Mechanistic Insights into Changes in Blood Flow Following Application of Intermittent Negative Pressure

  • Jody McIntosh

Student thesis: Doctoral ThesisDoctor of Philosophy

Abstract

Since the 1930’s, intermittent negative pressure (INP) has been tested as a means of treating vascular diseases. Recently, the literature has indicated that INP can be used to reduce pain and facilitate wound healing in patients with peripheral arterial disease (PAD) however the physiological mechanism behind these clinical benefits remains unclear. The aim of this study was to evaluate the physiological effects of INP application, in particular vascular function, in both healthy and diseased physiology. Three study groups were assessed: healthy volunteers, PAD patients and volunteers suffering from cold hypersensitivity. INP was applied to participants using the Flow-Ox device with applies a negative pressure of -40mmHg in intermittent cycles of 10 seconds negative pressure followed by 7 seconds of no pressure. Vascular function was evaluated through assessment of blood perfusion and endothelial function using full field laser speckle contrast imaging. Systemic effects of INP on vascular function was tested by measuring arterial stiffness, in particular augmentation index and pulse wave velocity. Blood samples were collected to assess blood inflammatory and oxidative stress markers. In patients suffering from PAD, clinical markers including ankle-brachial pressure index and pain score were also evaluated. This study demonstrated that after one session of INP application, cutaneous blood perfusion and endothelial function local to the site of INP application improves in PAD patients but not in healthy physiology. Further, patients reported a significantly lower pain score after up to 8 weeks of INP application compared to baseline. No other significant findings were recorded for any other the other assessments. As microvascular function is severely impaired in PAD, the potential of using INP as a novel treatment modality capable of improving microvascular circulation and function with benefits in reducing pain and wound healing warrants further investigation.
Date of Award2022
Original languageEnglish
SponsorsOtivio AS
SupervisorFaisel Khan (Supervisor) & Stuart Suttie (Supervisor)

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