Ahmadi Naser, McQuilkin Gary L, Akhtar Mohammad W, Hajsadeghi Fereshteh, Kleis Stanley J, Hecht Harvey, Naghavi Morteza, Budoff Matthew
Los Angeles Biomedical Research Institute at Harbor UCLA Medical Center, Torrance, CA 90502, USA.
Clin Physiol Funct Imaging. 2011 Nov;31(6):422-8. doi: 10.1111/j.1475-097X.2011.01037.x. Epub 2011 Jul 3.
Previous studies demonstrated that digital thermal monitoring (DTM) of vascular reactivity, a new test for vascular function assessment, is well correlated with Framingham Risk Score, coronary calcium score and CT angiography. This study evaluates the variability and reproducibility of DTM measurements. We hypothesized that DTM is reproducible, and its variability falls within the accepted range of clinical diagnostic tests.
A fully automated DTM device (VENDYS, Endothelix Inc., Houston, TX, USA) was used for repeated measurement of vascular function in 18 healthy volunteers (age 35 ± 4 years, 74% men) after 24 h. All subjects underwent overnight fasting, and the test was preceded by 30-min rest in a supine position inside a dimmed room with temperature 22-24°C. The measurements were obtained during and after a 2-min supra systolic arm-cuff occlusion-induced reactive hyperaemia procedure. As a part of this study, the Doppler ultrasound hyperaemic, low-frequency, blood velocity of radial artery and a fingertip DTM of vascular function were compared simultaneously. Postcuff deflation temperature rebound and area under the curve, DTM indices of vascular function, were studied.
Temperature rebound area under the curve correlated closely with Doppler hyperaemic, low-frequency, blood velocity (r = 0·97, P = 0·0001). Day-to-day intra-subject variability was 6·2% for baseline temperature, 8·7% for mean blood pressure and 11·4% for heart rate. The coefficient of repeatability of temperature rebound and area under the curve were 2·4% and 2·8%.
In a controlled environment, the repeatability of DTM is excellent. DTM can be used as a reproducible and operator-independent test for non-invasive measurement of vascular function.
先前的研究表明，血管反应性数字热监测（DTM）作为一种评估血管功能的新测试，与弗雷明汉风险评分、冠状动脉钙化评分和CT血管造影密切相关。本研究评估了DTM测量的变异性和可重复性。我们假设DTM是可重复的，其变异性在临床诊断测试的可接受范围内。
使用全自动DTM设备（VENDYS，美国得克萨斯州休斯顿市Endothelix公司）对18名健康志愿者（年龄35±4岁，74%为男性）在24小时后重复测量血管功能。所有受试者均进行过夜禁食，测试前在温度为22 - 24°C的昏暗房间内仰卧休息30分钟。测量在2分钟的上肢袖带超收缩期闭塞诱发反应性充血过程中及之后进行。作为本研究的一部分，同时比较了桡动脉的多普勒超声充血、低频血流速度和指尖血管功能的DTM。研究了袖带放气后的温度反弹和曲线下面积，即血管功能的DTM指标。
曲线下温度反弹面积与多普勒充血、低频血流速度密切相关（r = 0·97，P = 0·0001）。受试者内每日基线温度变异性为6·2%，平均血压变异性为8·7%，心率变异性为11·4%。温度反弹和曲线下面积的重复性系数分别为2·4%和2·8%。
在可控环境中，DTM的可重复性极佳。DTM可作为一种可重复且独立于操作者的测试，用于无创测量血管功能。
