Digital Ankle Brachial Index (ABI) as a Screening Tool in Detecting Peripheral Arterial Disease

November 15, 2018 updated by: Keith Pereira, MD:, St. Louis University

Positive Predictive Value of Digital Ankle Brachial Index (ABI) as a Screening Tool in Detecting Peripheral Arterial Disease: A Single Center, Prospective Clinical Trial

Peripheral artery disease (PAD) affects 8-18 million in the US and is an economic burden, currently estimated to be greater than cancer and heart disease. Older age (> 65 years), smoking, diabetes and kidney diseases are some risk factors associated with PAD and are known to have increased morbidity and mortality.Early detection is critical for mitigating PAD progression. Ankle-brachial index (ABI) testing is recommended by the US Preventative Services Task Force as an affordable and effective screening tool for evaluating PAD risk.

QuantaFlo™ (Semler Scientific, Inc.) is a novel, noninvasive, 510K FDA approved digital device that is used as a screening tool to measure ABI of patients at risk of PAD. This single center prospective clinical trial will evaluate the sensitivity and specificity of digital ABI in detecting PAD using color Doppler ultrasound and 'gold standard' angiography as reference. Specifically in patient undergoing dialysis and who cannot undergo ABI using pressure cuffs dialysis grafts/ fistulae in the arms, we will evaluate the value of digital ABI in detecting PAD.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Peripheral artery disease (PAD) affects 8-18 million in the US and is an economic burden, currently estimated to be greater than cancer and heart disease. Older age (> 65 years), smoking, diabetes and kidney diseases are some risk factors associated with PAD and are known to have increased morbidity and mortality. PAD progression directly results in claudication, impaired walking, and amputation. Amputation is not benign - impacts are physical and emotional. Recovery from amputation involves long-term rehabilitation. The American Heart Association (AHA) in 2016 guidelines suggests an algorithm for diagnosis and management of PAD. They recommend a collaborative multidisciplinary team approach between the primary care physician and specialists including; a diabetologists/ endocrinologist, smoking cessation expert, hypertension and lipid specialist, interventional radiologist, vascular surgeon, orthopedist, neurologist, wound healing expert, and/or others for 'the greatest chance of providing optimal care for the patient with PAD'.

Early detection is critical for mitigating PAD progression. Ankle-brachial index (ABI) testing is recommended by the US Preventative Services Task Force as an affordable and effective screening tool for evaluating PAD risk. ABI testing is especially useful in primary care settings allowing for earlier diagnosis and treatment. Several ABI methods are used; classically this test uses a device for measuring blood pressure with an inflatable cuff, and blood pressure measurements are taken at the upper arm and the ankle; healthcare providers have used a doppler probe to detect audible systolic pressure signals within the arteries - Doppler ABI. Barriers to implementation include; time required to conduct tests, training and required technical skills. Hence, Doppler-based ABI in primary care has been limited. Recently designed oscillometric (manual or digital with automatic electronic calculation of blood pressure) and photophlethysmographic devices are now available. However current guidelines do not endorse the use of these newer devices but recommend the hand-held doppler technique.

Digital ABI is noninvasive, automated ABI using pulsatile blood volume changes - plethysmography, irrespective of vessel compressibility. The QuantaFlo™ (Semler Scientific, Inc.) is an innovative, 510K FDA approved device that provides bilateral, non-invasive physiologic studies of upper and lower extremity arteries using volume plethysmography of the posterior tibial and anterior tibial/dorsalis pedis arterial distributions. QuantaFlo™ uses an optical sensor attached onto a digit in the hand and feet to assess extremity blood volume. It then displays a signal, directly related to blood volume, on a Volume Plethysmography Chart used to calculate PAD probability. This test is easy to use and portable, delivering fast, accurate results in ~5 minutes; an attractive option in primary care settings. While maintaining accuracy, results comparing digital methods to Doppler show concordance above 90%. The American Medical Association (AMA) concluded, "Evaluation of the digits in both legs with volume plethysmography is appropriate for this code provided that an ankle/brachial index (ABI) be performed." QuantaFlo™ meets both of these standards.

ABI ≤ 0.9 has been used as the criterion for diagnosing PAD based on ACC/AHA guidelines for the management of patients with PAD ; the cutoff value of ABPI ≤0.9 it has been reported that the sensitivity of diagnosing PAD was 83% to 85% and a specificity of 95% to 100% [5]. ABI has been validated against lower extremity contrast angiography obtaining high sensitivity (85%-95%) and specificity (90%-100%), for diagnosing PAD . Many studies have reported more than 95% of sensitivity and specificity of colour duplex ultrasound scan in detecting a significant stenosis of the arteries .

QuantaFlo™ (Semler Scientific, Inc.) is a novel, noninvasive, 510K FDA approved digital device that is used as a screening tool to measure ABI of patients at risk of PAD. This single center prospective clinical trial will evaluate the sensitivity and specificity of digital ABI in detecting PAD using color Doppler ultrasound and 'gold standard' angiography as reference. Specifically in patient undergoing dialysis and who cannot undergo ABI using pressure cuffs dialysis grafts/ fistulae in the arms, we will evaluate the value of digital ABI in detecting PAD.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
238

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Missouri
      • Saint Louis, Missouri, United States, 63110
        • Saint Louis University

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 90 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

Answering yes to any of the following questions on the clinical screening questionnaire:

  • Are you 65 years or older?
  • Have you ever smoked?
  • Do you have diabetes?
  • Do you have high blood pressure or take medication for high blood pressure?
  • Do you have high cholesterol, or take medication for high cholesterol?
  • Have you previously had a stroke?
  • Do you have heart disease?
  • Do you experience any pain at rest in your lower legs or feet?
  • Do you have discomfort (aching, fatigue, tingling, cramping or pain) when you walk, which is relieved by rest? Does the pain go away within 10 minutes after stopping?
  • Are your toes or feet pale, discolored, or bluish?
  • Do you have an infection, skin wound, or ulcer on your feet or toes?

Exclusion Criteria:

  • Not meeting the above criteria.
  • Previously screened with ABI in past 12 months

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Other: ABI
ABI will be performed in patient
Device: ABI using QuantaFlo™

Perform Digital ABI:

  • Will be performed by the nurse/medical assistant with training to perform this test
  • The patient will be placed in the supine position, with the arms and legs at the same level as the heart, for a minimum of 5 minutes before measurement.
  • The optical sensor (similar to a pulse oximeter) will be placed sequentially in the fingers of the hands and feet: Right and left hand fingers and then right and left feet toes.
  • Usually each digit takes about 15 seconds to obtain a waveform
  • At the end of 60 seconds, an automated digital ABI will be generated.

Clinical course: If based on Screening questionnaire and digital ABI, I. Patient is diagnosed with PAD- the referring physician and patient will receive a phone call about the same. He/ she will then be advised any further testing/ referral to IR clinic.

II. There is no evidence of PAD- no further action will be taken. The patient will be informed of the same.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Positive Predictive Value of Digital ABI in Diagnosing PAD
Time Frame: 3 months
To evaluate the Positive predictive value of digital ABI in diagnosing PAD using color Doppler ultrasound and 'gold standard' angiography as reference.
3 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
St. Louis University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Keith Pereira, MD, Saint Louis University Hospital

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
July 15, 2017

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 14, 2017

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 14, 2017

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 18, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 18, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 19, 2017

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 11, 2018

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 15, 2018

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
November 1, 2018

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 28225

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

No

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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