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

Abstract

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.

Keywords: Acute remote ischaemic conditioning; BP, blood pressure; Blood pressure; CABG, coronary artery bypass grafting; CI, confidence interval; HR, heart rate; MD, mean difference; RIC; RIC, Remote ischaemic conditioning; Repeat remote ischaemic conditioning; SD, standard deviation; T2DM, type 2 diabetes mellitus; VEGF, vascular endothelial growth factor.

Fig. 1

PRISMA flow diagram.

Fig. 2

Changes in systolic and diastolic BP, MAP and HR after acute RIC exposure. Forest plots showing the effects of acute RIC exposure on systolic BP (A), diastolic BP (B), MAP (C) and HR (D). A p-value < 0.05 represents a significant pooled mean difference of overall effect. Horizontal lines across each present 95% CI for each study. The diamond represents the 95% CI for pooled estimates of effect of mean difference. CHD: chronic heart disease group; HLT: healthy group; IV: inverse variance; RIC: remote ischaemic conditioning; SD: standard deviation; Total: number of participants.

Fig. 3

Changes in systolic and diastolic BP, MAP and HR after repeat RIC exposure. Forest plots showing the effects of repeat RIC exposure on systolic blood pressure (A) and diastolic BP (B), MAP (C) and HR (D). A p-value < 0.05 represents a significant pooled mean difference of overall effect. Horizontal lines across each present 95% CI for each study. The diamond represents the 95% CI for pooled estimates of effect of mean difference. CL: contralateral arm; IV: inverse variance; PC: preconditioned; SD: standard deviation; Total: number of participants.