Ischemic preconditioning: a brief review.

Abstract

Myocardium which has been subjected to one or several brief period(s) of ischemia, of insufficient duration to cause myocyte necrosis, rapidly (within minutes) develops markedly increased resistance to myocyte injury when subjected to a subsequent episode of ischemia. This rapid adaptation to ischemic stress was first described and termed “ischemic preconditioning” (10) based on studies in which a 40-min test episode of ischemia in dogs was preceded by four 5-min episodes of ischemia, each separated by 5 min of reperfusion. Infarct size in the preconditioned dogs was only 25% of the size expected from a simple 40-min test episode of ischemia followed by reperfusion. We subsequently observed a similar marked limitation of infarct size using a single 15-min episode of ischemia prior to a 40-min test episode. Similar cardioprotection can be observed using a 60-min test episode. Ischemic preconditioning has been observed in several species in addition to dogs, including rats, rabbits, and pigs. Clinical studies suggest that it most likely occurs in patients with ischemic heart disease (23).