Automated ABPI in Peripheral Arterial Disease a Pilot Study (AUTO-PAD)

Assessing the Diagnostic Accuracy of AUTOmated Ankle-Brachial Pressure Index Devices Across the Spectrum of Peripheral Arterial Disease (AUTO-PAD)- A Pilot Study

The aim of this pilot study is to investigate the diagnostic accuracy of two automated ABPI devices across the spectrum of PAD (asymptomatic PAD, suspected symptomatic PAD [IC; including mild moderate and severe IC based on the Rutherford classification (21) and CLTI] and post-bypass surveillance). A second aim is to assess their useability and tolerability through semi-structured interviews with patients and clinicians. This means the research will be split into two workstreams.

Study Overview

• Status: Recruiting
• Conditions: Feasibility Studies; Ankle Brachial Index; Peripheral Arterial Disease (PAD); Diagnostic Accuracy
• Intervention / Treatment: Device: MESI mTablet; Device: BlueDop vascular Expert (BlueDopVE)

• Study Type: Observational
• Enrollment (Estimated): 400

Contacts and Locations

• Study Contact: Name: Jon Prosser; Phone Number: 01482 674703; Email: jonathon.prosser@nhs.net
• Study Contact Backup: Name: Judith Long; Email: judith.long3@nhs.net

Study Locations

• United Kingdom
  • Hull, United Kingdom, HU3 2JZ
    • Recruiting
    • Hull University Teaching Hospitals NHS Trust
    • Contact: James Illingworth; Phone Number: 01482 461903; Email: james.illingworth3@nhs.net

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Group 1: Asymptomatic PAD:

Patients identified by the GP (PIC sites). Records screened to identify 'at risk' of PAD with >1 cardiovascular disease risk factor

Group 2: Suspected symptomatic PAD:

2a. Patients with suspected IC referred to dedicated nurse-led claudication clinic.

Group 2b. Patients with suspected CLTI referred to dedicated urgent vascular (HOT) clinic.

Group 3: Patients undergoing surveillance seen in dedicated clinics by vascular scientists

Description

Inclusion Criteria:

Group 1: Asymptomatic

• Adults aged 18 and over
• At risk of PAD with ≥1 cardiovascular risk factor
• No previous diagnosis of PAD
• English speaking and able to understand test protocols

Group 2a: Suspected PAD (intermittent claudication)

• Adults aged 18 and over
• Referred and booked into the nurse-led claudication clinic due to signs/symptoms in keeping with suspected intermittent claudication
• English speaking and able to understand test protocols

Group 2b: Suspected PAD (CLTI)

• Adults aged 18 and over
• Referred and booked into the vascular HOT clinic due to signs/symptoms in keeping with suspected CLTI
• English speaking and able to understand test protocols

Group 3: Post-bypass surveillance

• Adults aged 18 and over
• History of lower limb bypass surgery, enrolled in and attending the local surveillance programme
• English speaking and able to understand test protocols

Exclusion Criteria:

• Patients who are unable to provide informed consent
• Recent (≤4 weeks) lower-limb surgery
• Ulcers, casts or bandages that cannot or should not be compressed
• Patients who have had a therapeutic intervention (stent or graft) which extends to the ankle
• Patients with known or suspected acute deep vein thrombosis (DVT) or superficial thrombophlebitis
• Marked oedema in one or both feet
• Inability to tolerate a supine position
• Patients with spasms or tremors of any kind
• Arm arteriovenous fistula
• Inability to cooperate due to impaired cognition

Study Plan

How is the study designed?

Design Details

• Observational Models: COHORT
• Time Perspectives: CROSS_SECTIONAL

Number of groups / cohorts

4

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Group 1 Asymptomatic; Participants with one or more CVD risk factors	Device: MESI mTablet; The MESI mTablet uses 3CUFFTM technology to detect pulse waveforms to assess ABPI. This involves placing a blood pressure cuff on all 4 limbs at the same time. The two arm cuffs then inflate and simultaneously measure the blood pressure in both brachial arteries. The cuff with the highest systolic pressure than reinflates with both the ankle cuffs simultaneously. The ABPI is then calculated and displayed on the tablet. A ratio of <0.9 will indicate the presence of PAD.; Device: BlueDop vascular Expert (BlueDopVE); The BlueDop device is a cuffless device which comprises an egg-shaped handheld probe component and an output monitor device. The device measures mean arterial blood pressure through an algorithm. Simply, it calculates the average blood pressure based on the normal rise and fall of pressure during each heartbeat. The device then automatically generates an ankle-brachial pressure index and a corresponding traffic-light classification for each lower-limb artery, based on waveform. This output is interpreted using table 2 below. Essentially an ABPI of 0.8-1.0 with a biphasic or triphasic waveform indicates no disease whereas an ABPI <0.8 and / or a monophasic/non-specific waveform indicates the presence of PAD.
Group 2a Suspected PAD (intermittent claudication); Partcipants presenting with Suspected PAD (intermittent claudication)	Device: MESI mTablet; The MESI mTablet uses 3CUFFTM technology to detect pulse waveforms to assess ABPI. This involves placing a blood pressure cuff on all 4 limbs at the same time. The two arm cuffs then inflate and simultaneously measure the blood pressure in both brachial arteries. The cuff with the highest systolic pressure than reinflates with both the ankle cuffs simultaneously. The ABPI is then calculated and displayed on the tablet. A ratio of <0.9 will indicate the presence of PAD.; Device: BlueDop vascular Expert (BlueDopVE); The BlueDop device is a cuffless device which comprises an egg-shaped handheld probe component and an output monitor device. The device measures mean arterial blood pressure through an algorithm. Simply, it calculates the average blood pressure based on the normal rise and fall of pressure during each heartbeat. The device then automatically generates an ankle-brachial pressure index and a corresponding traffic-light classification for each lower-limb artery, based on waveform. This output is interpreted using table 2 below. Essentially an ABPI of 0.8-1.0 with a biphasic or triphasic waveform indicates no disease whereas an ABPI <0.8 and / or a monophasic/non-specific waveform indicates the presence of PAD.
Group 2b Suspected PAD (CLTI); Participants presenting with tissue loss or rest pain	Device: MESI mTablet; The MESI mTablet uses 3CUFFTM technology to detect pulse waveforms to assess ABPI. This involves placing a blood pressure cuff on all 4 limbs at the same time. The two arm cuffs then inflate and simultaneously measure the blood pressure in both brachial arteries. The cuff with the highest systolic pressure than reinflates with both the ankle cuffs simultaneously. The ABPI is then calculated and displayed on the tablet. A ratio of <0.9 will indicate the presence of PAD.; Device: BlueDop vascular Expert (BlueDopVE); The BlueDop device is a cuffless device which comprises an egg-shaped handheld probe component and an output monitor device. The device measures mean arterial blood pressure through an algorithm. Simply, it calculates the average blood pressure based on the normal rise and fall of pressure during each heartbeat. The device then automatically generates an ankle-brachial pressure index and a corresponding traffic-light classification for each lower-limb artery, based on waveform. This output is interpreted using table 2 below. Essentially an ABPI of 0.8-1.0 with a biphasic or triphasic waveform indicates no disease whereas an ABPI <0.8 and / or a monophasic/non-specific waveform indicates the presence of PAD.
Group 3 Post-bypass surveillance; Participants presenting for post-bypass surveillance	Device: MESI mTablet; The MESI mTablet uses 3CUFFTM technology to detect pulse waveforms to assess ABPI. This involves placing a blood pressure cuff on all 4 limbs at the same time. The two arm cuffs then inflate and simultaneously measure the blood pressure in both brachial arteries. The cuff with the highest systolic pressure than reinflates with both the ankle cuffs simultaneously. The ABPI is then calculated and displayed on the tablet. A ratio of <0.9 will indicate the presence of PAD.; Device: BlueDop vascular Expert (BlueDopVE); The BlueDop device is a cuffless device which comprises an egg-shaped handheld probe component and an output monitor device. The device measures mean arterial blood pressure through an algorithm. Simply, it calculates the average blood pressure based on the normal rise and fall of pressure during each heartbeat. The device then automatically generates an ankle-brachial pressure index and a corresponding traffic-light classification for each lower-limb artery, based on waveform. This output is interpreted using table 2 below. Essentially an ABPI of 0.8-1.0 with a biphasic or triphasic waveform indicates no disease whereas an ABPI <0.8 and / or a monophasic/non-specific waveform indicates the presence of PAD.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic Accuracy	Diagnostic accuracy assessed via sensitivity, specificity, positive predictor value (PPV) and negative predictor value (NPV).	From enrolment to the end of treatment (1 day)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Validity assessed via correlation	Diagnostic performance assessed via area under the receiver operating characteristic (AUROC) curve and the assessment time difference, assessed via measurement of the time taken to perform each automated ABPI assessment and the manual ABPI assessment.	Data collected at enrolment (1 day)
Diagnostic performance	Assessed via area under the receiver operating characteristic (AUROC) curve.	Data collected at enrolment (1 day)
Time taken to perform each automated ABPI assessment and the manual ABPI assessment.	Time taken to perform each assessment in seconds	Data collected at enrolment (1 day)
Qualitative Workstream - Assessment of usability and tolerability of automated devices.	Semi structured interviews analysed using thematic analysis	Within the 2 year recruitment period
Visual Analogue Scale (VAS) score of 0-10	VAS used to assess tolerability	Data collected at point of enrolment (1 day)

Collaborators and Investigators

• Sponsor: Hull University Teaching Hospitals NHS Trust

Study record dates

Study Major Dates

• Study Start (Actual): June 24, 2026
• Primary Completion (Estimated): September 1, 2028
• Study Completion (Estimated): September 1, 2028

Study Registration Dates

• First Submitted: September 14, 2026
• First Submitted That Met QC Criteria: September 24, 2026
• First Posted (Actual): September 30, 2026

Study Record Updates

• Last Update Posted (Actual): October 1, 2026
• Last Update Submitted That Met QC Criteria: September 30, 2026
• Last Verified: September 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Vascular Diseases; Cardiovascular Diseases; Atherosclerosis; Arteriosclerosis; Arterial Occlusive Diseases; Peripheral Vascular Diseases; Peripheral Arterial Disease
• Other Study ID Numbers: R4364

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No