Artery Function Responses to Changes in Blood Flow (ASPEN)
January 16, 2018 updated by: McMaster University
Endothelial Function Responses to Manipulations in Blood Flow Pattern
The purpose of this study is to determine if different blood flow patterns change artery function.
We hypothesize that the temporary induction of an oscillatory blood flow pattern will result in an immediate improvement in artery function.
Participants will be asked to come to the Vascular Dynamics Lab (IWC E102) at McMaster University for a total of 3 visits.
The first visit will allow the participant to get comfortable with the lab and the upcoming tests; and the next 2 visits will be scheduled at the same time of day to collect data.
For visits 2 and 3, participants will be asked to arrive after a 4 hour fast.
At these visits, ultrasound imaging will be used to examine the arteries and how they may change when blood flow patterns through an artery in the arm are changed.
To change blood flow in the arm, heat, rhythmic squeezing of the forearm with a cuff, or handgrip exercise will be used.
These interventions will be applied to the left forearm, from the elbow to the fingertips.
A trained technician will also draw a blood sample during both data collection visits.
A total of 10 participants will be recruited for the entire study.
Study Overview
Status
Completed
Conditions
Intervention / Treatment
Detailed Description
Interested individuals will be invited to the lab for a screening and familiarization visit, in which the brachial artery (BA) will be scanned to vet for image quality and a BA flow-mediated dilation test will be performed to ensure participant tolerance during collection visits.
All qualified participants will be instructed to refrain from vigorous physical activity > 24 hours, alcohol and caffeine > 6 hours, and food > 4 hours prior to each of the two collection visits.
Upon arrival, basic anthropometric measures will be collected and hematocrit will be measured in duplicate with a finger prick blood sample equivalent to two 70 µl capillary tubes.
Each of the two data collection visits will begin 10 minutes of supine rest, while the participant is instrumented with skin temperature probes on the forearms and hands for measurement of skin temperature, single-lead ECG (Powerlab model ML795, ADInstruments, Colorado Springs, CO, USA) and non-invasive finger cuff (Finometer MIDI, Finapres, The Netherlands) for continuous heart rate and blood pressure monitoring.
On the first data collection visit, following rest, the participant will then undergo three 10-minute interventions applied to the left forearm in the following sequence: (1) ECG-gated suprasystolic (300 mmHg) cuff compressions with inflation occurring every other heart cycle, (2) 42 °C heating with a heating blanket, and (3) ECG-gated rhythmic handgrip exercise at 30% MVC with contraction occurring every other heart cycle.
10-minute rest periods will separate each of the interventions to allow for return to baseline conditions.
On the second data collection visit, following rest, the participant will undergo three variations of the 10-minute cuff compression intervention, the order of which will be randomized.
The three variations differ in the trigger delay from the R spike of the ECG to cause inflation of the cuff for compressions.
The original intervention involves the data acquisition unit triggering inflation of the cuff at systole (R spike) (0s delay).
This condition will be compared to two other trigger delays, specifically triggering inflation of the cuff at 0.2s and 0.4s after the R spike.
For both data collection visits, BA blood velocities, blood flow turbulence, endothelial shear stress, and oscillatory shear index will be assessed before and during each of the interventions; and relative flow-mediated dilation will be assessed before and immediately after each of the interventions.
Participants will provide written informed consent prior to beginning any portion of the study.
Study Type
Interventional
Enrollment (Actual)
10
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 Locations
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Ontario
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Hamilton, Ontario, Canada, L8S 4L8
- McMaster University Vascular Dynamics Lab
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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 to 35 years (ADULT)
Accepts Healthy Volunteers
Yes
Genders Eligible for Study
Male
Description
Inclusion Criteria:
- Healthy (no cardiovascular, musculoskeletal, or metabolic disease)
- Male
- 18-35 years old
- Recreationally active (exercising 2-3 times per week)
Exclusion Criteria:
- Cardiovascular, musculoskeletal, or metabolic disease
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: NA
- Interventional Model: SINGLE_GROUP
- Masking: NONE
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
|---|---|
|
EXPERIMENTAL: Experimental-Control
Participants will undergo all interventions, while simultaneously serving as their own within-subject control.
The left side of the body will be designated "experimental", and all interventions will be applied to the left arm.
The right side of the body will be designated as "control", and will not receive any interventions.
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10 minutes of ECG-gated repeated suprasystolic (300 mmHg) cuff compressions, with inflation occurring every other heart cycle.
These cuff compressions may be triggered 0 seconds, 0.2 seconds, or 0.4 seconds from the R spike (systole) on the ECG signal.
10 minutes of ECG-gated rhythmic handgrip exercise at 30% maximal voluntary contraction, with contraction occurring every other heart cycle
10 minutes of passive heat stress at 42 degrees Celsius with a commercially available heating blanket
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What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Brachial artery flow-mediated dilation
Time Frame: Up to 2 weeks
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Collected using vascular ultrasound and analyzed using semi-automated edge-tracking software
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Up to 2 weeks
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
|---|---|---|
|
Mean blood velocity magnitude and direction
Time Frame: Up to 2 weeks
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Collected using vascular ultrasound and sent to spectral analyzer for calculation of intensity-weighted mean
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Up to 2 weeks
|
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Reynolds number (blood flow turbulence)
Time Frame: Up to 2 weeks
|
Calculated using blood velocity and artery diameter obtained from vascular ultrasound, and blood density and viscosity calculated using hematocrit
|
Up to 2 weeks
|
|
Endothelial shear stress
Time Frame: Up to 2 weeks
|
Calculated using blood velocity and artery diameter obtained from vascular ultrasound, and blood viscosity calculated using hematocrit
|
Up to 2 weeks
|
|
Oscillatory shear index
Time Frame: Up to 2 weeks
|
Calculated using blood velocity and artery diameter obtained from vascular ultrasound
|
Up to 2 weeks
|
|
Endothelial shear rate
Time Frame: Up to 2 weeks
|
Calculated using blood velocity and artery diameter obtained from vascular ultrasound
|
Up to 2 weeks
|
Collaborators and Investigators
This is where you will find people and organizations involved with this study.
Sponsor
Publications and helpful links
The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.
General Publications
- Wang C, Baker BM, Chen CS, Schwartz MA. Endothelial cell sensing of flow direction. Arterioscler Thromb Vasc Biol. 2013 Sep;33(9):2130-6. doi: 10.1161/ATVBAHA.113.301826. Epub 2013 Jun 27.
- Tinken TM, Thijssen DH, Hopkins N, Dawson EA, Cable NT, Green DJ. Shear stress mediates endothelial adaptations to exercise training in humans. Hypertension. 2010 Feb;55(2):312-8. doi: 10.1161/HYPERTENSIONAHA.109.146282. Epub 2010 Jan 4.
- Thijssen DH, Dawson EA, Black MA, Hopman MT, Cable NT, Green DJ. Brachial artery blood flow responses to different modalities of lower limb exercise. Med Sci Sports Exerc. 2009 May;41(5):1072-9. doi: 10.1249/MSS.0b013e3181923957.
- Gurovich AN, Braith RW. Enhanced external counterpulsation creates acute blood flow patterns responsible for improved flow-mediated dilation in humans. Hypertens Res. 2013 Apr;36(4):297-305. doi: 10.1038/hr.2012.169. Epub 2012 Oct 18.
- Reneman RS, Arts T, Hoeks AP. Wall shear stress--an important determinant of endothelial cell function and structure--in the arterial system in vivo. Discrepancies with theory. J Vasc Res. 2006;43(3):251-69. doi: 10.1159/000091648. Epub 2006 Feb 20.
- Totosy de Zepetnek JO, Ditor DS, Au JS, MacDonald MJ. Impact of shear rate pattern on upper and lower limb conduit artery endothelial function in both spinal cord-injured and able-bodied men. Exp Physiol. 2015 Oct;100(10):1107-17. doi: 10.1113/EP085056. Epub 2015 Aug 18.
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)
January 1, 2017
Primary Completion (ACTUAL)
March 1, 2017
Study Completion (ACTUAL)
March 1, 2017
Study Registration Dates
First Submitted
November 24, 2016
First Submitted That Met QC Criteria
December 1, 2016
First Posted (ESTIMATE)
December 5, 2016
Study Record Updates
Last Update Posted (ACTUAL)
January 18, 2018
Last Update Submitted That Met QC Criteria
January 16, 2018
Last Verified
January 1, 2018
More Information
Terms related to this study
Keywords
Other Study ID Numbers
- ASPEN
Plan for Individual participant data (IPD)
Plan to Share Individual Participant Data (IPD)?
NO
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