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Postembolic spectral patterns of Doppler microembolic signals
Dimitrios Georgiadis1, Frank Uhlmann, Alexander Schorch
1Department of Neurology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany. Dimitrios.Georgiadis@nos.usz.ch
Cerebrovascular Diseases (Basel, Switzerland)
|July 17, 2003
Summary
Spectral patterns like tail sign (TS) and lambda sign (LS) can detect microembolic signals (MES) in prosthetic heart valve patients. LS may indicate gaseous embolic material, especially under hyperbaric conditions.
Area of Science:
- Cardiovascular Research
- Biomedical Engineering
- Diagnostic Imaging
Background:
- Prosthetic heart valves are associated with embolic events.
- Identifying embolic material is crucial for patient management.
- Spectral patterns in Doppler ultrasound may offer diagnostic clues.
Purpose of the Study:
- To determine the prevalence of tail sign (TS) and lambda sign (LS) in patients with prosthetic heart valves.
- To evaluate the association of these spectral patterns with embolic material.
- To assess the impact of hyperbaric conditions on these signals.
Main Methods:
- Analysis of microembolic signals (MES) in 23 patients with artificial heart valves.
- Examination of TS and LS prevalence during normobaric and hyperbaric (1.75 and 2.5 bar) conditions.
- Distinguishing MES from artifact signals.
Main Results:
- A total of 1,721 MES were detected; TS and LS prevalence were 11% and 9.8%.
- Hyperbaric exposure significantly increased LS prevalence (13.7% at 2.5 bar) while TS remained stable.
- TS and LS were absent in artifact signals, indicating high specificity.
Conclusions:
- TS and LS exhibit high specificity but low sensitivity for MES detection.
- LS prevalence is influenced by hyperbaric conditions and may be linked to gaseous emboli.
- These spectral patterns can aid in characterizing embolic events in prosthetic heart valve patients.