The effect of remote ischaemic conditioning on blood pressure response: A systematic review and meta-analysis

Background: Previous work has evaluated the effect of remote ischaemic conditioning (RIC) in a number of clinical conditions (e.g. cardiac surgery and acute kidney injury), but only one analysis has examined blood pressure (BP) changes. While individual studies have reported the effects of acute bouts and repeated RIC exposure on resting BP, efficacy is equivocal. We conducted a systematic review and meta-analysis to evaluate the effects of acute and repeat RIC on BP. Methods: A systematic search was performed using PubMed, Web of Science, EMBASE, and Cochrane Library of Controlled Trials up until October 31, 2020. Additionally, manual searches of reference lists were performed. Studies that compared BP responses after exposing participants to either an acute bout or repeated cycles of RIC with a minimum one-week intervention period were considered. Results: Eighteen studies were included in this systematic review, ten examined acute effects while eight investigated repeat effects of RIC. Mean differences (MD) for outcome measures from acute RIC studies were: systolic BP 0.18 mmHg (95%CI -0.95, 1.31; p = 0.76), diastolic BP -0.43 mmHg (95%CI -2.36, 1.50; p = 0.66), MAP -1.73 mmHg (95%CI -3.11, -0.34; p = 0.01) and HR -1.15 bpm (95%CI -2.92, 0.62; p = 0.20). Only MAP was significantly reduced. Repeat RIC exposure showed non-significant change in systolic BP -3.23 mmHg (95%CI -6.57, 0.11; p = 0.06) and HR -0.16 bpm (95%CI -7.08, 6.77; p = 0.96) while diastolic BP -2.94 mmHg (95%CI -4.08, -1.79; p < 0.00001) and MAP -3.21 mmHg (95%CI -4.82, -1.61; p < 0.0001) were significantly reduced. Conclusions: Our data suggests repeated, but not acute, RIC produced clinically meaningful reductions in diastolic BP and MAP.