Pulmonary Atresia

PA/IVS occurs in 3% of all CHD and has a prevalence of 0.07:1000 live births.

PA/VSD occurs in 3.4% of all CHD.

20% of all cases of TOF are physiologically similar to PA/VSD due to extreme pulm artery stenosis.

Males are affected more than females.

RV failure (due to volume overload, pressure overload or both)

Hypoxemia (leading to metabolic acidosis)

Myocardial ischemia secondary to aberrant coronary circulation

RV-dependent coronary circulation in PA/IVS (rapid boluses of fluid through central line may precipitate myocardial ischemia).

Maintain a patent ductus arteriosus (continue prostaglandin infusion).

“Suicide RV” is sudden release of pulm valve obstruction leading to hyperdynamic RV and subpulmonic obstruction of RV outlet. Treatment involves a β blockade.

Hyperventilation and hyperoxia when excess “pulmonary-steal,” leading to low cardiac output syndrome and necrotizing colitis (maintain oxygen saturation to 70–80%), mainly in PA/VSD.

Physiologically, PA/IVS and PA/VSD present as two extremes of the same spectrum. Usually associated with other cardiac lesions (e.g., patent foramen ovale, patent ductus arteriosus, possible VSD, ASD).

PA/IVS often presents with varying extent of RV maldevelopment, TV hypoplasia and stenosis, and RV-dependent coronary blood flow (due to abnormal coronary arteries arising from sinusoids in the RV outlet musculature).

PA/VSD, on the other hand, the RV by virtue of ‘flow-growth phenomenon due to the presence of VSD, enjoys more blood flow and as a result is more completely developed. However, due to the reduced pulm blood flow in PA/VSD, MAPCA develop compensating for the limited blood flow in the maldeveloped PA.

Congenital