Novel Centroid Method for Robust Evaluation of Return Time of Reflected Waves in the Systemic Arterial Network

Area of Science:

• Cardiovascular physiology
• Biomedical engineering
• Wave dynamics in arteries

Background:

• Aging causes a shift in backward wave return time (RT) to central arteries.
• Current RT estimation methods rely on single waveform features, limiting accuracy.
• Existing techniques fail to capture the full spectrum of RT changes throughout life.

Purpose of the Study:

• To introduce and validate a novel centroid method for estimating RT.
• To compare the accuracy and sensitivity of the centroid method against traditional RT estimation techniques.
• To assess the ability of different methods to detect diastolic versus systolic RT.

Main Methods:

• A one-dimensional systemic arterial tree model was used for linear wave tracking.
• Ground truth RT (GTRT) was calculated as the amplitude-weighted mean RT in the ascending aorta.
• Sensitivity to diastolic/systolic RT was evaluated in sheep using a balloon catheter to manipulate backward wave arrival times.

Main Results:

• The centroid method demonstrated the highest accuracy, with the smallest mean difference from GTRT (-8 ms).
• Traditional methods (zero crossing, inflection point, foot) showed significantly larger errors and wider limits of agreement.
• Only the centroid method was sensitive to both diastolic and systolic RT; other methods were only sensitive to systolic RT.

Conclusions:

• The centroid method offers superior accuracy and robustness for estimating RT compared to existing techniques.
• This method provides a more comprehensive understanding of backward wave RT dynamics.
• The findings support the centroid method's utility in studying age-related shifts in arterial wave reflections.