Background:
Hemodynamic changes during exercise at right heart catheterisation (RHC) may be a diagnostic and prognostic tool in pulmonary arterial hypertension (PAH).
Method and Results:
We retrospectively assessed the hemodynamic response to exercise during RHC of 138 patients with PAH secondary to idiopathic PAH (IPAH), connective tissue disease (CTD) or congenital heart disease (CHD). RHCs were performed at a single centre between 2007 and 2018. A submaximal comfort-based protocol on a reclined bicycle or straight leg raise test (SLRT) was employed. IPAH demonstrated the highest mean pulmonary artery pressure (mPAP) at rest, rising 47% with exercise, but a 66% rise in CO allowed pulmonary vascular resistance (PVR) to fall. Those with CTD demonstrated a 56% rise in mPAP, 70% rise in CO and PVR remained unchanged. In CHD, there was a 46% rise in mPAP, 49% rise in CO and a rise in PVR. Notably, there was a rise in pulmonary artery wedge pressure (PAWP) in all groups, most marked in those with IPAH. Total peripheral resistance (TPR), pulmonary artery compliance (PAC) and pulmonary artery elastance (Ea) changes were variable. TPR marginally decreased in IPAH patients, remained unchanged in those with CTD and increased in CHD. PAC decreased in all groups, with the lowest values observed in those with IPAH. Ea increased in all groups but was most notably higher in those with IPAH. Right ventricular stroke work index (RVSWI) increased in all patients, the lowest values before and after exercise were observed in the CTD cohort. Mean pulmonary artery pulsatility index (PaPi) increased in all groups, although was subtle and didn’t meet statistical significance for those with CTD and CHD.
Conclusions:
The hemodynamic response to exercise in patients with PAH differs between aetiologies. A rise in PAWP occurred in all groups, with ventricular interdependence a possible explanation. Whether there is a relationship between exercise hemodynamic changes and prognosis remains undetermined.