Validation of WatchBP Office Ankle-brachial Index (ABI) Function (ABI)

January 20, 2012 updated by: George S. Stergiou, University of Athens

Assessment of the Oscillometric Measurement of the Ankle-brachial Index (ABI) With WatchBP Office ABI Device.

Measurement of the ankle-brachial index (ABI) with the oscillometric device WatchBP Office will be assessed compared to the reference method (Doppler).

Ninety three adult subjects assessed for hypertension, treated or untreated, with complete study data were included. Data on the presence of cardiovascular (CV) disease and classical CV risk factors were recorded.

All the ABI measurements of each individual participant will be performed by the same observer in a randomized order (concerning Doppler and WatchBP)

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

All study measurements were performed under standardized conditions in a quiet examination room with 10 min rest in the supine position before measurements. Ankle-brachial index (ABI) was measured manually by Doppler and automatically by the oscillometric device in randomized order by a single investigator. Manual Doppler ABI was measured according to the American Heart Association guidelines using a continuous wave Doppler device (Hadeco Bidop ES-100V3, Kawasaki, Japan) with a 8 MHz probe. Systolic blood pressure was defined with a standard mercury sphygmomanometer by the first Doppler flow signal while deflating the cuff from a suprasystolic level in brachial, dorsalis pedis and posterior tibial arteries. Systolic pressure was determined sequentially for brachial, dorsalis pedis and posterior tibial arteries for each side and ABI was calculated for each leg by dividing the highest ankle pressure to the highest arm pressure. Automated ABI measurement was performed using a validated oscillometric blood pressure monitor designed for professional use in the office (WatchBP Office device; Microlife, Widnau, Switzerland). This device allows automated simultaneous both arms or arm and leg blood pressure measurements and thereby the calculation of ABI. The ABI results are displayed on the device screen.

The study protocol included three steps: (i) an introductory familiarization automated ABI measurement, (ii) three simultaneous oscillometric both arms blood pressure measurements; in case of a consistent inter-arm difference ≥12 mmHg, the arm with the higher blood pressure was selected for the subsequent oscillometric ABI measurements (otherwise the right arm was used) and (iii) Doppler and automated ABI measurement in randomized order; Doppler ABI was measured once, whereas automated ABI calculation included triplicate simultaneous arm-leg measurements performed for each side. The occurrence of five sequential oscillometric errors was defined as a failure of the oscillometric device to measure ABI.

Study Type

Observational

Enrollment (Actual)

98

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

  • Greece
      • Athens, Greece, 11527
        • Hypertension Center, Sotiria Hospital

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

25 years to 85 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

Subjects assessed for hypertension including those with other cardiovascular risk factors

Description

Inclusion Criteria:

  • Treated or untreated subjects assessed for hypertension

Exclusion Criteria:

  • Atrial fibrillation
  • Incompressible ankle arteries

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

  • Observational Models: Case-Only
  • Time Perspectives: Cross-Sectional

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
All eligible patients

Subjects assessed for hypertension, were subjected to the measurement of ankle brachial index (ABI) by two methods:

  1. Doppler
  2. WatchBP Office oscillometric The order for performing the two methods was randomized.
Device: Doppler Ankle-Brachial Index measurement
Measurement of the Ankle-Brachial Index by Doppler.
Device: WatchBP Office Ankle-Brachial Index measurement.
Measurement of Ankle-Brachial Index by WatchBP Office device.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Watch BP Office Minus Doppler Ankle-Brachial Index Difference
Time Frame: once (cross-sectional)
The validation process consisted of two parts: (i) measurement validation, which compared Doppler and Watch BP Office ABI values and assessed their association, and (ii) clinical validation, which compared the diagnosis of peripheral artery disease (PAD) by the two methods and assessed the association of Watch BP Office and Doppler ABI values with cardiovascular risk factors.
once (cross-sectional)
Mean Doppler Ankle-Brachial Index
Time Frame: once (cross-sectional)
once (cross-sectional)
Mean Watch BP Office Ankle-Brachial Index
Time Frame: once (cross-sectional)
once (cross-sectional)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Agreement Between the Two Methods in Peripheral Artery Disease (PAD) Diagnosis
Time Frame: Once (cross-sectional)
This outcome measure represents what percentage of the patients diagnosed with PAD using Doppler ABI method (reference method) were diagnosed with PAD using WatchBP Office ABI method. It also represents in what percentage of the patients in whom PAD was excluded with Doppler ABI method (reference method), PAD was excluded using WatchBP Office ABI method as well.
Once (cross-sectional)

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Athens

Collaborators

Microlife

Investigators

  • Principal Investigator: George S Stergiou, Assoc. Prof., Hypertension Center, University of Athens, Greece

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

June 1, 2009

Primary Completion (Actual)

April 1, 2010

Study Completion (Actual)

June 1, 2010

Study Registration Dates

First Submitted

October 27, 2009

First Submitted That Met QC Criteria

October 27, 2009

First Posted (Estimate)

October 28, 2009

Study Record Updates

Last Update Posted (Estimate)

January 23, 2012

Last Update Submitted That Met QC Criteria

January 20, 2012

Last Verified

January 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Microlife ABI

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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