Glenn procedure


The Glenn procedure, also known as the bidirectional Glenn procedure, is a surgical operation designed to enhance blood flow in cases where a heart has a small left or right side. This typically involves either the valve connecting the upper and lower heart chambers or the pumping chamber itself. During this procedure, the superior vena cava of the child is connected to their pulmonary arteries, enabling oxygen-deprived blood to be directed straight to the child’s lungs.

The superior vena cava serves to return oxygen-poor blood from the upper part of the body. In a normal scenario, this blood would pass through the heart’s chambers before reaching the pulmonary artery for oxygenation. The Glenn surgery facilitates the redirection of this oxygen-poor blood to the lungs, bypassing any problematic areas within the heart.

Typically, this surgery follows one or more initial surgeries that babies may undergo soon after birth. In some cases, children may require additional surgery several years later to establish a more permanent solution.

Reasons for undergoing the procedure

The bidirectional Glenn procedure improves blood circulation in individuals with a congenital heart defect present at birth, preventing them from having a normal circulation route through their heart. Typically, the issue involves a single ventricle defect, indicating that one of the heart’s valves or lower chambers responsible for pumping blood is either malfunctioning or too small to be effective.

Surgeons typically conduct the Glenn heart procedure when a child is between 3 to 6 months old, typically not younger than 2 months old. The highest chances of survival occur when the Glenn procedure is performed three to six months after the initial neonatal operation, especially if the child has a condition necessitating the procedure to enhance circulation.

Doctors carry out the Glenn procedure to address the following heart defects:

  • Hypoplastic left heart syndrome.
  • Double inlet left or right ventricle.
  • Unbalanced atrioventricular canal defects.
  • Certain variations of congenitally corrected transposition of the great arteries, where the pulmonary artery and aorta are positioned incorrectly, and the valves and ventricles are improperly connected.
  • An intact ventricular septum accompanied by pulmonary atresia.
  • Tricuspid atresia (absence of the tricuspid valve formation between chambers).


Approximately 30% of individuals undergoing a Glenn procedure may experience complications, including:

  • Cardiac arrest.
  • High blood pressure.
  • Emergency cardiac catheterization.
  • Low oxygen level.
  • Reoperation is required.
  • A recent neurologic deficiency.
  • Difficulties with feeding that necessitate the use of a feeding tube.
  • Pleural effusions (accumulation of excess fluid outside your child’s lungs).

Before the procedure

Typically, individuals who have undergone a Blalock-Taussig (BT) shunt or had a pulmonary artery band in the past will often require a Glenn cardiac procedure as the subsequent step to enhance blood circulation in a heart with only one effective atrioventricular valve or ventricle (pumping chamber).

Before the surgical procedure, your child’s healthcare provider will want to:

  • Perform a cardiac catheterization or heart magnetic resonance imaging (MRI) to examine your child’s anatomy.
  • Be informed about all of your child’s medications (including non-prescription medicines and supplements they take).

During the procedure

A Glenn procedure typically lasts around four hours, although the duration may vary depending on the specific circumstances. Throughout the surgery, your child will be under general anesthesia, ensuring they are in a deep sleep and will not experience any sensations or memories of the procedure. While some children may require the use of a cardiopulmonary bypass machine to assist their heart and lungs during the surgery, it is not necessary for everyone. The surgeon will also address any issues stemming from previous procedures and establish a connection between your child’s superior vena cava and either their right or left pulmonary artery, making any other essential heart repairs as needed during this operation.

After the procedure

The surgical team will closely monitor your child in the intensive care unit (ICU), and it may take a few weeks for them to return to their normal state. It’s important to note that not all individuals with a single ventricle issue requiring a Glenn procedure will necessarily need a Fontan procedure in the future. However, if a Fontan procedure becomes necessary, it will establish distinct systems for managing oxygen transfer from your child’s lungs to their blood and ensuring the circulation of oxygen-rich blood throughout their body. The effects of the Glenn procedure can persist until your baby is ready for the subsequent surgery, typically the Fontan procedure, which becomes necessary for most children as they start walking. During this stage, physical activity can potentially exacerbate their already low oxygen levels.


Following the Glenn procedure, your child will require approximately three days of care in the ICU, followed by several additional days in a standard hospital room before they can be discharged. It’s important to note that the survival rate for the Glenn procedure is approximately 99%. Subsequently, your child will need to attend routine follow-up appointments with their healthcare provider, with the initial visit to the cardiologist (heart doctor) being scheduled before leaving the hospital.

Once your child is home, it’s essential to promptly contact their healthcare provider if your child experiences any of the following symptoms:

  • Fever.
  • Drainage of blood or other fluids from their chest wound.
  • Difficulty with feeding.
  • Struggles in gaining weight.