Tyler's Upcoming Glenn Procedure

The bidirectional Glenn procedure is the surgery used to prepare the heart for a Fontan procedure, Tyler's final stage of the Norwood typically done at 3-5 years. It is a surgery in which a detour (shunt) is created from the aorta to the pulmonary artery. The bidirectional shunt is performed by connecting the superior vena cava (SVC) to the right branch of the pulmonary artery using fine sutures, and dividing or tying up the pulmonary artery. Now, venous blood from the head and upper limbs will pass directly to the lungs, bypassing the right ventricle. The venous blood from the lower half of the body however will continue to enter the heart. At a second operation, the lower body venous blood will also be diverted to the lungs, thus creating the "complete" Fontan circulation.The bidirectional Glenn shunt is preferred in very small babies - below 2 years of age - in whom the lung vessel resistance is still quite high. While avoiding the risk of failure of a complete Fontan operation, it also partly relieves symptoms. Typically quality of life for HLHS infants increases after the Glenn procedure because of a decrease in volume load on the single ventricle while improving oxygen saturation as compared to the pre-operative state. In addition, by being a low-pressure shunt, it does not carry the risk of causing lung blood vessel thickening and hardening.