Anomalous pulmonary venous connection

Anomalous pulmonary venous connection(oranomalous pulmonary venous drainageoranomalous pulmonary venous return) is a congenital heart defect of thepulmonary veins. It can be a total anomalous pulmonary venous connection, wherein all four pulmonary veins are incorrectly positioned, or a partial anomalous pulmonary venous connection, wherein only some of the pulmonary veins are incorrectly positioned.
Total anomalous pulmonary venous connection, also known as totalanomalous pulmonary venous return, is a rarecyanoticcongenitalheart defectin which the pulmonary veins drain into the right side of the heart instead of the left, as is usually seen. This can happen within the heart (intracardiac) where it drains into the coronary sinus or right atrium, or below it (infracardiac) where it drains into the liver at the portal or hepatic vein. The anomalous connection causeslow blood oxygenationand limitation of venous return to the heart.
The diagnosis of TAPVC is dependent upon whether or not there is an obstruction.
TAPVC with obstruction will clinically present with cyanosis, tachypnea, dyspnea, and hypoxemia. Chest x-ray may show a ground-glass appearance due to pulmonary edema resulting from increased pressure in the obstructed pulmonary veins.
Cases of TAPVC with obstruction are considered a surgical emergency.
In TAPVC without obstruction, surgical redirection can be performed within the first month of life. The operation is performed under general anesthesia. The four pulmonary veins are reconnected to the left atrium, and any associated heart defects such as atrial septal defect, ventricular septal defect, patent foramen ovale, and/or patent ductus arteriosus are surgically closed. With obstruction, surgery should be undertaken urgently.PGE1should be given because apatent ductus arteriosusallows oxygenated blood to go from the circulation of the right heart to the systemic circulation.
APartial anomalous pulmonary venous connection(orPartial anomalous pulmonary venous drainageorPartial anomalous pulmonary venous return) is a congenital defect where theleft atriumis the point of return for the blood from some (but not all) of thepulmonary veins.
It is less severe thantotal anomalous pulmonary venous connectionwhich is a life-threatening anomaly requiring emergent surgical correction, usually diagnosed in the first few days of life. Partial anomalous venous connection may be diagnosed at any time from birth to old age.  The severity of symptoms, and thus the likelihood of diagnosis, varies significantly depending on the amount of blood flow through the anomalous connections.  In less severe cases, with smaller amounts of blood flow, diagnosis may be delayed until adulthood, when it can be confused with other causes of pulmonary hypertension.There is also evidence that a significant number of mild cases are never diagnosed, or diagnosed incidentally.It is associated with other vascular anomalies, and some genetic syndromes such asTurner syndrome.
It can be diagnosed withCT scan,angiography, transesophagealechocardiography, orcardiac MRI.
It is sometimes treated with surgery, which involves rerouting blood from the right atrium into the left atrium with a patch or use of the Warden procedure.However, interest is increasing in catheter-based interventional approaches, as well as medical therapy for less severe cases.
To understand the different types of anomalous pulmonary venous connection, it is important to establish the background in which normal fetal vasculature develops.
During embryonic development, the lungs start as outgrowths from the foregut and share its splanchnic vascular plexus. At around 25 to 27 days of gestation, there are no direct links to the heart. By 27 to 29 days of gestation, the primitive pulmonary vein begins to form as an outgrowth from the left atrium and eventually connects with the primitive pulmonary venous system.