Passive Limb Movement Study

Medical College of Wisconsin55 enrolled

Overview

Stroke survivors have compromised vascular function which may contribute to secondary stroke risk, cardiovascular disease, and may limit their exercise tolerance. No studies have examined how femoral blood flow responds to both passive leg movement, a measure of microvascular function, as well as active leg contractions, a measure of the hyperemic response to exercise. Leg muscles with a reduced blood flow response to movement could be associated with decreased neuromuscular function, such as leg strength and fatigue. Preliminary data showing a single bout of ischemic conditioning may improve vascular function and muscle activation in healthy adults and individuals post-stroke. Therefore, the investigators want to examine if ischemic conditioning will also improve the blood flow response to passive leg movements as well as during single leg active contractions.

Study Type

INTERVENTIONAL

Allocation

Purpose

OTHER

Masking

TRIPLE

Enrollment

Conditions

Stroke Vascular Diseases Ischemic

Ischemic ConditioningDEVICE

The cuff will be placed around the proximal, paretic thigh (or dominant thigh for controls) and inflated for 5 minutes in a supine or semi-reclined position, then released for a 5-minute recovery period. Five cycles of inflation and recovery will be performed (45 minutes total).These inflations will be done using a cuff similar to what is used for taking blood pressure.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 85 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Individuals Post-Stroke * 18 - 85 years of age * Cortical or sub-cortical stroke ≥ 6 months ago with residual hemiparesis * Able to give informed consent and follow 2-step command. * English Speaking * Age- and Sex-Matched Controls (CON) * Matched to age of individual post- stroke ± 5 years. * Matched to sex of individual post-stroke * Able to give informed consent and follow 2-step command. * English Speaking * Young Healthy Adults (CONyoung) * Age 18-30 years old * Able to give informed consent and follow 2-step command. * English Speaking Exclusion Criteria: * All Groups * Unable to stand from chair and walk 10 meters without physical assistance from another person (able to use assistive device). * History of blood clots in the extremities or any condition in which compression of the thigh or transient ischemia is contraindicated (i.e., wounds in the leg). * Chronic lasting symptoms (\> 6 months) of severe COVID-19 (i.e., hospitalization) * Low back or hip pain that limits lower extremity motor testing. * History of head trauma or concussion within the past 6 months * Comorbid neurological disorder * Peripheral vascular disease * Myocardial infarction in the previous year * Condition where fatiguing contractions or resisted leg contractions are contraindicated * Resting SBP ≥180 mmHg or DBP ≥ 100 mmHg * Pregnancy or breastfeeding. * Other significant medical condition likely to influence study or jeopardize safety as assessed by the Primary Investigator * CON and CONyoung * History of Stroke

Outcomes

Primary Outcomes

Ultrasound Measured Femoral Blood Flow during Passive Limb Movement (PLM)

Microvascular response to single passive leg movement

Time frame: Change from Baseline PLM Femoral Blood Flow after IC (3 hours)

Ultrasound Measured Femoral Blood Flow during Active Limb Contraction

Hyperemic Response to Maximal Voluntary Contractions (MVCs)

Time frame: Change from Baseline MVCs Femoral Blood Flow after IC (3 hours)

Secondary Outcomes

Ultrasound measured Femoral Blood Flow following Neuromuscular Fatigue Task

Hyperemic Response to Fatiguing Muscle Contractions

Time frame: Post Ischemic Conditioning (15 minutes)