Tricuspid atresia

Definition:

A type of congenital heart disease involving obstruction of blood flow from the right atrium to the right ventricle.

Causes, incidence, and risk factors:

The right atrium and ventricle supply the lungs with blood to be oxygenated. The right atrium receives blood return from the body (systemic) under low pressure, pumps the blood into the right ventricle under low pressure which then pumps blood under slightly higher pressure to the lungs. Blood returns from the lungs to the left atrium (low pressure), then left ventricle (high pressure), out the aorta and to the body. The right side of the heart provides the pulmonary blood flow.

Tricuspid atresia is one of the least common of the different forms of congenital heart disease. In this defect the flow of blood from the right atrium to the right ventricle is blocked by an absent or abnormally developed tricuspid valve. To maintain pulmonary blood flow, blood from the right atrium flows through a hole between the right and left atrium (foramen ovale) into the left atrium, and then the left ventricle. From the left ventricle a portion of the blood may flow directly into the right ventricle through a hole in the wall between the ventricles (ventricular septal defect, VSD) or out the aorta where a structure between the aorta and pulmonary artery that normally closes (called the ductus arteriosus) remains open allowing a portion of the aortic blood flow to flow into the pulmonary artery. This supplies the lungs with some, but less than optimal, blood flow. It also puts a strain on the left ventricle which must now pump both the systemic blood supply and the pulmonary blood supply.

Individuals with tricuspid atresia generally are cyanotic (bluish discoloration of skin) due to mixing of deoxygenated blood with the normally oxygenated aortic outflow. Exercise tolerance is very limited and they rapidly become short of breath (dyspneic).

Various surgical approaches have been developed and vary depending on the age of the individual at the time the surgery is done.