Abstract 5105: The Relationship of Inflammation and Thrombosis with Right Ventricular Mass and Function: The MESA-Right Ventricle Study
Right ventricular (RV) mass reflects response to afterload, whereas RV ejection fraction (RVEF) is an indicator of RV function. Pulmonary vascular disease is characterized by hemostatic abnormalities and inflammation and may affect RV mass and function. We hypothesized that increased levels of inflammatory markers (ICAM-1, TNF-α, E-Selectin, MMP-3, and MMP-9) would be associated with higher RV mass and lower RVEF, and increased levels of hemostatic markers (tissue factor, PAI-1, and CD40L) and decreased levels of TFPI would be associated with higher RV mass and lower RVEF. The Multi-Ethnic Study of Atherosclerosis (MESA) performed interpretable cardiac MRIs on 5,004 participants without clinical cardiovascular disease at six field centers. 785 randomly selected patients had plasma biomarkers measured, 730 of whom had complete interpretation of RV measures. Endocardial margins of the RV were manually contoured on diastolic and systolic images. End-diastolic volume (EDV) and end-systolic volume (ESV) were calculated by using a summation of disks method (“Simpson’s Rule”). RVEF was calculated from (EDV-ESV)/EDV. RV mass was determined from cine images of the heart. Biomarkers were analyzed in quintiles using multivariate linear regression. The 730 participants in the study sample were 59 ± 10 (mean ± SD) years old, 58% female, 45% Caucasian, 21% African-American, 11% Chinese-American, and 23% Hispanic. The RV mass was 22 g ± 5 g and RVEF was 69% ± 7%. Higher PAI-1 levels were associated with lower RV mass, after adjustment for age, gender, race, height, and weight (test for trend, p = 0.036, n = 710). Higher MMP-9 levels were associated with lower RV mass (test for trend, p = 0.006). Neither hemostatic nor inflammatory biomarkers were associated with RVEF. RV mass was inversely associated with PAI-1, a serine protease which inhibits thrombolysis, and MMP-9, which breaks down the extracellular matrix. The mechanism of these determinants of RV structure and function should be investigated.