7th March 2024

Pulmonary Valve

Pulmonary Stenosis

Pulmonary stenosis (PS) is mostly a congenital condition and is characterised by an ejection systolic murmur heard best in the pulmonary area. It causes a widely split S2. In 80% to 90% of all cases, PS is found at the level of the valve, but it can also occur below the level of the valve or distally in the pulmonary arteries. It can be asymptomatic. Symptoms range from those primarily due to right heart failure, such as dyspnoea, fatigue and peripheral edema to profound cyanosis and sudden death. PS is also associated with an increased risk of arrhythmias. Causes of PS include:

• Carcinoid syndrome
• Pellagra
• Tetralogy of Fallot
• Congenital
• LEOPARD syndrome
• Noonan syndrome

Diagnosis

Like other valvular diseases, echocardiography with Doppler study remains the mainstay of investigation, showing an abnormal morphology of the pulmonary valve and an increased transvalvular gradient across the pulmonary valve during systole (>10 mmHg). ECG is normal in 30-65% of patients but in moderate to severe PS can show right axis deviation and RV conduction delay. There may also be right atrial enlargement with tall and peaked P waves in lead II and in precordial leads V1 to V3. 

Arterial blood gas or pulse oximetry may show a low arterial oxygen saturation. 

Diagnostic cardiac catheterisation is indicated prior to therapeutic relief of moderate to critical stenosis. It is also indicated when peripheral pulmonary stenosis is suspected to determine its severity and anatomy. It shows an increased transvalvular gradient (>10 mmHg).

Management 

Mild disease is usually managed with watchful waiting. It requires only sequential cardiology follow-up into adulthood. Moderate to severe disease can be treated with percutaneous balloon pulmonary valvuloplasty (PBPV). 

Surgical valvuloplasty is used in patients not amenable to PBPV or those with multiple levels of fixed obstruction.

Valvectomy is also an option with or without a transannular patch. In patients with respiratory distress or cyanosis, supplemental oxygen with or without alprostadil is used in addition to the above.

Pulmonary Regurgitation

Any disease of the left side of the heart or the lungs that results in significant pulmonary hypertension and dilated pulmonary arteries may lead to acquired pulmonary regurgitation (PR). PR may also be due to a congenital defect. Acquired PR typically results from surgical repair of Tetralogy of Fallot; pulmonary stenosis, atresia, carcinoid syndrome, rheumatic fever or as a result of infective endocarditis. 

Isolated PR is rarely symptomatic; however, large regurgitant volume in the presence of dilated right ventricle may be associated with exertional dyspnoea, easy fatigability, and intermittent chest pain. 

PR is characterised by an early diastolic murmur along the left sternal border in the second intercostal space with the patient in full inspiration, called a Graham Steell Murmur. This murmur is often heard in patients with chronic cor pulmonale as a result of chronic obstructive pulmonary disease.

Since most PR is secondary to another cause, treatment revolves around treating the underlying cause. Surgical management is rarely required, with the mainstay of treatment being medical management of heart failure. 

References

• Pulmonary Stenosis BMJ Best Practice. [Online] https://bestpractice.bmj.com/topics/en-gb/475
• Pulmonary Regurgitation BMJ Best Practice. [Online] https://bestpractice.bmj.com/topics/en-us/474