Effects of reestablishing blood flow on extent of myocardial infarction in conscious dogs.
The effects of permanent circumflex coronary artery occlusion (PO) compared with reestablishing blood flow (OR) at 2 and 6 h after occlusion on the final extent of histological infarction (HI) was assessed in chronically instrumented awake dogs. The relationships between the extent of left ventricular ischemia measured by microsphere techniques and HI in the PO group were used as models to predict the expected infarction in the 2- and 6-h OR groups. Mean HI (+/-SD) in the PO and 6- and 2-h OR groups was 21 +/- 13, 19 +/- 10, and 13 +/- 12% of left ventricular weight, respectively; values were not significantly different. The extent of HI in samples grouped according to epicardial and endocardial layers and ischemic blood flow ranges (0-15, 16-30, 31-50, 51-75% of control region blood flow) was reduced in the 2-h but not 6-h OR group. Analysis of individual animals using total ischemic region blood flow to epicardial and endocardial layers demonstrated that OR at 2 h but not 6 h reduced infarction in most animals but not in certain animals with the largest ischemic regions.
D000818:Animals; D001794:Blood Pressure; D003243:Consciousness; D003326:Coronary Circulation; D004285:Dogs; D006339:Heart Rate; D008863:Microspheres; D009203:Myocardial Infarction / Q000473:pathology* / Q000503:physiopathology; D009206:Myocardium / Q000473:pathology; D011868:Radioisotopes; D012306:Risk; D013997:Time Factors
D011868:Radioisotopes