Even our blood needs to breathe. After blood delivers oxygen to the various tissues and cells within our bodies, it returns to the heart to be re-oxygenated. The blood enters through the right side of the heart, where it gets pumped to the lungs for oxygen. This newly oxygenated blood then travels through the left side of the heart and gets pumped to the rest of the body. This cycle repeats again and again.
Sometimes, however, inflammation causes our pulmonary arteries to constrict, which makes it more difficult for blood to flow through them, leading to high blood pressure. This condition is called pulmonary hypertension.
Pulmonary hypertension (PH) is a serious and chronic disease that can lead to heart failure, if left untreated. Although there is not a cure, treatment can help slow the progression of the disease.
“This is an exciting time in the field of pulmonary hypertension. There are several innovative ways to help identify early stages of the disease including novel imaging techniques and advanced cardiopulmonary exercise testing,” says Inderjit Singh, MD, the director of the pulmonary hypertension program at Yale Medicine.
What are the different types of pulmonary hypertension?
There are five types of pulmonary hypertension, all of which result in the narrowing of the pulmonary blood vessels:
- Pulmonary arterial hypertension (PAH). This type can be heritable or caused by connective tissue diseases (such as scleroderma, and rheumatoid arthritis), HIV, portal hypertension due to chronic liver disease, congenital heart disease (heart disease that affects atrial, ventricular, and great artery), and schistosomiasis (a rare disease caused by freshwater parasitic worms in certain tropical and subtropical countries). This type of pulmonary hypertension also includes “PH with no known cause,” often termed idiopathic pulmonary hypertension.
- Pulmonary hypertension due to left heart disease. This type is PH is caused by left heart conditions such as left-sided valvular heart disease or left heart failure.
- Pulmonary hypertension due to chronic lung disease and/or hypoxemia. This type of PH is associated with chronic lung conditions including COPD (chronic obstructive pulmonary disease) and interstitial lung disease. This type of PH can also be associated with sleep-related breathing disorders such as sleep apnea.
- Pulmonary hypertension due to chronic thromboembolic disease. This type of PH is caused by chronic blood clots in the lungs.
- Pulmonary hypertension due to unclear multifactorial mechanisms. This final category of PH is caused by a variety of different conditions, including polycythemia vera, sarcoidosis, metabolic disorders (such as thyroid disease), or cancer.
Who is at risk for pulmonary hypertension?
People are at greater risk for pulmonary hypertension if they have one or more of the following:
- A family history of the condition
- Certain heart or lung diseases, liver disease, HIV infection, or blood clots in the pulmonary arteries.
- The use illicit drugs such as methamphetamine or cocaine, which have the potential to cause damage to the lung blood vessels.
What are the symptoms of pulmonary hypertension?
The most common symptom of pulmonary hypertension is shortness of breath. Patients will also likely feel light-headed or fatigue during exertion. Other early signs of pulmonary hypertension include the following:
- Chest pain
- Racing heartbeat
As the condition worsens, patients may experience the following symptoms:
- Swelling in the ankles or legs
- Bluish lips or skin
What causes pulmonary hypertension?
There are many causes of pulmonary hypertension, but most come from inflammation that causes the walls of the small arteries of the lung to narrow. These structural changes can make it hard for your heart to push blood through your pulmonary arteries and into your lungs, causing high blood pressure.
How is pulmonary hypertension diagnosed?
- Pulmonary artery catheterization. Right heart catheterization is the gold standard for establishing the diagnosis of pulmonary hypertension and determining how severe it is. A tube is passed either through a vein in an arm or leg or neck into the right side of the heart to measure the blood pressure in the pulmonary artery. An average pulmonary arterial pressure that is greater than or equal to 25 mmHg is the criteria used to diagnose pulmonary hypertension.
- Electrocardiogram (EKG). An EKG is a noninvasive test that measures the electrical activity of the heart. The EKG provides information about how fast and regular the heart is beating. Certain wave patterns will tell a doctor if the high pulmonary artery pressure is affecting the right side of the heart.
- Imaging tests, such as a ventilation-perfusion, or VQ, scan and CT scan. A CT scan helps doctors make the diagnosis of interstitial lung disease. A VQ scan helps determine the presence or absence of chronic blood clots in the lungs.
- Blood tests: Pulmonary hypertension could be caused or worsened by many medical conditions. This is why doctors will conduct various blood tests during diagnosis to check for anemia (which is a possible cause of shortness of breath and fatigue) and measure the function of the liver, thyroid, and heart. Other blood tests include testing for specific antibodies often associated with the different connective tissue diseases. These blood tests will help the doctors determine the potential cause of PH.
- Submaximal cardiopulmonary exercise test. This test is performed at outpatient visits and provides doctors with a variety of data including information about the blood flow through the patients’ lungs, breathing efficiency, and oxygen consumption during exercise.
How is pulmonary hypertension treated?
Treatment will depend on the type of pulmonary hypertension that you have. Often, your doctor will aim to treat the underlying condition that’s causing the pulmonary hypertension. For instance, if COPD is causing the PH, your doctor will prescribe medications to manage the COPD. Below are some examples of medications and therapies used to treat PH:
- Nitric oxide promoting agents, such as phosphodiesterase-5 inhibitors, (isldenafil and tadalafil) and soluble guanylate cyclase stimulators, such as riociguat: These medications cause blood vessels to relax, increasing blood flow to the lungs and lowering blood pressure.
- Prostacyclin analogues or agonists, such as epoprostenol, treprostinil, and selexipag: These medications also cause blood vessels to relax, increasing blood flow to the lungs and lowering blood pressure.
- Endothelin receptor antagonists, such as bosentan, macitentan, and ambrisentan: These medications reduce the amount of the substance endothelin in the blood, which causes blood vessels to constrict.
- Calcium channel blockers, such as diltiazem: These medications also cause blood vessels to relax, increasing blood flow to the lungs and lowering blood pressure.
- Diuretics such as furosemide or spironolactone: These are water pills that help reduce the pressure in the heart chambers.
- Oxygen therapy: Patients with underlying lung conditions causing PH may require oxygen therapy to raise the level of oxygen in their blood. The oxygen is received through soft plastic prongs fitted into the nose.
- Blood thinners: If a blood clot in the lungs or blood clotting disorder is causing PH, your doctor will prescribe blood-thinning medications to prevent clots from forming or getting larger
- Lung transplant: In severe cases, when a patient’s clinical status does not improve with medication, a lung transplant may be required.
How does Yale Medicine treat pulmonary hypertension?
Yale Medicine’s pulmonary specialists collaborate with physicians in cardiology, rheumatology, hepatology, cardiothoracic surgery, diagnostic radiology, and pathology to provide one of the most comprehensive pulmonary hypertension care programs in the Northeast region. The pulmonary hypertension program provides a one-stop shop for diagnostic tests, treatment, and patient education. We are one of the few centers in the nation that is accredited by the Pulmonary Hypertension Association, a comprehensive care center for patients with PH. The PH Care Centers initiative of the Pulmonary Hypertension Association accredits centers with expertise in pulmonary hypertension that have demonstrated an ability to properly diagnose the disease and have the capability to manage these complex patients.