| Hemodynamic responses to continuous versus pulsatile mechanical unloading of the failing left ventricle. | |
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MedLine Citation:
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PMID: 20613490 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Debate exists regarding the merits and limitations of continuous versus pulsatile flow mechanical circulatory support. To characterize the hemodynamic differences between each mode of support, we investigated the acute effects of continuous versus pulsatile unloading of the failing left ventricle in a bovine model. Heart failure was induced in male calves (n = 14). During an acute study, animals were instrumented through thoracotomy for hemodynamic measurement. A continuous flow (n = 8) and/or pulsatile flow (n = 8) left ventricular assist device (LVAD) was implanted and studied during maximum support ( approximately 5 L/min) and moderate support ( approximately 2-3 L/min) modes. Pulse pressure (PP), surplus hemodynamic energy (SHE), and (energy equivalent pressure [EEP]/mean aortic pressure (MAP) - 1) x 100% were derived to characterize hemodynamic energy profiles during the different support modes. Standard hemodynamic parameters of cardiac performance were also derived. Data were analyzed by repeated measures one-way analysis of variance within groups and unpaired Student's t-tests across groups. During maximum and moderate continuous unloading, PP, SHE, and (EEP/MAP - 1) x 100% were significantly decreased compared with baseline and compared with pulsatile unloading. As a result, continuous unloading significantly altered left ventricular peak systolic pressure, aortic systolic and diastolic pressure, +/-dP/dt, and rate x pressure product, whereas pulsatile unloading preserved a normal profile of physiologic values. As continuous unloading increased, the pressure-volume relationship collapsed, and the aortic valve remained closed. In contrast, as pulsatile unloading increased, a comparable decrease in left ventricular volumes was noted. However, a normal range of left ventricular pressures was preserved. Continuous unloading deranged the physiologic profile of myocardial and vascular hemodynamic energy utilization, whereas pulsatile unloading preserved more normal physiologic values. These findings may have important implications for chronic LVAD therapy. |
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Authors:
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Carlo R Bartoli; Guruprasad A Giridharan; Kenneth N Litwak; Michael Sobieski; Sumanth D Prabhu; Mark S Slaughter; Steven C Koenig |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: ASAIO journal (American Society for Artificial Internal Organs : 1992) Volume: 56 ISSN: 1538-943X ISO Abbreviation: ASAIO J. Publication Date: 2010 Sep-Oct |
Date Detail:
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Created Date: 2010-09-02 Completed Date: 2011-01-04 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9204109 Medline TA: ASAIO J Country: United States |
Other Details:
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Languages: eng Pagination: 410-6 Citation Subset: IM |
Affiliation:
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University of Louisville School of Medicine, Kentucky, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animals Blood Pressure / physiology Cattle Heart Failure / surgery Heart Ventricles / surgery Heart-Assist Devices* Hemodynamics / physiology* Male Pulsatile Flow / physiology* |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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