Aortic stiffness is associated with aortic and coronary calcification in older adults
Aortic stiffness increases with age and blood pressure, even when the population prevalence of atherosclerosis is low. The extent to which atherosclerosis may exacerbate the aortic stiffening of aging remains unclear. Aortic stiffness was measured by carotid to femoral pulse wave velocity (PWV) and atherosclerosis by coronary artery calcification score (CCS) and aortic calcification score (ACS) by electron beam tomography in 484 participants (42% men, 23% black) aged 70-96 years (mean=79.4) from the Pittsburgh site of the Cardiovascular Health Study. The distributions of PWV (898, 851, 366-2183 cm/sec) (mean, median, range), CCS (676, 327, 0-4954) and ACS (5183, 3040, 0-57,950) were log-transformed when used as continuous variables. Median PWV and ACS were not different by gender but CCS was higher for men than women (median 637 vs. 187, p<0.01). Median PWV did not differ by race. Median CCS and ACS were higher in white participants (392 vs. 132; 3865 vs. 1154, p<0.01 for both). After adjustment for age and mean arterial pressure (MAP), PWV was higher for higher quartiles of CCS in women (792, 862, 854, 906, p for trend=0.02), but not men (879, 838, 888, 886, p for trend=0.67). Mean PWV was also higher by quartile of ACS (844, 918, 915, 942, p for trend=0.04) for the total group after adjustment for age, sex and MAP. When stratified by sex, the association was significant only for women (805, 861, 903, 933, p for trend=0.02), not men (910, 1021, 939, 966, p for trend=0.72). Similar results were found using linear regression with log CCS or log ACS as the independent variable, even after excluding participants with prevalent clinical disease. Race did not affect the associations. In these older adults, we found a cross-sectional association between aortic stiffness (PWV) and aortic and coronary calcification, independent of age and MAP, largely due to an association in women. The lack of association in these older men may be due to low power or survival bias. It will be important to determine whether aortic stiffness is an independent predictor of myocardial infarction and congestive heart failure, especially in conjunction with coronary calcification as a measure of atherosclerosis.