An RVOT stent is a specialized, minimally invasive intervention used in pediatric cardiology. This procedure involves placing a wire mesh tube into the heart’s outlet pathway to improve blood circulation to the lungs. It is primarily used in infants and neonates born with congenital heart defects that severely restrict pulmonary blood flow. The device is a temporary measure, acting as a bridge until the patient is stable enough to undergo definitive, open-heart surgical correction.
Understanding the Right Ventricular Outflow Tract
The right ventricular outflow tract (RVOT) is the specialized channel connecting the right ventricle to the pulmonary artery, the vessel carrying deoxygenated blood to the lungs. This tract includes a muscular funnel-shaped segment known as the infundibulum, which leads directly to the pulmonary valve.
In certain congenital heart conditions, this pathway is severely narrowed or obstructed, a problem known as pulmonary outflow tract obstruction. This obstruction prevents a sufficient volume of blood from reaching the lungs, leading to a reduction in the body’s overall oxygen saturation. The most common condition requiring intervention is severe Tetralogy of Fallot, which is characterized by a combination of defects including pulmonary stenosis. When the RVOT is significantly narrowed, the patient develops cyanosis, often referred to as “blue baby syndrome,” due to the systemic circulation of poorly oxygenated blood. The degree of obstruction directly correlates with the severity of cyanosis, making immediate intervention necessary to increase pulmonary blood flow.
The Role of the RVOT Stent
The RVOT stent is deployed to mechanically prop open the severely narrowed outflow tract, increasing the volume of blood flowing from the right ventricle into the pulmonary arteries. This action immediately boosts the patient’s oxygen saturation, alleviating cyanosis. By establishing a more reliable, forward-moving flow of blood, the stent bypasses the obstruction.
The stent serves as a palliative measure, not a permanent solution to the congenital defect. It provides a controlled, pulsatile blood flow directly from the right ventricle, which is important for the development of the pulmonary arteries. This pulsatile flow encourages the growth and expansion of small or underdeveloped pulmonary arteries, a major factor in determining the success of future corrective surgery.
Unlike a surgical shunt, the RVOT stent maintains the heart’s natural flow pattern. This more physiological circulation promotes balanced pulmonary artery growth in preparation for the ultimate surgical repair. The time the stent is in place, often several months, allows the infant to gain weight, mature, and stabilize before the open-heart operation.
Performing the Stent Placement Procedure
The placement of an RVOT stent is a minimally invasive procedure performed in a cardiac catheterization laboratory, avoiding open-heart surgery. The process is typically conducted under general anesthesia. Access to the circulatory system is usually gained through a large vein, such as the femoral vein in the groin or the internal jugular vein in the neck.
A thin, flexible catheter is carefully guided through the vein and into the heart’s right-sided chambers, using continuous X-ray imaging (fluoroscopy) for precise navigation. The catheter is advanced until it reaches the site of the obstruction within the RVOT. To counteract dynamic muscle spasms that can occur during the procedure, some institutions administer medications like an intravenous esmolol infusion.
A specialized guidewire is passed across the narrowed segment, and the stent, mounted on a balloon, is threaded over this wire. Once the stent is positioned correctly across the obstruction, the balloon is inflated to expand the stent against the wall of the RVOT. The expanded metal scaffolding anchors itself in place, holding the pathway open. After deployment, the balloon and catheter are withdrawn, leaving the stent permanently in the vessel wall. An angiogram is immediately performed to confirm successful positioning and the resulting increase in blood flow to the pulmonary arteries. The entire procedure often takes around 60 minutes.
Managing Stent Function and Follow-up Care
After successful RVOT stent placement, follow-up care monitors the patient for improved heart function and oxygenation. The most direct indicator of success is a significant rise in arterial oxygen saturation, often increasing from critically low levels to the mid-80s or low-90s. This improvement allows the infant to feed and grow more effectively, reducing stress on the heart and lungs.
To prevent blood clots from forming on the stent’s surface, patients are prescribed antiplatelet therapy. This often involves a daily, low-dose regimen of acetylsalicylic acid, or Aspirin, typically administered at a dose of 3 to 5 milligrams per kilogram of body weight. In some cases, a beta-blocker medication like propranolol may also be prescribed to reduce the risk of the RVOT muscle growing inward and narrowing the stent prematurely.
The long-term plan involves surveillance until the infant is ready for definitive open-heart surgery, typically scheduled when the patient reaches a favorable weight and age, often around 3 to 7 months. The stent is removed during this final corrective procedure, such as the total repair of Tetralogy of Fallot, which restores the heart’s normal anatomy.