Evaluation of Aktiia cuffless blood pressure monitor across 24-h, daytime, and night-time measurements versus ambulatory monitoring: a prospective, single-centre observational study

Figures

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  FIGURE 1. Scatter plots (upper) and Bland-Altman plots (bottom) comparing 24-h BP measurements performed by Aktiia monitor (7-day average) and ABPM (1-day average). A. Comparison of 24-h SBP. B. Comparison of 24-h DBP. C. Comparison of 24-h HR. Pearson's correlation (r) between the two modalities is shown on the bottom right of the scatter plots. ROI within ± 10 mmHg and ± 15 mmHg are highlighted in dark grey and light grey, respectively. The percentage of agreement for each region is shown on the bottom left of the Bland-Altman plots. The solid black line denotes the average mean of differences, while the dotted lines denote the limits of agreement (±1.96σ). BPM – beats per minute.

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  FIGURE 2. Scatter plots (upper) and Bland-Altman plots (bottom) comparing daytime BP measurements performed by Aktiia monitor (7-day average) and ABPM (1-day average). A. Comparison of daytime SBP. B. Comparison of daytime DBP. C. Comparison of daytime HR. Pearson's correlation (r) between the two modalities is shown on the bottom right of the scatter plots. ROI within ± 10 mmHg and ± 15 mmHg are highlighted in dark grey and light grey, respectively. The percentage of agreement for each region is shown on the bottom left of the Bland-Altman plots. The solid black line denotes the average mean of differences, while the dotted lines denote the limits of agreement (±1.96σ). BPM – beats per minute.

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  FIGURE 3. Scatter plots (upper) and Bland-Altman plots (bottom) comparing night-time BP measurements performed by Aktiia monitor (7-day average) and ABPM (1-day average). A. Comparison of night-time SBP. B. Comparison of night-time DBP. C. Comparison of night-time HR. Pearson's correlation (r) between the two modalities is shown on the bottom right of the scatter plots. ROI within ± 10 mmHg and ± 15 mmHg are highlighted in dark grey and light grey, respectively. The percentage of agreement for each region is shown on the bottom left of the Bland-Altman plots. The solid black line denotes the average mean of differences, while the dotted lines denote the limits of agreement (±1.96σ). BPM – beats per minute.

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  FIGURE 4. The performance of SBP night dipping identification by the Aktiia monitor considering -10% as the reference for ABPM night dip and a ± 6% exclusion zone around the ABPM dipping reference. A. The ROC curve created to test night dip detection by the Aktiia monitor, with an AUC of 0.72 and optimal operating point at -2.96% (red dot, 91% sensitivity, 63% specificity). B. Four-quadrant plot (FQP) comparing the nocturnal dips detected by the Aktiia monitor and ABPM, with a CR of 78.9% (83.3% precision).