The determination of the cause or "group" of pulmonary hypertension that you may fit into is complicated and often requires multiple investigations
The following is a guide to some of the investigations that you may be requested to undergo as part of your assessment
A right heart catheter is placed into the heart from the jugular (neck) or femoral (groin) vein to assess for fluid status, heart function and lung blood pressures.
The vein in your neck is located with an ultrasound.You will be given an injection of local anaesthetic. A fine tube (catheter) is put into the vein. You may feel pressure on your neck while the tube is placed in the vein. It is passed down the jugular vein or up the femoral vein until it reaches the heart and then goes up into the blood vessels of the lungs. This is usually painless. The doctor uses x-ray imaging to see the catheter.
Pressures in the lungs and the heart are recorded. A sample of blood is taken to look at the oxygen levels in various chambers of the heart.
At the end of the procedure, the catheter and sheath are removed. The whole procedure usually takes about 1 hour. Usually you can be discharged 1 hour after a neck procedure and 3-4 hours after a groin procedure.
You do not need to fast for this test.
Take all your usual medications the morning of the test except for frusemide.
The test can be done if you are taking warfarin but your INR must be between 2 and 2.5. You may be required to have this tested the day before the procedure.
A pulmonary angiogram is similar to a right heart catheter but a dye is injected into the pulmonary arteries instead of pressures being taken. It is used to detect blood clots and narrowing in the lung vessels. It takes a bit longer than a right heart catheter.
This is a non-invasive ultrasound of the heart which is used to obtain information about the cardiac structure and function. There are 4 chambers (2 on the left and 2 on the right) and 4 valves, plus large blood vessels entering and leaving the heart. The right side of the heart pushes blood into the lung blood vessels.
In pulmonary arterial hypertension, there is gradually progressive narrowing of these blood vessels, so much so that the pressure starts to rise. This puts extra strain on the right side of the heart.
Echo allows us to obtain an estimate of the pulmonary pressure and how well the heart is coping with the extra load. We use many features of the echo to estimate the pulmonary pressure as sometimes the direct measure cannot be seen due to technicalities of the test.
Echo also allows us to view the left side of the heart, which may sometimes contribute to pressure elevation on the right side.
Coronary angiography is considered the most accurate test to assess the coronary arteries. These arteries wrap around the outside of the heart and feed it with blood. Blockages in these arteries can cause heart attacks or angina. A coronary angiogram is a test to take pictures of these arteries. It is performed as a day-stay procedure in hospital.
It involves a small tube (catheter) approximately 2mm in diameter being inserted into the artery in the groin or wrist. The catheter is moved through the blood vessels until it reaches the heart. Radiographic contrast dye is then injected and X-ray images are obtained.
The procedure is performed under local anaesthesia with sedation.
An angiogram can determine whether coronary stenting or coronary artery bypass surgery might be needed.
You will need to fast for 4 hours prior to testing and will be directed as to which medications to take beforehand.
Stress testing is mostly used to assess the blood supply through the coronary arteries to the heart muscle. A resting heart with moderate or even severe blockages may receive enough blood supply. However, when “stressed”, the blood supply is inadequate to meet the increased demand and symptoms occur.
The most simple form (easily accessible and cheapest) is the exercise stress test using the treadmill and an ECG to monitor heart rate and rhythm. Blood pressure is also monitored. There is a standardised protocol for speed and elevation of the treadmill. The stress echocardiogram combines peak exercise ultrasound images of the heart muscle.
A medication which stimulates the heart can also be used if mobility is limited (dobutamine stress echo) and nuclear medicine used to assess blood flow (instead of ultrasound). We also use stress testing to assess the electricity in the heart and valvular function under cardiac “stress”.
A cardio pulmonary exercise test (CPET) is used to assess the response of the heart and lungs to exercise. The test is useful for a number of cardiac and respiratory conditions including pulmonary hypertension.
As a noninvasive test, CPET may be valuable in diagnosing resting and exercise-induced pulmonary hypertension in patients with unexplained exertional breathlessness. In patients with confirmed pulmonary hypertension, CPET provides information on disease severity above that which is obtained during a resting assessment.
The Six minute walk test is a worldwide standardised test which can assess physical function and response to treatment in patients with pulmonary arterial hypertension.
It is a supervised walking test to determine how many 30 metre “laps” of a corridor one can perform in 6 minutes. There is no “pass or fail”, just distance achieved. Healthy patients can usually walk 400-700 metres on the flat over 6 minutes.
In addition to the distance walked, we obtain pre and post exercise blood pressure and heart rate, plus oxygen saturations.
Current available evidence suggests that an improvement in 30 metres is clinically significant.
You should wear comfortable clothing, rest for 10 minutes prior to the test and walk as far as possible with brisk turning and no jogging.
Supplemental oxygen is recommended if usually used when walking.
We measure the level of breathlessness prior to and after the walk with the Borg dyspnoea scale.
V/Q scan is the preferred and recommended screening test for chronic thromboembolic disease (multiple blood clots) in patients with pulmonary hypertension.
The ventilation/perfusion method (V/Q) uses scintigraphy and medical isotopes to evaluate the circulation of air and blood in the lungs.
The ventilation scan detects radioactive gas inhaled by the patient and shows the distribution of air during breathing. The perfusion scan detects the distribution of lung blood flow. Both scans are usually performed together during a single visit.
A lack of blood flow in an area of adequate ventilation (ventilation/perfusion mismatch) suggests a blood clot in the lungs
Sleep disorders can make pulmonary hypertension worse due to low oxygen levels.
Obstructive sleep apnoea occurs when the muscles of the throat collapse inwards during sleep and cause oxygen levels to fall. This can make the brain wake up multiple times during sleep. It is usually associated with snoring and daytime sleepiness.
An overnight sleep study is designed to detect sleep apnoea. The test requires monitoring of the brain, heart and lungs during sleep and is usually performed in a specific sleep laboratory . Home studies are also possible but may be less accurate .
The team at SPHS will help you arrange a sleep study if there is a suggestion of sleep apnoea when we meet you .
These tests are very useful to understand causes of breathlessness.
From the tests, we gain information about the airways, the size of the lungs and the ability of the lungs to get oxygen into the bloodstream.
The testing process takes about 30mins and you will be instructed to breathe a few different ways into some machinery. A respiratory scientist will take you through it step-by-step to help get the most accurate results.
Patients with memory problems or communication difficulties may have trouble performing the test but most patients manage it easily.
A CT or “CAT” scan is a detailed test using XRAYS that gives us detailed pictures of the lungs and their blood supply. The test is performed at most radiology places.
For the test you need to lie down (on your back and sometimes your front) and hold your breath for a few seconds. The device used is like a large doughnut rather than a tunnel so claustrophobia is not usually a problem.
We will sometimes need to use an injection of contrast dye through a vein – a CT Pulmonary Angiogram . This helps look for blood clots. Please let us know if you have had a reaction to this sort of dye in the past or if you have kidney disease or diabetes.
A cardiac MRI is used to detect abnormal anatomy, particularly in congenital heart disease or to assess for shunts. It often requires injection of a contrast dye called Gadolinium.
It involves lying in a tunnel for 60-90mins which makes a loud banging noise but it is not painful. About 10% of people are too claustrophobic to complete the test.
For many people with lung conditions, the low oxygen and low pressure environment of the airplane cabin can prove to be very demanding on their cardiac and respiratory systems.
All airlines are required to maintain at least 75% of the air pressure at sea level. This lower air pressure equates to reduced oxygen levels. The body increases its breathing rate to counter this reduction in oxygen. A healthy individual could expect to see their oxygen saturations drop to 5% of normal.
Patients with pulmonary hypertension can experience a sharp decrease in oxygen levels especially while performing light exercise (such as standing and sitting) and therefore may require in-flight oxygen. This test will determine if you are safe to fly or require inflight oxygen.
Pulmonary Hypertension Society of Australia and New Zealand
The Thoracic Society of Australia and New Zealand (ANZCOTR)
The International Society for Heart & Lung Transplantation (ISHLT)
Lung Foundation Australia
St Vincents Hospital
Pulmonary Vascular Research Institute (PVRI)
Pulmonary Hypertension Association Australia (PHAA)