The right heart catheterisation (RHC) is the gold standard diagnostic test to confirm pulmonary hypertension. This allows direct measurement of the pulmonary artery pressures and indirect measure of the left atrial pressure. Pressure readings should be determined at the end of normal expiration. The manometer should be set at position of the LA which is normally the midthoracic level with the patient supine. The PAWP is the best determinant of the LA pressure but can be misleading and in some cases a left ventricular end diastolic pressure (LVEDP) is required. Vasoreactivity testing should be performed in patients suspected of having IPAH. This is usually performed with inhaled nitric oxide. Cardiac output can be determined most commonly by the thermodilution or Fick methods. A mixed venous oxygen saturation taken from the pulmonary artery should be measured in all cases and is a useful indicator of cardiac function and tissue delivery of oxygen. Other measurements which can be obtained at RHC include a saturation run which is used to investigate for left to right intracardiac shunts.
The RHC is usually performed at rest with patient supine but patients can be exercised on the table to give a good idea of pulmonary vascular responses to exercise.
Links to further reading:
- The Joint Task Force for the Diagnosis and Treatment of Pulmonary Hypertension of the European Society of Cardiology (ESC) and the European Respiratory Society (ERS). 2015 ESC/ERS Guidelines for the diagnosis and treatment of pulmonary hypertension. European Heart Journal (2016) 37, 16
- Zuckerman et al. Safety of cardiac catheterisation at a centre specialising in the care of patients with pulmonary arterial hypertension. Pulm Circ 2013 ; 3: 831
- Hoeper MM et al. Determination of cardiac output by Fick method, thermodilution and acetylene rebreathing in pulmonary hypertension. Am J Respir Crit Care Med 1999;160:535