Health Topics

The most commonly performed palliative procedure is a systemic to pulmonary shunt (also commonly called "Blalock-Taussig" or "B-T" shunts).

• These are performed in situations where the heart defect results in too little blood flow to the lungs which results in low oxygen levels in the blood, or cyanosis.
• The shunt is typically a short segment of artificial blood vessel, usually made of Gore-tex", which connects a branch off of the aorta to one of the pulmonary arteries.
• This allows more blood flow to the lungs, basically sidestepping the reason in the heart that is responsible for the low pulmonary blood flow.
• Because these shunts are synthetic, they will not grow. As a child gets bigger, he or she will outgrow the shunt, resulting in gradually falling oxygen levels.

Palliative procedures often allow more definitive surgery to be delayed four to six months or longer, to a time when such a procedure is possible with greater safety.

• Shunts may be performed either from the front of the chest (sternotomy) or the side (thoracotomy) depending on the child's specific anatomy.

Sometimes the increased blood flow to the lungs puts a sudden additional burden on the heart requiring a period of adjustment and careful intensive care unit support.

Longer-term problems from shunts are that they may close off (gradually or suddenly), or may cause scarring of the pulmonary artery where they are attached. Most children are placed on aspirin, which has a mild anticoagulant effect to lessen the risk of a shunt clotting off.

Some heart defects may be associated with too much blood flow to the lungs resulting in congestive heart failure or the risk that the delicate pulmonary blood vessels may sustain damage over time.

• A pulmonary artery band is a palliative procedure done in infants to limit the blood flow to the lungs using a constricting band around the first part of the main pulmonary artery.
• Like the shunt procedures, a child may be unstable initially after such a procedure. These may also be accomplished either from the front or the side, and will also gradually limit blood flow to the lungs too much as a child grows which determines the timing of subsequent operations.
• Sometimes shunts or bands are used during more complex reconstructive operations such as a Norwood operation for Hypoplastic Left Heart Syndrome. Such an operation would also be referred to as palliative because it does not completely correct the underlying defect.

Not surprisingly, because these operations are typically performed on high risk patients and because they involve significant changes in physiology, they are associated with significant morbidity and mortality. This is despite the fact that often a heart-lung machine is not necessary and the technical aspects of operation are simpler than other congenital procedures.

In most cases palliative procedures are one step in a multiple staged approach to complex or high-risk cardiac defects.

The timing of when the next operation in the sequence is performed depends on the specific heart defect and information that is obtained by the cardiologists through physical examination, echocardiograms, or cardiac catheterization.

The goal is to choose the optimal time to maximize the chance of success for the often more complex corrective operations.