Conference: 2012 International PHA Conference and Scientific Sessions
Release Date: 06.22.2012
Presentation Type: Abstracts
Zeenat Safdar and K. Rangavajhala
Baylor College of Medicine, United States of America
BACKGROUND: Pulmonary artery hypertension (PAH, group 1) is characterized by increased transpulmonary gradient (TPG) and increased pulmonary artery diastolic – pulmonary artery occlusion pressure gradient (PAD-PAOP), whereas pulmonary venous hypertension (PH, group 2) is characterized by the presence of normal gradients. Presence of elevated gradients in group 2 PH indicates ‘out-of-proportion’ PH. Although, PAD-PAOP is considered a better indicator of pulmonary vascular remodeling, studies comparing PAD-PAOP to TPG in PH population are lacking.
METHODS: Consecutive right heart catheterization (RHC) undertaken at the Baylor PH Center were reviewed between 2005 and 2009. PH was defined as resting mPAP of >25 mm Hg and PAH (group 1) with PAOP of <15 mm Hg and PH (group 2) with PAOP of >15 mm Hg, normal TPG (mPAP-PAOP) as <12 mm Hg and normal PAD-PAOP as <6 mm Hg. 89 RHC data were reviewed, 17 showed normal hemodynamic and 72 met the PH criteria. 42 had PAH (group 1), 23 had PH (group 2), and 3 had incomplete data (not analyzed).
RESULTS: Demographic and hemodynamic data for normal, group 1 PAH and group 2 PH patients is outlined in Table 1. In both group 1 and group 2 PH, there was a good correlation between PAD-PAOP and PVR, and TPG and PVR (r=0.72 vs.r=0.61). As compared to group 1 PAH, group 2 PH patients had higher CO (p=0.03) but similar CI (p=0.71). Although group 2 patients had lower PAD-PAOP and TPG as compared to group 2 (p<0.001), fourteen patients in group 2 had elevated PAD-PAOP and TPG whereas five patients had normal PAD-PAOP and TPG. In addition, four patients had elevated TPG but normal PAD-PAOP gradient at rest. Three out of these four patients underwent exercise testing during the RHC and post-exercise values showed normalization of TPG in two patients.
CONCLUSIONS: Unexpectedly, a large number of patients in group 2 PH had elevated TPG and PAD-PAOP gradient (61%), indicating the presence of ‘out-of proportion’ or reactive PH in this group. PAD-PAOP gradient was a better indicator of ‘out-of proportion’ PH in this population. Clinical significance of these findings needs to be further investigated.
FUNDING: National Institute of Health grant K23HL-093214 to ZS