Pulmonary hypertension (PH) is high blood pressure in the arteries that carry blood from the right side of the heart to the lungs. PH should not be confused with systemic hypertension — high blood pressure in blood vessels throughout the body. Systemic hypertension can damage organs and blood vessels over time, and PH specifically refers to high blood pressure between the heart and lungs.

PH is considered a lung disease, and hypertension is considered a cardiovascular (heart and blood vessel) disease. However, PH can cause heart disease, and some types of heart disease can cause PH. PH is a serious and progressive condition that can cause debilitating symptoms and lead to heart failure, dangerous blood clots, and shortened life expectancy.

What Is Pulmonary Hypertension?

The right ventricle of the heart pumps oxygen-depleted blood through the pulmonary arteries into the lungs to receive a fresh supply of oxygen. Changes in the pulmonary arteries, the lungs, or the heart can raise the blood pressure in the pulmonary arteries, making it harder for the right ventricle to pump blood into the lungs. As a result of PH, deoxygenated blood begins to back up in the heart and body, and the supply of oxygenated blood to the tissues of the body becomes insufficient.

PH refers to high blood pressure in the lungs due to any cause. Pulmonary arterial hypertension (PAH) is high blood pressure in the lungs specifically caused by narrowed arteries. There are five main types of PH that are defined by their causes.

Each person with PH is also evaluated for the severity of their symptoms and the limits imposed on their activities. The severity of PH is expressed as one of four functional classes, with people in class 1 experiencing no symptoms and those in class 4 experiencing severe, debilitating symptoms even when they are resting.

PH is usually diagnosed and treated by a PH specialist. Many types of doctors, including pulmonologists, cardiologists, and rheumatologists, have special training and experience to specialize in managing PH.

What Causes Pulmonary Hypertension?

PH has several possible causes. Some types of PH can be inherited or develop as a side effect of exposure to drugs or toxins. Other types are caused by left heart disease or lung disease, or associated with other conditions such as blood clots. Some cases of PH are idiopathic, which means the cause is unknown.

The History of Pulmonary Hypertension

Some of the earliest records of PH date back to 1891 when Ernst von Romberg, a German physician, diagnosed what he called “pulmonary vascular sclerosis” during autopsies. At that time, the cause of the disease was a mystery.

The pulmonary arteries could not be examined in a living person until the procedure for cardiac catheterization was developed. In 1929, German physician Werner Forssmann developed a catheterization process for humans and tested it on himself. Forssmann inserted the first catheter into his own arm and guided it into his heart. Forssmann’s discovery was largely ignored by the scientific community at the time, but in 1956 he received a Nobel Prize for his work on cardiac catheterization. Today, cardiac catheterization is considered the gold standard for diagnosing PH.

Before the 1950s, mitral stenosis associated with rheumatic fever was a common cause of PH. Additional causes of PH were discovered in the 1950s. In 1953, researchers found that PH could be caused by pulmonary embolisms. In 1956, American veterinarians R. E. Pierson and Randy Jensen studied the effects of a lack of oxygen at high altitude as a cause of death in cattle. Pierson and Jensen discovered that living at a high altitude can also cause PH.

Cases of PH spiked in the 1960s and 1970s. Otherwise healthy women in America and Europe were suddenly developing PH because they used appetite suppressants such as aminorex or fenfluramine. It is estimated that the use of certain appetite suppressants increased the risk of developing PH at least tenfold. The National Institutes of Health responded by creating a registry of PAH patients in the U.S., which led to more academic and medical research into the condition.

In 1995, the U.S. Food and Drug Administration (FDA) approved the first treatment for pulmonary arterial hypertension — a prostaglandin medication called Flolan (a formulation of epoprostenol). Prostaglandins dilate the blood vessels of the lungs, increasing the blood flow and the amount of oxygen cells receive. Prostaglandins can also help slow scarring in the blood vessels of the lungs, slowing the progress of the disease.

Over the past 20 years, the FDA has approved 10 new medications to treat PH. Many new drugs are currently in development.

How Common Is Pulmonary Hypertension?

PH is believed to affect between 50 million and 75 million people around the world. PH is often undiagnosed or misdiagnosed, so it is difficult to know how many people have PH but don’t know it.

PH most commonly develops between the ages of 20 and 60. However, it can affect people of any age, including children. The risk for PH increases with age. According to the Centers of Disease Control and Prevention (CDC), PH is most common among women, non-Hispanic Black people, and people over 75.

What Is the Prognosis for Pulmonary Hypertension?

Life expectancy for people with PH depends on many factors, including which type and functional class of PH they have and whether or not they have kidney problems. In general, people who have PH with low-risk features (no kidney disease, higher capacity for exercise, etc.) can expect to live more than 10 years. Newer treatments continue to increase life expectancy for people with PH.

Talk With Others Who Understand

On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 50,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.

Have you or someone you love been diagnosed with pulmonary hypertension? Share your experience in the comments below, or start a conversation by posting on your Activities page.