An algorithm for derivation of flow waveform of blood from its pressure waveform. The flow waveform derivation is personalized and provides a better understanding of heart functioning.
Pressure waveforms of blood flow have been used as indicators to understand discontinuities in arterial tree that act as reflectors of blood waves rising from heart. The reflected waves show characteristics of pressure on heart and morphology of arterial surface, whereas the waves emanating from heart are indicators of heart characteristics alone. Therefore, segregation of pressure waves into: forward wave (incident waves from heart) and backward wave (reflected waves from peripheries of arteries) is important.
Existing algorithms that perform pressure wave separation are too generalized to understand individual patient characteristics and thus do not help in accurate diagnosis. The proposed algorithm segregates the pressure wave form using flow waveform that is built by collecting characteristics of individual pressure waveform. The flow waveform derived from proposed algorithm matched the actual flow measurements in both men and women better than the triangular algorithm which is most commonly used at present.
Reflection magnitude (RM) is the ratio of backward pressure amplitude to forward pressure amplitude in heart. The plots demonstrate performance of algorithms by plotting difference between RM obtained from actual flow (measured using instrument) and RM obtained from algorithm calculated flow against mean of actual flow and calculated flow. The more the number of points on or close to y=0, the better is the algorithm.
The orange plot was obtained by the proposed algorithm and the blue plot was obtained by triangular model. We observe that the orange plot is less scattered along the y-axis with more points close to 0 as compared to the blue plot where points scatter beyond 0.2 and -0.2. These two plots demonstrate better performance of proposed algorithm in predicting flow in comparison with triangular model.
For understanding pressure on heart, artery stiffness and morphology
- Patient specific flow characteristic derivation from pressure waveform solely
- Provides reliable estimates of flow in both men and women
Stage of Development:
- The algorithm has been developed and the performance has been tested for both female and male pressure waveform data
- The better performance of proposed algorithm over presently used triangular model has been demonstrated
Docket # 18-8619