Mild, severe, acute pulmonary insufficiency: symptoms and treatment

By Cristiano Antonino On Apr 19, 2023

With “pulmonic valve insufficiency” or “pulmonary insufficiency” (hence the acronym “IP”) in cardiology we mean incontinence of the pulmonary valve, i.e. the heart valve that allows the passage of oxygen-poor blood from the right ventricle to the pulmonary artery, which will carry it to the lungs (pulmonary bloodstream)

Normally the blood emitted from the right ventricle during systole (contraction of the heart) goes towards the lungs without being able to go back, since as soon as the blood is expelled from the heart, the pulmonary valve closes again, preventing reflux.

If the pulmonic valve is leaky, it allows abnormal retrograde flow of blood from the pulmonary artery into the right ventricle during diastole (the filling phase of the ventricle).

Part of the blood then literally goes back to the heart, causing a greater work for the heart muscle which chronically becomes more and more inefficient.

Mild pulmonary insufficiency is a normal echocardiographic finding in most people and usually does not require any action.

The situation is different in the case of moderate or severe insufficiency, which must be carefully evaluated.

Pulmonary insufficiency or respiratory insufficiency?

While pulmonary insufficiency refers to a pathology involving a heart valve (mainly the responsibility of the cardiologist), on the contrary, respiratory insufficiency is a syndrome caused by the inability of the entire respiratory system to perform its many functions, including to ensure adequate gaseous exchange in the body.

Respiratory insufficiency is mainly the responsibility of the pulmonologist.

Causes of pulmonary insufficiency

The most frequent cause of pulmonary insufficiency is pulmonary hypertension, secondary to various pulmonary and cardiovascular diseases.

Less common causes of pulmonary insufficiency are:

infective endocarditis (among the most common causes);
surgical repair of tetralogy of Fallot;
idiopathic dilatation of the pulmonary artery;
congenital valvular heart disease.

Rare causes of lung failure are:

carcinoid syndrome;
rheumatic arthritis;
catheter-induced trauma.

Severe pulmonary insufficiency is rare and is most often due to an isolated birth defect that leads to dilatation of the pulmonary artery and pulmonary valve annulus.

Pulmonary insufficiency can lead to right ventricular enlargement and eventually right heart failure, but in most cases, pulmonary hypertension contributes much more significantly to these complications.

Rarely, heart failure caused by right ventricular dysfunction develops when endocarditis causes acute pulmonary valve regurgitation.

Symptomatology (part for the patient)

Pulmonary failure is usually asymptomatic: few patients develop symptoms of right heart failure.

Symptoms include tiredness and a heart murmur that usually only a doctor can detect.

Symptomatology (more technical part for medical personnel)

Palpable signs are attributable to pulmonary hypertension and right ventricular hypertrophy. They include a pulmonic component (P2) of the 2nd heart sound (S2) palpable at the left upper sternal border and a prolonged right ventricular stroke that is increased in amplitude at the left lower and middle sternal border.

On auscultation, the 1st heart sound (S1) is normal.

S2 can be split or single.

When split, the P2 component may be loud and audible shortly after the aortic component of S2 (A2) due to pulmonary hypertension, or P2 may be delayed due to increased right ventricular stroke volume.

S2 may be single due to prompt closure of the pulmonic valve, with fused A2-P2 components, or more rarely, due to congenital absence of the pulmonic valve.

A 3rd right ventricular sound (S3), a 4th sound (S4), or both may be heard in heart failure due to right ventricular dysfunction or right ventricular hypertrophy; these auscultatory findings can be distinguished from those of the LV because they are located at the level of the 4th intercostal space on the left parasternal and because they increase in intensity with inspiration.

The murmur of pulmonary insufficiency due to pulmonary hypertension is a high-pitched, decrescendo early diastolic murmur that begins with P2 and ends before S1 and radiates to the mid-right sternal manubrium (Graham Steell’s murmur); it is best heard with the diaphragm of the stethoscope at the level of the left upper sternal border, while the patient holds his breath at the end of exhalation and is in a sitting position.

The murmur of pulmonary regurgitation in the absence of pulmonary hypertension is shorter, low-pitched (with a rough timbre), and begins after P2.

Both murmurs resemble the murmur of aortic regurgitation but can be distinguished into inspiration (which makes the IP murmur more intense) and following Valsalva release.

After the release of the Valsalva, the murmur of pulmonary insufficiency immediately becomes more intense (due to the immediate venous return towards the right sections), while the murmur of aortic regurgitation requires 4 or 5 beats.

Also, a soft pulmonary regurgitation murmur can sometimes become even softer during inspiration because this murmur is usually best heard at the 2nd intercostal space, where inspiration moves the stethoscope away from the heart.

In some forms of congenital heart disease, the murmur of pulmonary insufficiency is quite short because the pressure gradient between the pulmonary artery and the right ventricle rapidly resets in diastole.

Diagnosis of pulmonary insufficiency

Lung failure is often diagnosed accidentally during a physical examination of the chest (in which the doctor hears the specific murmur) or a color Doppler ultrasound (in which the reflux of blood is clearly visible and measurable) done for other reasons.

Recall, however, that mild pulmonary insufficiency is a normal echocardiographic finding that usually requires no action.

An electrocardiogram and chest x-ray are usually done.

The ECG may show signs of right ventricular hypertrophy, while the chest radiograph may show right ventricular enlargement and signs of underlying disease of pulmonary hypertension.

Other techniques used in diagnosis include coronary angiography and magnetic resonance imaging.