Ischaemic conditioning shows no clear benefit on major clinical outcomes
Ischaemic conditioning has no overall effect on the mortality risk in people undergoing invasive procedures, and its possible effects on stroke and acute kidney injury remain unknown given methodological concerns and low event rates, according to a systematic review and meta-analysis.
Researchers searched Medline, Embase, Cochrane databases and International Clinical Trials Registry platform from inception through October 2015 for to summarise the benefits and harms of ischaemic conditioning on major clinical outcomes in various settings.
Data from 85 individual reports of 89 randomized comparisons (median 80 participants; median 1 month intended duration) were independently extracted by two researchers. Reports of multiple intervention arms were treated as separate trials. Random effects models were employed to calculate summary estimates for all-cause mortality and other pre-specified clinical outcomes.
Regardless of the clinical setting in which it was used or the particular intervention related characteristics, ischaemic conditioning had no effect on all-cause mortality (68 comparisons; 424 events; 11,619 participants; risk ratio [RR], 0.96; 95 percent CI, 0.80 to 1.16; p=0.68; moderate quality evidence).
Ischaemic conditioning could lower the rates of some secondary outcomes, such as stroke (18 trials; 5,995 participants; 149 events; RR, 0.72; 0.52 to 1.00; p=0.048; very low quality evidence) and acute kidney injury (36 trials; 8,493 participants; 1,443 events; RR, 0.83; 0.71 to 0.97; p=0.02; low quality evidence), although the benefits appear to be limited to non-surgical settings and to mild episodes of acute kidney injury only.
Researchers do not recommend the adoption of ischaemic conditioning for routine use unless further high-quality and well-powered evidence shows benefit.