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Assessment of pressure wave reflection: getting the timing right!
Patrick Segers1, Ernst R Rietzschel, Marc L De Buyzere
1Cardiovascular Mechanics and Biofluid Dynamics, IBiTech, Ghent University, B-9000 Gent, Belgium. patrick.segers@ugent.be
Physiological Measurement
|September 11, 2007
Summary
Wave separation analysis (WSA) is superior to waveform analysis (WFA) for assessing arterial wave reflection. WFA’s landmarks do not accurately reflect reflected wave timing or reduce gender-based differences in augmentation index.
Area of Science:
- Cardiovascular Physiology
- Biomedical Engineering
- Hemodynamics
Background:
- Arterial wave reflection analysis is crucial for understanding cardiovascular health.
- Wave separation analysis (WSA) is the gold standard, but waveform analysis (WFA) is commonly used clinically.
- Existing WFA methods use waveform landmarks to estimate reflected wave characteristics.
Purpose of the Study:
- To compare the accuracy of wave separation analysis (WSA) and waveform analysis (WFA) in assessing arterial wave reflection.
- To evaluate the reliability of WFA-derived parameters like timing, augmentation index, and arterial tree length.
Main Methods:
- Non-invasive measurement of carotid pressure, aortic flow, and carotid-femoral pulse wave velocity in 2132 healthy subjects (35-56 years old).
- WSA was used to determine the timing of reflected wave return (T(f-b)), pressure wave ratio (P(b)/P(f)), and effective arterial length (L(eff)).
- WFA identified landmarks (T(sho), T(inf)) to derive augmentation index (AIx) and L(eff) (AIx(sho), L(eff,sho), AIx(inf), L(eff,inf)).
Main Results:
- WFA landmarks (T(inf), T(sho)) did not correspond to WSA-derived timing (T(f-b)).
- L(eff) decreased with age, while L(eff,inf) increased with age in women, showing discrepancies with physiological expectations.
- WFA-derived AIx showed persistent gender differences, which were significantly reduced when calculated using WSA-based timing (AIx(f-b)).
Conclusions:
- Waveform analysis (WFA) landmarks are unreliable for accurately assessing the timing and magnitude of arterial wave reflection.
- WSA provides more accurate and physiologically consistent measures of arterial wave reflection compared to WFA.
- Accurate analysis of pressure wave reflection necessitates simultaneous measurement of pressure and flow (WSA), not solely waveform analysis (WFA).
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