Abstract Body (Do not enter title and authors here): Background Advanced age is associated with left ventricular (LV) remodeling and increased pulmonary pressure; both these alterations are associated with increased risk of heart failure. However, there is a lack of data regarding morphologic changes in the pulmonary vasculature underlying these associations.

Aims Determine the extent to which LV remodeling associates with pulmonary arterial (PA) pruning, and the relationship of PA pruning with pulmonary pressure.

Methods Among 2,275 participants in the community-based Atherosclerosis Risk in Communities (ARIC) study who underwent echocardiography and non-contrast chest CT at Visit 7 (2018-2019), we quantified the fraction of total pulmonary vascular area comprised of arterial vessels with diameter <5 mm (BV5/TBV) using validated image processing (Panel A). We used multivariable linear regression to assess the association of BV5/TBV with echocardiographic measures of pulmonary artery systolic pressure (PASP) and LV structure, systolic function, and diastolic function. Models were adjusted for age, BMI, eGFR, gender, race, lung volume, SBP, prevalent CAD, diabetes, atrial fibrillation, and hypertension, cumulative pack years smoked at Visit 7, and low and high attenuation areas on CT.

Results Mean age was 80 ±4 years, 61% were women, 22% reported Black race, and mean LVEF was 64 ±7%. Mean BV5/TBV was 0.30 ±0.08. Lower BV5/TBV – reflecting greater PA pruning – was associated with older age, male sex, Black race, and greater BMI. There was no correlation between prevalent atrial fibrillation, hypertension, CAD, or stroke and PA pruning. Greater LV volume and mass, lower LVEF, and greater left atrial volume were each associated with lower BV5/TBV (Panel B). Lower BV5/TBV demonstrated a nonlinear association with greater PASP (Panel C), with increases in PASP noted at BV5/TBV values <0.30.

Conclusions Worse LV systolic and diastolic function are associated with greater PA pruning, which is in turn associated with greater PASP once BV5/TBV falls below 0.30. Our findings clarify the pulmonary vascular remodeling that links cardiac dysfunction to elevated pulmonary pressure in late life and may help identify persons at particularly high risk for pulmonary hypertension.