Document Detail


Coronary vasodilatory capacity and flow reserve in normal myocardium supplied by bypass grafts late after surgery.
MedLine Citation:
PMID:  9205015     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Coronary artery bypass surgery is used widely for treating myocardial ischemia. However, blood flow and flow reserve of normally perfused myocardium subtended by bypass grafts have not been evaluated late after surgery. Also, it is unknown whether pharmacologic vasodilation evokes comparable myocardial flow responses in arterial and venous conduits. Myocardial blood flow was quantified at rest and during dipyridamole hyperemia using N-13 ammonia and positron emission tomography (PET) in 15 patients 9 +/- 3 years after bypass surgery and in 10 healthy volunteers. Blood flow was analyzed in 26 territories subtended by bypass grafts with normal wall motion and normal perfusion. Myocardial blood flow at rest did not differ between patients and controls (0.65 +/- 0.14 vs 0.68 +/- 0.16 ml/ g/min) and was similar in normal myocardium subtended by saphenous vein (n = 16) and internal mammary artery grafts (n = 10; 0.64 +/- 0.13 vs 0.66 +/- 0.15 ml/g/min). However, the hyperemic response in normal myocardium supplied by bypass grafts was less than that in controls (1.61 +/- 0.33 vs 2.04 +/- 0.30 ml/g/min, p <0.005). No differences between territories supplied by venous and arterial conduits were observed (1.61 +/- 0.35 vs 1.63 +/- 0.32 ml/g/min). Normal myocardium subtended by bypass grafts exhibited a lower flow reserve than that in controls (2.54 +/- 0.51 vs 3.16 +/- 0.85, p <0.02). Myocardial flow reserve was almost identical in regions supplied by venous and arterial grafts (2.55 +/- 0.48 vs 2.52 +/- 0.58). The similar reduction in vasodilatory capacity together with the normal PET polar map findings during dipyridamole argue against flow limiting stenoses in both venous and arterial bypass conduits late after revascularization. Rather, nonobstructive proliferative fibrointimal changes of the bypass conduits or atherosclerosis of the native resistance vessels might account for this finding.
Authors:
R Campisi; J Czernin; H L Karpman; H R Schelbert
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Publication Detail:
Type:  Clinical Trial; Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American journal of cardiology     Volume:  80     ISSN:  0002-9149     ISO Abbreviation:  Am. J. Cardiol.     Publication Date:  1997 Jul 
Date Detail:
Created Date:  1997-07-10     Completed Date:  1997-07-10     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0207277     Medline TA:  Am J Cardiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  27-31     Citation Subset:  AIM; IM    
Affiliation:
Department of Molecular and Medical Pharmacology, UCLA School of Medicine, University of California, Los Angeles 90095-6948, USA.
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MeSH Terms
Descriptor/Qualifier:
Aged
Coronary Angiography
Coronary Artery Bypass*
Coronary Circulation / physiology*
Dipyridamole / diagnostic use
Echocardiography
Female
Heart / physiology,  radionuclide imaging*
Hemodynamics / physiology
Humans
Image Processing, Computer-Assisted
Male
Middle Aged
Reference Values
Tomography, Emission-Computed
Vascular Resistance / physiology
Vasodilation / physiology*
Grant Support
ID/Acronym/Agency:
HL 33177/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
58-32-2/Dipyridamole

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


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