So it is not the oxygen saturation that is the problem with these patients, but it's the reduced amount of blood volume that gets to the systemic circulation due to pulmonary overcirculation. This could be explained by the presence of virus that could cross the placental barrier and reach the fetus where they would affect the normal development of fetal organs during a period where the heart is developing. They are usually born after a normal, full-term pregnancy. After the ductus closes, hypoperfusion of the systemic circulation leads to multiple organ failure if the condition is not corrected. This is important because it gives parents the chance of understanding the syndrome and knowing what to expect and time to think about their options.
Early detection allows parents to deliver the baby at or near an experienced facility.
It also gives a chance for the medical staff to be prepared and ready for the newborn. This way the time for circulatory instability is minimized and organ failure can be avoided. Postnatally, the ultimate diagnosis is made by two-dimensional echocardiogram and Doppler echocardiography to visualize the morphology of the heart and arch hypoplasia. Cardiac catheterization is not used for diagnostic purposes. The aortic arch can now be visualized with high accuracy using the echocardiogram.