Remote ischaemic preconditioning, induced by brief periods of limb ischaemia (for example by inflating a blood pressure cuff), has previously been shown to reduce ischaemic damage in the heart if applied prior to predictable ischaemia (e.g. cardiac surgery).  However, it has not previously been investigated whether remote ischaemic preconditioning can be used to reduce myocardial damage during acute myocardial infarction.  In this randomised trial of 333 patients based in Denmark, 166 patients were randomised to receive primary percutaneous coronary intervention with remote conditioning, which was applied as intermittent arm ischaemia through four cycles of 5-min inflation and 5-min deflation of a blood-pressure cuff during transportation to hospital.  The primary endpoint was myocardial salvage index at 30 days after PCI, measured by myocardial perfusion imaging.The median salvage index was 0.75 in the remote conditioning group versus 0.55 in the control group, with a median difference of 0.10 (p=0.033, see figure).  No difference was observed between rates of death, reinfarction and heart failure in either group.

Conclusions:

Remote ischaemic conditioning ambulance transfer to hospital for primary percutaneous intervention increases myocardial salvage.  However, larger trials are needed to see if this can translate into improved clinical outcomes.

Bøtker HE, Kharbanda R, Schmidt MR, et al. Remote ischaemic conditioning before hospital admission as a complement to angioplasty, and effect on myocardial salvage in patients with acute myocardial infarction: a randomized trial. Lancet 2010; 375:727-734.Ovize M, Bonnefoy E. Giving the ischaemic heart a shot in the arm. Lancet 2010; 375:699-700.