Accuracy and repeatability of the Dopplex Ability

ABSTRACT

Background: Ankle-brachial index (ABI) and pulse volume recordings (PVR) are non-invasive tests used in diagnosis of peripheral arterial disease (PAD). The Dopplex Ability is an automated ABI/PVR device utilising air plethysmography, offering easy and rapid PAD diagnosis. The accuracy and repeatability of the Dopplex were assessed in comparison to the Doppler/air plethysmography-based Parks Flo-Lab system.

Methods: Sixty-six patients (n = 129 lower limbs) were assessed with both Dopplex and Parks systems. For Dopplex ABI and PVR to be deemed accurate, it had to be within ±10% of the Parks ABI, and the PVR grade (1–4) had to be equal. The coefficient of variation (CV) was calculated from three repeat ABI/PVR readings to assess repeatability.

Results: The Dopplex and Parks devices correlated poorly for ABI (R2 = 0.17) with only 43% of ABIs and 69% of PVRs meeting the accuracy criteria compared to the Parks values. The specificity and sensitivity were 56% and 82%, respectively for ABI, and 91% and 89%, respectively for PVRs. The Dopplex showed a significantly higher CV for both ABIs and PVRs compared to the Parks.

Conclusion: We found the Dopplex device to demonstrate suboptimal accuracy and repeatability in assessing ABI/PVR, and it was deemed unsuitable for use in our community.

KEYWORDS:

• Dopplex
• ankle-brachial index
• pulse volume recording
• accuracy
• repeatability

Author contributions statement

AM, BH and JK were involved in the study conception and ethical approval. RM, KT and BH were involved in study conduct and data collection. RM analyzed the data. RM wrote the manuscript in consultation with KT, BH, AVR and JK. All authors were involved in the study design, data interpretation, and final revision of the manuscript. All authors agree to be accountable for all aspects of the work.

Acknowledgments

We would like to thank Huntleigh Diagnostics for the use of the Dopplex Ability device; to the members of the Otago Vascular Diagnostics Laboratory for their assistance with data collection; and to the study participants for their involvement in the study.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper is not funded.