Comprehensive assessment of coronary pulse wave velocity in anesthetized pigs

Figures

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  FIGURE 1. Morphology of the intra‐coronary pressure at the proximal and distal levels in normal conditions. The propagation of the backward (BK) and forward (FW) pressure waves is shown at several positions across the coronary artery between proximal and distal locations on the pressure waves (upward: P prox and P dist) and on their first derivatives (downward: P’prox and P’dist)

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  FIGURE 2. Illustration of the four methods used for measuring CoPWV. The transit time (∆t) of the pressure wave between the proximal (P prox) and the distal (P dist) sites can be calculated in four different ways; ∆t FW, tangent intersection method applied to the forward pressure (FW) rise (green lines); ∆t BK, tangent intersection method applied to the backward (BK) pressure rise (brown arrows); ∆t DIC, maximum of the second derivative corresponding to the dicrotic notch (DIC) (black lines); ∆t TM, template matching (TM) between two segments after a rescaling (blue lines). In all cases, CoPWV is calculated from the ratio ∆t/d; d is the distance between proximal and distal recording sites

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  FIGURE 3. Bland–Altman plots comparing all the possible combinations between the four analysis methods in spontaneous baseline conditions: method BK versus FW (a), method DIC versus BK (b), method TM versus BK (C), method TM versus DIC (d), method DIC versus FW (e) and method TM versus FW (F). Horizontal lines indicate mean and 95% confidence interval (±1.96 SD). The smallest confidence interval was observed between the method TM and DIC (d) and between the methods BK and FW (a). The only proportional bias was observed for the plot between the method TM ans DIC (D)

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  FIGURE 4. Impact of flow limitation on the amplitudes of the backward (BK) wave and of the dicrotic notch (DIC) in the proximal (P prox) and distal pressure (P dist) signals. Conditions 1, 2, and 3 are for baseline, flow limitation I (mild), and flow limitation II (moderate), respectively, at fixed hemodynamic conditions (heart rate = 110 bpm and aortic mean arterial pressure = 80 mmHg). All drawings show typical real traces: detail of a pressure wavefrom during one cardiac cycle at the left side and condensed concecutive pressure waveforms during a respiratory cycle at the right side