Practical recommendations relating to parameters measured or derived from right heart catheterisation
| Haemodynamic variable | Method of measurement | Range in healthy subjects# | Range in PAH | Practical recommendation¶ |
| Cardiac output L·min−1 | Measure pulmonary blood flow: 1) Using the indicator dilution principle (thermodilution) or 2) Based on oxygen consumption (Fick method) Oxygen consumption can be obtained from blood gas analysis or pulse oximetry | 4–6 | Normal or decreased | The preferred method is thermodilution, although the indirect Fick technique is acceptable Perform oximetry in patients with a pulmonary artery oxygen saturation >75% and in the event of suspected cardiac left-to-right shunt |
| Cardiac index L·min−1·m−2 | Calculated using: Cardiac index=cardiac output/BSA | 2.4–4 | Normal or decreased | |
| PAWP mmHg | Tracings to measure pressure waveforms | 4–12 | ≤15 | Inflate the balloon in the right atrium and advance the catheter until it reaches the PAWP position Avoid repeated inflations and deflations of the balloon (and removal when inflated) to minimise risk of pulmonary artery rupture Record PAWP as the mean of three end-expiratory measurements |
| mPAP mmHg | Calculated using: mPAP=diastolic PAP+ (systolic–diastolic PAP)/3 | Systolic: 15–25 Diastolic: 4–12 mPAP: 14±3 | mPAP: ≥25 | |
| PVR Wood units and PVRI Wood units·m−2 | Calculated using: PVR=(mPAP–mean PAWP)/cardiac output PVRI=PVR/BSA | ≤3 | PVR: >3 PVRI: ≥6 | For harmonisation, PVR should be expressed in Wood units It may also be expressed as dyn·s−1·cm−5 (conversion: Wood units×80) |
| RAP mmHg | Tracings to measure pressure waveforms | 1–6 | Normal or elevated | |
| RVP mmHg | Tracings to measure pressure waveforms | Systolic: 15–25 Diastolic 1–8 | >30 Normal, or elevated | |
| SVR Wood units | Calculated using: SVR=(mSAP–RAP)/cardiac output | 8.8–20 | PVR/SVR: <0.75 | In general, a ratio of PVR to SVR >0.75 indicates significant pulmonary vascular disease |
| TPG mmHg | Calculated using: TPG=mPAP–PAWP | ≤12 | >12 | May be used to determine a pre-capillary component in post-capillary PH |
| DPG mmHg | Calculated using: DPG=diastolic PAP–PAWP | <6 | >3 | May be used to determine a pre-capillary component in post-capillary PH |
PAH: pulmonary arterial hypertension; PAWP: pulmonary arterial wedge pressure; PAP: pulmonary arterial pressure; PVR: pulmonary vascular resistance; PVRI: pulmonary vascular resistance index; RAP: right atrial pressure; RVP: right ventricular pressure; SVR: systemic vascular resistance; TPG: transpulmonary pressure gradient; DPG: diastolic pressure gradient; BSA: body surface area; mPAP: mean pulmonary arterial pressure; mSAP: mean systemic arterial pressure; PH: pulmonary hypertension. #: values for PVR and PAP have been identified in additional studies of healthy subjects [18, 19]; ¶: information for practical recommendations from [3, 15, 17]. Information from [3, 11–19].