Early changes in collateral blood flow to ischemic myocardium and their influence on bimodal vulnerability during the first 30 min of acute coronary artery occlusion in dogs

1988 ◽  
Vol 83 (1) ◽  
pp. 94-106 ◽  
Author(s):  
S. Mutius ◽  
M. Neumann ◽  
W. Meesmann
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Ischemic Myocardium ◽  
Collateral Blood Flow

Reactive oxygen species are critical mediators of coronary collateral development in a canine model

2003 ◽  
Vol 285 (4) ◽  
pp. H1582-H1589 ◽  
Author(s):  
Weidong Gu ◽  
Dorothee Weihrauch ◽  
Katsuya Tanaka ◽  
John P. Tessmer ◽  
Paul S. Pagel ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Blood Flow ◽  
Coronary Artery ◽  
Reactive Oxygen ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Oxygen Species ◽  
Collateral Blood Flow ◽  
Collateral Development ◽  
Coronary Collateral

Recent evidence suggests that reactive oxygen species (ROS) promote proliferation and migration of vascular smooth muscle (VSMC) and endothelial cells (EC). We tested the hypothesis that ROS serve as crucial messengers during coronary collateral development. Dogs were subjected to brief (2 min), repetitive coronary artery occlusions (1/h, 8/day, 21 day duration) in the absence (occlusion, n = 8) or presence of N-acetylcysteine (NAC) (occlusion + NAC, n = 8). A sham group ( n = 8) was instrumented identically but received no occlusions. In separate experiments, ROS generation after a single 2-min coronary artery occlusion was assessed with dihydroethidium fluorescence. Coronary collateral blood flow (expressed as a percentage of normal zone flow) was significantly increased (71 ± 7%) in occlusion dogs after 21 days but remained unchanged (13 ± 3%) in sham dogs. Treatment with NAC attenuated increases in collateral blood flow (28 ± 8%). Brief coronary artery occlusion and reperfusion caused ROS production (256 ± 33% of baseline values), which was abolished with NAC (104 ± 12%). Myocardial interstitial fluid produced tube formation and proliferation of VSMC and EC in occlusion but not in NAC-treated or sham dogs. The results indicate that ROS are critical for the development of the coronary collateral circulation.

Early changes in collateral blood flow during myocardial infarction in conscious dogs

1979 ◽  
Vol 237 (3) ◽  
pp. H371-H380
Author(s):  
B. I. Jugdutt ◽  
L. C. Becker ◽  
G. M. Hutchins
Keyword(s):  
Myocardial Infarction ◽  
Blood Flow ◽  
Coronary Artery ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Conscious Dogs ◽  
Collateral Blood Flow ◽  
Radioactive Microspheres ◽  
Circumflex Artery ◽  
Over Time

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.

Transmural DC electrograms after coronary artery occlusion and latex embolization in pigs

1984 ◽  
Vol 246 (4) ◽  
pp. H475-H482 ◽  
Author(s):  
J. Cinca ◽  
J. Figueras ◽  
G. Senador ◽  
E. Garcia-Moreno ◽  
A. Salas ◽  
...  
Keyword(s):  
Blood Flow ◽  
Coronary Artery ◽  
Ventricular Fibrillation ◽  
Time Course ◽  
Coronary Artery Occlusion ◽  
Artery Occlusion ◽  
Collateral Blood Flow ◽  
Ischemic Area ◽  
T Wave Alternans

Changes in epicardial and endocardial direct current (DC) electrograms and ventricular arrhythmias observed during 60 min of left anterior descending coronary artery (LAD) occlusion in nine anesthetized pigs were compared with those observed in eight other pigs after embolization of the LAD with latex, a procedure able to block collateral blood flow to the ischemic area. After LAD occlusion 1) T-Q segment depression and S-T segment elevation showed a faster rate of development, and monophasic potentials occurred earlier in the endocardium than in the epicardium; 2) T-Q segment depression was greater at the center than at the periphery of the ischemic area during the first 20-30 min, and later it become greater at the periphery than at the center; and 3) a period of transient recovery in the local activation beginning after 8-15 min and lasting for 10-20 min occurred in all cases, commonly associated with T-wave alternans. LAD embolization with latex induced greater T-Q and S-T segment changes in the epicardium than in the endocardium, increased the incidence of ventricular fibrillation, and failed to impede the appearance of the period of transient electrical recovery. Thus, within an acutely ischemic area in the in situ pig heart, there are inhomogeneities in the magnitude and time course of the electrical changes, which are not prevented by procedures able to block collateral blood flow to the ischemic area. Ventricular fibrillation was also not prevented by such a procedure.

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