Sub-Total: €0.00
Automated Ankle Brachial Pressure Index Measurement Devices to Detect Peripheral Arterial Disease in People With Leg Ulcers
Published:
1 Recommendations
1.1 There is not enough evidence to recommend routine adoption of automated ankle brachial pressure index (ABPI) measurement devices to detect peripheral arterial disease in people with leg ulcers. They should only be used in the context of research for these people.
1.2 Centres already using automated ABPI measurement devices to detect peripheral arterial disease in people with leg ulcers can continue to use them, only if:
- they collect data or do research to assess their value and how well they identify people with peripheral arterial disease (see the section on further research)
- people using the devices have experience assessing peripheral arterial disease
- people using the devices are aware of their limitations, particularly diagnostic accuracy and the risk of missing peripheral arterial disease, and that there are differences between devices
- further assessment using other methods, including manual doppler, is available.
1.3 Further research is recommended on automated ABPI measurement devices (see the section on further research) to:
- assess their ability to detect peripheral arterial disease in people with leg ulcers
- assess how they affect time to treatment for venous leg ulcers
- assess clinical outcomes for treatments started after ABPI assessment
- explore the most appropriate user (specialist and non-specialist in assessing peripheral arterial disease) and the most appropriate healthcare setting for their use
- explore whether different ABPI thresholds can improve their sensitivity for detecting peripheral arterial disease.
Why the committee made these recommendations
Treatment for leg ulcers caused by a problem with blood flow in the veins (venous) involves compression therapy with bandages or stockings. Compression therapy is not suitable for some people with peripheral arterial disease because it could disrupt blood flow to the leg. Measuring ABPI as part of a clinical assessment can help detect if someone has peripheral arterial disease and therefore should not have compression therapy.
Currently, ABPI is measured and calculated manually. The assessment takes up to 1 hour and can be uncomfortable for people with leg ulcers. Automated ABPI measurement devices may potentially be easier and faster to use than manual doppler measurement, and more comfortable for people with leg ulcers. But there is limited evidence on whether automated devices can reduce the length of time an ABPI assessment takes.
There is a lack of clinical evidence on automated ABPI measurement devices and most studies were done in people without leg ulcers. So, it is unclear how well automated devices detect peripheral arterial disease in people with leg ulcers. There is also uncertainty about which healthcare setting the devices should be used in (for example, hospital or community) and who should use them (specialist or non-specialist in assessing peripheral arterial disease). It is therefore unclear:
- whether automated devices reduce the length of time before starting treatment for venous leg ulcers
- how inaccurate test results impact clinical decision making and health outcomes.
Economic modelling shows that automated ABPI devices are unlikely to be cost effective compared with manual doppler measurement unless they reduce the length of time before treatment starts, which is uncertain. The results of the economic model are also uncertain because there is no evidence on how results from automated ABPI measurement devices affect clinical decision making or clinical outcomes. So, automated ABPI measurement devices are only recommended in the context of research. Centres already using the devices can continue to use them if they do research and ensure safety.
Clinical need and practice
The condition
2.1 Leg ulcers are slow-healing wounds that usually develop on the inside of the leg, just above the ankle. It is estimated that about 1 million or 2% of adults in the UK have a leg ulcer (Guest et al. 2020). Around 65% of leg ulcers are venous, meaning they are caused by a problem in the blood flow in the veins. Treatment involves using compression such as bandages or stockings. Strong compression therapy can disturb the arterial blood supply in the leg, so it should not be offered to people with peripheral arterial disease.
2.2 People with peripheral arterial disease may not have any symptoms, but it can lead to serious complications such as chronic limb-threatening ischaemia. In this condition, loss of blood supply to the leg causes tissue to die and there is a significant risk of losing a limb and premature death.
Care pathway
2.3 The National Wound Care Strategy Programme (NWCSP) recommendations for lower limb ulcers advise using the ankle brachial pressure index (ABPI) to screen for peripheral arterial disease in people with leg ulcers alongside a full clinical assessment. This is currently measured manually using a handheld doppler ultrasound probe.
2.4 People with leg ulcers may present in primary care. NWCSP guidance recommends that immediate care for ulcers should include cleaning, application of emollient and a simple low-adherent dressing. In the absence of any ‘red flag symptoms’ (such as infection, symptoms of sepsis, ischaemia, suspected deep vein thrombosis or skin cancer), mild graduated compression should be applied until full clinical assessment and ABPI measurement can take place. However, if there are not enough staff able to do manual doppler assessment, delayed assessment may lead to longer periods without compression or sub-optimal compression. Clinical experts noted that in practice some practitioners are uncomfortable applying even mild compression without ABPI measurement. People should be offered a full clinical assessment within 14 days of initial presentation, but clinical experts noted this is a challenge and it can take substantially longer in some areas.
Potential value of the technologies
2.5 Automated ABPI measurement devices may be easier to use than manual devices. This may reduce the time needed to complete the assessment and make ABPI measurement more comfortable for people with leg ulcers. A further potential benefit could be a reduction in the time to assessment and, consequently, treatment for people with venous ulcers when there are not enough staff able to do manual doppler assessment.
The interventions
2.6 Automated ABPI devices include doppler-based, oscillometry-based and plethysmography-based devices. Doppler-based devices use a doppler probe and provide doppler waveform signals as an output. Oscillometry-based devices assess oscillations in the vessel wall, and plethysmography-based devices assess blood volume changes. These devices either estimate blood pressure directly or use a pressure cuff to help with the measurement. Diabetes, rheumatoid arthritis, systemic vasculitis, atherosclerotic disease and advanced chronic renal failure can cause calcium build-up and hardening of the arteries, which can make ABPI measurements appear misleadingly normal. Clinical experts highlighted the value of information provided by doppler waveform signals in these situations. Devices that do not provide doppler waveform signals may provide information about the quality of arterial circulation in the ankles, but there is uncertainty about whether these alternative outputs are comparable with doppler waveform signals.
2.7 This evaluation considers 7 automated devices for measuring ABPI and assessing arterial circulation (see table 1). Costs shown in table 1 exclude VAT and include the cost of the equipment and other fixed costs such as purchase of additional cuffs to complete the set, and software when applicable.
Article by, nice.
