Evaluating the State of Microvessels by Minimum Rise Time (MRT01)

Healthy Clinical Trial

— MRT01  

Official title:

Evaluating an Optical Index (Minimum Rise Time) as a Measure for the State of Microvessels

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02527070
• Other study ID #: 2080-15-SMC
• Status: Completed
• Phase: N/A
• First received: July 28, 2015
• Last updated: October 13, 2016
• Start date: September 2015
• Est. completion date: October 2016

Study information

• Verified date: October 2016
• Source: Afeka, The Tel-Aviv Academic College of Engineering
• Contact: n/a
• Is FDA regulated: No
• Health authority: Israel: Israeli Health Ministry Pharmaceutical Administration
• Study type: Interventional

Clinical Trial Summary

Photoplethysmography (PPG) is a simple uncalibrated optical method of monitoring variations in skin blood volume. The objective of the current study is to investigate a potential relationship between MRT (minimum rise time, in time units) a measure derived from PPG and the state of microvessels.

This study includes a 1-2 hour single session per subject during which PPG and other microvascular and systemic variables will be monitored in response to non-invasive interventions that are known to elicit microvascular responses.

Description:

Photoplethysmography (PPG) is a simple uncalibrated optical method of monitoring variations in skin blood volume. A major limitation of PPG is the lack of a quantitative method for calibrating this signal. A method that provides an absolute measure (in time units) called 'minimum rise time' (MRT) was published in 1985 by Dr. Benjamin Gavish, one of the study investigators. However, a possible relationship between MRT and the state of arterioles that determines the microvascular flow has never been investigated. Such relationship, if validated, could have clinical impact in noninvasive diagnosis of vascular diseases and monitoring microvascular response to treatments that affect at both clinic and home setting.

The objective of the current study is to investigate a potential relationship between variations of MRT (minimum rise time, in time units) and microcirculatory variables induced by interventions that are expected to have acute effect on the state of arterioles and the tissue oxygenation.

This study includes a single 1-2 hour session per subject, during which PPG and other microvascular and systemic variables will be monitored in healthy volunteers in response to a number of non-invasive interventions/device that are approved for clinical use and known to elicit microvascular responses. These interventions are applied consecutively, include breathing at different rates, low power visible light in the red-to-near-infrared range, and local temperature changes. The experimental sessions will be conducted at the Afeka College by the study investigators.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 33
• Est. completion date: October 2016
• Est. primary completion date: June 2016
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 65 Years

Eligibility

Inclusion Criteria:

1. Healthy males and females, between 18 and 65 years of age.

2. Willing to sign informed consent.

Exclusion Criteria:

1. Currently smoking

2. Any abnormal skin condition in the area of light irradiation.

3. Pregnant having given birth less than 3 months ago, and/or breastfeeding.

4. Having a history of diseases stimulated by heat, such as recurrent Herpes Simplex in the treated area, unless treatment is conducted following a prophylactic regimen.

5. Having any illness that might affect the vasculature, such as diabetes (type I or II)

6. Suffering from significant concurrent illness, such as cardiac disorders, , or pertinent neurological disorders.

7. As per the Investigator's discretion, any physical or mental condition which might make it unsafe for the subject to participate in this study.

Study Design

Allocation: Randomized, Intervention Model: Parallel Assignment, Masking: Single Blind (Outcomes Assessor), Primary Purpose: Diagnostic

Related Conditions & MeSH terms

• Healthy

Intervention

Device:
• RESPeRATE (Paced Breathing)
The subjects will be guided by a digital metronome to breath at 15, 10, and 6 breaths/min for 2 minutes each using the metronome function of the device RESPeRATE (InterCure, Israel) that guides breathing using musical tones played at selectable rhythm.
• Quantum Warp10 (Red LED)

• Omnilux new-U (Near Infrared LED)

Other:
• Heat/cold provocation
Immersion of one foot in a warm water bath ( 43-45 degrees C) for few seconds and then immersion of the same foot in cold water bath (5-7 degrees C) for 1 min.

Locations

Country	Name	City	State
Israel	Afeka, Tel-Aviv Academic College of Engineering	Tel Aviv

Sponsors (2)

Lead Sponsor	Collaborator
Afeka, The Tel-Aviv Academic College of Engineering	Sheba Medical Center

Country where clinical trial is conducted

Israel, 

References & Publications (1)

Gavish B. Plethysmographic characterization of vascular wall by a new parameter--minimum rise-time: age dependence in health. Microcirc Endothelium Lymphatics. 1986-1987;3(3-4):281-96. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	MRT as measured from finger Photoplethysmography in response to changes in breathing rate		Change from baseline to up to 1 minute after termination of 2 minutes of constant breathing rate (15, 10, and 6 breath/min)	No
Primary	MRT as measured from finger Photoplethysmography in response to light source		Change from immediately before exposure to light source to up to 10 minutes after exposure to light source	No
Primary	MRT as measured from finger Photoplethysmography in response to temperature changes		Change from immediately before exposure to temperature provocations to up to 2 minutes after exposure to warm water, and up to 2 minutes after exposure to cold water	No
Secondary	Capillary blood flow (red blood cell velocity or flux in 'perfusion units') as measured by laser doppler		At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes	No
Secondary	Transcutaneous oxygen pressure (tcpO2 in mmHg)		At baseline, 1 minute after each changes in breathing rate, 5 and 10 minutes after exposure to light source, 1 minutes after each exposure to temperature changes	No