Document Detail


Adaptive responses of coronary circulation and myocardium to chronic reduction in perfusion pressure and flow.
MedLine Citation:
PMID:  8141345     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
We tested the hypothesis that chronic reduction in perfusion pressure and flow in the coronary circulation induces a state of myocardial "hibernation" characterized not only by a steady-state reduction in myocardial O2 consumption (MVO2) but also by evidence of persistent dilator reserve of the distal vasculature. Biochemical and morphological changes in the coronary vasculature were also assessed. Experiments were conducted in swine with an extraluminal coronary stenosis placed 4-32 wk before study. Stenosis reduced lumen diameter by approximately 80% at the time of final experimentation. Baseline, regional myocardial blood flow distal to the stenosis in both endocardial and epicardial layers was reduced vs. that of the normal zone. Vasodilator reserve persisted in both endocardial and epicardial layers of the stenosis zone. Flow increased in each layer in response to adenosine plus phenylephrine and failed to decline despite a marked reduction in perfusion pressure in response to adenosine alone. Regional MVO2 at baseline was reduced vs. historical controls without coronary stenosis. Protein synthesis rate in coronary vessels of the stenosis zone was reduced vs. that of the normal zone. Morphological responses of stenosis zone vessel walls were heterogeneous. Smaller microvessels exhibited mild hypertrophy of their walls, whereas walls of larger microvessels tended to atrophy. Thus chronic reduction in perfusion pressure and flow induces a state of myocardial hibernation characterized by a steady-state reduction in MVO2 in association with persistent dilator capacity. Biochemical and morphological changes occur in microvessel walls and may contribute to observed physiological responses.
Authors:
I Mills; J T Fallon; D Wrenn; H Sasken; W Gray; J Bier; D Levine; S Berman; M Gilson; H Gewirtz
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of physiology     Volume:  266     ISSN:  0002-9513     ISO Abbreviation:  Am. J. Physiol.     Publication Date:  1994 Feb 
Date Detail:
Created Date:  1994-04-26     Completed Date:  1994-04-26     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370511     Medline TA:  Am J Physiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  H447-57     Citation Subset:  IM    
Affiliation:
Department of Medicine, Rhode Island Hospital.
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MeSH Terms
Descriptor/Qualifier:
Acclimatization
Animals
Blood Pressure
Coronary Circulation / physiology*
Coronary Vessels / metabolism,  physiology*
Heart / physiology*
Heart Rate
Methionine / metabolism
Microcirculation / pathology,  physiology,  physiopathology
Muscle, Smooth, Vascular / pathology,  physiology,  physiopathology
Myocardium / metabolism*
Oxygen / blood
Oxygen Consumption
Partial Pressure
Perfusion / methods*
Pressure
Protein Biosynthesis
Regional Blood Flow
Swine
Vasodilation
Grant Support
ID/Acronym/Agency:
HL-29951/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
63-68-3/Methionine; 7782-44-7/Oxygen

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


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