Ischemic Conditioning Chronic Stroke Study

Summary

Stroke is the leading cause of disability in adults in the United States. Despite advances in hyperacute stroke care, advancements in stroke rehabilitation are lagging. We have previously shown that a non-invasive, cost-effective, easy to perform intervention, called ischemic conditioning (IC), can improve paretic leg strength, reduce muscle fatigue, and increase walking speed in chronic stroke survivors (\>1 year post-stroke). The IC procedure makes the paretic leg transiently ischemic (5 minutes) using a cuff inflated to 225 mmHg, and repeats the occlusion 5 times with 5 minute periods of rest between cycles (45 total minutes). It is well accepted that the response to IC is complex and involves local, humoral and neural factors. The mechanism by which IC can confer motor benefit in stroke survivors is unknown. The aim of this study is to examine if IC can increase sympathetic nervous system (SNS) activity, which would promote an increased cardiovascular response to exercise and increased muscle strength. We hypothesize that plasma epinephrine and norepinephrine levels will increase more during a cold pressor test (a well-tolerated test to induce a sympathetic response) in chronic stroke survivors who undergo a single session of IC vs. IC-Sham. To accomplish the goals of this study, 15 chronic stroke survivors will each make two visits to the adult translational research unit at Medical College of Wisconsin (MCW) to have either IC or IC-Sham performed on their paretic leg in a counterbalanced order. Venous blood will be drawn before and after the IC or IC-Sham procedure and after a two-minute cold pressor test where the study participants submerge their hand into a bucket of ice water. This will cause an increased sympathetic response, which will be assessed by measuring blood pressure and the relative increase in the levels of circulating catecholamines (epinephrine and norepinephrine, assessed by high performance liquid chromatography).

Conditions

• Stroke

Interventions

PROCEDURE

Ischemic Conditioning

Ischemic conditioning is a well-defined, non-invasive procedure which consists of inflating a blood pressure cuff around a limb (in our study, the paretic leg), inflating the cuff to 225 mmHg to occlude blood flow to the limb for 5 minutes, releasing the cuff for 5 minutes, and repeating 5 times. In our study, participants will receive one session of the intervention (45 minutes total).

PROCEDURE

Sham Ischemic Conditioning

There will also be an IC Sham group which is identical to the IC intervention, except the cuff is only inflated to 10 mmHg, which is a high enough pressure to perceive cuff tightness but not high enough to have any physiological effects.

Sponsors & Collaborators

• Medical College of Wisconsin

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

DOUBLE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

85 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2019-07-01

Primary Completion

2023-08-23

Completion

2023-08-23

Countries

• United States

Study Locations