Pediatric Cardiology

Pulmonary Valve Stenosis: Symptoms, Causes, Diagnosis and Treatment

Posted on by Prof. Dr. İbrahim Cansaran TANIDIR

Pulmonary valve stenosis (pulmonary stenosis) is a condition in which the valve between the right ventricle of the heart and the pulmonary artery does not open completely, obstructing blood flow. This condition creates a physical obstruction that makes it difficult for deoxygenated blood to reach the lungs to receive oxygen.

Functioning like a perfect one-way valve, this valve allows blood to flow only forward. A reduction in the valve opening directly disrupts the hemodynamic balance on the right side of the heart, affecting the circulatory system.

Forcing blood to pass through a narrow area keeps the mechanical load and internal pressure on the heart chamber continuously elevated. Maintaining this resistance within normal values is vital for the healthy functioning of the circulatory network.

This congenital cardiovascular problem, when diagnosed at an early stage, is a structural disorder that can now be safely managed with modern cardiology approaches.

How Does Pulmonary Valve Stenosis (Pulmonary Stenosis) Disrupt Heart Function?

Our heart is a highly advanced pumping system consisting of chambers and valves that ensures the distribution and collection of deoxygenated and oxygenated blood throughout the body without allowing them to mix. Blood with reduced oxygen levels in the body reaches the upper right chamber of the heart and then passes into the lower right chamber, known as the right ventricle. The most important function of the right ventricle is to contract and send this blood to the lungs for oxygenation. The pulmonary valve is located between the right ventricle and the main artery leading to the lungs. This valve functions like a one-way valve that opens when the heart contracts, allowing blood to move forward, and closes when the heart relaxes, preventing blood from flowing backward.

In a narrowed pulmonary valve, however, this one-way opening cannot open sufficiently. Just as you need to exert more force when trying to push water through a narrow pipe, the right ventricle begins to make an extraordinary effort to propel blood through the narrow valve into the lungs. Over time, this chronic strain causes the heart muscle to thicken. Just as the muscles of an athlete who lifts weights become more prominent, the heart muscle also increases in size to withstand this pressure. However, this thickening of the heart muscle may eventually reduce the heart’s flexibility, make it more difficult to fill with blood, and create conditions in which pressure affects the other heart chambers and disrupts their structure. In the long term, the muscle layer immediately beneath the valve may even become so thick that muscular compression from below is added to the existing valve stenosis, significantly obstructing blood flow.

Which Processes in the Womb Contribute to the Development of Pulmonary Valve Stenosis (Pulmonary Stenosis)?

Embryological development in the womb consists of highly sensitive and complex stages. Interruptions that occur while the tissues forming the heart are developing during the early stages of pregnancy may prevent the small leaflets forming the pulmonary valve from separating sufficiently. These leaflets, which should normally separate delicately from one another to open and close, may remain attached and form a membrane with only a small opening in its center.

In some cases, the problem is not limited to the leaflets being attached to one another. The tissue forming the valve may be much thicker than normal, have lost its elasticity, and have an irregular structure. This condition, known as the dysplastic form, may sometimes occur alongside various syndromes with a genetic background. Regardless of the structural form of the valve, the main problem is the physical obstruction to blood flow into the lungs, and the degree of this obstruction is the most important factor determining the course of the disease.

What Symptoms Does Pulmonary Valve Stenosis (Pulmonary Stenosis) Cause in Children?

The symptoms caused by this condition in children vary considerably depending on how narrow the valve is and the child’s age. In mild or moderate stenosis during infancy and childhood, there are usually no obvious symptoms that can be noticed externally. Children often appear extremely energetic and healthy. The disease is usually detected during a routine examination through an additional sound, called a heart murmur, that the doctor hears while listening to the heart. This sound results from turbulence created as blood passes through a narrow opening.

However, in older children with severe stenosis, certain clinical signs may appear because the heart begins to struggle against this high resistance. Reduced exercise capacity and various symptoms may become noticeable to families.

Symptoms commonly encountered in advanced cases include:

  • Getting tired easily
  • Shortness of breath during exertion
  • Pain in the chest area
  • Dizziness and fainting during exercise
  • Bluish discoloration around the lips
  • Bluish discoloration of the nail beds
  • Distension of the neck veins
  • Swelling in the legs
  • Swelling in the abdominal area
  • A sensation of palpitations

During the neonatal period, however, the condition may follow a very different course. In critical stenosis, where the valve opening is reduced to just a few millimeters, the right ventricle can send almost no blood to the lungs. Because babies’ lungs do not function in the womb, blood is distributed throughout the body through a special vascular connection. When this connection begins to close after birth, if the baby has critical stenosis, blood flow to the lungs is largely interrupted, and bluish discoloration, oxygen deprivation, and cardiac strain may develop rapidly.

Which Methods Are Used in Hospitals to Diagnose Pulmonary Valve Stenosis (Pulmonary Stenosis)?

Our primary diagnostic tool is echocardiography, which uses sound waves to visualize the heart. This procedure is painless, does not involve radiation, and is quite comfortable for the child. The anatomy of the heart is examined in detail using a gel applied to the chest area and a probe. Thanks to color Doppler technology, the speed of blood passing through the narrowed valve is measured in real time.

These measured velocity values are converted into pressure differences within the heart using various physical formulas. The higher the pressure difference between the right ventricle and the pulmonary artery, the more severe the stenosis. However, the assessment is not limited to pressure measurements alone. The thickness of the valve leaflets, their opening capacity, the contraction strength of the right ventricle, the degree of heart muscle thickening, the child’s symptoms, and overall condition are also comprehensively examined.

Today, except in rare cases accompanied by highly complex anatomical problems, diagnostic angiography (catheterization) performed through the groin is rarely used solely for diagnosis. Catheterization is generally preferred when it is used for treatment rather than diagnosis or when it is necessary to measure the actual pressures inside the heart with high precision during the procedure.

According to Which Criteria Is the Severity of Pulmonary Valve Stenosis (Pulmonary Stenosis) Classified?

When this condition is detected in a child, the degree of stenosis is classified to determine the approach to be followed. This classification is based on the pressure difference between the right ventricle and the pulmonary artery and forms the basis of the follow-up and treatment plan.

The levels of stenosis determined according to the pressure difference are:

  • Mild stenosis
  • Moderate stenosis
  • Severe stenosis
  • Critical stenosis

In mild stenosis, the pressure difference is quite low. The heart can easily tolerate this condition. Intervention is generally unnecessary, and monitoring through echocardiographic examinations performed at regular intervals is considered sufficient.

In moderate stenosis, the pressure difference begins to place some strain on the heart. At this stage, the disease may carry a risk of progressing over time. If the child has developed symptoms or pressure measurements show an increasing trend during follow-up, plans are made to open the valve before the heart muscle becomes damaged.

In severe stenosis, the heart muscle is attempting to pump blood against extremely high pressure. Even if the child reports having no symptoms, intervention without delay is generally considered necessary to prevent permanent cellular changes in the heart muscle and potential rhythm problems in the future.

In the group defined as critical stenosis, which is generally encountered in newborn babies, the valve opening is too narrow to sustain life. In this situation, the body’s circulation is at serious risk, and the aim is to initiate emergency intervention protocols within hours.

How Is Pulmonary Valve Stenosis (Pulmonary Stenosis) Treated Without Open Surgery?

While surgically opening the valve was the only option in previous years, catheter-based methods called balloon valvuloplasty are now used in the vast majority of suitable cases. This procedure is performed not in an operating room but in catheterization laboratories equipped with advanced X-ray devices. Anesthesia or deep sedation is provided for the child’s comfort and the safety of the procedure.

The procedure begins by inserting a thin needle into a large vein in the groin area. Through a cannula called a sheath placed inside the blood vessel, a very soft and flexible wire is slowly advanced toward the heart through a long, thin tube (catheter). This wire is guided from the right atrium into the right ventricle and then through the narrowed valve into the pulmonary artery. The wire serves as a safe guiding rail for the balloons that will be used.

The central part of the treatment is selecting the size of the special balloon that will be used to widen the valve. The balloon is chosen to be a certain proportion larger than the narrowed valve annulus so that it can separate the attached portions of the valve. The balloon size is calculated with millimeter precision under X-ray guidance. The narrow, deflated balloon catheter is slid over the wire and positioned precisely in the center of the valve.

Once the correct position is achieved, a special fluid is pumped into the balloon at high pressure. As the balloon inflates, the attached portions of the valve resist the balloon, and an hourglass-shaped indentation appears in the middle of the balloon on the X-ray screen. As the pressure increases, the adhesions separate, and the hourglass appearance suddenly disappears as the balloon takes on a complete cylindrical shape. This is a sign that the stenosis has been mechanically opened. Because blood flow stops briefly when the balloon is inflated, completing the inflation and deflation process rapidly within approximately ten to fifteen seconds is extremely important for safety.

How Is Critical Pulmonary Valve Stenosis (Pulmonary Stenosis) Managed in Newborn Babies?

Critical stenosis encountered in newborn babies who are only a few days old requires a technically different approach. The extremely small size of the heart structures and the fact that the valve opening is almost as small as the head of a pin make the direct use of standard balloons difficult.

In these babies, special medications are first administered to keep the temporary vascular connection leading to the lungs open and stabilize the condition. The baby is then taken to the catheterization laboratory, where a gradual dilation technique is applied. In the first stage, very low-profile coronary balloons, generally designed to open blockages in the coronary arteries, are used. These thin balloons are passed through the tiny opening and inflated to stretch the valve slightly. Once the valve has been opened a little, standard valvuloplasty balloons appropriate for the baby’s age, which will provide the main treatment, are safely positioned across the valve to achieve the desired opening. This technique greatly helps protect babies from undergoing major open-heart surgery.

Why Can the Heart Muscle React Unexpectedly After Pulmonary Valve Stenosis (Pulmonary Stenosis) Is Relieved?

Sometimes, although the valve appears to have been successfully widened with a balloon, pressure measurements taken after the procedure may reveal that the values are still high or even higher than before the procedure. This does not mean that the procedure has failed; rather, it is a mechanical response of the heart muscle called dynamic infundibular obstruction or spasm.

The right ventricle, which has been trying to pump blood through a narrow valve for months or years, has excessively strengthened and thickened the muscle layer beneath the valve. When the valve is suddenly opened with a balloon, the resistance in that area disappears. Because the resistance has been eliminated, these powerful muscles strike against one another so forcefully with every contraction that the muscle mass beneath the valve begins to obstruct the blood flow instead.

If the images on the screen confirm that the valve has opened, this muscular reaction is controlled with medication rather than repeatedly intervening on the valve with large balloons. Special medications that reduce the speed and force of heart contractions are started to relieve the spasm in that area. Because the valve stenosis is no longer present, the heart muscle begins returning to its natural structure over the following months, and this muscle-related obstruction often disappears on its own.

Which Valve Implantation Methods Are Preferred for Pulmonary Valve Stenosis (Pulmonary Stenosis) in Patients with Different Anatomical Structures?

Although balloon dilation is generally very suitable for membranous stenosis, it may not produce the desired response in every valve structure. In some cases, the valve tissue may have become excessively thick, lost its normal structure, and become resistant to stretching. In addition, some patients who previously underwent open surgery for congenital heart diseases and had an artificial conduit placed between the heart and pulmonary artery may experience calcification, narrowing, or loss of function of this artificial conduit or the prosthetic valve inside it over the years.

While these patients previously had to undergo repeated open-heart surgeries, it is now possible to implant a new valve through a catheter using a method called transcatheter valve replacement. In this procedure, a new heart valve, usually made from biological materials, is folded and mounted onto the tip of a thick catheter. Once the affected area is reached through the groin, the new valve inside the catheter is positioned over the problematic blood vessel or old valve and expanded. The new valve immediately begins functioning and regulates blood flow. Thus, the patient is largely spared the difficulties associated with another surgery. Through meticulous examinations performed before the procedure, whether the newly implanted valve might compress surrounding tissues or coronary arteries is carefully evaluated.

What Are the Differences Between Pulmonary Valve Stenosis (Pulmonary Stenosis) Interventions Performed Through the Groin and Open Surgery?

Except for special conditions that require surgery because of anatomical characteristics, catheter-based methods for isolated valve stenosis offer patients significant advantages in various respects. These benefits positively affect both the speed of recovery and psychological comfort during hospitalization.

The general advantages of interventional methods for patients include:

  • No incision scar on the chest
  • No need for a heart-lung machine
  • Short hospital stay
  • Rapid return to daily life
  • Low need for blood transfusion
  • Low risk of infection

While open-heart surgery requires stopping the heart, transferring blood circulation to machines, and opening the breastbone, the heart continues beating in its natural rhythm during balloon procedures. After the procedure, instead of a large surgical scar, there is only a small needle entry site in the groin area, and applying a small adhesive dressing is often sufficient.

While the average hospital stay after surgery is around one week and bone healing takes several weeks, a patient treated with a balloon can generally get up within hours after the procedure and return home within one or two days. Because the risk of blood loss is very low, the need for blood transfusion is extremely rare.

What Follow-Up Process Awaits Children After Pulmonary Valve Stenosis (Pulmonary Stenosis) Treatment?

The overall risks of complications after catheter-based treatments are quite low. The most common condition that families should be informed about after treatment is the possibility of pulmonary valve insufficiency, meaning backward leakage of blood. Separating the adhesions in the valve using pressure may create very small gaps that prevent the valve from closing completely. These mild leaks can be observed in a certain proportion of children who undergo the procedure. However, the right side of our heart naturally adapts quite easily to these low-pressure leaks. Therefore, mild or moderate insufficiency does not cause symptoms in the child or affect their overall condition. If, during years of follow-up, the leakage increases and places strain on the heart, although this is rare, it is possible to intervene again using valve implantation methods performed through the groin.

After the procedure, follow-up examinations are performed with echocardiography at certain intervals, for example, in the first month, sixth month, and once a year thereafter. During these examinations, whether the pressure difference across the valve remains low and the process of normalization of the thickened heart muscle are evaluated. In most cases treated with the balloon method, we expect the valve to remain permanently open and the overall heart structure to enter a process of recovery.

The aim is for children who have completed the diagnosis and treatment processes for this condition to have the same quality of life as their peers. As long as they follow the monitoring program recommended by their doctors, children can continue their social lives, play activities, and education without restrictions.

Güncellenme Tarihi: 13.10.2026

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