Remote ischemic preconditioning does no good

The conclusions from the RIPHeart study and the ERRICA study are definitive: Remote ischemic preconditioning is ineffective in adults undergoing on-pump cardiac surgery.

We do not yet understand why. Cardiopulmonary bypass itself, as well as hypothermia and cardioplegia, are known to be cardioprotective, so it may be that further cardioprotection is simply not possible. It also might be that concomitant medications, particularly propofol and opioids, diminish or even block the cardioprotective effects of remote ischemic preconditioning.

The most obvious explanation for the negative results of these two large trials is that other cardioprotective measures may have masked the effect of remote ischemic preconditioning or rendered it redundant.

Dr. Michael Zaugg and Eliana Lucchinetti, Ph.D., of the departments of anesthesiology and pain medicine and in the Cardiovascular Research Centre at the University of Alberta, Edmonton, made these remarks in an editorial accompanying the two reports on remote ischemic preconditioning (N Engl J Med. 2015 Oct 5. doi: 10.1056/MEJMe1510338). Their financial disclosures are available at NEJM.org.