24-hour Blood Pressure Measurements and Ischemic Conditioning

To determine if 24-hr ambulatory blood pressure monitoring effects endothelial function, we will measure flow-mediated dilation before and after the blood pressure monitoring (ischemia conditioning).

Study Overview

• Status: Completed
• Conditions: Blood Pressure
• Intervention / Treatment: Device: Ambulatory (24-hour) Blood Pressure

Detailed Description

Reestablishing blood flow (reperfusion) to organs that had their blood supply restricted (ischemia) can cause damage to the vasculature via injury and tissue death resulting in endothelial dysfunction. This ischemia-reperfusion (blood flow occlusion and resupply) triggered injury can be reduced or prevented by preceding brief periods of ischemia called preconditioning. Properly-performed preconditioning can exert a powerful protection against a subsequent sustained period of ischemia in a variety of organs in the body including the heart, kidney, and skeletal muscle. Preconditioning protocol involves repeated brief inflation and deflation of a blood pressure cuff. In many of human cardiovascular research studies, it is common to measure endothelial function and ambulatory (24-hour) blood pressure. The ambulatory blood pressure device takes repeated blood pressure readings every 15-30 minutes during the daytime and 30-60 minutes at night. It is possible that repeated bouts of inflation/deflation of the blood pressure cuff could induce preconditioning effects and influence endothelial function. Therefore, in the proposed study we aim to address this hypothesis.

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Austin, Texas, United States, 78713
      • Dr. Hirofumi Tanaka

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 30 years to 60 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

Adults aged between 30 to 60 years old.

Exclusion Criteria:

Exclusion from the study may be due to: i) pregnancy (by asking the subjects when the last time she had menstruation; we do have simple testing kits available if a subject is unsure about her status); ii) a recent illness, recent surgery, or any medical intervention in the 48 hours before any of the study days; iii) personal history of diabetes (fasting blood glucose > 126 mg/dL), heart disease, or other cardiovascular problems.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Ambulatory (24-hour) Blood Pressure

Device: Ambulatory (24-hour) Blood Pressure; Unlike casual blood pressure measurements, 24-hour ambulatory blood pressure monitoring provides an insight into blood pressure changes in everyday life and an estimate of the overall blood pressure load exerted on the cardiovascular system over 24 hours. Blood pressure recordings over a 24-hour period of normal daily activity will be made using a noninvasive ambulatory monitor (Spacelabs, Redlands, WA). The ambulatory system will be calibrated against a mercury sphygmomanometer, and the cuff will be programmed to inflate automatically every 15 min from 6 AM to 11 PM and every 20 min between 11 PM and 6 AM. For each individual subject, the nighttime period will be defined as the time when the subject goes to bed at night until rising in the morning. Daytime will be defined as the remainder of the 24-hour period. Daytime and nighttime states will be monitored by an Actiwatch (Mini-MItter, Bend, OR), a watch-like device placed on the wrist that measures gross motor activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change From Baseline in Flow Mediated Dilation After 24 Hour Ischemic Conditioning With Blood Pressure Cuff	Flow-mediated dilatation (FMD) is a common and non-invasive method to assess vascular endothelial function by measuring the Brachial artery's responsiveness (diameter percent increase) following a brief period of occlusion.	Baseline, Post 24 hour conditioning

Collaborators and Investigators

• Sponsor: University of Texas at Austin

Publications and helpful links

General Publications

• Fico BG, Zhu W, Tanaka H. Does 24-h ambulatory blood pressure monitoring act as ischemic preconditioning and influence endothelial function? J Hum Hypertens. 2019 Nov;33(11):817-820. doi: 10.1038/s41371-019-0214-y. Epub 2019 Jun 27.

Study record dates

Study Major Dates

• Study Start (Actual): September 12, 2017
• Primary Completion (Actual): September 20, 2018
• Study Completion (Actual): September 20, 2018

Study Registration Dates

• First Submitted: October 2, 2017
• First Submitted That Met QC Criteria: October 2, 2017
• First Posted (Actual): October 6, 2017

Study Record Updates

• Last Update Posted (Actual): December 22, 2020
• Last Update Submitted That Met QC Criteria: December 21, 2020
• Last Verified: December 1, 2020

More Information

Terms related to this study

• Other Study ID Numbers: 2017-07-0043

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: Yes