Abstract 14867: Pulmonary Venous and Arterial Remodeling in Experimental Group 2 Pulmonary Hypertension

Introduction:Left heart disease (LHD) leads to pulmonary venous hypertension (PVH) and isolated post-capillary (IpcPH) or combined post-capillary and pre-capillary (CpcPH) pulmonary hypertension (PH). While CpcPH is usually attributed to pulmonary arterial remodeling, we hypothesized that in a large animal model of PVH, remodeling of pulmonary veins also occurs and is associated with PH severity.Methods:Domestic swine (10 PVH and 9 Sham) underwent baseline right heart catheterization (RHC). PVH was produced by superior and common inferior pulmonary vein banding just proximal to the left atrium. All pigs underwent monthly RHC. PVH pigs were sacrificed at end-study (ES), defined as clinical instability (n=3), severe CpcPH (n=6) at RHC or 4 months post-banding (n=1). Sham pigs were sacrificed at similar time points to PVH pigs. Pulmonary arteries and veins were specifically labeled at sacrifice using pressurized perfusion with microbead- or barium-agarose solution for quantitative histomorphometry.Results:(See Table) At ES, mean PAP, TPG, PVR, and Cpa differed between groups, while PAWP, CO and body weight did not. Wall thickness relative to external diameter (% Wall Th) was increased in arteries and veins (Figure) and both arterial and venous % Wall Th correlated with mean PAP, TPG and PVR (R2?0.60, p?0.0014 for all).Conclusion:Arterial and venous pulmonary vascular remodeling is associated with CpcPH severity in a large animal model of CpcPH due to chronic PVH (as occurs in LHD). Further study in this model is needed to characterize potentially unique mediators of pulmonary arterial versus venous remodeling and thus novel therapies in CpcPH associated with LHD.