Document Detail

Evaluation of cardiovascular risks of spaceflight does not support the NASA bioastronautics critical path roadmap.
MedLine Citation:
PMID:  16173685     Owner:  NLM     Status:  MEDLINE    
INTRODUCTION: Occurrence of serious cardiac dysrhythmias and diminished cardiac and vascular function are the primary cardiovascular risks of spaceflight identified in the 2005 NASA Bioastronautics Critical Path Roadmap. METHODS: A review of the literature was conducted on experimental results and observational data obtained from spaceflight and relevant ground simulation studies that addressed occurrence of cardiac dysrhythmias, cardiac contractile and vascular function, manifestation of asymptomatic cardiovascular disease, orthostatic intolerance, and response to exercise stress. RESULTS: Based on data from astronauts who have flown in space, there is no compelling experimental evidence to support significant occurrence of cardiac dysrhythmias, manifestation of asymptomatic cardiovascular disease, or reduction in myocardial contractile function. Although there are post-spaceflight data that demonstrate lower peripheral resistance in astronauts who become presyncopal compared with non-presyncopal astronauts, it is not clear that these differences are the result of decreased vascular function. However, the evidence of postflight orthostatic intolerance and reduced exercise capacity is well substantiated by both spaceflight and ground experiments. Although attenuation of baroreflex function(s) may contribute to postflight orthostatic instability, a primary mechanism of orthostatic intolerance and reduced exercise capacity is reduced end-diastolic and stroke volume associated with lower blood volumes and consequent cardiac remodeling. CONCLUSION: Data from the literature on the current population of astronauts support the notion that the primary cardiovascular risks of spaceflight are compromised hemodynamic responses to central hypovolemia resulting in reduced orthostatic tolerance and exercise capacity rather than occurrence of cardiac dysrhythmias, reduced cardiac contractile and vascular function, or manifestation of asymptomatic cardiovascular disease. These observations warrant a critical review and revision of the 2005 Bioastronautics Critical Path Roadmap.
Victor A Convertino; William H Cooke
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Aviation, space, and environmental medicine     Volume:  76     ISSN:  0095-6562     ISO Abbreviation:  Aviat Space Environ Med     Publication Date:  2005 Sep 
Date Detail:
Created Date:  2005-09-21     Completed Date:  2005-11-29     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  7501714     Medline TA:  Aviat Space Environ Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  869-76     Citation Subset:  IM; S    
U.S. Army Institute of Surgical Research, Fort Sam Houston, TX, USA.
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MeSH Terms
Arrhythmias, Cardiac / etiology*
Cardiovascular Diseases / etiology*
Critical Pathways*
Middle Aged
Myocardial Contraction / physiology
Retrospective Studies
Risk Factors
Space Flight*
Stroke Volume
United States
United States National Aeronautics and Space Administration
Ventricular Remodeling
V A Convertino / US Army Inst Surg Res, Ft Sam Houston, TX

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