Repair of Tetralogy of Fallot (TOF)

Tetralogy of Fallot is the most common cyanotic ("blue baby") heart defect. It has four parts: a hole between the ventricles (VSD), narrowing at or below the pulmonary valve that blocks blood leaving the right ventricle, an aorta that sits over the VSD, and a thickened right ventricle. Because blood has trouble reaching the lungs, oxygen-poor blood crosses the VSD into the aorta, and the child may have sudden spells of deep cyanosis (tet spells). Without repair, few patients survive to adulthood. Complete repair closes the VSD with a patch and opens the right ventricular outflow tract by cutting away obstructing muscle, opening a fused pulmonary valve and, when needed, widening the outflow tract or the pulmonary valve ring with a patch. It is done through a median sternotomy on cardiopulmonary bypass, most often in the first year of life. Some infants first have a palliative shunt between a systemic artery and the pulmonary artery to increase lung blood flow until full repair. Surgeons increasingly work through the right atrium and pulmonary artery to avoid a large cut in the ventricle, and some anatomy requires a conduit from the right ventricle to the pulmonary artery. The setup is an open-heart setup with pediatric-sized instruments and several patches. Risks include heart block from stitches near the conduction system, bleeding, residual obstruction or leak, rhythm problems and infection. Warming, accurate tracking of irrigation and blood loss, and patch materials ready on time are key for the scrub.