Age‐Related Increase in Extra‐Media Thickness is Associated with Arterial Stiffening and Carotid Blood Pressure

Abstract

Older age is a primary risk factor associated with future cardiovascular disease (CVD) related events. Age‐related changes in perivascular adipose tissue (PVAT) and vascular remodeling both contribute to arterial stiffening and increased blood pressure which are established CVD risk factors. The non‐invasively measured extra‐media thickness (EMT) is a novel and composite measure, which includes PVAT, arterial adventitia, and the jugular vein that may provide translational insight for these factors contributing to age‐related arterial stiffening and higher blood pressure. However, it is unknown if aging increases EMT and is associated with arterial stiffness and blood pressure. We hypothesized that age‐related increases in EMT will be associated with higher arterial stiffness and blood pressure. Forty participants (young: 8M/12F, 23.2 ± 1.1 yrs and middle‐aged/older: 7M/13F, 60.7 ± 9.4 yrs) underwent measures of blood pressure (brachial; carotid), arterial stiffness (carotid b‐stiffness), EMT via ultrasonography and body composition with dual x‐ray absorptiometry. All measurements were taken in the supine position. Group mean differences between young and middle‐aged/older participants were analyzed with unpaired t‐tests and Pearson correlations were used to assess relations between EMT and arterial stiffness and blood pressure endpoints. Compared to younger participants, middle‐aged/older participants had higher EMT (0.80 ± 0.03 vs. 0.69 ± 0.02 mm), carotid beta stiffness (3.24 ± 0.08 vs. 2.60 ± 0.04), carotid SBP (116.5 ± 4.9 vs. 99.1 ± 2.3 mmHg), and carotid PP (44.6 ± 4.2 vs. 34.8 ± 1.5 mmHg) (all, p<0.05). Brachial SBP was not different between groups (p>0.05). Carotid beta stiffness (r= 0.410), carotid SBP (r= 0.501), and carotid PP (r= 0.5037) were all positively correlated with EMT for the entire cohort (all, p<0.05). Our findings indicate that there is an age‐related increase in EMT that is associated with both carotid arterial stiffness and pressure. These data suggest that increases in arterial stiffness and blood pressure with advancing age may be attributable, in part, to increases in EMT, which may be due to changes in PVAT and arterial adventitial remodeling. Therefore, EMT, a potential surrogate for PVAT and arterial remodeling, may provide novel insight into age‐related arterial stiffening, higher blood pressure and increased CVD risk with aging.