Pilt Kristjan, Ferenets Rain, Meigas Kalju, Lindberg Lars-Göran, Temitski Kristina, Viigimaa Margus
Department of Biomedical Engineering, Technomedicum, Tallinn University of Technology, Tallinn, Estonia.
ScientificWorldJournal. 2013 Aug 4;2013:169035. doi: 10.1155/2013/169035. eCollection 2013.
The ability to identify premature arterial stiffening is of considerable value in the prevention of cardiovascular diseases. The "ageing index" (AGI), which is calculated from the second derivative photoplethysmographic (SDPPG) waveform, has been used as one method for arterial stiffness estimation and the evaluation of cardiovascular ageing. In this study, the new SDPPG analysis algorithm is proposed with optimal filtering and signal normalization in time. The filter parameters were optimized in order to achieve the minimal standard deviation of AGI, which gives more effective differentiation between the levels of arterial stiffness. As a result, the optimal low-pass filter edge frequency of 6 Hz and transitionband of 1 Hz were found, which facilitates AGI calculation with a standard deviation of 0.06. The study was carried out on 21 healthy subjects and 20 diabetes patients. The linear relationship (r = 0.91) between each subject's age and AGI was found, and a linear model with regression line was constructed. For diabetes patients, the mean AGI value difference from the proposed model y AGI was found to be 0.359. The difference was found between healthy and diabetes patients groups with significance level of P < 0.0005.
识别动脉过早僵硬的能力在预防心血管疾病方面具有重要价值。“衰老指数”（AGI）由二阶导数光电容积脉搏波描记法（SDPPG）波形计算得出，已被用作评估动脉僵硬度和心血管衰老的一种方法。在本研究中，提出了一种新的SDPPG分析算法，该算法具有最佳滤波和时间信号归一化功能。为使AGI的标准差最小化对滤波参数进行了优化，这能更有效地区分不同程度的动脉僵硬度。结果发现，最佳低通滤波器边缘频率为6Hz，过渡带为1Hz，这有助于以标准差为(0.06)来计算AGI。该研究对21名健康受试者和20名糖尿病患者进行。发现每个受试者的年龄与AGI之间存在线性关系（(r = 0.91)），并构建了带有回归线的线性模型。对于糖尿病患者，发现其AGI值与所提出模型(y_{AGI})的平均差值为(0.359)。在健康组和糖尿病患者组之间发现了差异，显著性水平为(P < 0.0005)。
