Patent Ductus Arteriosus
Introduction
A congenital heart defect
A neonate's ductus arteriosus fails to close after birth.
Symptoms are uncommon but in the first year of life include increased work of breathing and poor weight gain. With age, the PDA may lead to congestive heart failure if left uncorrected.
Aetiology
A patent ductus arteriosus can be
idiopathic
Premature infants
Congenital rubella syndrome
Chromosomal abnormalities such as Down Syndrome
Pathophysiology
In the developing fetus, the ductus arteriosus (DA) is the vascular connection between the pulmonary artery and the aortic arch
It allows most of the blood from the right ventricle to bypass the fetus' fluid-filled compressed lungs.
During fetal development, this shunt protects the right ventricle from pumping against the high resistance in the lungs, which can lead to right ventricular failure if the DA closes in-utero.
When the newborn takes its first breath, the lungs open and pulmonary vascular resistance decreases.
The lungs release bradykinin to constrict the smooth muscle wall of the DA
In normal newborns, the DA is substantially closed within 12-24 hours after birth, and is completely sealed after three weeks.
Withdrawal from maternal prostaglandins also contributes to ductal closure.
The fibrotic remnants of DA is called the ligamentum arteriosum.
Patent Ductus Arteriosus
Signs and symptoms
While some cases of PDA are asymptomatic, common symptoms include:
* tachycardia or other arrhythmia
* respiratory problems
* shortness of breath
* continuous machine-like murmur
* enlarged heart
* Left subclavicular thrill
* Bounding pulse
* Widened pulse pressure
Investigations
X-ray : enlarged cardiac silhouette and increased blood flow to the lungs.
Echocardiography.
Treatment
surgical methods
Surgically, the DA may be closed by ligation or with intravascular coils or plugs that leads to formation of a thrombus in the DA.
In certain cases it may be beneficial to the neonate to prevent closure of the ductus arteriosus. For example, in transposition of the great vessels, a PDA may prolong the newborn's life until surgical correction is possible. The ductus arteriosus can be induced to remain open by administering prostaglandin analogs such as alprostadil (a prostaglandin E1 analog).
percutaneous interventional method : - PDA can be closedthrough femoral vein or femoral artery, a coil can be placed with the help of myocardial forceps to make an embolus, which closes the PDA without open heart surgery.
other anomalies
