What is Pulmonary Valve Stenosis

Overview

Our heart consists of chambers and valves. Consider chambers as rooms and valves as gates. Blood enters from one chamber to another through valves. If valves are stiff and hard, it means the gates are nearly locked and will not allow the blood to circulate freely. In medical linguistics, this stiffness of valves is called Valve stenosis. 

What is pulmonary valve stenosis

It’s a heart valve disorder caused by a defect in the pulmonary valve. This valve is between the right heart chamber and the pulmonary artery supplying blood to the lungs. 

Heart valves allow the blood to go out by opening their flaps and preventing the blood from returning by closing their leaflets. When they become stiff and rigid, the space available for blood to pass through is reduced, making it challenging for the blood to go to the lungs out of the heart. This condition is called pulmonary valve stenosis (PVS), where the pulmonary valve stops behaving normally.¹

Consider the pulmonary valve as the main exit where blood leaves the heart and enters the lungs to get oxygen. If the main exit is out of order, blood will get trapped, and the heart will work harder to pump it into the lungs. This thickens the heart muscles, can lead to heart failure, and thewhole body will suffer due to a lack of oxygen. 

In this article, we will explore the following: 

• Causes and diagnosis of pulmonary valve stenosis
• Management and treatment options for pulmonary valve stenosis. 
• Risk factors and complications 

Causes of pulmonary valve stenosis

Several unpredictable or unprecedented events cause the heart to be mal-developed during the first six weeks of pregnancy. At this stage of conception, the heart develops from a tube-like structure to a full-shaped heart. 

The root cause of PVS is specifically congenital because it originates from a heart problem developed during the embryonic stage before birth. However, adults can also acquire PVS, which can be due to other illnesses.⁴ In the case of adults, we call it acquired pulmonary stenosis rather than congenital PVS because it is not present at birth and happens later in life. 

Signs and symptoms of pulmonary valve stenosis

In the case of mild pulmonic stenosis, no typical symptoms appear; however, when it’s severe, the following symptoms occur more frequently: 

• Fatigue and Tiredness: Due to reduced cardiac output (amount of blood supplied by the heart per minute), the body lacks oxygenated blood supply. This depletes the energy stocks of the body which leads to fatigue
• Whooshing Heart Sounds: This is the noise the blood makes while passing through the narrowed pulmonary valve. Such sounds indicate defects in the heart valves
• Chest Pain: During exertion or physical exercise, the heartbeat goes up, and heart muscles are forced to work harder. Since these are already weak and extended, pain and discomfort get triggered
• Rapid Breathing: Due to a deficit of oxygen in the body, metabolic cells send signals to the brain to breathe faster to bring more oxygen inside. To meet the body’s demands, faster breathing is initiated. This phenomenon particularly dominates at times of physical activity
• Swollen legs, feet, ankles, or abdomen: Due to the failure of the right heart chambers, blood accumulates in the circulation system and exerts pressure on the peripheral venous system. Since the lower extremities (e.g., legs, feet, ankles) are under more influence of gravity, fluid accumulation is predominant there. Hence, these parts appear swollen compared to the rest of the body

Diagnosis of pulmonary valve stenosis

Once the physician hears the heart murmurs, it indicates that something is wrong with the heart. To gain clarity, the physician may suggest some imaging tests: 

• Echocardiography (Heart Ultrasound): In this imaging technique, sound waves produce a moving picture of the heart and make it easy to assess whether structural or functional anomalies exist. It reveals the intensity and location of pulmonary stenosis
• Electrocardiogram (ECG or EKG):² Electrodes are placed on the chest to generate a visual graph of heart rhythms. This does not reflect the structure of the heart, rather it gives deep insights into whether the electrical conductivity or pumping action of the heart is normal
• MRI / CT Scans: Sometimes, additional imaging tests are recommended to confirm the diagnosis, such as magnetic resonance imaging (the use of magnets to visualize the body) or computed tomography (CT) scans (the use of 3D X-rays to visualize the body), to confirm pulmonary valve stenosis

Management and treatment for pulmonary valve stenosis

The management and treatment of PVS depend on the severity of symptoms and the patient’s condition. Treatments for mild stenosis are not needed; however, regular check-ups with healthcare providers are necessary to track disease progression.

When symptoms are severe, surgical or non-surgical interventions are needed: 

• Cardiac catheterization: It’s a quick and minimally invasive procedure that opens up the narrowed space between flaps of the pulmonary valve

In this procedure, a catheter (a narrow tube with a balloon at the terminal) is inserted into the pulmonary valves, and the balloon is inflated when the tube reaches close to the space between valves. It pushes the valve leaflets apart, easing the passage for the blood to pass through. This procedure is also known as balloon valvuloplasty. 

Sometimes, even after heart catheterization, many patients feel relapse, and their symptoms reappear. For such patients, open heart surgery is recommended.

Valvotomy: Open-heart surgery involves valvotomy (valve repair) and valvectomy (valve removal). In valvotomy, scar tissue is removed. Removal of the hard matrix reverts the valves to normal functioning.

• Valvectomy: This is valve replacement surgery in which the pulmonic valve is completely removed and replaced with tissue from another human or animal. Usually, this procedure is  avoided in children  and is performed when they reach adulthood

Each treatment procedure has its risks and complications. It is always better to consult a physician regarding pre and post-surgical recommendations.   

Complications

Severe PVS increases the risk of other heart-related problems and leads to  complications such as: 

• Infection of the inner lining of the heart: Due to a narrowed pulmonary valve, the right chamber of the heart makes a greater effort to pump the blood against resistance. Therefore , turbulent blood flow makes the inner lining of the heart rough and creates a surface for the microbes to stay. So, microbial colonization causes endocarditis, which is the infection of the inner lining of the heart
• Enlargement of heart chambers: Due to the intense narrowing of the pulmonary valve, the lower right chamber of the heart (right ventricle) works harder to pump blood against resistance. The workload of the right ventricle increases; it expands in size and thickness, which is called ventricular hypertrophy
• Heart failure :  Sustained ventricular hypertrophy ultimately reduces the pumping efficiency of heart chambers and causes heart right ventricle failure—compromised functioning of the heart can cause leg swelling, chest pain, fatigue, and fainting

Risk factors

Some of the following factors increase the risk of pulmonary valve stenosis or congenital heart diseases if pregnant women are exposed to:

• German Measles (Rubella): A viral infection causing deafness and congenital heart defects in babies born to infected pregnant mothers. According to the NHS Vaccination schedule, all pregnant people should be vaccinated against rubella
• Alcohol: Too much alcohol affects the development of foetal tissues and increases the risk of heart disorders in developing fetuses. Pregnant individuals  should quit alcohol consumption. 
•  Diabetes: If a childbearing person  has type 1 or type 2 diabetes, there’s a higher risk of congenital heart problems in the baby. This is  due to increased insulin which interferes with the normal development of foetal tissues
• Medications: Certain medications are also linked to the risk of PVS if the person takes these during pregnancy

Anti-seizure medicines: particularly benzodiazepines (e.g. diazepam)  

Anti-acne medicines: specifically topical retinoids. 

Painkillers: Ibuprofen should not be taken during pregnancy. People  who take this after 30 or more weeks of pregnancy increase the risk of heart problems in their unborn babies.

FAQs

How can I prevent pulmonary valve stenosis?

Given that it is  a congenital heart defect a problem from birth, it is  not preventable; however, regular prenatal checks during pregnancy could be beneficial. According to the physician's recommendations, if the heart is not normally developing in the embryonic stages, something can be done to arrest the mal-development. 

If a child is born with PVS, a healthy and balanced diet can lower the chances of complications.

How common is pulmonary valve stenosis

Out of every 100 children  who are born with congenital heart defects, 50 are diagnosed with PVS¹ and its probability is greater in children with genetic disorders like Noonan and William Syndrome.

When should I see a doctor

During the following circumstances, it is advised to seek medical care: 

• When pregnant people  face severe symptoms of pulmonary stenosis, they cannot  handle pregnancy. Immediate consultation with a cardiac practitioner is necessary³
• When you feel your child's symptoms are worsening or when you notice a fast heartbeat, rapid breathing, and swelling in legs and ankles, a physician must be consulted
• If a child is pre-diagnosed with PVS , they are  at a higher risk of developing complications later in life.  In the case of such children, regular check-ups are recommended to avoid the risk of disease progression
• If pregnant people suspect heart problems in their fetuses, it is best to consult a pediatric cardiologist for early detection and management

Summary

Pulmonary vascular stenosis is a congenital heart disease and one of the common heart defects developed in unborn babies. Its risk factors include  diabetes, German measles, and alcohol consumption by the expecting individual. . Consulting healthcare professionals and maintaining a healthy lifestyle can mitigate the risk of serious complications.