title: Early changes in collateral blood flow during myocardial infarction in conscious dogs.
abstract: We studied the early changes in collateral blood flow (CBF) after acute coronary artery occlusion and the relation of these changes to subsequent necrosis. We measured CBF with 7--9 microns radioactive microspheres before and at various times after circumflex artery occlusion in 42 conscious dogs that were killed 48 h later. CBF increased from 20 s postocclusion to later measurements (5 min, 15 min, 1 h, or 6 h) and did so in both necrotic and nonnecrotic areas of the occluded bed. However, the increase in CBF over time was not gradual, but appeared to occur between 20 s and 5 min, with no further changes for up to 6 h. There was a gradation of CBF in the occluded bed, from periphery to center and subepicardium to subendocardium. Central and subendocardial regions with CBF less than 0.40 ml-min-1-g-1 at 5--15 min postocclusion subsequently showed necrosis whereas epicardial and lateral regions with CBF greater than 0.50 ml/min did not. Thus CBF increases very early throughout the occluded coronary bed, and the level of CBF by 5 min appears to determine whether necrosis ultimately occurs.
mesh_terms: D000818:Animals; D002588:Cesium Radioisotopes; D003326:Coronary Circulation; D003327:Coronary Disease / Q000503:physiopathology; D004285:Dogs; D007457:Iodine Radioisotopes; D008863:Microspheres; D009203:Myocardial Infarction / Q000473:pathology*; D009556:Niobium; D011868:Radioisotopes; D012039:Regional Blood Flow; D012538:Scandium; D013326:Strontium Radioisotopes
chemical_list: D002588:Cesium Radioisotopes; D007457:Iodine Radioisotopes; D011868:Radioisotopes; D013326:Strontium Radioisotopes; D009556:Niobium; D012538:Scandium