stenosis leading into the pulmonary circulation.
Now then, what about patent ductus arteriosus?
We saw previously that that normally closes
roundabout birth, just subsequent to birth
and it may, therefore, happen to still remains
open. Again, this may be asymptomatic, maybe
no serious symptoms as a result of it. But
equally, it could be associated with hypoxia
during the birth process. So the lack of oxygen
may have disturbed the normal closure, and
therefore, it remains open longer than it
should do. If this condition persists, it
may result in pulmonary hypertension later in
life as a young adult or even as an older adult.
Under some circumstances, as the arrow in the
diagram shows, then there may be a
reversal of blood flow. So instead of flowing
up through the ductus arteriosus, it’s flowing
down from the aorta. Of course, that can cause
lower body cyanosis because the blood would
normally flow down the aorta descending down
the body, and then supplying the lower part
of the body. If there’s an interruption of this
kind where oxygenated blood is not
making out all the way down to the lower part
of the body, then you may find that the lower
part of the body shows cyanosis. Perhaps,
the femoral pulses may be less strong than
they are normally as a consequence. Coarctation
of the aorta means a narrowing of the aorta.