Patent ductus arteriosus
In a healthy
developing fetus, the ductus arteriosus is a shunt connecting the pulmonary
artery to the
aortic arch that allows much of the blood from the right ventricle to
bypass the fetus' fluid-filled lungs. During fetal development, this shunt protects the lungs from being overworked
and allows the right ventricle to strengthen. However, if
the PDA
fails to close shortly after birth, blood from the left side of the heart is also
pumped into the pulmonary artery and thereby into the lungs. This defect is
sometimes called simply patent, or open, ductus. The chances of this happening
are much higher in premature infants due to a lack of mature muscle tone in the
wall of this blood vessel.
PDA symptoms
If the PDA does not close, blood from the aorta will flow back through
the PDA into the lung vessels, producing a heart murmur. This may be the only
symptom that the child has. However, some premature babies with a large PDA may
be quite sick, requiring medication and surgical treatment.
PDA treatment
The PDA may be closed by a coiling procedure done in
the cardiac catheterization lab. Small coils are placed in the PDA through a
catheter threaded to the heart through a large vessel. The coil will cause the PDA to
clot and close.
Premature infants who are not candidates for medical management or fail
the pharmacologic therapy should have surgical ductal ligation within a few days
of diagnosis.