Pulmonary valve disease

Definitions & Key takeaways

Pulmonary valve disease is a condition that affects the pulmonary valve, which is located between the right ventricle and the pulmonary artery.

Pulmonary valve diseases include pulmonary valve stenosis, which is associated with congenital heart conditions like Tetralogy of Fallot. It results in the pulmonary valve not opening fully and has a characteristic crescendo-decrescendo murmur on auscultation. Over time, it can lead to right-sided heart failure and signs of cyanosis but can be treated with balloon valvuloplasty.

There is also pulmonary valve regurgitation, which results in blood flowing backward into the right ventricle, and it is characterized by a diastolic-decrescendo murmur. It's usually asymptomatic, but over time it can also lead to right-sided heart failure. Pulmonary valve regurgitation can be treated with valve replacement.

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Introduction0:00–0:38

The pulmonary valve is typically made up of three leaflets - the anterior, the left and the right, and it opens during systole to allow blood to be ejected to the lungs.
During diastole, it closes, to allow the heart to fill with blood and get ready for another systole. If the pulmonary valve doesn’t open all the way, it gets harder to pump out to the lungs, and this is called pulmonary stenosis.
If it doesn’t close all the way, then blood leaks back into the right ventricle, and this is called pulmonary valve regurgitation or pulmonary insufficiency.

Causes of pulmonary stenosis0:38–1:14

Pulmonary valve stenosis is often congenital, meaning that from birth the leaflets may not be fully developed, or irregularly shaped.
Pulmonic valve stenosis is often associated with congenital heart conditions like Tetralogy of Fallot, which affects all four chamber of the heart, as well as a genetic condition called Noonan's syndrome.
Other times, there can be mechanical stress over time, which damages endothelial cells around the valves, causing fibrosis and calcification, which hardens the valve and makes it more difficult to open all the way.

Pathology of pulmonary stenosis1:14–1:48

Because it’s kind of hard to open when the right ventricle tries to eject blood it resists for a second and then finally snaps open.
And this causes a characteristic “ejection click”. Also since the blood has to flow through a narrow opening, there ends up being turbulence after which creates a noise or a murmur, which gets louder as more blood flows past the opening and then gets quieter as the amount of blood flowing subsides because less in the ventricle.
This sound is described as a crescendo-decrescendo murmur. Since it’s harder to open and push blood past this hardened valve, the right ventricle has to generate really high pressures, and to achieve those pressures it thickens its muscles, called concentric right ventricular hypertrophy.

Complications of pulmonary stenosis1:48–2:47

This happens because new sarcomeres are added in parallel to the existing ones. Even though you have this bulked up ventricle, the heart still might struggle to get enough blood through the narrowed opening and the lungs, and ultimately that means having blood get backed up, and and so the person can develop right-sided heart failure.
A final different complication is called microangiopathic hemolytic anemia, which is essentially damage to red blood cells as they’re forced through the smaller valve, and this splits them into smaller fragments called schistocytes, which leads them to get peed out in the urine and leads to hemoglobinuria or hemoglobin in the urine.

Symptoms of pulmonary stenosis2:47–3:18

As far as signs and symptoms go, when the blood gets backed up into the body it can lead to distended neck veins, swelling of the ankles and feet as well as hepatosplenomegaly, which is an enlarged liver and spleen.
Since less blood is able to get into the lungs, it can also cause symptoms like cyanosis, which is blue or purple discoloration of the skin, as well as shortness of breath and fatigue - which are most noticeable when the body’s demand for oxygen is high - like during exercise.

Diagnosis and Treatment of pulmonary stenosis3:18–3:35

Diagnosis is usually done with an echocardiogram, and treatment of pulmonic valve stenosis usually involves a balloon valvuloplasty, which means that a balloon is inserted and then inflated to open the narrowed valve and allow more blood flow through it.

Causes of pulmonary regurgitation3:35–4:30

Alright so that was pulmonary stenosis, what about pulmonary regurgitation? With pulmonary regurgitation, the valve doesn’t close all the way during diastole, or ventricular filling, so blood ends up flowing back from the pulmonary artery into the right ventricle.
Regurgitation can happen due to valvular damage, from something like infective endocarditis, which is a bacterial infection of the inner lining of the heart.
Another cause is rheumatic heart disease, where chronic inflammation leads to fibrosis, but instead of fusing the valve leaflets together, it makes it so that they don’t form a nice seal and instead let blood leak through.
Sometimes pulmonic regurgitation can be caused by previous heart surgeries, as well, like a balloon pulmonary valvuloplasty for pulmonary stenosis that opens the valve too far, or a malfunctioning prosthetic valve.

Pathology and complications of pulmonary regurgitation4:30–5:20

In pulmonary regurgitation, since blood’s leaking back from the pulmonary artery into the right ventricle, there’s a diastolic decrescendo murmur.
It’s considered a decrescendo murmur because it starts out loudest and then becomes more quiet over time. The backflow of blood increases the right ventricular blood volume and the amount of work that the right ventricle has to do during systole, so over time the right ventricle grows larger, a process this time called eccentric ventricular hypertrophy.
In this situation, new sarcomeres are added in series to existing ones. This compensation works for a little while, but eventually the right ventricle might not be able to keep up and this can again lead to right-sided heart failure.

Symptoms of pulmonary regurgitation5:20–5:36

Initially, pulmonary valve regurgitation might cause no symptoms at all, but over time can lead to right-sided heart failure which can lead to blood backing up and symptoms like distended neck veins, swelling of the ankles and feet and hepatosplenomegaly.

Diagnosis and treatment of pulmonary regurgitation5:36–5:46

Diagnosis is usually again done with echocardiogram, and treatment for pulmonary regurgitation is usually valve replacement if right-sided heart failure develops.

Review5:46–7:39

All right, as a quick recap, pulmonary valve stenosis is associated with congenital heart conditions like Tetralogy of Fallot, and it results in the pulmonary valve not opening fully, and causes a crescendo-decrescendo murmur.
Over time it can lead to right-sided heart failure and signs of cyanosis, but can be treated with balloon valvuloplasty.
Pulmonary valve regurgitation is associated with things like infection and surgeries, and results in blood flowing backwards into the right ventricle and it can cause a diastolic-decrescendo murmur.
It’s usually asymptomatic, but over time it can lead to right-sided heart failure, and can be treated with valve replacement.