Pulmonary hypertension (PH) can be difficult to diagnose in a routine medical examination because the most common symptoms of PH, such as breathlessness, fatigue and dizziness, are also associated with many other conditions. If your doctor suspects that you have PH, he or she will want to review your medical and family history, perform a physical exam and perform one or more diagnostic tests.

To determine if you have PH, your medical team will schedule specialized tests. If your medical team suspects PH as a result of one or more of the following tests, they will go on to schedule a right-heart catheterization, which is required to confirm diagnosis.

Blood tests check the oxygen levels in the blood, they observe liver and kidney function, and they identify whether the patient has collagen vascular disease, thyroid problems, signs of infection or HIV antibodies. One test, the brain natriuretic peptide, helps to assess the strain on the heart and may also be used to monitor response to treatment.

Chest X-rays can reveal an enlarged right ventricle or pulmonary arteries. Chest X-rays can also show signs of emphysema or scarring (interstitial fibrosis) of the lungs.

An electrocardiogram checks the electrical impulses of the heart. Electrodes are attached to the patient's skin, and a recording of these impulses is made. However, an ECG alone is not enough to indicate a PH diagnosis. If your doctor performs an ECG, he or she will also perform one or more additional procedures to identify PH.

In this procedure a sonogram of the heart is taken. This painless procedure is often used to make a preliminary diagnosis by estimating the pressures in the right heart and assessing how well the heart is functioning. Other heart conditions that produce symptoms similar to PH may be diagnosed with an echocardiogram. In addition, an echocardiogram may be used to monitor a patient’s condition.

These tests measure how much air your lungs can hold, how much air moves in and out of them and the lungs’ ability to exchange oxygen. These tests may be performed to potentially identify its cause.

During this test, a patient will be asked to perform an exercise, most commonly a six-minute walk. The purpose is to identity the patient’s exercise tolerance level.

This diagnostic tool tests for blood clots in the lungs by producing a picture of air and blood flow to the lungs. A small dose of radioactive material is breathed in and another small dose is injected via a blood vessel into the lungs. The doctor will review the images that are produced to evaluate the health of the lungs.

Right-Heart Catheterization

If the results of initial tests point to PH, your doctor will schedule a right-heart catheterization (commonly referred to as a “right heart cath” or Angiogramme). Right-heart catheterization is one of the most accurate and useful tests to get a definitive diagnosis for pulmonary hypertension. This is the only test that directly measures the pressure inside the pulmonary arteries, and it should be done in all patients at least once to confirm a patient's diagnosis of PH. During the test, doctors insert a catheter (a thin rubber tube) through a large vein in the patient's groin or neck. They then pass the catheter up into the patient's heart to measure the blood pressure in the right side of the heart and lungs.

Vasodilator Study (Acute Vasodilator Challenge)

This test is used for patients who have already been diagnosed with pulmonary hypertension to determine how much their pulmonary blood vessels can relax over a brief period of time. Its main purpose is to screen for patients who might respond favourably to calcium channel blockers, a form of medication. The test can also help determine the patient's prognosis. With a right heart catheter in place, the patient is given drugs that relax the pulmonary arteries. The test drug is given to the patient in higher and higher doses, pausing at each dose to see how the patient reacts. Once a significant response occurs or the side effects become intolerable, the test is considered complete.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by old blood clots in the lungs (pulmonary embolism). In most patients who have suffered a blood clot, blood thinners are enough to restore blood flow to the lungs, improving breathing and exercise tolerance, and preventing development of pulmonary hypertension.

However, a minority of patients will not respond adequately to blood thinners, and may develop CTEPH. In these patients, problems arise not only from lung segments being obstructed by clots, but because seemingly healthy blood vessels (supplying uninvolved lung segments) may develop progressive narrowing, similar to pulmonary arterial hypertension (PAH).

Importantly, patients may develop CTEPH without any history of a blood clot. It is also possible for CTEPH to develop from multiple small clots over a long period of time, as opposed to one or two large blood clots.

The symptoms of CTEPH are non-specific, and similar to other types of pulmonary hypertension. The most common symptoms of CTEPH are shortness of breath and exercise intolerance. Less frequent symptoms include a dry cough, chest pain, and heart palpitations. As the disease progresses, symptoms of light-headedness or exercise-related dizziness may occur. Abdominal and lower extremity swelling may develop as lung pressures increase, and the right ventricle, which pumps blood into the lungs, begins to weaken.

Approximately 1% of patients with an acute pulmonary embolism will develop CTEPH. People who have very large pulmonary emboli may be at increased risk of developing CTEPH. Patients who already manifest some pulmonary hypertension at the time of diagnosis of a pulmonary embolism may also have an increased likelihood of developing CTEPH. Some underlying blood clotting disorders are more common in patients with CTEPH, though not all clotting disorders increase risk. Additionally, some chronic medical conditions, such as inflammatory bowel disease and osteomyelitis, are associated with increased CTEPH risk.

If a doctor suspects that you have CTEPH, he or she will run a number of tests. The goals of these tests are to establish whether you have CTEPH or another type of PH. If you do have CTEPH, he or she will want to determine if you are a candidate for pulmonary thromboendartectomy (PTE) surgery.

Common tests include

1. Nuclear Scan (a.k.a. Ventilation/Perfusion Scan or V.Q. Scan). This test shows any areas in the lung that are not receiving the appropriate amount of blood flow due to blockage of the arteries by clots.
2. Echocardiogram In this procedure, electrodes are placed on the patient’s skin and a sonogram of the heart is taken. This painless procedure is often used to make a preliminary diagnosis by estimating the pressures in the right heart and assessing how well the heart is functioning.
3. CT scan Some patients undergo this test to look for blood clots and to evaluate the condition of the rest of the lung besides the arteries. If you get a CT scan, your veins will be injected with dye and photographed.
4. Right-heart catheterization This is the only test that directly measures the pressure inside the pulmonary arteries, and it should be done in all patients at least once to confirm a patient's diagnosis with PH. During the test, doctors insert a catheter (a thin rubber tube) through a large vein in the patient's groin or neck. They then pass the catheter up into the patient's heart to measure the blood pressure in the right side of the heart and lungs.
5. Pulmonary angiography Like a right-heart catheterization, a catheter is placed through a vein in the neck (or groin) into the pulmonary arteries. This is done by injecting dye into the arteries and taking pictures. This test will confirm if chronic blood clots are the cause of the pulmonary hypertension and if PTE surgery would improve pulmonary pressures.
6. Coronary angiography Patients who are deemed candidates for PTE surgery and are at risk for coronary artery disease will also undergo this test to see if they have significant coronary artery disease (blockages in the arteries that supply the heart muscle with blood and oxygen). If the doctors identify significant coronary artery disease, they will typically treat it when they remove blood clots from the arteries in the lung.

The symptoms of CTEPH are quite similar to those of pulmonary arterial hypertension (PAH) and the other types of PH. Chest pain may be a more prominent feature of CTEPH, particularly in those patients who have had scarring in an area of lung from a prior blood clot. The distinguishing feature of CTEPH is that it is the only type of PH that truly has a potential “cure” for those who are eligible for PTE surgery.

The therapy of choice for operable patients is a pulmonary thromboendarterectomy, or PTE surgery, a highly specialized surgical procedure that removes chronic blood clots from the arteries in the lung.

All CTEPH patients will need to be on a blood thinner, typically warfarin, for the rest of their lives. For patients who have prominent abdominal swelling and swollen legs, diuretics may be beneficial.

PH-specific medications have been investigated in CTEPH, though the number of patients studied is much smaller than those enrolled in PAH clinical trials. These studies have confirmed the safety of several therapies, and varying degrees of benefit. Medical therapies are mainly used for inoperable patients, or for patients who have residual pulmonary hypertension after surgery. If you fall into one of these categories, your PH team will work with you to choose a medication based on your disease severity, side effects, and other relevant personal factors.