Definition and Overview
Patent ductus arteriosus (PDA) is a common congenital heart defect wherein the ductus arteriosus (patent means open), a blood vessel that connects the proximal descending aorta and the pulmonary artery, fails to close at birth. Unless the condition is treated early in life, it can cause several health problems because the blood flow between the pulmonary artery and the aortic arch is reversed. This causes the patient to experience labored breathing, poor weight gain, and other symptoms that may become noticeable during the first year of life. A patent ductus arteriosus closure is the primary surgical treatment for this condition.
Who Should Undergo and Expected Results
The procedure is performed on infants diagnosed with patent ductus arteriosus, one of the most common congenital heart defects. Statistics show that the disorder, also known simply as PDA, makes up 5 to 10 percent of all cases of congenital heart defects that affect newborns.
The ductus arteriosus is designed to close on its own after birth, a process that is signaled by the baby’s first breath. Normally, the blood vessel narrows significantly during the first 24 hours of life and continues to do so until it closes completely within three weeks after birth. Its failure to close can cause several health problems primarily because the blood flow between the pulmonary artery and the aortic arch is reversed.
The risk of patent ductus arteriosus is highest in pre-term infants due to their underdeveloped or immature organs, especially the heart and the lungs. Other risk factors include congenital rubella syndrome, the presence of any chromosomal abnormalities, and certain genetic disorders, an example of which is the Loeys-Dietz syndrome.
The condition can be mild or severe in nature. Some patients only have a small opening and are able to live normally even without treatment. However, in severe cases wherein patients experience the symptoms listed below, both nonsurgical and surgical interventions are highly considered.
- Respiratory distress
- Dyspnea, or shortness of breath
- Continuous heart murmur with higher systole flow and lower diastole flow
- Tachycardia, or a heart rate that is higher than normal
- Cardiomegaly, or an enlarged heart with ventricular dilation
- Wide pulse pressure
- Poor growth or physical development
- Cyanosis, usually affecting only the lower part of the body
The above symptoms tend to be more pronounced if the opening of the ductus arteriosus is large. Despite this, most patients who get treated for the condition are in relatively good health.
A successful patent ductus arteriosus closure is expected to close up the opening of the ductus arteriosus, normalizing the patient’s cardiovascular structure and clearing up all associated symptoms in the process.
How is the Procedure Performed?
Prior to undergoing patent ductus arteriosus closure, patients are first diagnosed using cardiovascular tests, namely echocardiography (ECG) and chest X-ray, which evaluates the size of the heart. An enlarged heart may indicate PDA due to the increased flow of blood caused by the patent blood vessel. Once the condition is confirmed, the patient will first undergo a period of monitoring. Should the patient exhibits symptoms listed above, the doctor will decide on the best method of treatment, which may involve surgical intervention and non-surgical alternatives. If patients are not suitable candidates for surgical PDA closure, they are treated using pulmonary vasodilating agents, including PGI2, chronic oxygen, calcium channel blockers, and phosphodiesterase type V inhibitors.
During a conventional surgical PDA closure, the ductus arteriosus is closed by manually tying it shut or forming a thrombus using intravascular plugs or coils. It is also possible to achieve the same effect through ligation.
More recently, however, minimally invasive alternative techniques such as percutaneous interventional method are performed so an open-heart surgery will not be necessary. This alternative, which poses fewer risks to the young patient, involves deploying a platinum coil into the ductus arteriosus through a catheter, passing it through either the femoral artery or vein to close the ductus arteriosus. Another alternative is the use of PDA occluder device made with nitinol mesh to achieve the same effect.
Possible Risks and Complications
Despite the presence of some risks and possible complications, a patent ductus arteriosus closure is a critical part of PDA treatment. While the procedure is not considered a medical emergency, it is almost always necessary, since PDA is known to be progressive and may lead to serious health complications, such as:
- Eisenmenger’s syndrome
- Pulmonary hypertension
- Hypertensive pulmonary vascular disease
- Intraventricular hemorrhage
- Myocardial ischemia
- Necrotizing enterocolitis
- Bacterial endocarditis
If the disorder is left untreated, there is also a risk of congestive heart failure and that the patient will require a heart transplant later on in life.
Close evaluation and monitoring of patients who present with PDA and its symptoms are important to ensure that risks and complications do not occur as a result of PDA closure. Furthermore, the use of modern, minimally invasive procedures can help reduce these risks to ensure the safety of young patients.
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