Tufts Medical Center, Department of Radiology, 800 Washington Street, Box 299, Boston, MA 02111, USA.
J Am Soc Echocardiogr. 2012 Sep;25(9):1023-8. doi: 10.1016/j.echo.2012.05.007. Epub 2012 Jun 20.
Common carotid artery intima-media thickness (IMT), a measure of atherosclerosis, varies between peak systole and end-diastole. This difference might affect cardiovascular risk assessment.
IMT measurements of the right and left common carotid arteries were synchronized with an electrocardiogram, using the R wave for end-diastole and the T wave for peak systole. IMT was measured in 2,930 members of the Framingham Offspring Study. Multivariate regression models were generated with end-diastolic IMT, peak systolic IMT, and change in IMT as dependent variables and Framingham risk factors as independent variables. End-diastolic IMT estimates were compared with the upper quartile of IMT on the basis of normative data obtained at peak systole.
The average age of the study population was 57.9 years. The average difference in IMT during the cardiac cycle was 0.037 mm (95% confidence interval, 0.035-0.038 mm). End-diastolic IMT and peak systolic IMT had similar associations with Framingham risk factors (total R(2) = 0.292 vs 0.275) and were significantly associated with all risk factors. In a fully adjusted multivariate model, thinner IMT at peak systole was associated with pulse pressure (P < .0001), low-density lipoprotein cholesterol (P = .0064), age (P = .046), and no other risk factors. Performing end-diastolic IMT measurements while using upper quartile peak systolic IMT normative data led to inappropriately increasing by 42.1% the number of individuals in the fourth IMT quartile (high cardiovascular risk category).
The difference in IMT between peak systole and end diastole is associated with pulse pressure, low-density lipoprotein cholesterol, and age. In this study, the mean IMT difference during the cardiac cycle led to an overestimation by 42.1% of individuals at high risk for cardiovascular disease.
颈总动脉内膜中层厚度（IMT）是动脉粥样硬化的一种衡量指标，其在收缩期峰值和舒张末期之间存在差异。这种差异可能会影响心血管风险评估。
使用心电图的 R 波作为舒张末期，T 波作为收缩期峰值，对 2930 名弗雷明汉后代研究的参与者的左右颈总动脉 IMT 进行同步测量。以舒张末期 IMT、收缩期峰值 IMT 和 IMT 变化为因变量，以弗雷明汉风险因素为自变量，生成多元回归模型。基于收缩期峰值获得的正常数据，将舒张末期 IMT 估计值与 IMT 的上四分位数进行比较。
研究人群的平均年龄为 57.9 岁。心动周期中 IMT 的平均差异为 0.037 毫米（95%置信区间，0.035-0.038 毫米）。舒张末期 IMT 和收缩期峰值 IMT 与弗雷明汉风险因素的相关性相似（总 R²=0.292 与 0.275），与所有风险因素均显著相关。在完全调整的多元模型中，收缩期峰值时较薄的 IMT 与脉压（P<0.0001）、低密度脂蛋白胆固醇（P=0.0064）、年龄（P=0.046）相关，而与其他风险因素无关。在使用收缩期峰值的上四分位正常数据进行舒张末期 IMT 测量时，将处于第四 IMT 四分位（心血管高危类别）的个体数量错误地增加了 42.1%。
收缩期峰值和舒张末期之间的 IMT 差异与脉压、低密度脂蛋白胆固醇和年龄有关。在这项研究中，心动周期期间 IMT 的平均差异导致对心血管疾病高危个体的估计错误增加了 42.1%。
