Abstract P139: Association Of Thoracic Aorta Calcification And Aortic Arch Stiffness: The Multi-ethnic Study Of Atherosclerosis

Abstract

Background: Arterial stiffness (AS) is a robust risk factor for HTN and CVD. It remains unclear how thoracic aortic calcification (TAC) presence, volume, and density relate to AS in the aortic arch. Improved understanding of central AS may provide insight to future mechanistic approaches to prevent and control CVD. Methods: We evaluated 1,385 participants from MESA Exam 5 with TAC data throughout the thoracic aorta via Chest CT and pulse wave velocity (PWV) as a measure of AS across the aortic arch via MRI. We used linear regression models to assess cross-sectional associations of TAC presence, volume, and density with aortic arch PWV with adjustment for 1) age, sex, and race; and 2) age, sex, race, BMI, diabetes, estimated glomerular filtration rate, HTN-medication use, SBP, DBP, total cholesterol/high-density lipoprotein ratio, smoking status, CAC volume, CAC density, education, physical activity, and sedentary behavior. Results: Participants were a mean age of 69 years (SD 9) [717 (52%) female; 509 (37%) White, 359 (26%) Black, 285 (21%) Hispanic/Latino, and 232 (17%) Chinese]. Calcification was present in 1,263 (91%) and 1,228 (89%) participants in the entire thoracic aorta and aortic arch, respectively, compared to 848 (61%) and 138 (10%) in the descending and ascending aorta segments. Calcium volume in the entire thoracic aorta and aortic arch were highly correlated (r=0.94) with respective means of 866 (SD 1,724) and 564 (1,014) mm 3 . Mean PWV across the aortic arch was 9 m/sec (SD 4). After full adjustment, the presence of aortic arch calcification, compared to no aortic arch calcification, was associated with a 0.76 m/sec higher mean PWV (95% CI: 0.34 - 1.18; p<0.01), while a 1,000 mm 3 increment in aortic arch calcium volume was associated with 0.36 m/sec higher mean PWV (95% CI: 0.08-0.64; p=0.01). Results were similar when calcification in the entire thoracic aorta was the primary predictor variable. Conversely, there were no significant associations between mean or maximum calcium density measures and aortic arch PWV. Conclusion: TAC is highly prevalent in the thoracic aorta, especially the aortic arch. Calcification presence and higher calcification volume in the thoracic aorta, as well as the aortic arch itself, are associated with greater aortic arch AS.