24-hour Blood Pressure Measurements and Ischemic Conditioning

NCT ID: NCT03303404

Last Updated: 2020-12-22

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 22 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-09-12
• Study Completion Date: 2018-09-20

Brief Summary

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).

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.

Conditions

Blood Pressure

Study Design

• Allocation Method: NA
• Intervention Model: SINGLE_GROUP
• Primary Study Purpose: OTHER
• Blinding Strategy: NONE

Study Groups

Ambulatory (24-hour) Blood Pressure

Group Type: EXPERIMENTAL

Ambulatory (24-hour) Blood Pressure

Intervention Type: DEVICE

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.

Interventions

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.

Intervention Type: DEVICE

Eligibility Criteria

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.

• Minimum Eligible Age: 30 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

University of Texas at Austin

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Locations

Dr. Hirofumi Tanaka

Austin, Texas, United States

Countries

United States

References

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.

Reference Type: DERIVED

PMID: 31249371 (View on PubMed)

Provided Documents

Document Type: Study Protocol and Statistical Analysis Plan

View Document

Other Identifiers

2017-07-0043

Identifier Type: -

Identifier Source: org_study_id