Comparison of Arterial Stiffness among Prehypertensive and Normotensive Subjects using Photo Pulse Plethysmography: A Pilot Study

Abstract

Introduction: Increased arterial stiffness is a marker of Cardiovascular Disease (CVD), even before clinical signs and symptoms become evident. Hypertension is an established risk factor for CVD. However, recent studies have revealed increased arterial stiffness even among prehypertensives. Photo Pulse Plethysmography (PPG) is an efficient non-invasive, and cost-effective technique to measure arterial stiffness. Studying arterial stiffness using PPG can serve as a surrogate marker of Cardiovascular (CV) risk among prehypertensives. Aim: To compare arterial wall stiffness among prehypertensives and normotensives using PPG. Materials and Methods: This pilot study was conducted at the Sri Ramachandra Institute of Higher Education and Research, Chennai, TamilNadu, India from December 2022 to February 2023. The study population included 10 non diabetic prehypertensives and 10 normotensives, aged between 30- 50 years, with normal lipid profiles. The peripheral pulse was recorded using a PPG module and digitised using AUDACITY software. The Arterial Stiffness Index (SI) was calculated and compared between the two groups. The correlation between anthropometry and arterial SI was also determined. Pearson’s correlation test was used to assess the association using Statistical Package for Social Sciences (SPSS) version 24.0. Results: The SI was found to be higher in prehypertensives compared to normotensives, and this difference was statistically significant (p-value=0.04). SI showed a positive correlation with increasing Blood Pressure (BP) and anthropometric variables (Body Mass Index [BMI] and Waist-Hip Ratio [WHR]; r=0.2 and r=0.15, respectively); however, no significant relationship was observed among these variables. Conclusion: This study concludes that the SI, an important CV risk marker, shows a significant increase in prehypertensive subjects compared to normotensive subjects. However, SI showed mild positive correlation with BP and other anthropometric measurements, though not statistically significant.