Is balloon dilation a reasonable option for the palliation of Fallot's tetralogy?

PRIMARY CORRECTION, WITH LOW EARLY AND late mortality, is now the aim of many, if not most, leading centres for the management of Fallot's Tetralogy. The presence of a variety of risk factors, such as hypoplastic pulmonary arteries and coronary arterial abnormalities, makes this difficult to achieve. Yet other neonates, some with low weight at birth, present with severe hypoxia, making them poor candidates for open heart surgery. Most surgeons would agree that the presence of some of these risk factors is an indication for initial palliation rather than primary corrective surgery. Centres where the development of early primary open heart surgery in the first year is less well advanced will choose to palliate a higher proportion of patients. Until 1969, when Erickson and his associates demonstrated long term improvement and relief of cyanotic spells in selected patients following the administration of propranolol, the only reliable means of palliation was the surgical construction of an arterio-pulmonary anastomosis. Such palliative surgery carries low risk, and encourages growth of the pulmonary valve and pulmonary arteries. Arciniegas and colleagues were able to demonstrate that, in patients of comparable age, repair following a Blalock shunt carried a mortality not significantly higher than primary repair. Palliative operations, however, are not free of risk and complications. A recent report from Toronto demonstrated that pulmonary arterial hypoplasia and distortion are common after palliation by modified Blalock Taussig shunts. Even after excluding noncardiac causes of death, survival was only 90% in