Arterial Waveforms Measured at the Wrist and Penile as Indicators of Vascular Endothelial Function in the Human Body and Its Clinical Application Study

Autor: Chun-Ho Lee, 李俊和
Rok vydání: 2012
Druh dokumentu: 學位論文 ; thesis
Popis: 100
According to publication of Department of Health, Executive Yuan, Taiwan (ROC), in past five years the mortality caused by atherosclerosis ranked high in top ten causes mortality in Taiwan. However, current medical techniques have difficulties with early home health care detection of formation of atherosclerosis, therefore the simple and home care of the new methods for atherosclerosis assessment have become a hot topic for domestic and foreign researchers. Vascular endothelial injury leading to dysfunction is thought to be a precursor to most if not all cardiovascular diseases (CVD), and has been implicated as a critical event in atherosclerosis and erectile dysfunction (ED). Nitric oxide (NO) is recognized to be a potent smooth muscle relaxant responsible, in large part, for vasodilation in response to stimulation of an intact endothelium. The common approach to endothelial function assessment is the quantification of reactive hyperemia (RH), which is a vasodilatatory phenomenon brought about by an enhanced release of endothelium-derived relaxing factor (i.e. NO) from the endothelium through an increase in shear stress during reperfusion after a brief period of ischemia. The obligatory role of the endothelium in vasodilation offers a mechanism whereby arterial “health” can be assessed prior to the development of arteriosclerosis, ED and CVD. This research integrates specialties from three organizations, which are National Dong Hwa University, Hua-lien Tzu Chi Hospital, Mennonite Christian Hospital. First, we had injected a specific nitric oxide (NO) synthesize inhibitor intra-arterially into five adult male rats to verify the validation of our proposed photoplethysmograpy (PPG) system for endothelial function assessment. However, the reproducibility was not good for the system applied for measuring fingertip peripheral arteries on human. Based on the principle of RH after a brief period of arm ischemia, in this study, we tested the validity of a Air pressure sensing system (APSS) in assessing the systemic endothelial function. The APSS proposed in this study has only 8.49±3.26 (%) of measurement error, the lower the value of measurement error, the better the reliability of the system is, thus, better reproducibility. The wrist waveform signals from the APSS were obtained and analyzed using Hilbert-Huang transform (HHT). Through ensemble empirical mode decomposition (EEMD), the further refined the validity of Dilatation index (DI), Reflection index (RI) and Stiffness index (SI) obtained through APSS, which is a simple self-operable system in evaluating endothelial function for the general public. Second, continuation of the APSS theoretical basis, in this study, we tested the validity of a Penile Arterial Waveform Analyzer (PAWA) in assessing the penile endothelial function. By dividing the area under waveform contour of hyperemic and baseline signals after EEMD, a Penile perfusion index (PPI) and Penile arterial waveform amplitude (PAWA) ratio was calculated. The PAWA proposed in this study has only 5.83 (%) of measurement error, the lower the value of measurement error, the better the reliability of the system is, thus, better reproducibility. Not only could the PAWA assess penile endothelial function in young adults, but the results also showed significant associations with their Penile brachial index (PBI), Visual sexual stimulation (VSS) RigiScan, serum testosterone levels and metabolic parameters. The findings suggest that PPI, PAWA ratio may serve as an indicator for early identification and treatment of young adults at risk of erectile dysfunction. Third, based on the previous finding that a positive correlation exists between the systemic and penile endothelial function in individuals with normal erectile function using the Flow-mediated dilation (FMD) method, the present study aimed at assessing the validity of using an Dilatation index (DI) calculated from the amplitudes of RH-induced vasodilatation of the forearm acquired through an APSS in evaluating penile endothelial function in young adults. Data from PAWA were used for comparison. Remarkable positive correlation was noted between APSS and PAWA (R=0.640, P
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