Document Detail

Progressive perfusion impairment during prolonged low flow myocardial ischemia in dogs.
MedLine Citation:
PMID:  939013     Owner:  NLM     Status:  MEDLINE    
Recent studies have shown that after total coronary artery occlusion, there is impaired "reflow" of blood accompanied by myocardial and capillary endothelial cell swelling. To investigate the effect of prolonged low flow myocardial ischemia on coronary vascular resistance, regional hypoperfusion of the distal left anterior descending coronary artery was studied in 31 autonomically blocked dogs on right heart bypass. Heart rate, aortic pressure, and, during ischemia, left ventricular end-diastolic pressure were held constant. The distal left anterior descending coronary artery was perfused at a substantially reduced perfusion pressure which resulted in an antegrade coronary blood flow that usually was between 3% and 7% (0.5-1 ml/min) of control. When relative hypothermia (33-34 degrees C) was induced in nine dogs, left anterior descending coronary artery vascular resistance did not change during 2.5-3 hours of low flow ischemia. Under euthermic conditions (37-40 degrees C) in 17 dogs there was a consistent progressive increase in distal left anterior descending coronary artery vascular resistance starting at 90 minutes (median) after onset of ischemia. By 110-140 minutes ischemic antegrade flow decreased by 35 +/- 4% (SEM) (P less than 0.01). Directionally similar flow changes were observed in six euthermic experiments using the krypton-85 washout technique. Light microscopy did not reveal hemorrhage as a cause of the increased vascular resistance. The perfusion impairment did not occur in two euthermic, nonischemic hearts. In five dogs elevation of serum osmolality by 23 +/- 11 mOsmol/liter with mannitol attenuated the progressive decrease in flow. Thus, a progressive perfusion defect exists in the ischemic low flow state in the heart which presumably contributes to the extent of eventual necrosis.
L H Frame; W J Powell
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Circulation research     Volume:  39     ISSN:  0009-7330     ISO Abbreviation:  Circ. Res.     Publication Date:  1976 Aug 
Date Detail:
Created Date:  1976-09-25     Completed Date:  1976-09-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0047103     Medline TA:  Circ Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  269-76     Citation Subset:  IM    
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MeSH Terms
Body Temperature
Coronary Circulation*
Coronary Disease / physiopathology*
Heart / physiopathology
Hypothermia, Induced
Mannitol / pharmacology
Osmolar Concentration
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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