Investigations

When PH is suspected, a number of tests are required to confirm the diagnosis and to clarify the underlying cause, as this will guide subsequent treatment decisions and estimated prognosis.

These tests include:

• Blood tests, which assess for connective tissue diseases or viruses such as HIV or hepatitis that are linked with certain types of PH.
• An ultrasound of the heart called an echocardiogram, which provides useful information regarding the size and function of the chambers on the right and left side of the heart.
• Imaging of the chest (such as a chest radiograph or CT thorax) and lung function tests (called pulmonary function tests) to assess for potential lung disease that might lead to PH.
• An additional scan called perfusion scan (or V/Q scan) is also performed to exclude group 4 PH (CTEPH), which is a type of PH linked to residual clots and scarring in the pulmonary vessels.
• If CTEPH is suspected, then we might also request a special type of interventional pulmonary angiogram, to further assess for residual clots or scarring within the pulmonary arteries, that might be amenable to surgical interventions.
• A liver ultrasound is often performed to exclude liver disease, as a potential cause for PH.

• Right heart catheterisation is the definitive tool to confirm PH.
  • During this procedure, a thin flexible tube with a small inflatable balloon on the tip is inserted through a large vessel (typically in the groin, wrist or neck) and carefully threaded all the way to the right side of the heart and into the pulmonary artery, where pressures are recorded.
  • This is a really important test to confirm the diagnosis and to guide us regarding the associated severity.
  • In specific circumstances, during the right heart catheterisation we might also perform a test called a vasoreactivity test. This involves administering a short acting drug such as inhaled nitric oxide, to assess whether the pulmonary vessels dilate and there is a ‘positive’ vasoreactivity test. If so, this is associated with a favourable response to treatment with calcium channel blockers, so it’s important to identify these cases, even though it is rare (click/tap on table below to see full size view)