Tetralogy of Fallot - TOF : Heart Disease : Heart Disease Online

	From your Guide Dr.MANI
*Tetralogy of Fallot*

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SURGERY FOR TETRALOGY OF FALLOT

Lets see what an Intra-cardiac repair of ToF - also called a Total Correction operation - is all about.

What is done in an INTRA-CARDIAC REPAIR for ToF ?

To refresh your memory, ToF has four defects - a VSD, pulmonary valve narrowing (stenosis), thickening of the right ventricle, and an aorta over-riding the wall between the two ventricles.

So how does the surgeon correct these defects all at once ?

Repair of ToF is an open heart operation. The patient is hooked up to the heart and lung machine, and the heart is stopped. The surgeon may approach the area of repair by one of many routes, which depend on the arrangement of the different structures. The repair may be done through the right atrium, the right ventricle, the pulmonary artery, or maybe even a combination of more than one of these.
The surgeon makes a suitable opening in the chamber, and looks at the defect, to decide

Whether a one-stage repair is possible ? and
How to proceed with it ?

The actual steps of the one-stage intra-cardiac repair are

To "open up" the narrowed pulmonary valve
To divide and sometimes remove a portion of the thickened muscle of the right ventricle, particularly a band below the pulmonary valve. This thick muscle band (or "infundibulum") blocks blood flow into the pulmonary artery.
To close the ventricular septal defect (VSD) using a synthetic "patch" made of fabric like Dacron or PTFE (Poly tetra-fluoro ethylene). The surgeon places the patch so that the aorta is now connected only to the left ventricle. This restores the normal pattern of blood flow, and prevents veno-arterial mixing.

Sometimes variations occur which require the surgeon to modify the operation to fit the patient. I will describe some of the common variations. We saw how "opening up" a narrow pulmonary valve can relieve obstruction to blood flow into the lungs. In addition, if a muscle band in the right ventricle (infundibulum) is causing obstruction, it may be divided or removed. In rare cases, even this may not be enough to adequately reduce the obstruction to blood flow into the pulmonary artery. The reasons for this may be

the "ring" or annulus to which the pulmonary valve is attached is itself very narrow - a condition called "Annular Hypoplasia".
there may be additional narrowing ABOVE the pulmonary valve. This may be because

the pulmonary artery itself is small (Hypoplasia of the main pulmonary artery)
the branches or divisions of the pulmonary artery are narrow (pulmonary artery "branch stenosis")
the branches or divisions of the pulmonary artery have NOT DEVELOPED AT ALL (a condition called Pulmonary Atresia)

What is an "outflow patch" ? Go on .....

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