What is Patent Ductus Arteriosus or PDA?
The ductus arteriosus (DA) is a fetal vascular connection between the main pulmonary artery and the aorta that diverts blood away from the pulmonary bed. After birth, the DA undergoes active constriction and eventual closure. A patent ductus arteriosus (PDA) occurs when the DA fails to completely close after birth (Figure 1). The incidence of PDA ranges from 3 to 8 per 10,000 live births in term infants. Premature babies have a much higher incidence of PDA.
What effects does PDA have?
Symptoms due to the presence of PDA in infants and children depends on the size of ductus arteriosus. Small PDAs are asymptomatic whereas moderate, and large PDAs can have a failure to thrive or poor weight gain. They can have frequent respiratory infections sometimes requiring hospital admissions. There can be feeding issues and excessive sweating during feeds in infants. In children, poor weight gain and frequent respiratory infections are commonly seen because of PDA. Older children may have easy fatigue and palpitations. There is also a risk of infective endarteritis even with small PDAs. Hence closure of PDA is required. Depending on the size of the duct and symptoms, recommendations on the timing of PDA closure differs. Large PDAs may need early closure usually around 6months to 1 year of life. Moderate PDAs can be closed around 12 – 18 months of life and small audible PDAs around 2 years of life or even later.
What are the treatment options?
In preterm infants, medicines such as indomethacin and ibuprofen, are used as the initial interventions for PDA closure along with medications to manage heart failure. But if the infant remains symptomatic in spite of medical therapy and the ductus arteriosus is unresponsive to medical closure, then intervention may be required.
What is Device closure of Patent Ductus Arteriosus?
Device closure of PDA is a less invasive method to close the ductus without surgery. It can be accomplished successfully in most of the infants with weight above 5 kilos. Even large PDAs in infants and children can be closed by this percutaneous device closure technique thereby avoiding surgical intervention. The choice of the occluder (coil versus the various devices) is dependent upon ductal morphology and size, and the size of the patient. Access is generally achieved through the femoral artery or vein. Children usually fully recover after the procedure and can be discharged the same day or after overnight observation. Although a variety of techniques have been developed, occlusion devices (picture 1) are most commonly used, which allows successful PDA occlusion with normalization of left heart chamber sizes.
What is a PDA device?
The PDA device is a top-hat shaped, repositionable plug occluder made of nitinol wire mesh, which is delivered through a long sheath the size of which depends on the size of the device being used. A retention skirt extends radially around the distal part of the device and is positioned in the aortic ampulla, assuring secure fixation in the mouth of the PDA. Polyester fabric, which is sewn into the occluder, induces thrombosis that closes the communication. The technique of percutaneous PDA closure with the use of PDA occluder is less invasive; there is no scar and recovery is faster. Most of the PDAs in infants and children are amenable to device closure which is the procedure of choice in present practice. (Picture 2)
Follow up is recommended after PDA device closure usually for a period of 1- 2 years. Children can be discharged from pediatric cardiology follow up after this time frame if there is no residual shunt, no pulmonary artery distortion or stenosis, and no aortic obstruction. Infective endocarditis prophylaxis is recommended for 6 months post PDA device closure. Children who have undergone an uncomplicated PDA device closure can participate in all kinds of sports, and all activities can be undertaken.
How does the Patent Ductus Arteriosus device help?
Device closure of patent ductus arteriosus is an effective, safe, less invasive technique of closing the ductus arteriosus with excellent long term outcomes. Successful device closure can be accomplished in most of the children and infants with weight more than 5 kilos. Infants and children who have undergone PDA device closure can lead a completely normal life with no activity restriction or limitation. Percutaneous Device closure is the procedure of choice for PDA closure in the present era.
DR. KAVYA MALLIKARJUN
Consultant Pediatric Cardiologist, Pediatric and Child Care
Hal Airport Road – Bengaluru,