Ability of a 24-h ambulatory cuffless blood pressure monitoring device to track blood pressure changes in clinical practice

Figures

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  FIGURE 1. Sample participant. (a) Arrangement of TestBP and RefBP devices. (b) Result of this sample participant in a plot comparing the difference between the RefBP and the TestBP (here -31 mmHg) with the difference between the CalibBP and the RefBP (here 27 mmHg), exemplarily systolic 24 h mean. (c) TestBP of a sample participant with the SBP in Red, DBP in purple. The CalibBP is framed in red, the awake BP in yellow, the asleep BP in blue, and the 24 h mean BP in brown. The systolic CalibBP is 161 mmHg, the systolic 24 h mean is 165 mmHg. (d) RefBP of the same sample participant. The CalibBP is framed in red, the awake BP in yellow, the asleep BP in blue, and the 24 h mean BP in brown. The systolic 24 h mean is 134 mmHg, thus resulting in a s24hRefBP - s24hTestBP of 134 mmHg - 165 mmHg = -31 mmHg, and a sCalibBP - s24hBP of 161 mmHg - 134 mmHg = 27 mmHg.

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  FIGURE 2. Explanations for comparison plots: (a) The green vertical line represents a hypothetical perfect correlation between TestBP and RefBP, the red line a hypothetical TestBP which is exactly equal to the CalibBP. (b) A hypothetical TestBP with a systematic error in comparison to the RefBP would be depicted in a horizontally displaced vertical line. (c) Shifting of a measurement point in a vertical direction depicts a difference between the CalibBP and the Reference BP with the upper half of the plot representing CalibBP values higher than the RefBP (white-coat pattern, at least as a tendency), and the lower half representing CalibBP values lower than the RefBP (masked pattern, at least as a tendency). (d) Shifting of a measurement point in a horizontal direction depicts a difference between TestBP and RefBP with the left side of the plot representing TestBP values higher than the RefBP and the right side of the plot representing TestBP values lower than the RefBP.

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  FIGURE 3. Boxplots comparing the difference between the systolic (a) or diastolic (b) CalibBP and the systolic (a) or diastolic (b) 24h, awake and asleep RefBP (purple) / TestBP (orange) with P values generated by a one-sided Wilcoxon signed-rank test.

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  FIGURE 4. Plots comparing the difference between systolic or diastolic CalibBP and 24h, awake and asleep systolic or diastolic RefBP on the y-axis and the difference between the 24h, awake and asleep systolic or diastolic RefBP and corresponding TestBP on the x-axis. Plots a, c, e are showing the SBP and plots b, d and f the DBP. BP blood pressure, CalibBP calibration BP measurement, d diastolic, RefBP standard cuff-based BP measurement, s systolic, TestBP cuffless BP measurement. Red line shows the assumption that TestBP follows CalibBP without changes, the blue line shows the generated linear regression for the data and the green line shows an ideal agreement between RefBP and TestBP.