Patent Ductus Arteriosus(PDA) is an Acyanotic congenital heart disease, with shunting of blood from left side of heart to the right side. In foetus the blood circulation is different from that of the adults, where the blood being pumped from the right side of heart reaches the lungs and it gets oxygenated. In foetus, this site of oxygenation is placenta. To shunt the blood pumped from the right heart to placenta, there exist a communication between the two great blood vessels– the aorta and the pulmonary artery, called Ductus Arteriosus. This communication usually closes off at the time of birth and the circulation soon switches on to the adult type. The persistence of this communication in adult life is termed as the Patent Ductus Arteriosus. Incidence of PDA in general population is 8–10 per 1000 live birth.
A Patent Ductus Arteriosus can be without an identifiable cause, or secondary to another condition. Some common contributing factors in humans include: Premature infants, history of Rubella infection in mother when she was in her first three months of pregnancy, life at high altitude, chromosomal abnormalities such as Down Syndrome.
Symptoms are uncommon but in the first year of life common complaints by the mothers include – increased rate of heart beat, recurrent respiratory infections, decreased weight gain, growth stunting, increased work of breathing, poor breast feeding. With age, the PDA may lead to heart failure if left uncorrected.
PDA can be diagnosed by non invasive techniques like Chest X-ray, Echocardiography and Electrocardiogram. These combine with the clinical findings and history can pinpoint the defect. Depending on the severity of PDA, the asymptomatic cases can be managed on an outpatient basis. The symptomatic ones have to be treated by either surgical or non surgical approach. In case of a premature infant, non surgical technique using a drug, INDOMETHACIN, can close the Patent ductus. But in older children, closure by open surgical process i.e by direct ligation can be done. A useful alternative is using interventional endoluminal catheterization and coiling of the patent ductus. This involves passing of a guide wire through an artery in the thigh and reaching the patent ductus and introduction of a coil that will fit in the ductus and cause clotting of blood and closure of the ductus.
Without treatments, Disease may progress from left-to-right(acyanotic heart) shunt to right-to-left shunt(cyanotic heart) called Eisenmenger syndrome, which has a grave outcome.