Newman A B, Siscovick D S, Manolio T A, Polak J, Fried L P, Borhani N O, Wolfson S K
Department of Medicine, Medical College of Pennsylvania, Pittsburgh.
Circulation. 1993 Sep;88(3):837-45. doi: 10.1161/01.cir.88.3.837.
Peripheral arterial disease measured noninvasively by the ankle-arm index (AAI) is common in older adults, largely asymptomatic, and associated with clinically manifest cardiovascular disease (CVD). The criteria for an abnormal AAI have varied in previous studies. To determine whether there is an inverse dose-response relation between the AAI and clinical CVD, subclinical disease, and risk factors, we examined the relation of the AAI to cardiovascular risk factors, other noninvasive measures of subclinical atherosclerosis using carotid ultrasound, echocardiography and electrocardiography, and clinical CVD.
The AAI was measured in 5084 participants > or = 65 years old at the baseline examination of the Cardiovascular Health Study. All subjects had detailed assessment of prevalent CVD, measures of cardiovascular risk factors, and noninvasive measures of disease. Participants were stratified by baseline clinical CVD status and AAI (< 0.8, > or = 0.8 to < 0.9, > or = 0.9 to < 1.0, > or = 1.0 to < 1.5). Analyses tested for a dose-response relation of the AAI with clinical CVD, risk factors, and subclinical disease. The cumulative frequency of a low AAI was 7.4% of participants < 0.8, 12.4% < 0.9, and 23.6% < 1.0. participants with an AAI < 0.8 were more than twice as likely as those with an AAI of 1.0 to 1.5 to have a history of myocardial infarction, angina, congestive heart failure, stroke, or transient ischemic attack (all P < .01). In participants free of clinical CVD at baseline, the AAI was inversely related to history of hypertension, history of diabetes, and smoking, as well as systolic blood pressure, serum creatinine, fasting glucose, fasting insulin, measures of pulmonary function, and fibrinogen level (all P < .01). Risk factor associations with the AAI were similar in men and women free of CVD except for serum total and low-density lipoprotein cholesterol, which were inversely associated with AAI level only in women. Risk factors associated with an AAI of < 1.0 in multivariate analysis included smoking (odds ratio [OR], 2.55), history of diabetes (OR, 3.84), increasing age (OR, 1.54), and nonwhite race (OR, 2.36). In the 3372 participants free of clinical CVD, other noninvasive measures of subclinical CVD, including carotid stenosis by duplex scanning, segmental wall motion abnormalities by echocardiogram, and major ECG abnormalities were inversely related to the AAI (all P < .01).
There was an inverse dose-response relation of the AAI with CVD risk factors and subclinical and clinical CVD among older adults. The lower the AAI, the greater the increase in CVD risk; however, even those with modest, asymptomatic reductions in the AAI (0.8 to 1.0) appear to be at increased risk of CVD.
通过踝臂指数（AAI）进行无创测量的外周动脉疾病在老年人中很常见，大多无症状，并与临床显性心血管疾病（CVD）相关。先前研究中异常AAI的标准各不相同。为了确定AAI与临床CVD、亚临床疾病及危险因素之间是否存在剂量反应负相关关系，我们研究了AAI与心血管危险因素、使用颈动脉超声、超声心动图和心电图的亚临床动脉粥样硬化的其他无创测量方法以及临床CVD之间的关系。
在心血管健康研究的基线检查中，对5084名年龄≥65岁的参与者测量了AAI。所有受试者都对现患CVD、心血管危险因素测量以及疾病的无创测量进行了详细评估。参与者按基线临床CVD状态和AAI（<0.8、≥0.8至<0.9、≥0.9至<1.0、≥1.0至<1.5）进行分层。分析测试了AAI与临床CVD、危险因素和亚临床疾病之间的剂量反应关系。AAI低的累积频率在AAI<0.8的参与者中为7.4%，<0.9的为12.4%，<1.0的为23.6%。AAI<0.8的参与者发生心肌梗死、心绞痛、充血性心力衰竭、中风或短暂性脑缺血发作病史的可能性是AAI为1.0至1.5者的两倍多（所有P<.01）。在基线时无临床CVD的参与者中，AAI与高血压病史、糖尿病病史、吸烟以及收缩压、血清肌酐、空腹血糖、空腹胰岛素、肺功能指标和纤维蛋白原水平呈负相关（所有P<.01）。在无CVD的男性和女性中，除血清总胆固醇和低密度脂蛋白胆固醇外，与AAI相关的危险因素相似，血清总胆固醇和低密度脂蛋白胆固醇仅在女性中与AAI水平呈负相关。多变量分析中与AAI<1.0相关的危险因素包括吸烟（比值比[OR]，2.55）、糖尿病病史（OR，3.84）、年龄增加（OR，1.54）和非白人种族（OR，2.36）。在3372名无临床CVD的参与者中，亚临床CVD的其他无创测量方法，包括双功扫描显示的颈动脉狭窄、超声心动图显示的节段性室壁运动异常和主要心电图异常与AAI呈负相关（所有P<.01）。
在老年人中，AAI与CVD危险因素、亚临床和临床CVD之间存在剂量反应负相关关系。AAI越低，CVD风险增加越大；然而，即使是AAI有适度无症状降低（0.8至1.0）的人，CVD风险似乎也会增加。
