Document Detail


Quantification of right to left shunt at rest and during exercise in patients with pulmonary arteriovenous malformations.
MedLine Citation:
PMID:  1481178     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Current treatment of patients with pulmonary arteriovenous malformations requires serial embolisations by means of steel coils or balloons. Measurement of right to left shunt is the most specific index of response to treatment. A new method of measuring shunt has been developed that is less invasive than traditional methods. METHODS: Right to left pulmonary shunt (expressed as percentage of cardiac output) was measured at rest in 19 patients with pulmonary arteriovenous malformations and six normal subjects by using intravenously injected albumin microspheres labelled with technetium-99m. The technique was compared with a simultaneous shunt measurement in subjects breathing 100% oxygen while they rested. The microsphere technique was adapted to measure the right to left shunt during exercise in 12 patients and five normal subjects with a new method of quantification. RESULTS: The mean (SD) shunt at rest as measured by the microsphere method was 23.2% (15.6%) in the patients and 2.7% (1.2%) in the normal subjects. When these values were compared with those of the 100% oxygen method the difference in mean values was 1% and the limits of agreement between the two methods -32% to +45%. The microsphere method is less invasive (arterial blood gas sampling is not required), quicker, and more comfortable for patients than the 100% oxygen method. In five of the normal subjects the mean (SD) 99mTc microsphere shunt increased from 2.9% (1.3%) at rest to 5.1% (2.9%) during exercise. In the 12 patients studied during exercise the shunt increased from 33.7% (12.7%) at rest to 41.7% (13.3%) during exercise in eight but decreased from 22.6% (2.4%) at rest to 17.6% (2.2%) during exercise in four. Arterial desaturation during exercise correlated with change in the size of the right to left shunt during exercise (r = +0.80). CONCLUSIONS: The microsphere method allows measurement of right to left shunt at rest and during exercise. Serial measurements at rest provide a simple, safe assessment of the physiological response to embolisation in patients with pulmonary arteriovenous malformations.
Authors:
M K Whyte; A M Peters; J M Hughes; B L Henderson; G J Bellingan; J E Jackson; E R Chilvers
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Thorax     Volume:  47     ISSN:  0040-6376     ISO Abbreviation:  Thorax     Publication Date:  1992 Oct 
Date Detail:
Created Date:  1993-02-11     Completed Date:  1993-02-11     Revised Date:  2010-09-07    
Medline Journal Info:
Nlm Unique ID:  0417353     Medline TA:  Thorax     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  790-6     Citation Subset:  IM    
Affiliation:
Department of Medicine (Respiratory Division), Royal Postgraduate Medical School, Hammersmith Hospital, London.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adult
Aged
Arteriovenous Anastomosis / physiopathology,  radionuclide imaging
Arteriovenous Malformations / blood,  physiopathology*,  radionuclide imaging
Exercise
Female
Humans
Lung / radionuclide imaging
Male
Microspheres
Middle Aged
Oxygen / blood
Pulmonary Artery / abnormalities*
Pulmonary Circulation / physiology*
Pulmonary Veins / abnormalities*
Technetium Tc 99m Aggregated Albumin / diagnostic use
Chemical
Reg. No./Substance:
0/Technetium Tc 99m Aggregated Albumin; 7782-44-7/Oxygen
Comments/Corrections

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