Tuesday, February 7, 2023
HomePediatrics: Cardiac Disease and Critical Care MedicineSystemic to Pulmonary Artery Shunting for Palliation

Systemic to Pulmonary Artery Shunting for Palliation

Introduction and History

A surgically created connection between a systemic artery and the pulmonary artery (PA) is termed a systemic-to-pulmonary artery shunt or, more commonly, a BT shunt (after Blalock and Taussig, the first physicians to describe the connection). Most would agree that the description of this procedure in the Journal of the American Medical Association (JAMA) in 1945 has revolutionized the field of pediatric cardiology.

Helen Taussig, a pediatric cardiologist at Johns Hopkins at the time, had several patients with complex cyanotic heart disease with right-sided heart obstruction in the form of either pulmonary stenosis or pulmonary atresia. In that seminal paper, she noted that their cyanosis increased or became more apparent after closure of the ductus arteriosus. She approached Robert Gross, a surgeon in Boston (who, in 1938, was the first to close a patent ductus arteriosus), and asked if he would surgically create a ductuslike connection in these patients. After he refused, she posed the same question to Alfred Blalock, the Chief of Surgery at Johns Hopkins.

Blalock, a few years prior to her request, had attempted to create an animal model for pulmonary hypertension through an anastomosis of the divided subclavian artery to the pulmonary artery.
He was also attempting to treat coarctation of the aorta by turning the subclavian artery down and anastomosing it to the aorta below the area of the coarctation.
A young African American surgical technician named Vivien Thomas was performing this work in an experimental animal laboratory.

After Taussig met with Blalock and Thomas, they decided to use the subclavian artery–to–pulmonary artery connection as a way to augment the pulmonary blood flow. Thomas confirmed this in the laboratory, and Blalock finally performed the procedure on a 15-month-old child with severe cyanosis.
Thomas alone had done all of the previous animal work (in >200 animals), and Blalock had practiced the procedure only once in the animal laboratory.

During the surgery on the child, Blalock had Thomas stand behind him on a stool so that he could observe and instruct him accordingly. This team went on to perform this operation on 2 more children and published their results in JAMA in 1945 to worldwide acclaim. However, the paper listed only the names of Blalock and Taussig, and not until decades later were Thomas’s many and important contributions officially recognized. Johns Hopkins bestowed upon him an honorary Doctor of Laws degree in 1976. At the time of Blalock’s retirement in 1964, more than 2000 shunt operations had been performed at Hopkins.

Various surgeons have since described many other modifications to this original operation. Since its initial use in tetralogy of Fallot (TOF) and other cyanotic cardiac conditions associated with pulmonary stenosis or pulmonary atresia, the systemic-to-pulmonary artery shunt has been applied to other cardiac defects. For example, systemic-to-pulmonary artery shunting is usually the first of several operations for the treatment of different forms of a single ventricle.

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