How it's calculated
PAPi = (Pulmonary artery systolic pressure − Pulmonary artery diastolic pressure) ÷ Right atrial pressure, derived from right heart catheterisation data.
Interpretation
| PAPi | Interpretation |
|---|---|
| < 1.85 | Low — associated with right ventricular dysfunction/failure risk in studied populations |
| ≥ 1.85 | Preserved |
Clinical use
- Most studied in right ventricular failure after inferior/right ventricular myocardial infarction, and around mechanical circulatory support (e.g. predicting RV failure after LVAD implantation).
- A low PAPi suggests reduced right ventricular pulsatility relative to its afterload/filling pressure, consistent with RV dysfunction.
- Reported cutoffs vary meaningfully by clinical context and population studied — interpret alongside echocardiographic RV assessment and the overall haemodynamic picture, not as an isolated number.
- Requires right heart catheterisation data (pulmonary artery pressures and right atrial pressure), so it is generally used in cardiac catheterisation labs or intensive/coronary care settings with invasive monitoring.
Frequently asked questions
What is PAPi used for?
It assesses right ventricular function from right heart catheterisation data, most studied in right ventricular failure after inferior MI and in predicting RV failure around mechanical circulatory support.
What does a low PAPi mean?
It suggests reduced right ventricular pulsatility relative to right atrial pressure, consistent with right ventricular dysfunction — commonly cited cutoffs are around 1.85, though this varies by study population.
What data does PAPi require?
Pulmonary artery systolic and diastolic pressure, and right atrial pressure — all obtained via right heart catheterisation, so this isn't calculable from non-invasive measurements.
Does PAPi replace echocardiographic assessment of the right ventricle?
No — it's a complementary haemodynamic marker and should be interpreted alongside echocardiographic RV size/function assessment and the broader clinical picture.
References
- Korabathina R, et al. The pulmonary artery pulsatility index as a predictor of right ventricular failure in acute inferior myocardial infarction. Catheter Cardiovasc Interv. 2012;80(4):593-600.
- Kang G, et al. Pulmonary artery pulsatility index predicts right ventricular failure after left ventricular assist device implantation. J Heart Lung Transplant. 2016;35(1):67-73.