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

Terminated

Conditions: Peripheral Artery Disease

Interventions: Diagnostic Test: FlowMet-R
Diagnostic Test: ABI
Diagnostic Test: TBI

Registration Number: NCT04120610

Lead Sponsor: Medtronic Endovascular

Brief 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.

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.

Recruitment & Eligibility

Status: TERMINATED

Sex: All

Target Recruitment: 195

Inclusion Criteria

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

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.

Exclusion Criteria

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.
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

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Healthy	TBI	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.
PAD	FlowMet-R	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. PAD cohort patients will receive FlowMet-R measurement in addition to their routine standard of care.
Healthy	FlowMet-R	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.
PAD	TBI	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. PAD cohort patients will receive FlowMet-R measurement in addition to their routine standard of care.
Healthy	ABI	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.
PAD	ABI	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. PAD cohort patients will receive FlowMet-R measurement in addition to their routine standard of care.

Primary Outcome Measures

Name	Time	Method
Sensitivity and Specificity of FlowMet-R for Diagnosis of PAD and CLI	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).

Secondary Outcome Measures

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

Trial Locations

Locations (5): The Iowa Clinic
🇺🇸
Des Moines, Iowa, United States
The Mt. Sinai Hospital
🇺🇸
New York, New York, United States
Ohio Health
🇺🇸
Columbus, Ohio, United States
Mercy Research
🇺🇸
Chesterfield, Missouri, United States
Ascension Seton
🇺🇸
Austin, Texas, United States