Pulmonary hypertension (PH) is a lung and heart disease caused by high pressure in the arteries that carry blood from the heart to the lungs. As PH progresses, increased stress on the heart can cause cardiovascular issues like an irregular heart beat, blood clots, and heart failure.
Fortunately, there are many treatments to manage PH. Part of finding the treatments that work best for you is getting a detailed diagnosis of your PH. The current gold standard for the diagnosis of PH is right heart catheterization (RHC).
Diagnosing PH can be difficult because the symptoms are similar to other lung or heart diseases. Testing for PH usually depends on the symptoms you experience, such as difficulty breathing, chest pain (angina), fatigue, “brain fog,” and swelling (edema).
If your doctor suspects you have PH, they can perform several noninvasive tests to measure the function of your heart and lungs. These tests include:
These tests are used to understand how your lungs and heart function and if you may have PH. Since RHC is invasive, health care providers will often perform other, less-invasive tests first to make sure that an RHC is necessary. However, the best available test for diagnosing and understanding PH is RHC.
While RHC can be used to diagnose PH, it can also help you and your doctor keep track of your PH after you begin treatments. If certain treatments are not working well, your doctor can change your treatment plan to something more effective for you.
RHC is a procedure where a health care provider inserts a small, hollow tube called a catheter through your veins and into different areas of the right side of your heart. The catheter measures pressure in the heart and pulmonary artery. High pressures show that you have PH.
To understand RHC, it helps to understand how the heart works.
The heart is a large muscle with several chambers that work together to pump blood first to the lungs and then throughout the body. Blood delivers oxygen from the lungs to the body so that it can survive and grow. The two upper chambers in the heart (atria) receive blood from the body and send it to the lower chambers (ventricles).
The left and right sides of the heart have different jobs. The left side of the heart receives oxygen-rich blood from the lungs and sends it to the rest of the body. The right side of the heart receives oxygen-low blood from the body; this blood has delivered oxygen to the body and has now returned to the lungs to pick up more oxygen. The right ventricle sends blood to the lungs through the pulmonary artery. Once the blood picks up more oxygen in the lungs, it flows back to the left side of the heart to start the cycle over again.
In PH, changes in the heart, lungs, or blood vessels can raise the blood pressure in the pulmonary artery. This makes it more difficult for the right ventricle to pump blood to the lungs. It also makes it harder for your heart to send life-sustaining oxygen to your body.
Over time, the extra stress on the right ventricle makes it grow weaker and larger (right ventricle hypertrophy). If left untreated, the right side of the heart becomes too weak to pump blood (right heart failure), which can result in shortness of breath, fluid retention, and even death.
One specific type of PH is called pulmonary arterial hypertension (PAH). In PAH, the lung arteries are narrow and thickened. Other types of PH can be caused by genetics, chronic diseases, diseases of the heart and lungs, blood clots, drugs, and toxins.
An RHC is usually performed in a special room called a cardiac catheterization lab, but it may be performed in an intensive care unit for people who are very ill.
Before the RHC, your doctor will go over your full medical history. You may be asked to not eat or drink anything for eight hours or more before the procedure.
To begin the procedure, your doctor will start an intravenous (IV) line in your arm. This IV line can give you fluids and any medications you may need. You will lie on your back on a padded table during the RHC. The doctor will connect an EKG to measure your heart activity during the procedure. They may give you a mild sedative to help you relax, but it will not put you to sleep.
The doctor will clean and inject a numbing medication in the area where the catheter will be inserted. The numbing medication can cause a brief burning sensation. The catheter is usually inserted through a vein in the neck, but it may also be inserted through a vein in the arm or near the groin. The small catheter is directed through your veins and into the right side of your heart.
Once the catheter reaches the heart, the doctor can take measurements in the right atrium, right ventricle, and pulmonary artery. When they have all of the measurements they need, the doctor will remove the catheter. You may be asked to stay for a couple of hours to recover and so your doctor can discuss your results and treatment plan with you.
An RHC gives your doctor a lot of information about the hemodynamics (how blood moves) of your heart and lungs. This information can be used to determine what kind of PH you have, how mild or severe your PH is, and what medications may work best for you.
Mean pulmonary arterial pressure, or mPAP, is a major measurement doctors use to determine whether a person has PH. mPAP measures the pressure in your pulmonary artery. PH is defined as mPAP equal to or more than 20 mmHg.
The RHC can also provide information about what kind of PH you may have by measuring the pulmonary arterial wedge pressure (PAWP), which is also called pulmonary capillary wedge pressure. The PAWP is the pressure in the left atrium. These measurements can determine if someone has postcapillary PH, which is associated with left heart disease, or precapillary PH, which is associated with pulmonary vessel damage and right heart disease.
The mPAP and PAWP measurements are used to calculate the transpulmonary pressure gradient, or the range of pressures throughout the heart and pulmonary artery. This value can help diagnose PAH specifically.
Pulmonary vascular resistance (PVR) is a measurement of the resistance of blood flow from the pulmonary artery to the left atrium. Blood should flow easily through the pulmonary arteries; however, thickened arteries in PH can increase the resistance to blood flow. PVR is measured in “Wood units.” A PVR of more than 3 Wood units is crucial for a PH diagnosis.
Cardiac output measures how much blood your heart is able to pump in a minute. If your heart is weakened or failing, it may have a low cardiac output. Doctors can measure your heart’s output during an RHC using thermodilution. During this technique, cold saline (a saltwater solution) is injected into the heart using the catheter. The catheter can detect the change in blood temperature when the saline is injected. A computer uses the temperature change to calculate how much blood your heart is pumping.
Measuring the cardiac output and amount of oxygen in the blood allows health care providers to see if there is a left-to-right shunt, or backflow of blood in the heart. A left-to-right shunt may be caused by a hole in the heart that allows blood from the left side of the heart to flow back into the right side. The increased amount of blood in the right heart increases pressure on the right side of the heart and the pulmonary artery.
Your doctor may suspect a shunt if the blood oxygen in your pulmonary artery is unusually high. Since the blood in the pulmonary artery has already traveled through the body, it should be fairly low in oxygen. Higher oxygen suggests that oxygen-rich blood is flowing backward from the left side of the heart.
During the RHC, your doctor can inject different medications and measure how they affect your heart and pulmonary arteries. Vasodilators are medications that relax and open up (dilate) your blood vessels. This lowers blood pressure and allows better blood flow. Calcium channel blockers are common vasodilators used to treat PH. When the doctor injects this medication during an RHC, they can measure how well the medication works for you to help figure out your treatment plan.
Though an RHC can sound scary, the procedure has a very low risk of complications in experienced facilities.
A study of over 7,000 people with PH who received RHC in experienced centers across the United States and Europe found that only 1.1 percent of people had serious complications from the procedure. Other studies show that risk from RHC complications is higher for children or infants (under 2 years old) or people with more severe PH (higher right atrial pressure).
There are some reasons that someone should not get an RHC, such as having mechanical or prosthetic valves in the heart, masses in the heart (such as tumors), or inflammation in the right side of the heart (endocarditis). Your doctor will get your full medical history before an RHC. This is a good time to discuss any of your concerns.
RHC can sound scary, but it is a safe and informative procedure that can help you understand and manage your PH. Many myPHteam members have expressed concern about RHC. One member asked, “Did you have to have a right catheterization as well? Gosh, I am so scared.”
However, most myPHteam members who have had an RHC experienced little to no pain and had an overall easy experience. One member said, “I was scared, too, but it wasn’t bad or painful at all.” Another noted, “I had the right catheterization, and there was nothing to it. It was over before I knew it, and there was no pain whatsoever.”
Some members describe a bit of soreness from where the catheter is inserted in the neck or groin. One member said, “Only issue I have is a very sore neck.” Another shared, “I was somewhat sore in my groin after for a day or two.”
Overall, myPHteam members described RHC as a painless and easy procedure. One member noted, “It’s easy peasy, especially if they use a vein in your arm. I was nervous with my first one, and now it’s no big thing.” Another member said, “I had one Monday; there was no pain, and I got to come home after lying still for two hours. I worked myself up for nothing. It’s not a bad test at all.”
Members also value the information gained from the RHC: “I like having them. It is the one true way to know how things are going in your heart.”
On myPHteam, the social network for people with pulmonary hypertension and their loved ones, more than 44,000 members come together to ask questions, give advice, and share their stories with others who understand life with pulmonary hypertension.
Have you had a right heart catheterization? Share your experience in the comments below, or share your story on myPHteam.
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