New Technologies Effective for Hypoplastic Left Heart Syndrome
A congenital defect that leaves infants with only one heart ventricle used to be fatal. However, new technologies and surgical techniques have been found that can allow babies to survive into adulthood. The “landmark” study, funded by the Adult and Pediatric Cardiac Research Program at the US National Heart, Lung, and Blood Institute, is published in the May 27th issue of the New England Journal of Medicine.
The study compared an older implanted shunt used in the classic Norwood procedure, called a modified Blalock-Taussig shunt, with a newer shunt called RVPA in 549 children born with hypoplastic left heart syndrome, a condition in which the left ventricle of the heart – the chamber that pumps blood into the body – is nonfunctioning or non-existent. About one in 5,000 children are born with the condition in the United States each year.
In the Norwood procedure, a three-phase operation, a shunt is used to connect the aorta (the main artery of the heart) with the pulmonary artery that leads to the lungs. It now has a 64% survival rate without need for a heart transplant for the first 12 months, but few children survived when the first surgery was performed in the 1980’s.
The new shunt connects the heart’s right ventricle directly to the pulmonary artery and has a 74% survival in the first 12 months. However, the new model does have more complications, including the need for additional treatments such as stents or balloons to keep the shunt open.
"We found that the right ventricle-to-pulmonary artery shunt improved the chances of being alive without a heart transplant one year after surgery. However, the benefit appears to be limited to the first 12 months, as the two shunts showed similar results after about two years," said Richard G. Ohye, M.D., head, Pediatric Cardiovascular Surgery Division at the University of Michigan, Ann Arbor, and lead author of the study.
The researchers are going to continue to follow the children until they are at least 6 years old. They are also going to continue to research for even newer and better approaches, such as a hybrid combination of surgical banding of the pulmonary artery branches and endovascular stenting of the ductus with balloon atrial septosomy.
Sources: New England Journal of Medicine
Ohye RG, et al "Comparison of shunt types in the Norwood procedure for single-ventricle lesions" N Engl J Med 2010; 362: 1980-92.
Bondy CA "Hypoplastic left heart syndrome" N Engl J Med 2010; 362: 2026-28.