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Table 13A.1. Indications for cardiac transplantation at Children's Memorial Hospital 1988-2003

Diagnosis # Patients

Infants

Hypoplastic Left Heart Syndrome 19 Children

Cardiomyopathy 51

Congenital structural disease, s/p failed surgical repair 26

Graft coronary disease 3

TOTAL 99

Table 13A.1. Table 13A.2 shows the broad indications by age group from the International Society for Heart and Lung Transplantation (ISHLT) Pediatric Registry.5

Pretransplant Evaluation

The diagnosis of hypoplastic left heart syndrome (HLHS) is made by echocardiography (ECHO), these babies do not usually require cardiac catheterization. The initial medical support of these infants is quite specific and not intuitively obvious. Prostaglandin (PGE1) is infused at 0.05 mcg/kg/min to maintain patency of the ductus arteriosus. The key to successful hemodynamic management is to maintain a delicate balance between the systemic and pulmonary vascular resistance. The FiO2 is kept low (often at 0.21) to maintain the systemic arterial oxygen saturation at 75-80%. Higher 02 concentrations will lead to a decrease in pulmonary vascular resistance (PVR), with too much pulmonary blood flow at the expense of decreased systemic perfusion. This may, in some cases, require a decrease in the inspired FiO2 to 18%. The ventilation is controlled to maintain a pCO2 of45-55 mm Hg, again to keep the PVR elevated and maintain systemic perfusion.

For older children with cardiomyopathy or status post failed conventional cardiac procedures, cardiac catheterization is critical to determine the child's pulmonary vascular resistance (PVR) index and transpulmonary artery gradient (TPG). PVRI(units/m2) = Mean PAP (mm Hg)-PAWP (mm Hg)

CI(L/min/m2) TPG (mm Hg) = Mean PAP (mm Hg)-PAWP (mm Hg) PAP = Pulmonary artery pressure, PAWP = Pulmonary artery wedge pressure CI = Cardiac Index

After a prolonged period of time with congestive heart failure, many pediatric patients will have an elevated PVR. The pharmacologic reduction of the pretransplant PVR with vasodilator therapy (nitric oxide, milrinone, nitroglycerine, etc.) accurately predicts what the PVR will be after cardiac transplant.7 If the PVR is above 6 units/m2 and/or the TPG > 15 mm Hg, and the PVR is unresponsive to vasodilator therapy, heart transplantation may result in donor right ventricular failure with recipient death. For children with cardiomyopathy, many will

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