Ebrahim S, Papacosta O, Whincup P, Wannamethee G, Walker M, Nicolaides A N, Dhanjil S, Griffin M, Belcaro G, Rumley A, Lowe G D
Department of Social Medicine, University of Bristol, UK.
Stroke. 1999 Apr;30(4):841-50. doi: 10.1161/01.str.30.4.841.
B-mode ultrasound is a noninvasive method of examining the walls of peripheral arteries and provides measures of the intima-media thickness (IMT) at various sites (common carotid artery, bifurcation, internal carotid artery) and of plaques that may indicate early presymptomatic disease. The reported associations between cardiovascular risk factors, clinical disease, IMT, and plaques are inconsistent. We sought to clarify these relationships in a large, representative sample of men and women living in 2 British towns.
The study was performed during 1996 in 2 towns (Dewsbury and Maidstone) of the British Regional Heart Study that have an approximately 2-fold difference in coronary heart disease risk. The male participants were drawn from the British Regional Heart Study and were recruited in 1978-1980 and form part of a national cohort study of 7735 men. A random sample of women of similar age to the men (55 to 77 years) was also selected from the age-sex register of the general practices used in the original survey. A wide range of data on social, lifestyle, and physiological factors, cardiovascular disease symptoms, and diagnoses was collected. Measures of right and left common carotid IMT (IMTcca) and bifurcation IMT (IMTbif) were made, and the arteries were examined for plaques 1.5 cm above and below the flow divider.
Totals of 425 men and 375 women were surveyed (mean age, 66 years; range, 56 to 77 years). The mean (SD) IMTcca observed were 0. 84 (0.21) and 0.75 (0.16) mm for men and women, respectively. The mean (SD) IMTbif were 1.69 (0.61) and 1.50 (0.77) mm for men and women, respectively. The correlation between IMTcca and IMTbif was similar in men (r=0.36) and women (r=0.38). There were no differences in mean IMTcca or IMTbif between the 2 towns. Carotid plaques were very common, affecting 57% (n=239) of men and 58% (n=211) of women. Severe carotid plaques with flow disturbance were rare, affecting 9 men (2%) and 6 women (1.6%). Plaques increased in prevalence with age, affecting 49% men and 39% of women aged <60 years and 65% and 75% of men and women, respectively, aged >70 years. Plaques were most common among men in Dewsbury (79% affected) and least common among men in Maidstone (34% affected). IMTcca showed a different pattern of association with cardiovascular risk factors from IMTbif and was associated with age, SBP, and FEV1 but not with social, lifestyle, or other physiological risk factors. IMTbif and carotid plaques were associated with smoking, manual social class, and plasma fibrinogen. IMTbif and carotid plaques were associated with symptoms and diagnoses of cardiovascular diseases. IMTbif associations with cardiovascular risk factors and prevalent cardiovascular disease appeared to be explained by the presence of plaques in regression models and in analyses stratified by plaque status.
IMTcca, IMTbif, and plaque are correlated with each other but show differing patterns of association with risk factors and prevalent disease. IMTcca is strongly associated with risk factors for stroke and with prevalent stroke, whereas IMTbif and plaque are more directly associated with ischemic heart disease risk factors and prevalent ischemic heart disease. Our analyses suggest that presence of plaque, rather than the thickness of IMTbif, appears to be the major criterion of high risk of disease, but confirmation of these findings in other populations and in prospective studies is required. The association of fibrinogen with plaque appears to be similar to its association with incident cardiovascular disease. Further work elucidating the composition of plaques using ultrasound imaging would be helpful, and more data, analyzed to distinguish plaque from IMTbif and IMTcca, are required to understand the significance of thicker IMT in the absence of plaque.
B 型超声是一种用于检查外周动脉血管壁的非侵入性方法，可测量不同部位（颈总动脉、分叉处、颈内动脉）的内膜中层厚度（IMT）以及可能提示症状前期疾病的斑块情况。心血管危险因素、临床疾病、IMT 与斑块之间的报道关联并不一致。我们试图在居住于英国两个城镇的大量具有代表性的男性和女性样本中阐明这些关系。
该研究于 1996 年在英国地区心脏研究的两个城镇（德斯伯里和梅德斯通）进行，这两个城镇的冠心病风险存在约 2 倍差异。男性参与者来自英国地区心脏研究，于 1978 - 1980 年招募，是一项 7735 名男性的全国队列研究的一部分。还从原始调查中使用的全科医疗年龄 - 性别登记册中随机抽取了与男性年龄相仿（55 至 77 岁）的女性样本。收集了关于社会、生活方式和生理因素、心血管疾病症状及诊断的广泛数据。测量了左右颈总动脉 IMT（IMTcca）和分叉处 IMT（IMTbif），并在血流分流器上下 1.5 cm 处检查动脉是否有斑块。
共调查了 425 名男性和 375 名女性（平均年龄 66 岁；范围 56 至 77 岁）。男性和女性观察到的平均（标准差）IMTcca 分别为 0.84（0.21）和 0.75（0.16）mm。男性和女性的平均（标准差）IMTbif 分别为 1.69（0.61）和 1.50（0.77）mm。IMTcca 和 IMTbif 之间的相关性在男性（r = 0.36）和女性（r = 0.38）中相似。两个城镇之间的平均 IMTcca 或 IMTbif 没有差异。颈动脉斑块非常常见，男性中有 57%（n = 239）、女性中有 58%（n = 211）受影响。伴有血流紊乱的严重颈动脉斑块很少见，9 名男性（2%）和 6 名女性（1.6%）受影响。斑块患病率随年龄增加，年龄＜60 岁的男性和女性中分别有 49%和 39%受影响，年龄＞70 岁的男性和女性中分别有 65%和 75%受影响。斑块在德斯伯里的男性中最常见（79%受影响），在梅德斯通的男性中最不常见（34%受影响）。IMTcca 与心血管危险因素的关联模式与 IMTbif 不同，且与年龄、收缩压和第一秒用力呼气容积相关，但与社会、生活方式或其他生理危险因素无关。IMTbif 和颈动脉斑块与吸烟、体力劳动者社会阶层和血浆纤维蛋白原相关。IMTbif 和颈动脉斑块与心血管疾病的症状及诊断相关。在回归模型以及按斑块状态分层的分析中，IMTbif 与心血管危险因素及心血管疾病患病率之间的关联似乎可由斑块的存在来解释。
IMTcca、IMTbif 和斑块相互关联，但与危险因素及患病率的关联模式不同。IMTcca 与中风危险因素及中风患病率密切相关，而 IMTbif 和斑块与缺血性心脏病危险因素及缺血性心脏病患病率更直接相关。我们的分析表明，斑块的存在而非 IMTbif 的厚度似乎是疾病高风险的主要标准，但需要在其他人群和前瞻性研究中证实这些发现。纤维蛋白原与斑块的关联似乎与其与心血管疾病发病的关联相似。使用超声成像进一步阐明斑块成分的工作将有所帮助，并且需要更多数据来区分斑块与 IMTbif 和 IMTcca，以了解在无斑块情况下 IMT 增厚的意义。
