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

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ClinicalTrials.gov Identifier: NCT03161327

Recruitment Status : Completed

First Posted : May 19, 2017

Results First Posted : December 11, 2018

Last Update Posted : December 11, 2018

Sponsor:

Information provided by (Responsible Party):

Keith Pereira, MD:, St. Louis University

Study Description

Brief Summary:

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.

Condition or disease	Intervention/treatment	Phase
Peripheral Artery Disease Amputation Smoking Diabetes Hypercholesterolemia Hypertension	Device: ABI using QuantaFlo™	Not Applicable

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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 .

Study Design

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Study Type :	Interventional (Clinical Trial)
Actual Enrollment :	238 participants
Allocation:	N/A
Intervention Model:	Single Group Assignment
Masking:	None (Open Label)
Primary Purpose:	Prevention
Official Title:	Positive Predictive Value of Digital Ankle Brachial Index (ABI) as a Screening Tool in Detecting Peripheral Arterial Disease: A Single Center, Prospective Clinical Trial
Actual Study Start Date :	July 15, 2017
Actual Primary Completion Date :	September 14, 2017
Actual Study Completion Date :	September 14, 2017

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Peripheral Arterial Disease

U.S. FDA Resources

Arms and Interventions

Arm	Intervention/treatment
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.

Arm

Intervention/treatment

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.

Outcome Measures

Primary Outcome Measures :

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.

Eligibility Criteria

Information from the National Library of Medicine

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Ages Eligible for Study:	18 Years to 90 Years (Adult, Older Adult)
Sexes Eligible for Study:	All
Accepts Healthy Volunteers:	Yes

Criteria

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

Contacts and Locations

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03161327

Locations

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

Sponsors and Collaborators

St. Louis University

Investigators

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Principal Investigator:	Keith Pereira, MD	Saint Louis University Hospital

Study Documents (Full-Text)

Documents provided by Keith Pereira, MD:, St. Louis University:

Study Protocol and Statistical Analysis Plan [PDF] April 26, 2018

More Information

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Responsible Party:	Keith Pereira, MD:, Assistant Professor, St. Louis University
ClinicalTrials.gov Identifier:	NCT03161327
Other Study ID Numbers:	28225
First Posted:	May 19, 2017 Key Record Dates
Results First Posted:	December 11, 2018
Last Update Posted:	December 11, 2018
Last Verified:	November 2018
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD:	No

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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

Keywords provided by Keith Pereira, MD:, St. Louis University:


ankle brachial index peripheral arterial disease

Additional relevant MeSH terms:

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Peripheral Arterial Disease Peripheral Vascular Diseases Hypercholesterolemia Vascular Diseases Cardiovascular Diseases Hyperlipidemias	Dyslipidemias Lipid Metabolism Disorders Metabolic Diseases Atherosclerosis Arteriosclerosis Arterial Occlusive Diseases

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