The project studies the carotid artery and intracerebral blood flow velocity using doppler ultrasonography in Baltimore Longitudinal Study of Aging participants. The goal is to determine how arterial anatomic and physiologic properties are associated with cerebrovascular diseases and aging. We are currently examining the relationship between several carotid arterial measurements and alcohol usage in the BLSA. We find that mild to moderate alcohol usage is associated with greater arterial elasticity and decreased stiffness in the common carotid artery. A less impressive association was observed with arterial wall thickness and diameter. The changes were independent of blood pressure and age. The response of the artery to alcohol usage may represent one mechanism for its protective effect against cardiovascular disease. In previous work we had shown that the use of estrogen replacement in postmenopausal women was associated with lower arterial stiffness. Male sex hormones are known to decline with increasing age, and have been associated with atherosclerotic disease and with risk factors for atherosclerosis. We have examined the relationship between androgenic hormones and arterial stiffness (beta stiffness index). Both testosterone and free testosterone (assessed by the free testosterone index) were negatively correlated with age, pulse pressure and stiffness index, while SHBG was positively correlated with age and stiffness index. Multiple regression analysis revealed that T was the only hormone that predicted the arterial stiffness index after adjustment for risk parameters. T values 5 to 10 years prior to the carotid study were also a predictor of the stiffness index. A path analysis revealed that decreasing T with advancing age increased stiffness index directly and indirectly through increasing pulse pressure. Neither DHEAS nor Androsteindione were associated with T or FTI or appeared to contribute to arterial stiffness. The determination of arterial stiffness from carotid doppler requires interactive measurements by the sonographer that adds several minutes to the clinical examination. To simplify the process, we have explored using the shape of the doppler waveform as a measure of arterial stiffness with a program that automatically identifies the shape of the curve. An exponential function was applied to the post-peak ICA Doppler waveform contour. The exponential coefficient, termed """"""""Decay Index"""""""" (DI), is associated with central arterial stiffness and modestly with peripheral resistance and appears to reflect the Windkessel function. The Windkessel function represents the elastic buffering capacity of the vascular system and reduces cardiac afterload and improves ventricular relaxation. We have examined the DI and found that it increased with increasing age and was higher in women suggesting a decline in the Windkessel function.
| Nagai, Y; Helwegen, J; Fleg, J L et al. (2001) Associations of aortic Windkessel function with age, gender and cardiovascular risk factors. Ultrasound Med Biol 27:1207-10 |
| Anderson, D E; Scuteri, A; Metter, E J et al. (2001) Association of high resting end tidal CO2 with carotid artery thickness in women, but not men. J Hypertens 19:459-63 |
| Ajmani, R S; Metter, E J; Jaykumar, R et al. (2000) Hemodynamic changes during aging associated with cerebral blood flow and impaired cognitive function. Neurobiol Aging 21:257-69 |
