Implications of ischaemic preconditioning at the ankle in people with diabetes

Introduction: In the UK, 4.6 million people are living with diabetes, resulting in serious health complications, including ~184 lower-limb amputations per week. Amputations typically stem from diabetic foot, associated with a 25% lifetime risk of ulceration, placing a long-term burden on healthcare services. The thesis aims to use ischaemic preconditioning (IPC), which involves alternating occlusion-reperfusion cycles, to improve foot health in people with diabetes. By applying IPC, there will be potential improvements in the microcirculation and endothelial function.Methods: Firstly, a systematic review investigated the existing evidence base for IPC and the associated physiological responses. Following ethical approval, four experimental studies were conducted using near-infrared spectroscopy (NIRS) as a proxy indicator of foot health. The first investigated the reliability of NIRS during three intra-session occlusions. The following two studies applied a four-week IPC intervention in a healthy population and people with diabetes. The final study explored the longitudinal monitoring of the foot over six months.Results: The systematic review highlighted few studies investigating reliability during lower limb IPC, with no relevant publications investigating the ankle. The reliability study successfully applied IPC at the ankle, showing good to excellent reliability in the NIRS variables. The four-week intervention demonstrated no changes in foot health in a healthy population. However, four weeks of IPC in people with diabetes significantly increased the maximum oxygen saturation, indicating improved foot oxygenation. Finally, the longitudinal study observed no changes over six months during the long-term monitoring of the foot.Conclusion: IPC combined with NIRS can both monitor and improve foot health in people with diabetes. This thesis explored a novel repeated ankle IPC intervention, offering an alternative approach for people with foot complications who are unable to exercise. Long-term, this has important clinical implications to potentially reduce complications and develop measures for detecting any deterioration in foot health.