Peripheral Artery DiseaseNCT04120610

FlowMet-R Blood Flow Measurement for the Diagnosis of Peripheral Artery Disease and Critical Limb Ischemia

An observational study of Peripheral Artery Disease, run by Medtronic Endovascular at 5 sites in United States.

Terminated

Stopped early. The study ended before it was planned to and will not resume.

Trial summary

Non-randomized, multi-center, longitudinal study of healthy subjects and subjects with PAD who are scheduled for ABI, TBI, and either Duplex Ultrasound or Angiographic assessments in a vascular clinic. Read more about this study

Who is it for?: Ages 40 years and olderHealthy volunteers can take part
Conditions the study is for: Peripheral Artery Disease
What is being tested?: FlowMet-R, ABI and TBI
How many people: 195 participants
Where: 5 sitesUnited States
Study dates: 9 Dec 2019to 21 Nov 2022
How long will I take part?: 6 Months
Phase: Observational
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 40 years and older
All sexes
Healthy volunteers accepted
Adult, Older adult

Study population: The PAD cohort population is persons who have known or suspected peripheral artery disease, and are being seen at a vascular clinic for evaluation. The Healthy cohort population is adult persons over 40 without history of PAD and who are not currently suspected of suffering from PAD.

Who may be able to join

PAD Positive Cohort
Subject meets PAD positive criteria
Subject is willing and able to provide informed consent
Subject is willing and able to comply with study procedures
Subject is able to understand the study procedures
Subject is scheduled for vascular examination that includes noninvasive assessments as standard of care: ABI, TBI, and either a Duplex Ultrasound or Angiogram

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Healthy Cohort
Subject is willing and able to provide informed consent.
Subject is willing and able to comply with the study procedures.
Subject is able to understand the study procedures.
Subject has no history of positive PAD diagnosis, and is not currently suspected of having PAD.

Who cannot join

PAD Positive Cohort
Subject is under 40 or unable to consent.
Subject has any medical condition, which, in the judgment of the Investigator and/or designee, makes the subject a poor candidate for the investigational study.
Subject is excluded from analysis if no stenosis is found during Doppler but Tibial disease is suspected and Tibial ultrasound is not able to be performed.
Subject does not have a suitable finger to attach the FlowMet-R probe.
Subject does not have a suitable 1st or 2nd digit to attach FlowMet-R probe on the limb of interest.

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Subject has undergone revascularization within the last 90 days
Subject cannot lay safely in a supine position.
Healthy Cohort
Subject is under 40 or unable to consent.
Subject has any medical condition, which, in the judgment of the Investigator and/or designee, makes the subject a poor candidate for the investigational study.
One or more limbs has a prior or current diagnosis of PAD, or is reasonably suspected of having a diagnosis of PAD.
Subject does not have a suitable finger to attach the FlowMet-R probe.
Subject does not have a suitable 1st or 2nd digit to attach FlowMet-R probe.
Subject has undergone revascularization within the last 90 days

Trial locations and contacts

5 sites in 1 country.

City, postcode or hospital

5 sites in 1 country

United States5 sites

Ascension Seton
Austin, Texas, 78705
Mercy Research
Chesterfield, Missouri, 63017
Ohio Health
Columbus, Ohio, 43214
The Iowa Clinic
Des Moines, Iowa, 50266
The Mt. Sinai Hospital
New York, New York, 10029

Other trials in United States

About this study

Official title: FlowMet-R Blood Flow Measurement for the Diagnosis of Peripheral Artery Disease (PAD) and Critical Limb Ischemia (CLI)

Read the detailed description

Patients scheduled for peripheral vascular examination and healthy controls will be measured with the FlowMet-R, a noninvasive blood flow monitor, and compared to gold standard diagnostics - ABI, TBI, and Doppler Ultrasound. Sensitivity and specificity of the FlowMet-R device output in diagnosing PAD and CLI will be assessed on initial visit, 3-month followup, and 6-month followup.

Conditions: Peripheral Artery Disease
Being tested: FlowMet-R, ABI, TBI
Keywords: Peripheral Artery Disease, Claudication, Critical Limb Ischemia
Medical subject headings: Peripheral Arterial Disease, Intermittent Claudication, Chronic Limb-Threatening Ischemia

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

FlowMet-RDiagnostic test
FlowMet-R is a noninvasive blood flow measurement.
ABIDiagnostic test
Ankle Brachial Index is a ratio-metric blood pressure measurement in the ankle and arm.
TBIDiagnostic test
Ankle Brachial Index is a ratio-metric blood pressure measurement in the toe and arm.

Study groups in NCT04120610
Study group	Role	What they receive
Healthy		Healthy cohort is an age-matched population (over 40 years old) without history of PAD or suspected PAD. Healthy cohort will receive FlowMet-R measurement, Ankle Brachial Index (ABI), and Toe Brachial Index (TBI) measurements. Receives: Diagnostic Test: FlowMet-R; Diagnostic Test: ABI; Diagnostic Test: TBI
Peripheral Artery Disease		PAD cohort is all-comers to the vascular lab that are scheduled to undergo assessment for Peripheral Artery Disease (PAD) or have a planned endovascular or surgical intervention to address PAD and will receive FlowMet-R measurement in addition to their routine standard of care. Receives: Diagnostic Test: FlowMet-R; Diagnostic Test: ABI; Diagnostic Test: TBI

What is being measured

The primary outcome is the main question the study is designed to answer.

Sensitivity and Specificity of FlowMet-R for Diagnosis of PAD and CLI
Primary objective is to determine the efficacy of FlowMet-R measurements in diagnosing PAD \& CLI. All patients were combined from healthy \& PAD groups to form one cohort, ABI and TBI were then used to assign patients in PAD (1), PAD (2) \& CLI. FlowMet-R data (comprised of blood flow measurements and/or feature analysis of the blood flow waveform) were used to create a predictive model of PAD severity. This model was used to generate diagnostic receiver operating characteristic (ROC) curves for PAD and, independently, CLI, at three time points.
ROC curves were used to compute the peak sensitivity, peak specificity, and area under the curve (AUC) at the initial, 3-month and 6-month time points. Sensitivity, specificity and AUC are unitless. Sensitivity is the percentage of true positives \& specificity is the percentage of true negatives at the location on the ROC curve where it was closest to the upper left of the unit square from an ROC curve (peak).
Measured: Initial, three month, and six month time points.

Secondary outcomes (6)

Sensitivity and Specificity of FlowMet-R for Prognosis of Requiring a Peripheral Vascular Intervention
ROC curves for predicting if a patient will undergo intervention following their initial visit were generated using FlowMet-R measurement data. ROC curves were used to compute the peak sensitivity, peak specificity, and area under the curve (AUC) within the 3-month and 6-month time points, separately. Sensitivity, specificity and AUC are unitless. Sensitivity is the percentage of true positives \& specificity is the percentage of true negatives at the location on the ROC curve where it was closest to the upper left of the unit square from an ROC curve (peak).
Measured: Within three and six months following initial visit
Sensitivity, Specificity and Area Under the Curve (AUC) of FlowMet-R in Diagnosing Significant Stenosis
ROC curves for predicting a patient has significant stenosis, defined by greater than 50%, in at least one peripheral artery will be generated using FlowMet-R measurement data. ROC curves will be used to compute the peak sensitivity, peak specificity, and area under the curve (AUC) at the initial visit. Sensitivity, specificity and AUC are unitless. Sensitivity is the percentage of true positives \& specificity is the percentage of true negatives at the location on the ROC curve where it was closest to the upper left of the unit square from an ROC curve (peak).
Measured: Initial visit
Stenosis Percentage
A correlation test will be performed between FlowMet-R and stenosis percentage.
The correlations between the acceleration time from the FlowMet-R device and peripheral artery stenosis will be computed using a Pearson correlation. Correlation will be computed using available FlowMet-R data from PAD participants with significant stenosis, defined by greater than 50%, in at least one peripheral artery at the initial visit.
Measured: Initial visit
Changes in Ankle Brachial Index (ABI)
The outcome ABI is a ratio of blood pressures in the arm and ankle. Values less than 1 generally indicate narrower arteries. The outcome used the change in ABI for: 0 to 3 months, 0 to 6 months, and 3 to 6 months. The correlation with this outcome was estimated using the corresponding change in acceleration time from the FlowMet-R device.
Measured: Within three and six months following initial visit.
Changes in Toe Brachial Index (TBI)
The outcome TBI is a ratio of blood pressures in the arm and toe. Values less than 1 generally indicate narrower arteries. The outcome used the change in TBI for: 0 to 3 months, 0 to 6 months, and 3 to 6 months. The correlation with this outcome was estimated using the corresponding change in acceleration time from the FlowMet-R device.
Measured: Within three and six months following initial visit.
Changes in Rutherford Classification
Rutherford Classification is an ordinal scale that ranges from 0 to 6 and is used to measure peripheral arterial disease severity and chronic limb threatening ischemia. Higher values indicate more severe disease. The changes for Rutherford Classification were computed for: 0 to 3 months, 0 to 6 months, and 3 to 6 months. The correlation with this outcome was estimated using the corresponding change in acceleration time from the FlowMet-R device.
Measured: Within three and six months following initial visit.

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

9 Dec 201921 Nov 2022

First posted9 Oct 2019
Study start9 Dec 2019
Primary completion21 Nov 2022
Study completion21 Nov 2022

Why it stopped: Sponsor decision to terminate study prior to reaching full sample size.

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Peripheral Artery DiseaseStudies of the same condition, open and under way.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Observational
Observational model: Cohort
Time perspective: Prospective
Enrolment: 195 participants (actual)
Target duration: 6 Months

IDs, dates and publications

ClinicalTrials.gov ID: NCT04120610
Sponsor's protocol ID: 30081919
Status last verified: Mar 2024
First submitted: 7 Oct 2019
Last updated: 11 Apr 2025
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: No
FDA-regulated drug: No
FDA-regulated device: Yes
Individual data sharing: No

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

Active, not recruiting
SUCCESS (SelUtion, Safety, effiCaCy, hEalth economicS and promS) PTA Study
Peripheral Artery Disease
RecruitingPhase 3
Reducing Adverse Vascular Outcomes With Factor XI Inhibition in Adult Participants With Peripheral Artery Disease
Peripheral Artery Disease (PAD)
Recruiting
The THOR IDE Study
Peripheral Artery Disease, Peripheral Artery Stenosis
Not yet recruiting
Daily Stretching to Improve Walking in Older Patients With Peripheral Artery Disease: The STRETCH PAD Study
Peripheral Artery Disease (PAD), Intermittent Claudication
Recruiting
WIN Ratio Analysis to Determine a Strategy of Non- Invasive SUpport for Respiratory Failure in the EmeRgency Department
Acute Hypoxic Respiratory Failure, Acute Respiratory Distress Syndrome (ARDS)

All Peripheral Artery Disease trials

Study at a glance

From the registry record, last updated by the sponsor on 11 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: FlowMet-R Blood Flow Measurement for the Diagnosis of Peripheral Artery Disease (PAD) and Critical Limb Ischemia (CLI)
ClinicalTrials.gov ID: NCT04120610
Acronym / sponsor ID: 30081919
Conditions: Peripheral Artery Disease
Keywords: Peripheral Artery Disease, Claudication, Critical Limb Ischemia
Study type: Observational
Recruitment status: TerminatedReason stopped: Sponsor decision to terminate study prior to reaching full sample size.
Enrolment: 195 participants (actual)
Lead sponsor: Medtronic EndovascularIndustry (pharma, biotech, devices)
Collaborators: ICON plc
Study start: 9 Dec 2019 (actual)
Primary completion: 21 Nov 2022 (actual)
Study completion: 21 Nov 2022 (actual)
First posted: 9 Oct 2019 (actual)
Results: Posted 11 Apr 2025

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Observational model: Cohort
Time perspective: Prospective
Target follow-up: 6 Months
Number of arms: 2

Arm	Type	Receives
Healthy	–	Diagnostic Test: FlowMet-R, Diagnostic Test: ABI, Diagnostic Test: TBIHealthy cohort is an age-matched population (over 40 years old) without history of PAD or suspected PAD. Healthy cohort will receive FlowMet-R measurement, Ankle Brachial Index (ABI), and Toe Brachial Index (TBI) measurements.
Peripheral Artery Disease	–	Diagnostic Test: FlowMet-R, Diagnostic Test: ABI, Diagnostic Test: TBIPAD cohort is all-comers to the vascular lab that are scheduled to undergo assessment for Peripheral Artery Disease (PAD) or have a planned endovascular or surgical intervention to address PAD and will receive FlowMet-R measurement in addition to their routine standard of care.

Who may qualify

Ages: 40 years and older
Sex: All
Healthy volunteers: Accepted
Age groups: Adult, Older adult
Study population: The PAD cohort population is persons who have known or suspected peripheral artery disease, and are being seen at a vascular clinic for evaluation. The Healthy cohort population is adult persons over 40 without history of PAD and who are not currently suspected of suffering from PAD.

Key inclusion criteria (11 listed)

PAD Positive Cohort
Subject meets PAD positive criteria
Subject is willing and able to provide informed consent
Subject is willing and able to comply with study procedures
Subject is able to understand the study procedures

Key exclusion criteria (15 listed)

PAD Positive Cohort
Subject is under 40 or unable to consent.
Subject has any medical condition, which, in the judgment of the Investigator and/or designee, makes the subject a poor candidate for the investigational study.
Subject is excluded from analysis if no stenosis is found during Doppler but Tibial disease is suspected and Tibial ultrasound is not able to be performed.
Subject does not have a suitable finger to attach the FlowMet-R probe.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
FlowMet-RFlowMet-R is a noninvasive blood flow measurement.	Diagnostic test	Healthy, Peripheral Artery Disease
ABIAnkle Brachial Index is a ratio-metric blood pressure measurement in the ankle and arm.	Diagnostic test	Healthy, Peripheral Artery Disease
TBIAnkle Brachial Index is a ratio-metric blood pressure measurement in the toe and arm.	Diagnostic test	Healthy, Peripheral Artery Disease

Primary outcome

Sensitivity and Specificity of FlowMet-R for Diagnosis of PAD and CLI
Time frame: Initial, three month, and six month time points.
Primary objective is to determine the efficacy of FlowMet-R measurements in diagnosing PAD \& CLI. All patients were combined from healthy \& PAD groups to form one cohort, ABI and TBI were then used to assign patients in PAD (1), PAD (2) \& CLI. FlowMet-R data (comprised of blood flow measurements and/or feature analysis of the blood flow waveform) were used to create a predictive model of PAD severity. This model was used to generate diagnostic receiver operating characteristic (ROC) curves for PAD and, independently, CLI, at three time points. ROC curves were used to compute the peak sensitivity, peak specificity, and area under the curve (AUC) at the initial, 3-month and 6-month time points. Sensitivity, specificity and AUC are unitless. Sensitivity is the percentage of true positives \& specificity is the percentage of true negatives at the location on the ROC curve where it was closest to the upper left of the unit square from an ROC curve (peak).

6 secondary outcomes

Sensitivity and Specificity of FlowMet-R for Prognosis of Requiring a Peripheral Vascular Intervention
Time frame: Within three and six months following initial visit
Sensitivity, Specificity and Area Under the Curve (AUC) of FlowMet-R in Diagnosing Significant Stenosis
Time frame: Initial visit
Stenosis Percentage
Time frame: Initial visit
Changes in Ankle Brachial Index (ABI)
Time frame: Within three and six months following initial visit.
Changes in Toe Brachial Index (TBI)
Time frame: Within three and six months following initial visit.
Changes in Rutherford Classification
Time frame: Within three and six months following initial visit.

Results and safety

Results posted to the registry on 11 Apr 2025, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Healthy	52	52
Peripheral Artery Disease	143	83

Primary outcome: Sensitivity and Specificity of FlowMet-R for Diagnosis of PAD and CLI

Time frame: Initial, three month, and six month time points.. Number (95% Confidence Interval). Unit: probability

Measure	Peripheral Artery Disease (1) vs Not PAD n = 190	Peripheral Artery Disease (2) vs Not PAD n = 190	Critical Limb Ischemia (CLI) vs Not CLI n = 192
Sensitivity (Initial)	0.80 (0.73 to 0.87)	0.78 (0.71 to 0.85)	0.82 (0.66 to 0.98)
Specificity (Initial)	0.78 (0.70 to 0.87)	0.86 (0.78 to 0.94)	0.78 (0.72 to 0.84)
Area Under the Curve (Initial)	0.84 (0.78 to 0.89)	0.87 (0.82 to 0.92)	0.86 (0.80 to 0.93)
Sensitivity (3 months)	0.52 (0.38 to 0.67)	0.57 (0.44 to 0.71)	1.00 (1.00 to 1.00)
Specificity (3 months)	0.63 (0.46 to 0.81)	0.77 (0.60 to 0.95)	0.91 (0.84 to 0.97)
Area Under the Curve (3 months)	0.58 (0.45 to 0.71)	0.67 (0.54 to 0.80)	0.95 (0.86 to 1.00)
Sensitivity (6 months)	0.74 (0.62 to 0.86)	0.73 (0.62 to 0.84)	1.00 (1.00 to 1.00)
Specificity (6 months)	0.58 (0.41 to 0.74)	0.67 (0.48 to 0.86)	0.59 (0.48 to 0.69)

Population analysed: Sensitivity, specificity and area under the curve (AUC) were calculated for PAD (1) vs. not PAD (1), PAD (2) vs not PAD (2), and CLI vs. not CLI at initial, three-month and six-month timepoints.

6 secondary outcomes are reported in the full results.

Adverse events

Time frame: Adverse events were collected from the baseline assessment visit throughout 6-month follow-up.. Other adverse events reported at 0% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Healthy	0 of 52 (0%)	0 of 52 (0%)	0 of 52
Peripheral Artery Disease	6 of 143 (4.2%)	2 of 143 (1.4%)	4 of 143

Limitations and caveats (from the sponsor): The study was terminated by Medtronic prior to completing enrollment. Difficulties with enrollment and limited compliance partially related to the COVID-19 pandemic limited the conclusions. Analyses described in the protocol were computed, but no hypothesis tests were completed. The AUC and its 95% CI are provided to assess the potential for the FlowMet device to classify CLI, PAD (1), PAD (2) at 0-, 3-, and 6-months, reintervention within 3- and 6-months, and significant stenosis.

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 11 Apr 2025.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Individual participant dataSharing planned: No

Related trials for Peripheral Artery Disease

Active, not recruiting
SUCCESS (SelUtion, Safety, effiCaCy, hEalth economicS and promS) PTA Study
Peripheral Artery Disease
RecruitingPhase 3
Reducing Adverse Vascular Outcomes With Factor XI Inhibition in Adult Participants With Peripheral Artery Disease
Peripheral Artery Disease (PAD)
Recruiting
The THOR IDE Study
Peripheral Artery Disease, Peripheral Artery Stenosis
Not yet recruiting
Daily Stretching to Improve Walking in Older Patients With Peripheral Artery Disease: The STRETCH PAD Study
Peripheral Artery Disease (PAD), Intermittent Claudication
Recruiting
WIN Ratio Analysis to Determine a Strategy of Non- Invasive SUpport for Respiratory Failure in the EmeRgency Department
Acute Hypoxic Respiratory Failure, Acute Respiratory Distress Syndrome (ARDS)

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

The record lists no contact. Use the official record to reach the sponsor.

5 sites in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

An observational study of Peripheral Artery Disease, run by Medtronic Endovascular at 5 sites in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 11 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: stopped early, as of the sponsor's last update on 11 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 5 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 11 Apr 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Sensitivity and Specificity of FlowMet-R for Diagnosis of PAD and CLI (time frame: Initial, three month, and six month time points.). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT04120610.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 11 Apr 2025.