Patent Ducts Arteriosus

Subject: Midwifery III (Theory)

Overview

Patent ductus arteriosus (PDA) is a heart condition that develops in some babies shortly after birth. In PDA, abnormal blood flow occurs between two of the major arteries that connect to the heart. However, in some infants, the ductus arteriosus remains open (patent). This opening allows oxygen-rich blood from the aorta to mix with oxygen-depleted blood from the pulmonary artery. This can put a strain on the heart and raise blood pressure in the lung arteries. A PDA can be idiopathic. Premature birth, congenital rubella syndrome, chromosomal abnormalities, and genetic conditions such as Loeys-Dietz syndrome are all known risk factors. Patients are usually in good health, with normal respirations and heart rates. When the PDA is moderate or large, widened pulse pressure and bounding peripheral pulses are frequently present, indicating increased left ventricular function.

Patent ductus arteriosus (PDA) is a heart condition that occurs in some babies shortly after birth. PDA is characterized by abnormal blood flow between two major arteries that supply the heart. The ductus arteriosus connects the two major arteries, the aorta, and the pulmonary (PULL-mun-ary) artery, before birth. This vessel is critical to fetal blood circulation. The vessel is supposed to close within minutes or up to a few days after birth as part of the normal changes in the baby's circulation.

However, in some babies, the ductus arteriosus remains open (patent). This opening allows oxygen-rich aortic blood to mix with oxygen-depleted pulmonary artery blood. This can put a strain on the heart and raise blood pressure in the arteries leading to the lungs.

Causes:

PDA can be idiopathic in some cases. Among the known risk factors are:

  • Premature birth 
  • Rubella syndrome at birth 
  • Anomalies in the chromosomes (e.g., Down syndrome)
  • Loeys-Dietz syndrome is an example of a genetic condition (would also present with other heart defects)

Signs and symptoms:

  • tachycardia (rapid heartbeat) (a heart rate exceeding the normal resting rate)
  • respiratory issues
  • hypopnea (shortness of breath)
  • on-going "machine-like" (also described as "rolling-thunder" and "to-and-fro") murmur in the heart (usually from the aorta to the pulmonary artery, with the higher flow during systole and lower flow during diastole)
  • Cardiomegaly (enlarged heart due to ventricular dilation and volume overload) caused the sub-clavicular thrill bounding pulse to be absent.
  • increased pulse pressure
  • Poor growth differential cyanosis, that is, cyanosis of the lower extremities but not the upper body.

Patients are usually in good health when they arrive, with normal respirations and heart rates. When the PDA is moderate or large, widened pulse pressure and bounding peripheral pulses are common, indicating increased left ventricular stroke volume and diastolic run-off of blood into the (at first lower-resistance) pulmonary vascular bed. Due to increased left ventricular stroke volume, prominent suprasternal and carotid pulsations may be observed.

Diagnosis:

Noninvasive techniques are typically used to diagnose PDA. The primary methods of detecting PDA are echocardiography (the use of sound waves to capture the motion of the heart) and associated Doppler studies. Electrocardiography (ECG), which uses electrodes to record the electrical activity of the heart, is ineffective because no specific rhythms or ECG patterns can be used to detect PDA.

A chest X-ray may be performed to determine overall heart size (as a reflection of the combined mass of the cardiac chambers) and the appearance of blood flow to the lungs. A small PDA is usually associated with a normal-sized heart and normal blood flow to the lungs. In most cases, a large PDA is associated with an enlarged cardiac silhouette and increased blood flow to the lungs.

Treatment:

Neonates with no adverse symptoms may be monitored as outpatients, whereas symptomatic PDA can be treated surgically or non-surgically. The DA can be closed surgically by ligation (though support in premature infants is mixed), either manually tied shut, or with intravascular coils or plugs that cause a thrombus to form in the DA. Franz Freudenthal's devices block blood vessels with woven structures of nitinol wire.

Because prostaglandin E2 is responsible for keeping the DA open, NSAIDs (which can inhibit prostaglandin synthesis) such as indomethacin, a type of ibuprofen, have been used to cause PDA closure. A recent systematic review concluded that ibuprofen is as effective as Indomethacin in closing a PDA in preterm and/or low birth weight infants. It also has fewer side effects (for example, transient renal insufficiency) and lowers the risk of necrotizing enterocolitis. Another recent study found that paracetamol may be effective in closing a PDA in premature infants.

PDAs can now be closed using a percutaneous interventional method (avoiding open-heart surgery). A platinum coil can be inserted through a catheter into the femoral vein or artery, causing thrombosis (coil embolization). Alternatively, a nitinol mesh PDA occluder device is deployed from the pulmonary artery through the PDA.
Things to remember
  • Patent ductus arteriosus (PDA) is a heart condition that occurs in some babies shortly after birth. PDA is characterized by abnormal blood flow between two major arteries that supply the heart. However, in some babies, the ductus arteriosus remains open (patent).
  • This opening allows oxygen-rich aortic blood to mix with oxygen-depleted pulmonary artery blood.
  • This can put a strain on the heart and raise blood pressure in the arteries leading to the lungs.
  • PDA can be idiopathic in some cases.
  • Preterm birth, congenital rubella syndrome, chromosomal abnormalities, and genetic conditions such as Loeys-Dietz syndrome are all known risk factors.
  • Patients are usually in good health when they arrive, with normal respirations and heart rates.
  • When the PDA is moderate or large, widened pulse pressure and bounding peripheral pulses are common, indicating increased left ventricular stroke volume and diastolic run-off of blood into the (at first lower-resistance) pulmonary vascular bed.
  • Neonates with no adverse symptoms may be monitored as outpatients, whereas symptomatic PDA can be treated surgically or non-surgically.
  • PDAs can now be closed using a percutaneous interventional method (avoiding open-heart surgery).
Questions and Answers

Some newborns develop patent ductus arteriosus (PDA), a cardiac condition, shortly after birth. In PDA, there is an irregular blood flow between two of the heart's major arteries.

PDAs can occasionally be idiopathic. Known risk elements consist of:

  • Early birth
  • Rubella congenital syndrome
  • Aberrant chromosomal conditions (e.g.,Down syndrome)
  • Gene-related disorders like Loeys-Dietz syndrome (would also present with other heart defects)

Common symptoms include:

  • Tachycardia (a heart rate beyond the typical resting rate) (a heart rate exceeding the normal resting rate)
  • Breathing difficulties
  • Dyspnea (shortness of breath) (shortness of breath)
  • Perpetually "machine-like" (also described as "rolling-thunder" and "to-and-fro") cardiac murmur (usually from the aorta to the pulmonary artery,
  • With the higher flow duringsystoleand lower flow duringdiastole)
  • The subclavicular thrill-bounding pulse was left due to cardiomegaly (enlarged heart, suggesting ventricular dilatation and volume overload).
  • Increased heart rate pressure
  • Having cyanosis only in the lower extremities but not the upper body is known as poor growth differential cyanosis.

Neonatals who don't exhibit any negative symptoms may only need to be followed as outpatients, whereas PDA symptoms can be addressed surgically or non-surgically. The DA can be tied shut manually, with intravascular coils or plugs that cause a thrombus to form in the DA, or by surgical ligation (though support in premature children is mixed). Franz Freudenthal's inventions use woven nitinol wire structures to block the blood vessel. Because prostaglandin E2 keeps the DA open, NSAIDS (which can block prostaglandin synthesis) have been used to start PDA closure. Indomethacin is one such medication. Ibuprofen is as effective as Indomethacin for the closure of a PDA in preterm and/or low birth weight infants, according to recent findings from a comprehensive study. Additionally, it has fewer adverse effects and lowers the risk of necrotizing enterocolitis (such as temporary renal insufficiency). Another recent study shown that paracetamol might be useful for preterm infants' PDA closure. PDAs can now be closed via a percutaneous interventional procedure (avoiding open heart surgery). A catheter can be used to insert a platinum coil into the femoral vein or artery, causing thrombosis (coil embolization). 

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