Glenn procedure

The Glenn procedure is the second of three congenital open heart surgeries performed to correct hypoplastic left heart syndrome (HLHS) and other single ventricle heart defects. It is usually performed about six months after birth, following the Norwood procedure. 

What is the Glenn procedure?

During the Glenn surgery, congenital heart surgeons finish rerouting the baby's blood flow from the upper body to the lungs. They do this by disconnecting the superior vena cava – the large vein that carries the oxygen-poor blood from the upper body (head and arms) to the heart – and attaching it to the pulmonary artery. As a result, the blood will go directly to the lungs without circulating through the heart at all. This redirect means that the temporary shunt placed during the Norwood procedure is no longer needed, so it is removed. After the Glenn procedure, your baby's heart will no longer have to work twice as hard, and the risk for problems is usually lowered. 

Sometimes, the redirect that's created from the Glenn procedure creates increased pressure for the superior vena cava. This pressure can result in some swelling in the brain that can result in headaches, known as "Glenn head." This typically appears within a week after the procedure, and often dissipates within a few days to a week. During this time, the headaches can be treated with medication to help alleviate the discomfort. 

Excellent Glenn procedure surgery outcomes

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The Glenn procedure is much less complicated than the multi-step first (Norwood) surgery, but still requires the expertise of highly experienced congenital surgeons to build successfully on the previous procedure. Children's Wisconsin offers survival rates exceeding 96 percent – among the best in the world. Our pediatric congenital heart surgery program is recognized nationally for consistently achieving outstanding outcomes for even the most complex types of heart disease. Learn more about our heart surgery outcomes.

Note: Data is provided from the Society of Thoracic Surgeons (STS). New data is not available beyond June 2019, as STS is in the process of refining their reporting methodologies. Hospitals are also limited in providing updated data due to the demands of the COVID-19 pandemic.

The Glenn procedure requires open heart surgery and will take about three hours to complete. During that time your baby will be on a heart-lung machine to temporarily take over breathing and blood circulation. Babies usually stay in the hospital a week after surgery, initially recovering in the cardiac intensive care unit (CICU). Learn more about postoperative care following surgeries for hypoplastic left heart syndrome.

Eventually, your surgeon will discuss the third and final procedure, the Fontan procedure. This usually occurs after your child is 18 months old, but can take place later in life.