Getting to a Diagnosis of Pulmonary Hypertension (PH)
Yon Sung, MD, Clinical Assistant Professor of Pulmonary Medicine, Stanford School of Medicine
What kinds of symptoms do patients with PH have?
The most common symptom of PH is shortness of breath, particularly with activity or exercise. In the early stages of this disease, this can be mild. For example, some patients may feel a little more winded doing a big hike or running to catch a train. However, as the disease progresses, the shortness of breath can get more severe and people can find it hard to breathe when doing everyday activities like walking up a flight of steps or going grocery shopping. Many patients with PH also experience significant fatigue. Some people may also notice symptoms of palpitations and rarely chest pain. In more severe disease, patients may experience lightheadedness or dizziness and passing out is a serious sign. Lastly, people with more advanced disease can often notice fluid retention, usually in their legs.
Now, most of these symptoms are nonspecific and many of them can be seen in more common heart and lung diseases including coronary artery disease, congestive heart failure, asthma, COPD, or even just being out of shape. So, it is important to see a doctor before jumping to any conclusions!
What testing should I have to find out if I have PH?
Most people who present to their doctor with these symptoms will probably have already gotten a chest X-ray and / or an EKG. Signs of PH on these tests can be subtle, so PH can be missed with these. The best initial screening test for PH is an echocardiogram, which is an ultrasound of the heart. With this, we can estimate the pressure in the lungs with the right ventricular systolic pressure or the pulmonary artery systolic pressure. In patients without disease, it should be lower than ~35 mmHg and is often unmeasurable. We worry about PH when the pressure is >40 mmHg. The echo also gives us information about the right side of the heart. The right heart is responsible for pumping blood to the lung and if the pressure in the lungs is elevated, this puts strain on the right heart, so we may see right sided enlargement and dysfunction.
My echo looks like I may have PH. Now what?
The first thing that we would recommend is a full evaluation. When, we first evaluate patients, we need to take a thorough history of symptoms, previous medical history, family history, and history of substance use. Also a complete physical exam is helpful for looking for signs of possible PH. If, after those things, we have a strong suspicion for PH, we recommend a bunch of testing to look for what the possible cause for PH. There are a lot of causes for PH, so buckle in – this is a long list of stuff.
For all patients, we do routine blood testing to check blood count, kidney function and liver function. We also include blood testing for autoimmune diseases, hepatitis, and HIV as these can be causes for PH. Underlying lung disease can also cause PH, so patients should have full pulmonary function tests and we also recommend a CT scan of the chest. Patients should be screened for obstructive sleep apnea and referred for a sleep study if appropriate. Chronic blood clots in the lung can also cause PH, so all patients should have a lung imaging test called a VQ scan. Also, we routinely do assessments of how well you can exercise. This is usually done with a six minute walk test, but sometimes we recommend more advanced exercise testing with a bicycle or treadmill test. Finally, in order to know for sure that you have PH, we need to perform a procedure called a right heart catheterization. In this procedure, we take a catheter, which is a long thin tube, insert it into a vein in either your leg or your neck, and then fish it into the right side of the heart and then into the lung. With this, we can directly measure the pressure in your lungs.
Do I really need to have a right heart catheterization?
Yes! Many studies have shown that while the echocardiogram is a great screening test, the pressure measured can differ from the catheter measured pressure by +/- 20 mmHg! The cath is the only way to confirm that you definitely have PH. Also, not only does the right heart cath tell us how high the pressure is, but it can also tell us how well the heart is functioning, it can help clarify the cause of PH, and it allows us to do testing to see if you can be treated with certain medications. It is a same-day, relatively low risk procedure that is essential to helping us know how your PH should be treated.