Dependency of location of salvageable myocardium on type of intervention.
The purpose of this study were (1) to determine the location of the salvageable border zone in relation to the ischemic coronary bed, and (2) to determine whether the location of salvaged tissue differs depending on the mechanism of salvage and the type of intervention. Forty-four open chest dogs were subjected to either 6 hours of occlusion of the left anterior descending coronary artery or 4 hours of occlusion of this artery followed by 2 hours of reperfusion. Dogs with 6 hours of occlusion received either saline solution (Group I, n = 9), ibuprofen, 12.5 mg/kg body weight, (Group II, n = 7), flurbiprofen, 1 mg/kg (Group III, n = 10), or L-hydroxyphenylglycine, 10 mg/kg (Group IV, n = 8) intravenously 30 minutes and 3 hours after coronary occlusion. Dogs in Group V (n = 10) were subjected to 4 hours of coronary occlusion followed by 2 hours of reperfusion, but received no drugs. Although from 17 to 42 percent of the myocardium at risk did not become infarcted in Groups II through V compared with only 6 percent in Group I, the location of salvaged tissue was different in dogs receiving reperfusion (Group V) from that of dogs receiving drug interactions (Groups II, III and IV). In Group V, the salvaged tissue was primarily subepicardial with virtually no lateral zone of salvaged tissue (ratio of salvaged subepicardium to salvaged subendocardium 14.8 +/- 1.9 to 1). In Groups II, III and IV, there was a portion of the myocardium at risk at both lateral margins that did not become infarcted, as well as a portion of subepicardial tissue (ratio of subepicardium to subendocardium salvaged 3.3 +/- 0.4 in Group II, 2.5 +/- 0.1 in Group III and 2.0 +/- 0.2 in Group IV). Thus, infarct size reduction by ibuprofen, flurbiprofen and L-hydroxyphenylglycine is accompanied by lateral and subepicardial zones of salvage, whereas tissue salvaged by reperfusion is located primarily in the subepicardium. These observations should help to resolve the controversy regarding the existence and location of the various zones of ischemic myocardium that can be salvaged by drugs or reperfusion.
D000818:Animals; D003326:Coronary Circulation; D003327:Coronary Disease / Q000188:drug therapy / Q000473:pathology*; D004285:Dogs; D005260:Female; D005480:Flurbiprofen / Q000627:therapeutic use; D005998:Glycine / Q000031:analogs & derivatives / Q000627:therapeutic use; D006321:Heart / Q000187:drug effects; D007052:Ibuprofen / Q000627:therapeutic use; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy / Q000473:pathology*; D009206:Myocardium / Q000473:pathology*; D009336:Necrosis; D012306:Risk
D005480:Flurbiprofen; C023010:4-hydroxyphenylglycine; D005998:Glycine; D007052:Ibuprofen