- Describes the ratio of PA pulse pressure and RAP (CVP)
- Originally evaluated in patients with RV infarction (2012) who had an RVAD fitted. RV flow largely determined cardiac output and so PAPi was developed in an attempt to determine suitability for weaning. Now has found utility in managing patients with advanced heart failure and those with LVAD.
- PA pulse pressure should increase with increasing RV stroke volume and increases by an increased amount if pulmonary capacitance is LOW. Note that normal capcitance should be around 4ml/mmHg and this decreases to 2.5 or less in established HF
- Provides an overall assessment of RV function although the context of RV impairment is very important (Acute RV infarction vs chronic biventricular failure)
- Found to be a predictive risk index for mortality in patients with PAH
- ePAPi was significantly associated with 60 day mortality in one study looking at echo-derived parameters in patients with cardiogenic shock
- Can also be used to assess responsiveness to treatment e.g. PAPi changes pre and post administration of pulnonary vasodilator therapy.
