Mustard procedure

Overview
The Mustard procedure was developed in 1963 by Dr. William Mustard at the Hospital for Sick Children in Toronto, Canada. It was the first procedure to show that congenital heart defects could be repaired.

History
Dr. Mustard, with support from the Heart and Stroke Foundation of Canada, developed the first operation to correct a congenital heart defect that produced “blue babies”. The defect is called transposition of the great vessels. The condition was common and fatal.

Pathophysiology
Transposition of the great vessels causes blood from the lungs to flow back to the lungs and blood from the body to flow back to the body. This occurs because the aorta and the pulmonary artery, the two major arteries coming out of the heart, are connected to the wrong chambers. The babies look blue or cyanotic because there is insufficient oxygen circulating in their bodies.

Surgical procedure
The Mustard Procedure allows total correction of transposition of the great vessels. The procedure employs a baffle to direct oxygenated pulmonary venous return into the right atrium and thence into the right ventricle which is the pumping ventricle for the aorta and the systemic circulation. In other words, the Mustard Procedure restores the circulation but reverses the direction of the blood flow in the heart.

In a normal heart, de-oxygenated, blue, blood is pumped into the lungs via the right ventricle. Then it is distributed throughout the body via the left ventricle. In the Mustard procedure, blood is pumped to the lungs via the left ventricle and disseminated throughout the body via the right ventricle.

Efficacy of the procedure
The Mustard procedure reduced an 80% mortality in the first year of life to an 80% survival at age 20.