Modeling the Relationship between Central Aortic Pressure and Radial Photoplethysmogram in Flow-mediated Dilation Test

Parsafar, Mohammad Habib | 2018

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  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 50561 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Vosughi Vahdat, Bijan; Zahedi, Edmond
  7. Abstract:
  8. According to the World Health Organization, about 35% of deaths worldwide are due to cardiovascular diseases, therefore the evaluation of vascular endothelial function has great prognostic and diagnostic value for cardiovascular diseases. The conventional noninvasive method for endothelial function evaluation is the measurement of flow-mediated dilation in brachial artery using ultrasound imaging (FMD-US). As the accuracy of FMD-US depends on the operator's skill and the resolution of the ultrasound images, this method has not been adopted. In this work, we propose to use a low cost, easily-accessible surrogate signal, the photoplethysmogram (PPG) to implement the FMD test. Whereas previous works focus mostly on the features extracted from the PPG, we investigate the changes in physiologic vascular parameters to get a better insight of endothelial control mechanisms. In this research, a model based on physiologic vascular parameters is proposed for the relation between central aortic pressure and finger/radial plethysmogram signals. The model parameters are then estimated for 3 groups of subjects: young with normal blood pressure (NBP: N=10), young with high blood pressure (HBP: N=10), and Old (N=10). Our results indicate that the estimated model parameters during baseline are significantly different between the Old and the other two young groups (p<0.05). The behavior of the estimated parameters during FMD are compatible with previous studies. The results show the ability of the proposed model in revealing vascular parameter changes during FMD test
  9. Keywords:
  10. Photoplethysmography ; Flow Mediated Dilation ; Cardiovascular System ; Endothelial Function ; Heart Diseases ; Physiologic Model

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