Abstract 14324: Low Pulmonary Venous Flow Drives Cpc-PH Development in a Pulmonary Venous Banding Swine Model of Cpc-PH

Abstract

Introduction: Combined pre- and post-capillary pulmonary hypertension (Cpc-PH) is the most severe form of PH-LHF. While the impact of elevated left atrial and consequently elevated pulmonary venous (PV) pressure on Cpc-PH progression is well studied, little is known about how compromised PV flow secondary to LHF affects disease progression. To assess the hypothesis that decreased PV flow induces Cpc-PH, we developed a large animal model of Cpc-PH by decreasing PV flow independent of LHF. Methods: Survival pulmonary venous banding (PVB) surgery was performed on a large white male pig (9kg), which was then followed for 16 weeks. A pig of the same sex and weight underwent a sham operation as control. Both animals underwent cardiac 4D flow MRI and right heart catheterization (RHC) in a terminal study. Results: At 16 weeks post-surgery, MR imaging demonstrated that PVB decreased mean flow and peak velocity in the right (RIPV) and left inferior pulmonary veins (LIPV) and MPA (figure and table). PVB also decreased MPA relative area change (RAC) (table). RHC demonstrated elevated PCWP, mPAP, PVR, and decreased RV EF (table). Also, Fulton index was increased demonstrating RV hypertrophy (table). Discussion: In conclusion, this study utilized PVB to demonstrate the ability of decreased PV flow to drive Cpc-PH development in the absence of LHF. Our preliminary data suggest a low flow state in the lung can increase RV afterload and induce RV dysfunction. Further studies with a larger sample size are needed to confirm this pathomechanical mechanism. Figure. MRI image of PV confluence narrowing from the PVB. Insert shows flow rates from RIPV and LIPV (blue), across PVB (red), and into LA (green).