Congenital heart disease – Repair or Palliate?

Congenital Heart Disease (CHD) in infants presents as inadequate systemic or pulmonary blood flow, or heart failure from intra-cardiac shunts. Approaches to surgical intervention comprise primary repair, early palliation with subsequent repair or definitive palliation.  CHD palliation evolved in the pre-cardiopulmonary bypass era. In 1938 a patent ductus arteriosus was ligated, in 1944 pulmonary blood flow was established via subclavian artery to pulmonary artery anastomosis (Blalock, Taussig and Thomas), and in 1952 pulmonary artery banding was employed to protect pulmonary vasculature. In the 1950s-60s symptomatic infants underwent these palliative procedures with reparative intra-cardiac interventions delayed due to perceived risk. In the late 1960s emerging publications shifted the focus to early primary repair.   An exponential increase in the complexity of surgical repairs over the past 50 years have built on early innovation, exemplified by management of transposition of the great arteries. Surgical approach transitioned from palliative atrial switch procedures (Senning 1957 and Mustard 1963) with low early mortality but impressive late morbidity to the reparative arterial switch procedure (Jatene 1975) which remains standard of care.  Despite advances in the field, biventricular repair is not an option for all patients. Children born with a single functional left ventricle benefited from staged palliative procedures to the Fontan circulation. First described in 1971, the Fontan procedure established passive pulmonary blood flow, using the single ventricle for systemic circulation. Further innovation by Norwood (1981) facilitated similar staged palliation of patients with single right ventricles. While for most patients with functionally univentricular CHD, staged palliation is dictated by underlying anatomy, it is increasingly recognized that a proportion of these patients may have anatomy and physiology amenable to biventricular circulation.   As we embark on the next era of innovation in CHD, patient selection, multicenter collaboration and meaningful outcome measures are challenges to be addressed.