Comparison of VxWave and Standard Ultrasound Measurements of Blood Vessels in the Arm

All participants undergo VxWave scanning followed by Philips Lumify scanning of the same arm during one study visit. The first 20 consecutive participants after Participant ID 030 who complete comparator acquisition also undergo a repeat Lumify scan after probe lift-off and at least two minutes of rest.

Robotically controlled acquisition of duplex B-mode and Doppler ultrasound data of the upper-limb vasculature, excluding the hand. The participant rests the limb on the scan bed while the probe moves beneath it. Images are measured offline using VxView. VxWave scanning occurs before the comparator scan.

Qualified vascular-sonographer acquisition of ultrasound data from the same upper-limb vascular locations after VxWave scanning. Images are measured offline using OsiriX MD. The specified repeatability subset undergoes a separate repeat comparator acquisition after probe lift-off and at least two minutes of rest.

Mean bias and 95% limits of agreement for VxWave minus comparator arterial diameter in millimetres at three pre-specified brachial/radial artery locations. Each location uses the mean of three diameter measurements. Multilevel Bland-Altman analysis accounts for measurements within participants, with 95% confidence intervals for bias and limits of agreement. The +/-0.5 mm margin is a descriptive benchmark and does not define a binary study-success criterion. Only diagnostic-quality measurements are included in agreement analysis.

Mean percentage bias and 95% limits of agreement in symmetric relative percentage differences between VxWave and comparator peak systolic velocity at the three pre-specified brachial/radial artery locations. Mean of three representative peak systolic velocity measurements per location. Multilevel Bland-Altman analysis accounts for measurements within participants, with 95% confidence intervals for bias and limits of agreement. Absolute-scale agreement in cm/s is a sensitivity analysis. No PSV acceptance criterion is specified. Only diagnostic-quality measurements are included.

Percentage of participants for whom VxWave completes the peripheral vascular imaging examination, with scan data judged by the reporting sonographer to be of diagnostic quality for measurement and able to confirm measurements. Reasons for failure include inability to perform both B-mode and Doppler measurements at two of the three discrete locations, or failure to complete scan data acquisition within a reasonable time (less than 55 minutes).

Elapsed time in minutes from initiation of the first acquisition run on the VxWave console to scan status complete on the final acquisition run, including time between runs. A scan may contain more than one acquisition run, including restarts after participant repositioning.

Four questionnaire items assess overall comfort, satisfaction with scanning time, satisfaction with audible noise and overall satisfaction. Each item has five ordered response categories: Excellent, Very good, Good, Fair and Poor, with Excellent representing the most favorable response. Ordinal responses will be summarised using median/interquartile range or proportions. No composite score is specified in the protocol or supplied assessment form.

For the first 20 consecutive participants after Participant ID 030 who complete comparator acquisition, assess mean difference (bias), 95% limits of agreement and repeatability coefficient between first and repeat comparator arterial diameter measurements in millimetres at each pre-specified location. Multilevel Bland-Altman analysis accounts for measurements within participants, with 95% confidence intervals for bias and limits of agreement. The first comparator acquisition remains the reference for the primary endpoint; repeat acquisition is used for this secondary endpoint only.

For the same 20-participant repeatability cohort, assess mean difference (bias), 95% limits of agreement and repeatability coefficient between first and repeat comparator peak systolic velocity measurements, expressed as symmetric relative percentage differences, at each pre-specified location. Multilevel Bland-Altman analysis accounts for measurements within participants, with 95% confidence intervals. This descriptive endpoint characterises reference-pathway repeatability and does not define an acceptance test.

100 multiplied by the number of unique scanned participants whose scan is associated with at least one VxWave device deficiency, divided by the total number of unique participants who undergo a scan. Include attempted scans regardless of successful completion or diagnostic image quality. Each participant is counted once, even if more than one deficiency or scan occurs. Device deficiencies include those identified before scan completion.

100 multiplied by the number of unique scanned participants who experience at least one adverse event (AE), divided by the total number of unique participants who undergo a scan. AEs are counted regardless of their relationship to the device or study procedure. Include attempted scans regardless of successful completion. Each participant is counted once, even if multiple AEs or scans occur. Device/procedure-related AEs are included in this overall AE measure and are also reported separately as adverse device effects.

100 multiplied by the number of unique scanned participants who experience at least one adverse device effect (ADE), divided by the total number of unique participants who undergo a scan. Per the protocol, an ADE is an AE related to the VxWave Ultrasound Imaging System or study procedure. Include attempted scans regardless of successful completion. Each participant is counted once, even if multiple ADEs or scans occur. ADEs are a subset of all AEs; the overall AE percentage and ADE percentage must not be added together.