An investigation to optimise stimulation parameters of Remote Ischaemic Conditioning with digital stimulation
Background: Many ongoing clinical trials are investigating the ability of Remote Ischemic Conditioning (RIC) to limit ischemic injury in major organs such as the heart and brain, focussing on cardiac surgery, myocardial infarction, and acute ischemic stroke. Literature is fraught with neutral outcomes while some boast great success in reducing infarct size and improving functional outcomes and clinical endpoints. Fewer studies have attempted to identify an optimal application protocol for the therapy, indicating that clinical potential is being hindered by a lack of appropriate implementation.Aims: Among the many variables of RIC use, the aims of this study were to firstly identify the most efficacious limb or limbs for application previously tested, and to test novel limbs (ankle and wrist) for more feasible approaches such as wearable technologies. Secondly, durations of application were tested.Methods: One hundred and thirty-six experimental simulations were performed using the ADAN circulatory model in the program OpenCOR. Specific limb arteries were “occluded” for differing durations to observe the best improvement in Middle Cerebral Artery velocity (MCAv). Resulting velocities were compared between single limbs or limb combinations, within one duration setting for the first aim. Resulting velocities were compared within single limbs or limb combinations between all duration settings for the second aim. Results: The combination of the radial and ulnar artery (representing the wrist) produced extremely similar results to occluding the brachial artery alone (representing the upper arm): an MCAv increase from baseline of 5.14% vs. 5.57%, respectively. Occluding multiple limbs had a larger effect than occluding one alone, occluding all four extremities at once produced the largest change (+43%) in MCAv. Larger arteries provided a higher MCAv than smaller arteries during occlusion. Conclusion: To my knowledge, this is the first study to attempt to observe occlusion of wrist arteries on MCAv, if not the only to attempt wrist artery occlusion as a form of RIC at all. The results of this study have implications for the ease and accessibility of RIC as a future potential therapy for those at risk of or suffering affects from ischemic injury. Future research should investigate effects of wrist occlusion in in vivo and must focus on cycle number and duration protocol for RIC.
Advisor: Cakmak, Yusuf
Degree Name: Bachelor of Medical Science with Honours
Degree Discipline: Anatomy
Publisher: University of Otago
Keywords: New Zealand; RIC; Remote Ischemic Conditioning; Remote Ischemic Preconditioning; RIPreC; OpenCOR; ADAN; Limb selection; Ischemic Tolerance; MCAv; Middle Cerebral Artery flow velocity
Research Type: Thesis