The Effect of Ischemic Conditioning on Strength and Ambulation in Subjects With PAD

April 13, 2023 updated by: Lindsay Slater, University of Illinois at Chicago

The Effect of Ischemic Conditioning on Strength and Ambulation in Subjects With Peripheral Artery Disease (PAD)

Lower limb amputation is common in the United States, with approximately 150,000 amputations annually. Most individuals walking with a prosthesis demonstrate asymmetrical loading-i.e., they favor the amputated side by placing more weight and increased ground reaction forces through the intact limb-which likely contributes to increased metabolic cost of walking. Lack of adequate muscular strength in the lower limb to attenuate these forces places increased stress on the joints, which may be displaced proximally, and may play a role in reported knee and hip pain in the intact limb.

Lower limb muscle weakness following amputation has been well documented. Increasing quadriceps strength is important after an amputation because it is positively correlated with gait speed. Gait speed may also be associated with successful community mobility, which leads to improved quality of life following amputation. Individuals with amputation who resume an active lifestyle are able to maintain strength. However, these individuals represent a minority of persons with lower limb amputation; most individuals report more barriers than motivators to adopt an active lifestyle.

Ischemic conditioning (IC) may strengthen leg muscles and reduce the metabolic cost of activity after amputation. In IC, the limb is exposed to brief, repeated bouts of ischemia (reduced blood flow) immediately followed by reperfusion. IC has been shown to improve muscle performance in healthy and diseased populations. IC has also been used more recently in patients with peripheral artery disease (PAD) as an intervention to improve function, such as walking ability. Acute exposure to IC increases muscle strength and activation, both in healthy, active individuals and in those with severe neuromuscular dysfunction, such as stroke survivors. IC also attenuates muscular fatigue. Increased fatigue resistance at submaximal contraction levels following IC may be due to increased neural activation of skeletal muscle. Changes in neural activation of muscle may be particularly beneficial during cortical reorganization after amputation. Reduced quadriceps fatigue during submaximal activities may also drive changes in gait kinematics, such as increased knee flexion during loading and mid-stance. Exposure to IC may also increase the oxidative properties of skeletal muscle, offering a direct pathway to reduce metabolic cost. Therefore, IC may lead to cellular changes that lower the metabolic cost of activity.

The primary aim of this study is to quantify the benefits of acute and chronic IC on quadriceps strength and walking economy in individuals with PAD and history of lower limb amputation.

Study Overview

Study Type

Interventional

Enrollment (Anticipated)

80

Phase

  • 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 Contact

Study Locations

    • Illinois
      • Chicago, Illinois, United States, 60608
        • Recruiting
        • UIC Physical Therapy Faculty Practice
        • Contact:

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

Ages Eligible for Study

18 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • 18 years or older
  • Able to ambulate independently without the use of aids (i.e., walking cane)
  • Able to walk at least 10 minutes continuously without stopping
  • History of diagnosed peripheral artery disease.
  • For Amputees: History lower limb unilateral transtibial or transfemoral amputation.

Exclusion Criteria:

  • Inability to give informed consent
  • neurological disorder that affects gait
  • two or more falls within the previous 12 months
  • currently pregnant (or intend to become pregnant while participating in study)
  • history of any condition where fatiguing contractions or resisted leg contractions are contraindicated
  • blood clots in the leg, or any condition in which compression of the thigh or transient ischemia is contraindicated (e.g. open wounds in the leg).
  • history of hypertension
  • history of heart failure
  • Head injury within the previous 6 months
  • Seizure disorder
  • Adverse reaction to ultrasound gel
  • History of thrombosis
  • History of sickle cell trait

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: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Sham Comparator: Ischemic Conditioning Low
Blood flow restriction with low compression
The use of a Hokanson rapid inflator cuff to restrict blood flow at 25mmHg for 5 minutes followed by a 5 minute reperfusion period, repeated for 5 cycles.
Active Comparator: Ischemic Conditioning High
Blood flow restriction with high compression
The use of a Hokanson rapid inflator cuff to restrict blood flow at 225mmHg for 5 minutes followed by a 5 minute reperfusion period, repeated for 5 cycles.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in quadriceps strength
Time Frame: through study completion, an average of 6 weeks
Quadriceps strength assessed by a Biodex dynamometer
through study completion, an average of 6 weeks
Change in gait kinematics
Time Frame: through study completion, an average of 6 weeks
Gait mechanics assessed by joint angles using Vicon cameras and reflective markers
through study completion, an average of 6 weeks
Change in gait kinetics
Time Frame: through study completion, an average of 6 weeks
Gait mechanics assessed by joint forces using a Bertec instrumented treadmill in combination with gait kinematics
through study completion, an average of 6 weeks
Change in gait metabolics
Time Frame: through study completion, an average of 6 weeks
Assessment of oxygen consumption during walking using a metabolic cart
through study completion, an average of 6 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Six-minute walk test
Time Frame: through study completion, an average of 6 weeks
Measurement of distance walked in six minutes
through study completion, an average of 6 weeks

Collaborators and Investigators

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

Investigators

  • Principal Investigator: Lindsay Slater, PhD, University of Illinois at Chicago

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)

July 1, 2022

Primary Completion (Anticipated)

November 1, 2023

Study Completion (Anticipated)

December 31, 2023

Study Registration Dates

First Submitted

May 27, 2021

First Submitted That Met QC Criteria

June 14, 2021

First Posted (Actual)

June 23, 2021

Study Record Updates

Last Update Posted (Actual)

April 14, 2023

Last Update Submitted That Met QC Criteria

April 13, 2023

Last Verified

April 1, 2023

More Information

Terms related to this study

Other Study ID Numbers

  • 2021-0223
  • 20CDA35310419 (Other Identifier: American Heart Association)

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

No

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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