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Microembolic signal counts increase during hyperbaric exposure in patients with prosthetic heart valves

Baumgartner, R W; Frick, A; Kremer, Christine LU ; Oechslin, E; Russi, E; Turina, J and Georgiadis, D (2001) In Journal of Thoracic and Cardiovascular Surgery 122(6). p.1142-1146
Abstract
BACKGROUND: Patients with prosthetic heart valves have an increased risk of thromboembolic events, and transcranial Doppler sonography reveals microembolic signals. Whereas microembolic signals were initially assumed to be of particulate matter, recent studies suggest that they are partially gaseous in origin. If this is true, alteration of environmental pressure should change microembolic signal counts. We undertook this study to evaluate the influence of hyperbaric exposure on microembolic signal counts in persons with prosthetic heart valves. METHODS AND RESULTS: Microembolic signal counts were monitored by transcranial Doppler sonography of both middle cerebral arteries under normobaria (normobaria 1), 2 subsequent periods of... (More)
BACKGROUND: Patients with prosthetic heart valves have an increased risk of thromboembolic events, and transcranial Doppler sonography reveals microembolic signals. Whereas microembolic signals were initially assumed to be of particulate matter, recent studies suggest that they are partially gaseous in origin. If this is true, alteration of environmental pressure should change microembolic signal counts. We undertook this study to evaluate the influence of hyperbaric exposure on microembolic signal counts in persons with prosthetic heart valves. METHODS AND RESULTS: Microembolic signal counts were monitored by transcranial Doppler sonography of both middle cerebral arteries under normobaria (normobaria 1), 2 subsequent periods of hyperbaria (2.5 and 1.75 bar), and a second period of normobaria (normobaria 2) in 15 patients with prosthetic heart valves. Each monitoring period lasted 30 minutes. Compression and decompression rates were 0.1 bar/min. Microembolic signal counts increased from 20 (12-78) at normobaria 1 to 79 (30-165) at 2.5 bar (P <.01 vs normobaria 1 and 2), decreased to 44 (18-128) at 1.75 bar (P <.01 vs normobaria 1 and 2.5 bar; P <.001 vs normobaria 2), and returned to 20 (8-96) at normobaria 2 (values are medians and 95% confidence intervals). CONCLUSIONS: Our results strongly suggest that gaseous bubbles are underlying material for part of the microembolic signals detected in patients with prosthetic heart valves. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Thoracic and Cardiovascular Surgery
volume
122
issue
6
pages
1142 - 1146
publisher
Mosby
external identifiers
  • pmid:11726888
  • scopus:0035783915
ISSN
1097-685X
DOI
10.1067/mtc.2001.117282
language
English
LU publication?
yes
id
7a52c041-8cab-4eb0-b840-c1412822dfcc (old id 1122734)
date added to LUP
2008-06-24 12:50:34
date last changed
2018-05-29 09:44:39
@article{7a52c041-8cab-4eb0-b840-c1412822dfcc,
  abstract     = {BACKGROUND: Patients with prosthetic heart valves have an increased risk of thromboembolic events, and transcranial Doppler sonography reveals microembolic signals. Whereas microembolic signals were initially assumed to be of particulate matter, recent studies suggest that they are partially gaseous in origin. If this is true, alteration of environmental pressure should change microembolic signal counts. We undertook this study to evaluate the influence of hyperbaric exposure on microembolic signal counts in persons with prosthetic heart valves. METHODS AND RESULTS: Microembolic signal counts were monitored by transcranial Doppler sonography of both middle cerebral arteries under normobaria (normobaria 1), 2 subsequent periods of hyperbaria (2.5 and 1.75 bar), and a second period of normobaria (normobaria 2) in 15 patients with prosthetic heart valves. Each monitoring period lasted 30 minutes. Compression and decompression rates were 0.1 bar/min. Microembolic signal counts increased from 20 (12-78) at normobaria 1 to 79 (30-165) at 2.5 bar (P &lt;.01 vs normobaria 1 and 2), decreased to 44 (18-128) at 1.75 bar (P &lt;.01 vs normobaria 1 and 2.5 bar; P &lt;.001 vs normobaria 2), and returned to 20 (8-96) at normobaria 2 (values are medians and 95% confidence intervals). CONCLUSIONS: Our results strongly suggest that gaseous bubbles are underlying material for part of the microembolic signals detected in patients with prosthetic heart valves.},
  author       = {Baumgartner, R W and Frick, A and Kremer, Christine and Oechslin, E and Russi, E and Turina, J and Georgiadis, D},
  issn         = {1097-685X},
  language     = {eng},
  number       = {6},
  pages        = {1142--1146},
  publisher    = {Mosby},
  series       = {Journal of Thoracic and Cardiovascular Surgery},
  title        = {Microembolic signal counts increase during hyperbaric exposure in patients with prosthetic heart valves},
  url          = {http://dx.doi.org/10.1067/mtc.2001.117282},
  volume       = {122},
  year         = {2001},
}