RACE & GENDER DIFFERENCES IN INTRACEREBRAL & CAROTID ARTERIAL VELOCITY--A

Yogi永井博士于1996年3月加入LSB， 他和我们一起参与了这个项目，并于1998年3月完成了他的奖学金。 该项目研究脑内血流速度和阻力， 多普勒超声检测颈动脉血流速度 BLSA参与者。我们的目标是确定这些因素， 与脑血管疾病相关的蛋白质， 年龄它补充了Lakatta博士和Fleg博士的研究， LCS对动脉僵硬度的影响，通过探索僵硬度对 大脑（Brain）已经完成了一些分析： (1)To确定是否内膜中层厚度的共同 颈动脉（CCA IMT）是动脉粥样硬化的一个建议指标， 在无症状的老年缺血性受试者中增加 ST段对踏车运动的反应。内中膜厚度 (IMT)颈总动脉（CCA）的血流速度随年龄增长而增加 伴随CCA扩张，收缩期血升高 压力和不同的性别。IMT的变化是 由于冠心病（CHD）的存在而加剧。在 事实上，无症状CHD患者显示室壁增厚， 低于症状性CHD患者，高于健康人 对照IMT每增加0.1 mm， 与1.78倍（95% CI 1.34-2.36，p<0.0001）相关 一致性阳性运动试验或表现的风险增加 CAD. (2)一个新的指数，衰变指数（DI），被开发出来， 检查收缩晚期血流速度的变化。得出 从录像带上记录的多普勒波中， 开发的计算机程序。DI与主动脉直接相关 僵硬，并在较小程度上与动脉外周阻力。它 与年龄和冠心病独立相关， 与其他颈动脉僵硬度指标相比。(3)AGI和 弹性的超声指数表示不同的 血管僵硬的特征。增强指数 （AGI）（r=.38，p=.000）和Ep随年龄增加，DC（r=-0.43，p =.000） p=.000）和CC（r=-.25，p=.021）随年龄增长而下降，而YM则随年龄增长而下降。 不随年龄变化。AGI并没有显著的相关性， 超声指标Ep、YM虽有显著性差异， 在控制年龄后与AGI的相关性（r2= 0.23，r2= 0.18， 分别）。研究结果表明，AGI和 超声测量应能更好地了解 动脉随年龄的变化，比单独测量。进一步 分析正在进行中，以检查雌激素对动脉的影响， 弹性在绝经后妇女，并比较流速 正常人颈总动脉、颈内动脉和大脑中动脉 女性和男性在整个成年期内。

Dr. Yogi Nagai joined LSB in March 1996 to work on the project with us and completed his fellowship in March 1998. The project studies intracerebral blood flow velocity and resistance, and carotid blood flow velocity using doppler ultrasonography in BLSA participants. The goal is to determine how these factors, which are associated with cerebrovascular diseases, change with age. It complements the studies of Drs. Lakatta and Fleg in the LCS on arterial stiffness, by exploring the effects of stiffness on an end organ (the brain). A number of analyses have been completed: (1)To determine whether intimal-medial thickness of the common carotid artery (CCA IMT), a proposed index of atherosclerosis, is increased in asymptomatic older subjects with an ischemic ST-segment response to treadmill exercise. Intimal medial thickness (IMT) of the common carotid artery (CCA) increases with age concomitant with CCA dilatation, elevation of systolic blood pressure and differently by gender. The change in IMT is exacerbated by the presence of coronary heart disease (CHD). In fact, individuals with asymptomatic CHD show wall thickening that is less than observed in symptomatic CHD and greater than healthy controls. Each 0.1 mm increase in IMT was independently associated with a 1.78 fold (95% CI 1.34-2.36, p<0.0001) increased risk for concordant positive exercise tests or manifest CAD. (2) A new index, the decay index (DI), was developed to examine changes in flow velocity during late systole. It is obtained from the Doppler waves recorded on videotapes using a newly developed computer program. DI is directly associated with aortic stiffness and to a lesser extent with arterial peripheral resistance. It was found to be independently related to age and CHD, as compared to other measures of carotid stiffness. (3) AGI and ultrasonographical indices of elasticity express different characteristic of vascular stiffness. Augmentation index (AGI)(r=.38, p=.000) and Ep increased with age, DC(r=-.43, p=.000) and CC(r=-.25, p=.021) decreased with age, while YM did not change with age. AGI did not significantly correlate with the ultrasonographical indices, though Ep and YM had significant correlations with AGI after controlling for age (r2=.23, r2=.18, respectively). The findings suggest that both the AGI and ultrasonographic measurements should give a better understanding of arterial changes with age, than either measurement alone. Further analyses are underway to examine the effects of estrogen on arterial elasticity in postmenopausal women, and to compare flow velocities in CCA, internal carotid and middle cerebral arteries in healthy women and men across the adult life span.