Patent ductus arteriosus (PDA) is a medical condition in which the ductus arteriosus fails to close after birth: this allows a portion of oxygenated blood from the left heart to flow back to the lungs by flowing from the aorta, which has a higher pressure, to the pulmonary artery. Symptoms are uncommon at birth and shortly thereafter, but later in the first year of life there is often the onset of an increased work of breathing and failure to gain weight at a normal rate. With time, an uncorrected PDA usually leads to pulmonary hypertension followed by right-sided heart failure. The ductus arteriosus is a fetal blood vessel that normally closes soon after birth. In a PDA, the vessel does not close, but remains patent (open), resulting in an abnormal transmission of blood from the aorta to the pulmonary artery. PDA is common in newborns with persistent respiratory problems such as hypoxia, and has a high occurrence in premature newborns. Premature newborns are more likely to be hypoxic and have PDA due to underdevelopment of the heart and lungs. If transposition of the great vessels is present in addition to a PDA, the PDA is not surgically closed since it is the only way that oxygenated blood can mix with deoxygenated blood. In these cases, prostaglandins are used to keep the PDA open, and NSAIDs are not administered until surgical correction of the two defects is completed.
Signs and symptoms
Common symptoms include:
dyspnea (shortness of breath)Signs include:
tachycardia (a heart rate exceeding the normal resting rate)
continuous "machine-like" (also described as "rolling-thunder" and "to-and-fro") heart murmur (usually from aorta to pulmonary artery, with higher flow during systole and lower flow during diastole)
cardiomegaly (enlarged heart, reflecting ventricular dilation and volume overload)
left subclavicular thrill
bounding pulse
widened pulse pressure
increased cardiac output
increased systolic pressure
poor growth
differential cyanosis, i.e. cyanosis of the lower extremities but not of the upper body.People with patent ductus arteriosus typically present in good health, with normal respirations and heart rate. If the PDA is moderate or large, widened pulse pressure and bounding peripheral pulses are frequently present, reflecting increased left ventricular stroke volume and diastolic run-off of blood into the (initially lower-resistance) pulmonary vascular bed. Eisenmenger physiology is pulmonary hypertension due to a left-to-right shunt. Prominent suprasternal and carotid pulsations may be noted secondary to increased left ventricular stroke volume. Risk factors
Known risk factors include:
Preterm birth
Congenital rubella syndrome
Chromosomal abnormalities (e.g., Down syndrome)
Genetic conditions such as Loeys–Dietz syndrome (would also present with other heart defects), Wiedemann–Steiner syndrome, and CHARGE syndrome. Fetal Alcohol Spectrum Disorder

Diagnosis
PDA is usually diagnosed using noninvasive techniques. Echocardiography (in which sound waves are used to capture the motion of the heart) and associated Doppler studies are the primary methods of detecting PDA.