▪ Echocardiogram ▪ Cardiac catheterization (hemodynamics, anatomy) ▪ MRI/MRA or CT angiography (anatomy) ▪ Exercise test ▪ Vascular ultrasound ▪ Blood group ▪ Human leukocyte antigen antibody testing ▪ Chemistry ▪ Renal function ▪ Liver function ▪ Lipid profile ▪ Immunoglobulins ▪ Hematology ▪ Infectious serologies Following a thorough review of the patient's data, consultations, and psychosocial assessment, the interdisciplinary team will determine if the patient is an appropriate transplant candidate, not an appropriate candidate (e.g., “too well” or “too sick”), or if further testing or consultations are required to make a determination Indications There are no absolute indications for transplantation of the heart during childhood, given the wide variability in cardiac diagnoses and pathophysiology Indications can be broadly divided into two groups, either lifesaving (Box 67.2) or life-enhancing Life-enhancing indications include treatment of excessive disability; unacceptably poor quality of life, usually in the setting of poor myocardial function; complex unoperated congenital heart disease; and failed surgical treatment Updated guidelines for listing for cardiac transplantation have recently been published by the ISHLT.21 Box 67.2 Lifesaving Indications for Heart Transplantation ▪ End-stage myocardial failure due to ▪ Cardiomyopathy or myocarditis ▪ Congenital heart disease ▪ Postcardiotomy heart failure ▪ Malignant arrhythmias refractory to medical therapy ▪ Complex congenital heart disease with no options for surgical palliation at an acceptable risk ▪ Unresectable cardiac tumors causing obstruction or ventricular dysfunction ▪ Unresectable ventricular diverticula Contraindications The contraindications to heart transplantation during childhood include fixed pulmonary hypertension, pulmonary venous atresia or progressive stenosis, and severe hypoplasia of the pulmonary arteries or the thoracic aorta Other contraindications include irreversible failure of multiple organs, a progressive systemic disease with early mortality independent of cardiac function, active infection, malignancy, morbid obesity, diabetes mellitus with end-organ damage, hypercoagulable states, and severe chromosomal, neurologic, or syndromic abnormalities Complicating factors that are no longer considered contraindications to heart transplantation include multispecific and high sensitization to human leukocyte antigen (HLA); intellectual disabilities; complex congenital cardiac disease such as abnormalities of atrial arrangement; systemic venous abnormalities; anomalous pulmonary venous drainage without stenosis and some pulmonary arterial anomalies; previous sternotomy or thoracotomy; reversible pulmonary hypertension or more minor noncardiac congenital abnormalities; kyphoscoliosis with restrictive pulmonary disease; nonprogressive or slowly progressive systemic diseases with life expectancies into the third or fourth decade, such as genetic or metabolic cardiomyopathies; and diabetes mellitus without end-organ damage Elevated pulmonary vascular resistance historically has been an independent risk factor for death both early and late after transplantation.22,23 The threshold precluding transplantation is poorly defined, since there is a continuum of increasing risk as pulmonary vascular resistance rises By convention, a pulmonary vascular resistance of greater than 6 Wood units per meter squared has been considered a contraindication based on historical data.22,23 These studies, however, showed that it is the reactivity of the vascular bed, as opposed to the absolute measure of resistance, that is correlated with outcome There is a role, therefore, for testing pulmonary vasoreactivity as part of the assessment prior to transplantation Nonetheless, accurate assessment of pulmonary vascular resistance and/or vasoreactivity with any diagnosis of functionally univentricular physiology, some complex malformations with variable sources of flow of blood to the lungs, or restrictive cardiomyopathy may be challenging More recent data show no difference in mortality in patient with elevated pulmonary vascular resistance.24,25