Twenty two RCTs (888 participants) were included. Quality scores were low: all studies scored 1 or 2.
There were no differences in perioperative deaths with ischaemic preconditioning compared to usual care (17 trials). Tests indicated the presence of publication bias.
Ischaemic preconditioning reduced the risk of inotrope use (OR 0.34, 95%CI: 0.17 to 0.68, heterogeneity p=0.01; 14 trials) and ventricular arrhythmias (OR 0.11, 95%CI: 0.04 to 0.29, heterogeneity p=0.43; eight trials). Intensive care unit stay was reduced with ischaemic preconditioning (WMD -3 hours, 95%CI: -4.6 to 1.5 hours, p=0.001). There was no effect on myocardial infarction or cerebrovascular accident.
Subgroup analyses: Ischaemic preconditioning reduced inotrope use with valve surgery and use of cold-blood cardioplegia; and incidence of ventricular arrhythmias with on-pump coronary artery bypass graft and use of cold-blood cardioplegia. There were no differences between treatments in all other subgroups.