Commonly Treated Heart Conditions
Atrial Septal Defect (ASD)
An atrial septal defect (ASD) is a hole in the wall (septum) between the two upper collecting chambers of the heart.
These holes may be of varying size and may be in any of several positions on the septum. The size of the defect and its location are factors which determine how serious the defect is with respect to the amount of strain on the heart and the degree to which blood crosses from one side of the heart to the other, causing a "flooding" of the lungs.
Patients with this lesion often have no symptoms, though they may have an increased incidence of lung problems. With time, however, the increased flow of blood to the lungs will cause irreversible damage.
The operation for ASD involves closing the hole, either by sewing its edges together or by placing a patch in the defect.
Coarctation of the Aorta
Coarctation of the aorta is defined as a narrowing of the upper thoracic aorta. To repair this defect, the aorta is clamped on either side of the narrowing, the segment of narrowing is removed and the two ends of the aorta are sewn together (end to end anastomosis). The two ends of the segment may also be joined using a graft.
In a normal heart, the tricuspid valve controls blood flow from the right atrium to the right ventricle. When a person has Ebstein’s anomaly, the leaflets of the tricuspid valve are not formed correctly, and the valve is located lower than normal.
The leaflets do not control the blood flow properly, resulting in a right ventricle that is too small and a right atrium that is too large. There are varying degrees of severity of Ebstein’s anomaly, and there is usually an atrial septal defect.
Hypoplastic Left Heart Syndrome (HLHS)
HLHS is a severe congenital heart defect in which the left side of the heart does not develop during pregnancy. This means the left ventricle (the pumping chamber that sends blood to the body) and the aorta (the main artery that carries the blood to the body) and the mitral and aortic valves are very small and cannot support life.
Surgical repair requires three stages to enable the single working chamber to do the work of two ventricles.
Stage 1: The Norwood I procedure is typically performed within the first 2 weeks of life.
Stage 2: The second stage, the bi-directional Glenn, is typically performed before the infant is 6 months old.
Stage 3: At two to three years old, the third, and final stage -- the Fontan operation -- is completed.
In rare cases, the staged approach cannot be performed on an HLHS heart, and a heart transplant is performed.
The Ross Procedure is a type of specialized aortic valve surgery where the patient's diseased aortic valve is replaced with his or her own pulmonary valve. The pulmonary valve is then replaced with cryopreserved cadaveric pulmonary valve. In children and young adults, or older particularly active patients, this procedure offers several advantages over traditional aortic valve replacement with manufactured prostheses.
Longevity of the pulmonary autograft in the aortic position is superior to bioprostheses such as porcine valves, which tend to degenerate after only a few years in patients under 35 years of age. Furthermore, anticoagulation is not required as with mechanical valves. Thus, individuals can lead an active life without the risks associated with anticoagulation therapy. This is especially important for women of child bearing age needing aortic valve replacement, as anticoagulation is contraindicated in pregnancy.
The pulmonary valve and a segment of the pulmonary artery are excised. This pulmonary segment will later be placed in the aortic position replacing the diseased aortic valve.
The diseased aortic valve and proximal tissue is removed, leaving the right and left coronary arteries with only a button of tissue.
The pulmonary autograft is placed in the aortic position and the buttons of tissue on both the right and left coronary arteries are then sewn into that pulmonary segment and closed. A cadaveric pulmonary valve and artery homograft is then replaced in the pulmonary position to replace the excised pulmonary segment.
Total Anomalous Pulmonary Venous Return
In the normal heart, pulmonary veins carry oxygenated blood from the lungs to the left side of the heart (left atrium), which pumps the oxygenated blood to the body. In a heart with Total Anomalous Pulmonary Venous Return (APVR), the pulmonary veins connect to the right atrium, where the oxygenated blood mixes with the un-oxygenated blood through a hole in between the left and right atria. The mixed blood does not provide enough oxygen for the entire body.
The surgical repair of anomalous pulmonary veins involves the redirection of the abnormal veins to the left atrium, usually by connecting them directly to the back wall of the atrium.
Transposition of the Great Arteries
In the normal heart, the right side of the heart pumps ‘blue’ blood (un-oxygenated) from the body to the lungs through the pulmonary artery (main artery to the lungs), while the left heart pumps "red" blood (oxygenated) from the lungs to the body through the aorta (main artery to the body).
In this defect, the position of the main vessels to the lungs and body is reversed so that the aorta arises from the right side of the heart and the pulmonary artery form the left side of the heart.
The consequences of this reversal are severe, since blood which has gone to the lungs to pick up oxygen is not pumped to the body as it should be, but instead returns to the lungs. The only way blood with oxygen can reach the body is by passing through a hole between the upper collecting chambers and mixing with the "blue" blood. The surgeons perform an arterial switch procedure for this anomaly, which connects the aorta to the left ventricle and connects the pulmonary artery to the right ventricle.
Ventricular Septal Defects (VSD)
The wall dividing the two lower pumping chambers of the heart (right and left ventricles) is known as the ventricular septum. Abnormal development of this structure may result in a hole usually located at the upper portion of the septum.
Because the pressure on the left side of the heart is higher than the right, blood crosses the hole (VSD) and causes "flooding" of the lung vessels. The amount of over-circulation to the lungs is dependent upon the size and location of the defect. If not corrected, the increased circulation to the right side of the heart and lungs may cause an overload on the muscle and permanent damage to the lung vessels. A VSD may occur as an isolated defect, or may be one of several congenital heart malformations.
The operation for VSD involves closing the hole. In some cases where the defect is small and the tissues firm, the edges may be brought together with stitches. More frequently a patch of synthetic material is sewn into place to close the defect.