Congenital heart abnormalities such as hypoplastic left heart syndromereduce the flow of blood from the heart to the lungs, such that it does not carry sufficient levels of oxygen through the body.  Complex surgeries shortly after birth are typically required to address the defects and increase blood flow to the lungs.  Procedures like the Norwood operation create new connections directly between the pulmonary artery and the right ventricle to increase blood flow to the lungs via a surgical shunt. This is typically the first surgery of a series of three where the blood flow is optimized to maintain proper oxygenation when a single ventricle is responsible for pumping blood throughout the body.  Following the first surgery, close attention is paid to the patients, with pharmacological and surgical procedures used to maintain optimal blood flow and mixing in a rapidly growing infant.  As the child grows, the small diameter of the grafted shunt makes it progressively harder to maintain proper oxygenation and subsequent surgeries are often required to replace the graft with one that has a larger diameter.

In an effort to make reduce the need for these follow up surgeries, cardiothoracic surgeon Dr. Randy Stevens of St. Christopher's Hospital for Children, biomedical engineers Dr. Kara Spiller, Dr. Amy Throckmorton and their teams have developed a new graft that directly addresses this problem.  Unlike the traditional graft, the new device consists of a larger diameter vessel that is lined with a hydrogel such that the channel is the appropriate diameter for the size of the child at the time of surgery.  Knowing the chemical properties of the hydrogel, it can be formulated in such a way that over time, the hydrogel lining elutes from the graft and the diameter of the vessel gets progressively larger as the child grows.  As such, the vessel grows with the infant in a way, reducing the need for follow up surgeries to replace the original graft.