Development of Coronary Pulse Wave Velocity: New Pathophysiological Insight Into Coronary Artery Disease

Figures

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  Figure 1. Illustration of the principle of coronary pulse wave velocity (CoPWV) measurement in the left descending artery. ECG–blood pressure delays (TR‐BP) are recorded successively at the distal (TR‐BP dist) and proximal (TR‐BP prox) sites. Coronary travel time (CoTT) and coronary travel distance (CoTD) allow the calculation of CoPWV.

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  Figure 2. Detection of onset time of the blood pressure (BP) rise in the proximal and the distal positions of a coronary artery. A, For each cardiac cycle, the peak corresponding to the pressure rise and the trough corresponding to the dicrotic notch were detected in the first derivative of the BP at the times Tpeak and Ttrough, respectively. When the catheter was in the proximal position, the onset time (Tonset) of the BP rise was calculated for each cardiac cycle as the intersection of the tangent to the BP wave at Tpeak, with the horizontal line passing through the preceding diastolic BP (DBP). To avoid the effect of microcirculation on the DBP, an extrapolated value (DBP*) was used, being equal to the value of the BP at the moment just before the onset of the R wave. B, A normalized BP wave was calculated for each cardiac cycle between Tpeak and Ttrough by subtracting from each BP sample the value of the preceding extrapolated DBP*. The average of all normalized BP waveforms in the proximal position resulted in an averaged normalized waveform of duration: ΔT=Ttrough−Tpeak(time interval:[0;ΔT]). The intersection of the tangent to the averaged normalized BP wave at time t=0 with the axis…

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  Figure 3. Delay between proximal and distal blood pressure (BP) wave fronts. A, Superimposed ECG, BP, and recomposed ECG signal for proximal and distal left descending artery (LDA), triggered by the R wave. The recomposed ECG signal was equal to the averaged R wave shape at the onset of the BP rise and zero elsewhere. B, Normalized cross‐correlation between ECG and recomposed ECG signal in (A) for a ±300 ms shift range. The peak of the cross‐correlation function corresponds to the delay between the R wave and the onset of the BP wave (R‐BP delay). C, Time series of diastolic BP (DBP) and R‐BP delays for adjacent periods containing 5 consecutive cardiac cycles in proximal and distal LDA. Both raw (dots) and extrapolated (open circles) R‐BP delay time series are shown. The delay that the pressure wave needs to propagate from the proximal to the distal location (CoTT) is the difference of averaged extrapolated R‐BP delays (arrows). D, Extrapolation of R‐BP delay time series for a common DBP (DBP c; mean of proximal and distal DBP), using linear regressions curves between R‐BP delay and DBP. CoTT indicates coronary travel time; Dist, distal; Prox, proximal; Recomp, recomposed ECG signal.

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  Figure 4. Systolic (A) and diastolic (B) coronary perfusion pressure at the proximal and distal sites.

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  Figure 5. Difference in coronary travel distance (CoTD) (A) and coronary travel time (CoTT) (B) in patients with stable coronary artery disease (CAD) and an acute coronary syndrome (ACS).

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  Figure 6. Correlation between coronary and aortic pulse wave velocities. AoPWV indicates aortic pulse wave velocity; CoPWV, coronary pulse wave velocity.

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  Figure 7. Coronary pulse wave velocity (CoPWV) (A) before and after stenting and (B) in patients with stable coronary artery (CAD) disease or an acute coronary syndrome (ACS). Dots indicate individual recordings, and whiskers represent means and standard deviations. *P=0.012; ***P<0.001.