This type of pulmonary hypertension can be caused by pulmonary arterial hypertension, lung disease, or blood clots in the lungs. Treatments include medications, lifestyle changes, and surgery.

Pulmonary hypertension (PH) is a condition meaning the blood pressure in the blood vessels of your lungs is too high.

About 1% of people worldwide have PH, according to the National Heart, Lung, and Blood Institute. Over time, the condition can lead to heart failure and arrhythmia.

PH can be divided into precapillary and postcapillary PH. This article explores precapillary PH in more detail.

When oxygen-depleted blood reaches the heart, it travels through the right side of the heart and into the pulmonary arteries. From the pulmonary arteries, it continues to move through smaller and smaller blood vessels.

Blood eventually reaches the capillaries surrounding the alveoli in your lungs. This is where gas exchange occurs, in which blood receives fresh oxygen while removing wastes like carbon dioxide.

Precapillary PH affects the pulmonary arteries before the oxygen-depleted blood reaches the capillaries in the lungs. It can be caused by:

Postcapillary PH happens due to factors after blood has passed through the capillaries in the lungs. It occurs due to heart disease that has damaged the blood vessels from the lungs to the heart.

This type of PH often happens because of left-sided heart failure. This is when the left ventricle, the heart’s primary pumping chamber, has weakened and can be caused by high blood pressure or coronary artery disease.

Pulmonary arterial hypertension (PAH) is a type of precapillary PH. It happens when small arteries within the lungs become narrowed or obstructed, leading to an increase in blood pressure.

Various factors can cause PAH, including:

Sometimes, the cause of PAH isn’t clear. When this happens, it’s referred to as idiopathic PAH. More than 50% of diagnoses of PAH are idiopathic.

The symptoms of PH, including precapillary PH, are typically nonspecific. They could be caused by various health conditions, including other lung and heart issues.

Symptoms may include:

A doctor will ask about your medical history and do a physical exam. Several tests may also be used during the diagnostic process, such as:

Two techniques can help determine the blood pressure in your pulmonary arteries. An echocardiogram creates an ultrasound image of the heart and can estimate pressure in your pulmonary arteries.

Cardiac catheterization is an invasive procedure and is done to confirm the diagnosis. It involves inserting a catheter into a large vein in your groin, neck, or arm. This is then threaded to the right side of your heart and pulmonary arteries to measure blood pressure.

Precapillary PH is specifically diagnosed based on the following measurements:

  • Mean pulmonary artery pressure (mPAP): This is the average pressure in your pulmonary arteries. A typical mPAP measurement is about 14 mmHg. People with precapillary PH have an mPAP greater than 20 mmHg.
  • Pulmonary artery wedge pressure (PAWP): PAWP is a measure of the pressure when a catheter is wedged into a pulmonary artery. People with precapillary PH have a PAWP of 15 mmHg or less.
  • Pulmonary vascular resistance (PVR): PVR measures the resistance against blood flow from the pulmonary arteries to the left atrium of your heart. Individuals with precapillary PH have a PVR of 3 Wood units (WUs) or more.

There’s no cure for precapillary PH, but treatment can help you manage it and prevent your symptoms from worsening.

The treatments for precapillary PH include:

  • Medications: Several medications for precapillary PH include:
  • Procedures: Various procedures can also help people with precapillary PH. These include:
    • balloon atrial septostomy, in which a small hole is made between the right and left atrium of your heart, which helps lower pressure in the righthand chambers
    • heart balloon pulmonary angioplasty, which uses a small balloon to help open up narrowed pulmonary arteries to reduce blood pressure
    • supplemental oxygen therapy
  • Transplants: A transplant may be needed for some people who don’t respond to medical therapy. This can include a single lung transplant, a bilateral lung transplant, or a heart-lung transplant.
  • Lifestyle changes: Some changes can help manage precapillary PH and improve quality of life. Examples include:
    • avoiding activities that strain the heart and lungs

Sometimes, precapillary PH is caused by an underlying health condition, such as an autoimmune disease. If this is the case, your doctor will work to treat that as well.

Precapillary PH is a condition in which high blood pressure affects the pulmonary arteries before reaching the capillaries in the lungs. It can be caused by various factors, including PAH, preexisting lung disease, or CTEPH.

Several tests can diagnose precapillary PH. Echocardiogram and cardiac catheterization are two that are essential for determining blood pressure in the pulmonary arteries.

There’s no cure for precapillary PH, but treatments can manage symptoms, prevent the condition from worsening, and improve quality of life.