Simplifying Technologies for Peripheral Arterial Disease Recognition
thesisposted on 21.09.2020, 13:43 by Ramesh Yap Kannan
Objectives : Novel diagnostics have been studied in the past to diagnose peripheral arterial disease (PAD) with variable results. These studies focused on correlation and reliability, with few comparing against an acceptable reference standard. In this study, we explore the role of novel diagnostics that measure functional parameters of peripheral circulation, for PAD diagnosis. Materials & Methods : A review of existing technologies for PAD diagnosis was performed. Pilot tests were performed to assess the feasibility of the methodology using suitable devices. Provocation tests of limb circulatory reserve, were used to test the perfusion, oxygenation and temperature of patients and healthy controls using different devices. 150 participants were recruited. Results: The study shows that oxygenation and temperature are suitable for diagnosis. Perfusion is too sensitive to movement and not suitable. 1-minute flexion extension (1MF) tests and the 6-minute walk test (6MWT) is better than Post occlusive reactive hyperemia as a provocation test. A temperature difference of 0.05°C, at 3 minutes after the 6MWT in the medial gastrocnemius (MG), yields a sensitivity of 62.5% and specificity of 63.16%. At the heel, 1-minute (cutoff 0.35°C), 2-minutes (cutoff 0.55°C) and 3 minutes (cutoff 0.15°C) post 6MWT, yields a sensitivity of 69.39%, 77.55% and 63.41% with a specificity of 60.98%, 53.85% and 72.97% respectively. For oxygenation, the sensitivity using baseline tissuesaturation index (bTSI), ranges from 57.94% to 73.2%, with a specificity from 72.73% to 74.42%. Difference in tissue saturation index (dTSI) post 6MWT, has a sensitivity of 61.36% to 71.43%, and specificity of 65.12% to 74.77%. Time of return to bTSI after 6MWT (T100) has a sensitivity of 75.51% and specificity of 58.97%. Conclusion : Devices that measure oxygenation or temperature have potential for diagnosing PAD in the future. Further studies should focus on these parameters.