Patent: open, unobstructed
Ductus: fetal blood vessel which joins the aorta and
pulmonary artery
Arteriosus: pertaining to artery
Patent Ductus Arteriosus: (PDA) This
abnormal opening between the pulmonary artery and the aorta allows left
to right shunting of blood from the aorta to the pulmonary artery.
This results in recirculation of arterial blood through the lungs.
In the early stages, PDA may produce no clinical effects, but in time
it can precipitate pulmonary vascular disease, causing symptoms to appear
by age 40. The patients with a small shunt or who undergo effective
surgical repair have a good chance of recovery. But PDA may advance
to intractable CHF, which may be fatal.
Most prevalent in premature infants, PDA often accompanies rubella syndrome.
It may be associated with other congenital defects, such as coarctation
of the aorta, ventricular septal defect, and pulmonary and aortic stenoses.
Cause: Results from failure of the fetal ductus arteriosus
(a fetal blood vessel that connects the pulmonary artery to the descending
aorta) to close within days to weeks after birth.
Symptoms:
For infants, especially premature ones with a large PDA usually develop
respiratory distress with signs of CHF.
Frequent respiratory infections
Slow motor development
Failure to thrive.
Most children with PDA have only cardiac symptoms. Others may
exhibit signs of heart disease, such as physical underdevelopment and fatigability.
By age 40, adults with untreated PDA may develop fatigability and dyspnea
on exertion. Cyanosis appears in the final stages of illness.
Murmur (called Gibson murmur) This continuous murmur is best heard
at the base of the heart, at the second left intercostal space under the
left clavicle in most children with PDA.
May have bounding peripheral arterial pulses (Corrigan’s pulse), may
have widened pulse pressure.
Cardiomegaly
Tachycardia
Dilated ascending aorta
Treatment:
For infants with PDA that has no symptoms (asymptomatic) the patient
may not require immediate treatment.
Those with CHF require fluid restriction, diuretic, and digitalis to
minimize or control symptoms. If theses measure does not control
CHF, the patient requires surgery to ligate the ductus. The doctor
may delay surgical correction until age 1 if the patient has only mild
symptoms.
Before surgery, children with PDA require antibiotics to protect against
infective endocarditis.
Other forms of therapy include cardiac catheterization to deposit a
plug in the ductus to stop shunting, or administration of indomethacin
I.V. (a prostaglandin inhibitor that provides an alternative to surgery
in premature infants) to induce ductus spasm and closure.