Document Detail


A modelling study of atrial septostomy for pulmonary arterial hypertension, and its effect on the state of tissue oxygenation and systemic blood flow.
MedLine Citation:
PMID:  20144254     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Atrial septostomy is performed in patients with severe pulmonary arterial hypertension, and has been shown to improve symptoms, quality of life and survival. Despite recognized clinical benefits, the underlying pathophysiologic mechanisms are poorly understood. We aimed to assess the effects of right-to-left shunting on arterial delivery of oxygen, mixed venous content of oxygen, and systemic cardiac output in patients with pulmonary arterial hypertension and a fixed flow of blood to the lungs. We formulated equations defining the mandatory relationship between physiologic variables and delivery of oxygen in patients with right-to-left shunting. Using calculus and computer modelling, we considered the simultaneous effects of right-to-left shunting on physiologies with different pulmonary flows, total metabolic rates, and capacities for carrying oxygen. Our study indicates that, when the flow of blood to the lungs is fixed, increasing right-to-left shunting improves systemic cardiac output, arterial blood pressure, and arterial delivery of oxygen. In contrast, the mixed venous content of oxygen, which mirrors the average state of tissue oxygenation, remains unchanged. Our model suggests that increasing the volume of right-to-left shunting cannot compensate for right ventricular failure. Atrial septostomy in the setting of pulmonary arterial hypertension, therefore, increases the arterial delivery of oxygen, but the mixed systemic saturation of oxygen, arguably the most important index of tissue oxygenation, stays constant. Our data suggest that the clinically observed beneficial effects of atrial septostomy are the result of improved flow of blood rather than augmented tissue oxygenation, provided that right ventricular function is adequate.
Authors:
Gerhard-Paul Diller; Astrid E Lammers; Sheila G Haworth; Konstantinos Dimopoulos; Graham Derrick; Philipp Bonhoeffer; Michael A Gatzoulis; Darrel P Francis
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-02-10
Journal Detail:
Title:  Cardiology in the young     Volume:  20     ISSN:  1467-1107     ISO Abbreviation:  Cardiol Young     Publication Date:  2010 Feb 
Date Detail:
Created Date:  2010-03-30     Completed Date:  2010-07-15     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9200019     Medline TA:  Cardiol Young     Country:  England    
Other Details:
Languages:  eng     Pagination:  25-32     Citation Subset:  IM    
Affiliation:
National Heart and Lung Institute, Imperial College of Science and Medicine, London, UK. g.diller@imperial.ac.uk
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MeSH Terms
Descriptor/Qualifier:
Atrial Septum / surgery*
Blood Gas Analysis
Cardiac Surgical Procedures / methods
Computer Simulation
Hemodynamics
Hemoglobins / analysis
Humans
Hypertension, Pulmonary / diagnosis,  physiopathology*,  surgery*
Models, Cardiovascular*
Oxygen / blood*
Oxygen Consumption*
Pulmonary Circulation*
Pulmonary Gas Exchange
Regional Blood Flow
Sensitivity and Specificity
Grant Support
ID/Acronym/Agency:
//British Heart Foundation
Chemical
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen

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


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