【作者】 赵安；

【导师】 吴宝明；

【作者基本信息】 第三军医大学 ， 生物医学工程， 2008， 博士

【摘要】 心脑血管疾病是严重威胁人类健康的重大疾病。严重的心脑血管事件,包括心肌梗塞、脑卒中、间歇性跛行、血管性痴呆一旦发生,即使治疗也不可逆转,而进行早期预防和治疗则可以避免这些严重的致死致残的心脑血管事件的发生。动脉是心脑血管疾病的主要靶器官,以动脉硬化和动脉粥样硬化为代表的早期动脉结构和功能病变是完全在隐袭中发生发展的,是一种无临床症状和后果的亚临床(subclinical)进程,仅仅表现为动脉弹性的减退,且动脉弹性功能改变要早于血管腔结构的明显改变。因此,研究亚临床动脉弹性功能对心脑血管疾病的预防具有重要的意义。本论文基于光电容积脉搏波研究了亚临床状态的动脉弹性功能检测和危险评价方法,主要包括以下几个部分的内容:1)研制了动脉弹性功能的检测平台,包括双通道光电容积脉搏描记模块和可以进行血压测量的动脉加压模块。基于小波分析和3σ域值选取法进行了容积脉搏波的滤波。基于补偿法削弱了呼吸等因素引起的基线漂移对时域指标测量的影响。结合示波法和容积脉搏波分析了平均压、舒张压和收缩压的测量方法。2)对容积脉搏波进行了时域特征和频域特征的分析和提取。详细分析了容积脉搏波时域特征点的检测方法,并动态检测了与大动脉僵硬度相关的动脉硬度系数SI(stiffness index)、手指-脚趾脉搏波速度FtPWV (finger-toe pulse wave velocity)、与小动脉顺应性相关的反射系数RI(reflection index)。从频域分析中得出了一个新的表征动脉弹性功能的整体指标,8～12Hz次高频成分衰减速度Kf。3)提出了一种新的动脉弹性动态检测方法。通过对肱动脉近似线性加压,动态地检测归一化脉搏波传递时间来评估肱动脉顺应性随透壁压的变化,从而得到不需要血压校正的外周中动脉弹性指标NPTT,该方法对于亚临床人群中动脉弹性功能减退具有更高的分辨能力。4)基于对肱动脉加压阻断一定时间产生血流介导的内皮依赖性舒张的原理,通过光电容积脉搏波研究了动脉内皮功能的检测方法,该方法能够分辨血压升高造成的动脉内皮功能损害。5)基于多指标检测和粗糙集理论探讨了亚临床动脉弹性功能的分级方法,初步进行了亚临床危险程度分级指标体系建立的研究,发现内皮功能障碍指标RH (reactive hyperaemia)是评价亚临床动脉病变是否存在的早期指标,Kf和RH是亚临床弹性功能的中期评价指标,SI可以作为亚临床动脉弹性功能独立的晚期评价指标。更多还原

【Abstract】 Cardiovascular and cerebrovascular diseases (CCD) are major threats to human health nowadays. Once severe CCD events happen, such as myocardial infarction, cerebral infarction, intermittent lameness and vascular dementia, people can not recover completely. However, early detection and treatment can prevent those severe CCD events. Artery is the main target organ of CCD. As an asymptomatic and unconscious subclinical process in the early stage,structural and functional changes of arterial wall which is mostly suffered atherosclerosis or arteriosclerosis, are the common pathological bases of CCD. Changes of arterial elastic function emerge earlier than obvious structural changes of vessel cavity in the early stage. Thus, subclinical arterial function has great preventive value to be investigated.Based on photoplethysmography (PPG) technology, detection of subclinical artery elastic function and risk evaluation of subclinical artery disease are investigated. This paper mainly includes the following distinctive works accomplished:1) Artery elastic function detection and risk evaluation platform has been designed and made, which includes dual channel photoplethysmography module and artery-suppress module that also can measure blood pressure. Signals are filtered using wavelet transform and 3σthreshold method. Baseline drift of PPG signal is cut off using compensation method. Determinations of mean artery pressure, systolic and diastolic pressure are analyzed using oscillation method and PPG.2) PPG signal is analyzed in time domain and frequency domain. Time domain features detections are analyzed in detail. Indicators of large artery stiffness, such as SI (stiffness index) and FtPWV (finger-toe pulse wave velocity), and indicator of small artery elasticity named RI (reflection index) are dynamically detected. An new overall artery elastic function indicator named Kf is proposed from the frequency point of view, which represent 8~12Hz attenuation speed in power spectral density.3) During the course of suppressing artery in an approximate linear way, normalized pulse transit time is dynamic detected to evaluate middle artery compliance which varies with transmural pressure. Indicator of middle artery compliance named NPTT30 is got which needs no emendation according to blood pressure and promises a higher resolution for subclinical artery elasticity function discrimination.4) Based on the principle of brachial artery flow mediated dilation, a new method using PPG signal to discriminate endothelium dysfunction has been investigated. Experiment shows this method can discriminate endothelium dysfunction caused by blood pressure elevation.5) Based on multi-indicator detection and rough set theory, risk classification and indicators of subclinical artery disease are discussed. Indicators for subclinical artery disease determination are found. RH is the early subclinical indicator. Kf combined with RH is the middle stage indicator of subclinical arterial disease. SI is an independent indicator of late subclinical arterial disease.更多还原