr, Robert G et al. (2006) Twenty-four hour cardiopulmonary stability in a model of assisted newborn Fontan circulation. Ann Thorac Surg 81:264-70; discussion 270-1 |
