Diagnosis of Patent Ductus Arteriosus
An infant or an adult may present with heart failure or lung infections due to moderate or large shunting of blood through the patent ductus arteriosus.
Apart from the symptoms of heart failure, there can be other signs that can be indicative of left ventricular volume overload and increased blood flow to the lungs. They are -
► Hepatomegaly or liver enlargement.
► Murmur (Machinery murmur) on auscultation.
► Bounding peripheral pulses.
► Upper left sternal border thrill – Vibration felt when a hand is placed on the patient’s chest at the upper left border.
Diagnostic testing can be done to reveal or confirm the presence of a patent ductus arteriosus.
Laboratory testing to analyze blood gas can be useful to determine the accurate oxygen saturation in blood. Increased presence of carbon dioxide or very low oxygen levels in blood can be determined.
An electrocardiogram may reveal enlargement and hypertrophy of the left ventricle when a significant amount of blood shunts through the ductus. In small PDAs, ECG is characteristically normal.
A Chest X-Ray is also normal when the shunt is very small. In larger shunts, there are prominent markings of left sided heart chambers, showing volume overload in the left side. Pulmonary arteries enlargement can also be seen.
An echocardiogram, other wise called as ECHO, can establish the diagnosis of PDA. A color echo and Doppler study can show the presence of a shunt between the aorta and the pulmonary artery. Associated cardiac defects, if any present, may be diagnosed.
A cardiac catheterization may not be necessary for all patients with PDA. This test is usually recommended for patients who are suspected of having high resistance of blood flow to the lungs or high pulmonary vascular resistance. When performed, it can reveal the amount of blood shunting through the ductus. Pressure inside each of the heart chamber can be assessed. Pulmonary hypertension can be diagnosed. Other congenital cardiac defects, if present, can be diagnosed and assessed.