Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases, accounting for 12%-15% of all congenital heart diseases. It is approximately twice as common in females as in males. About 10% of cases are associated with other cardiovascular anomalies.
Pathological Anatomy
The ductus arteriosus connects the main pulmonary artery to the descending aorta and serves as a key channel for fetal circulation. After birth, it typically closes within a few months due to lack of use. If it remains open beyond one year of age, it is classified as a patent ductus arteriosus.
Pathophysiology
The presence of a left-to-right shunt increases pulmonary blood flow, leading to an increased workload on the left heart, which subsequently enlarges.
Clinical Manifestations
Small Shunt
Patients may be asymptomatic.
Moderate Shunt
Symptoms such as fatigue, palpitations, dyspnea, and chest tightness after exertion are common. The most prominent sign is a continuous machinery murmur heard in the second intercostal space along the left sternal border and below the left clavicle. This murmur is often accompanied by a thrill and has a wide radiation.
Large Shunt
Patients often develop severe secondary pulmonary hypertension, resulting in a right-to-left shunt. Cyanosis and severe clinical symptoms are common in these cases.
Auxiliary Examinations
Electrocardiography (ECG)
Common findings include left ventricular and left atrial enlargement. In cases of pulmonary hypertension, right atrial enlargement and right ventricular hypertrophy may be present.
Chest X-ray
The characteristic finding is the hilar dance sign observed on fluoroscopy.
Echocardiography
Echocardiography visualizes the patent ductus arteriosus.
Diagnosis and Differential Diagnosis
A diagnosis can often be established based on the characteristic murmur, along with findings from x-ray and echocardiography. Differential diagnoses include conditions that cause diastolic or continuous murmurs, such as aortic regurgitation with ventricular septal defect and ruptured aortic sinus aneurysm (Valsalva sinus aneurysm).
Treatment
Most experts recommend that PDA should be treated as soon as it is diagnosed. Most cases can be resolved through interventional procedures.
Surgical options include ligation and division with suturing.
Prognosis
The overall prognosis is good, except in rare cases where the disease has progressed to a late stage, making surgical or interventional treatment no longer viable. PDA is prone to complications such as infective endocarditis.