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Pulmonary Artery Diastolic – Pulmonary Artery Occlusion Pressure Gradient to Characterize Patients with Pulmonary Hypertension

Zeenat Safdar

K. Rangavajhala


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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

BACKGROUNDPulmonary 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.

METHODSConsecutive 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).

RESULTSDemographic 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.

CONCLUSIONSUnexpectedly, 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