The Annals of Thoracic Surgery, Vol 40, 504-508, Copyright © 1985 by The Society of Thoracic Surgeons
Reperfusion before global ischemic arrest improves the salvage of infarcting myocardium
PJ Horneffer, VL Gott and TJ Gardner
To study the effect of hypothermic global ischemic arrest on an evolving
myocardial infarction and of perfusion of the ischemic zone or region at
risk before global ischemia, 62 farm pigs underwent 15, 30, or 60 minutes
of reversible coronary occlusion. Twenty-eight of these animals served as
controls: reflow to the region at risk was established by removal of the
coronary occluder without the addition of global ischemia. Another 26
animals had similar periods of coronary occlusion and then were placed on
cardiopulmonary bypass; they underwent aortic cross-clamping and
cardioplegia-induced global hypothermic arrest for 45 minutes. Eight
additional pigs had two hours of reflow to the region at risk after removal
of the occluder and before global ischemic arrest. When superimposed on
regional ischemia, global ischemia resulted in a 6-fold increase in infarct
size after 15 minutes of coronary occlusion (p less than 0.05), a 2.2-fold
increase after 30 minutes of coronary occlusion (p less than 0.05), and no
significant increase after 60 minutes of coronary occlusion. Reperfusion
prior to global ischemia completely prevented infarct extension with 0.4%
less infarction (not significant) in this group versus the controls without
global ischemia. These results clearly demonstrate that infarct extension
occurring when global ischemia is superimposed on regional ischemia is
greatest early in infarct evolution but that reflow to the region at risk
before global ischemic arrest prevents the additional infarction.(ABSTRACT
TRUNCATED AT 250 WORDS)
