When high blood pressure affects the lungs

High blood pressure (what doctors call hypertension) usually affects all the body's arteries, the vessels that carry blood from the heart to the rest of the body. But a separate condition, known as pulmonary hypertension, causes abnormally high blood pressure in the arteries that carry blood from the right side of the heart to the lungs (see illustration). This serious condition has many possible causes, including a range of diseases and underlying conditions, as well as genetic mutations and exposure to certain drugs. Pulmonary hypertension and classic hypertension can occur together in the same person, but the two conditions are not related.

While there's no cure for pulmonary hypertension, various treatments can ease symptoms and slow the progression of the disease. Earlier this year, researchers reported promising results with an experimental drug called sotatercept in people with pulmonary arterial hypertension (PAH), one of the five main types of pulmonary hypertension (see "Types of pulmonary hypertension").

"The drug targets one of the dysregulated signaling pathways that causes PAH," says cardiologist Dr. Jane Leopold, associate professor of medicine at Harvard Medical School. In a study of people with PAH (most of whom were already taking two or three other medications), the drug improved their ability to exercise as measured by a six-minute walk test. The study was published April 20, 2023, in The New England Journal of Medicine. Sotatercept, which is given by injection every three weeks, acts like a sponge, trapping specific molecules responsible for causing the pulmonary arteries to narrow and stiffen, says Dr. Leopold. While the drug was tested only in people with PAH, it might also prove beneficial for certain other types of pulmonary hypertension, she adds.

Diagnosis and treatment

Pulmonary hypertension doesn't have any distinct warning signs. Early in the disease, people feel fatigued and short of breath during physical activity. "But these vague symptoms are easy to attribute to being out of shape or simply growing older," says Dr. Leopold. As the disease advances, the most common symptoms, including dizziness, chest pressure, and palpitations, are similar to those of other heart and lung conditions. As a result, it takes an average of two years to correctly diagnose a person with pulmonary hypertension, Dr. Leopold says.

First, doctors rule out more common problems, including thyroid, liver, or heart problems, some of which may underlie pulmonary hypertension. But the only way to definitively diagnose pulmonary hypertension is a right heart catheterization, which directly measures the pressure inside the pulmonary arteries and checks how much blood your heart pumps per minute. Imaging tests (including ultrasounds and CT scans of the heart), lung function tests, blood tests, and other tests can help pinpoint the underlying cause.

In addition to addressing conditions that contribute to pulmonary hypertension, treatment may include medications that ease symptoms, slow the progression of the disease, and reduce its complications. People with pulmonary hypertension are now surviving longer than in the past, thanks to earlier diagnosis that enables treatment to start sooner, Dr. Leopold says. The Pulmonary Hypertension Association (www.www.phassociation.org) has additional information for patients, including resources for finding in-person, phone, and online support groups.

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