How To Diagnose Pulmonary Hypertension On Echo?

An echocardiogram is often the first test that suggests a diagnosis of pulmonary hypertension, but it does not make the final diagnosis by itself. The echo provides an estimate of the pressure inside the pulmonary artery, which is the blood vessel that carries blood from the heart to the lungs. When that pressure is high, the echo shows specific changes that prompt a doctor to order more testing.

What Does Pulmonary Hypertension Look Like on an Echo?

The echocardiogram uses sound waves to create moving images of the heart. For pulmonary hypertension, the technician and doctor look for three main things: the speed of blood flowing backward through the tricuspid valve, the shape of the right side of the heart, and the movement of the wall between the heart’s lower chambers.

The most important measurement is the tricuspid regurgitation velocity. The tricuspid valve sits between the right upper and right lower chambers of the heart. In many people with pulmonary hypertension, this valve leaks slightly. The leak creates a jet of blood that can be measured. The faster that jet moves, the higher the pressure in the lung’s blood vessels.

This measurement gives the doctor a number called the estimated pulmonary artery systolic pressure. A normal resting value is usually below 35 to 40 mmHg depending on the lab. Higher numbers suggest pulmonary hypertension may be present, but the number alone is not enough to confirm the disease.

Why the Echo Cannot Confirm the Diagnosis Alone

An echocardiogram estimates pressure. It does not measure it directly. The only way to directly measure the pressure inside the pulmonary artery is with a right heart catheterization. During this procedure, a thin tube is guided through a vein in the neck or groin into the right side of the heart and into the pulmonary artery.

This distinction matters because the echo estimate can be wrong. In some people, the estimate is higher than the true pressure. In others, it is lower. The quality of the ultrasound image, the person’s body size, and the angle of the ultrasound beam all affect the accuracy of the measurement.

Because of this, a doctor will never start long-term treatment for pulmonary hypertension based on an echo alone. If the echo suggests the condition, the next step is a right heart catheterization to confirm the pressure is truly elevated.

What Is the Normal Range for Pulmonary Artery Pressure?

At rest, the mean pulmonary artery pressure in a healthy adult is about 14 mmHg. The upper limit of normal is generally considered 20 mmHg. This is the average pressure throughout the cardiac cycle, not the peak pressure.

When doctors talk about diagnosing pulmonary hypertension, they use this mean pressure. A mean pulmonary artery pressure of 20 mmHg or less is normal. A pressure above 20 mmHg at rest is considered elevated and meets the definition of pulmonary hypertension.

The echo, however, reports a different number. It estimates the peak systolic pressure, which is the highest pressure during the heartbeat. A normal peak systolic pressure is typically under 35 to 40 mmHg. The two numbers are related but not the same, which is why the echo estimate and the catheter measurement do not always match perfectly.

What Other Echo Signs Point to Pulmonary Hypertension?

Beyond the pressure estimate, the echo reveals structural changes in the heart that support the diagnosis. These changes develop over time as the right side of the heart works harder against the elevated pressure.

The right ventricle, which is the chamber that pumps blood to the lungs, normally has a thin wall. In pulmonary hypertension, this wall thickens. The chamber itself may also enlarge. On the echo image, the right ventricle may appear larger than the left ventricle, which is not normal.

The septum, or the wall between the two lower chambers, normally curves toward the right ventricle. When pulmonary artery pressure is high, the septum flattens or bows toward the left ventricle. This change is visible on the echo and is a strong indicator that the pressure is significantly elevated.

Doctors also look at the right atrium, the chamber that receives blood returning from the body. This chamber often enlarges in pulmonary hypertension because the right ventricle struggles to push blood forward, causing blood to back up.

How Reliable Is the Echo in Detecting Pulmonary Hypertension?

The echo is a good screening tool but not a perfect one. Research consistently shows that the echo can miss pulmonary hypertension in some people and suggest it in others who do not have it.

When the echo suggests pulmonary hypertension, the right heart catheterization confirms the diagnosis in roughly half to two-thirds of cases. This means a significant number of people with an abnormal echo turn out to have normal pressures when measured directly.

The opposite problem also occurs. Some people with mild pulmonary hypertension have a normal-looking echo. The condition can be present even when the ultrasound images look reassuring. This is why doctors consider the whole clinical picture, including symptoms and risk factors, not just the echo report.

What Symptoms Prompt a Doctor to Order an Echo for Pulmonary Hypertension?

Shortness of breath with exertion is the most common symptom. People often describe feeling winded doing activities they previously managed without difficulty. Fatigue and weakness are also frequent complaints.

Chest pain, dizziness, and fainting can occur, especially with physical activity. Swelling in the ankles and legs may develop as the right side of the heart weakens. Some people notice their heart racing or pounding.

These symptoms are not specific to pulmonary hypertension. Many other heart and lung conditions cause the same complaints. This is why an echo is ordered as part of a broader evaluation rather than as a targeted test for pulmonary hypertension alone.

What Happens After the Echo Suggests Pulmonary Hypertension?

The next step is usually a right heart catheterization. This test provides the definitive pressure measurement. It also allows the doctor to test how the blood vessels in the lungs respond to medication during the procedure, which helps guide treatment.

Before the catheterization, the doctor will likely order additional tests to look for the cause. Pulmonary hypertension has many causes, and identifying the underlying condition is essential. Blood tests, lung function tests, a chest CT scan, and a sleep study are common parts of this evaluation.

The cause determines the treatment. Some forms of pulmonary hypertension respond to medications that relax the blood vessels in the lungs. Others improve when the underlying condition, such as sleep apnea or a blood clot in the lungs, is treated. In some cases, no cause is found, and the condition is called idiopathic pulmonary hypertension.

How To Diagnose Pulmonary Hypertension On Echo: The Practical Steps

Diagnosing pulmonary hypertension on echo requires a systematic approach. The doctor first measures the tricuspid regurgitation velocity to estimate the pressure. A velocity above 2.8 meters per second is considered elevated and raises suspicion for pulmonary hypertension.

The doctor then looks at the structural changes in the right side of the heart. Enlargement of the right atrium or right ventricle, thickening of the right ventricular wall, and flattening of the septum all support the diagnosis.

The final step is interpreting these findings in the context of symptoms and risk factors. An elevated pressure estimate in a person with no symptoms and no other echo changes may not warrant immediate catheterization. The same pressure estimate in a person with shortness of breath and an enlarged right ventricle is more concerning.

The echo report should state the estimated pressure, the quality of the measurement, and any structural abnormalities. This information helps the doctor decide whether catheterization is needed and how urgently.