| systolic flow augmentation in hearts ejecting into a model of stiff aging vasculature. Influence on myocardial perfusion-demand balance. | |
| | |
MedLine Citation:
|
PMID: 8001271 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Age-related arterial stiffening and widening of the pulse pressure elevates ventricular systolic wall stress while it lowers diastolic coronary perfusion pressure. These changes are thought to adversely alter the balance between myocardial work load and blood supply. To test this hypothesis, the native compliant thoracic aorta was surgically bypassed by a stiff tube in reflex-blocked anesthetized dogs. Ventricular outflow was directed into either native aorta or the bypass; the latter resulting in an increase in arterial pulse pressure from 37.8 to 107.5 mm Hg (P < .001), with minimal change in mean pressure and flow. Cardiac work load was assessed by pressure-volume area (PVA), which combines external and internal left ventricular work and is linearly related to myocardial oxygen consumption (MVO2), and by MVO2 itself. Regional phasic and mean coronary flow were measured in the left anterior descending coronary artery, and global flow was assessed by radiolabeled microspheres. Myocardial supply-demand balance was assessed by comparing flow at matched PVA or MVO2, flow-PVA relations, and endocardial-to-epicardial flow ratios. When blood flow was directed into the stiff bypass tube, peak systolic pressure, wall stress, and PVA all rose nearly 50%, yet diastolic perfusion pressure fell by 20 mm Hg (all P < .01). Rather than being compromised, however, mean coronary flow rose by 34%, maintaining the same endocardial-to-epicardial flow ratio (approximately 1.1). Flow augmentation persisted when data were compared at matched work load (PVA or MVO2), and mean arterial pressure, as well as over a range of work loads (P < .001 from ANCOVA of flow-PVA relations). The increased flow resulted from enhanced systolic perfusion, which nearly equaled diastolic flow when ejection passed into the stiff bypass. These data counter the notion that cardiac coupling with a stiff arterial system (as with aging) necessarily compromises myocardial flow versus metabolic demand. However, the data highlight a greater role of systolic flow under such conditions and also raise the novel suggestion that enhanced pulsatility of the arterial pressure waveform may itself augment coronary perfusion. |
| | |
Authors:
|
A Saeki; F Recchia; D A Kass |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
|
Title: Circulation research Volume: 76 ISSN: 0009-7330 ISO Abbreviation: Circ. Res. Publication Date: 1995 Jan |
Date Detail:
|
Created Date: 1995-01-26 Completed Date: 1995-01-26 Revised Date: 2007-11-14 |
Medline Journal Info:
|
Nlm Unique ID: 0047103 Medline TA: Circ Res Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 132-41 Citation Subset: IM |
Affiliation:
|
Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21287. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Aging
/
physiology* Animals Blood Pressure Compliance Coronary Circulation* Dogs Female Male Systole* |
| Grant Support | |
ID/Acronym/Agency:
|
HL-44545/HL/NHLBI NIH HHS |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Central command increases muscle sympathetic nerve activity during intense intermittent isometric ex...
Next Document: Alterations in the expression of the genes encoding specific muscarinic receptor subtypes in the hyp...