Cardiac catheterisation measurements
Cardiac catheterisation is a procedure that is used to confirm a diagnosis of pulmonary hypertension (PH). Several measurements can be taken using a cardiac catheter (a long, thin, flexible tube inserted into a vein).
Measurements taken using a cardiac catheter
| Measurement | Definition | Comment |
|---|---|---|
| Mean pulmonary artery pressure (mPAP) | Average blood pressure in the main pulmonary arteriesThe blood vessel delivering blood to the lungs from the right side of the heart. | mPAP above 25mmHg while a person is resting indicates PH |
| Mean right atrial pressure (mRAP) | Average blood pressure in the right atriumOne of the two upper chambers of the heart that receives blood. The left atrium receives oxygen-rich blood from the lungs. The right atrium receives oxygen-poor blood of the heart | mRAP above 10mmHg indicates the heart is beginning to find it difficult to pump blood efficiently |
| Pulmonary capillary wedge pressure (PCWP or ‘wedge’) | Estimation of the blood pressure on the left side of the heart (blood returning from the lungs to the heart) | PCWP above 15mmHg indicates the heart is finding it hard to pump blood through the lungs |
| Cardiac output | The amount of blood pumped through the heart in one minute | PH causes reduced cardiac output |
| Pulmonary vascular resistance (PVR) | The resistance the heart must pump against to force blood through the lungs | PVR is normally higher in people with PH |
| Mixed venous oxygen saturation | The amount of oxygen in the blood as it returns to the heart | Gives an idea of how much oxygen a persons' muscles and organs are extracting from the blood |
Watch a video of a cardiac catheterisation, taken from the Pulmonary Hypertension Association (PHA UK) DVD Understanding Pulmonary Hypertension – a guide to diagnosis and treatment, here.
