Accuracy and repeatability of the Dopplex Ability.

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.