Non-Contact Measurement of Aortic Compliance

Non Contact Measurement of Aortic Pulse Wave Velocity

Reduced aortic stiffness is a powerful way to predict the outcome of cardiovascular (CV) disease. There are several non invasive methods for its estimation, most of which are based on the measurement of speed of the arterial pulse wave. (The stiffer the artery, the faster the pulse wave travels.) They rely on detecting the arterial pulse with 2 sensors placed on the skin a known distance apart and measuring the time for the pulse to travel between them. However all current methods require skilled operators and are of limited accuracy. Thus, there is a need for an easy to use and reliable device to measure pulse speed. The aim of this project is to develop a non contact device to detect the aortic pulse as it moves into the small arteries following the ribs, using the principle of thermal imaging, by means of a high sensitivity infra red camera, directed towards the subjects back. The investigators plan to validate the device and conduct a small feasibility study in patients undergoing elective angiography, by simultaneously measuring pulse speed using established methods. These are Doppler ultrasound (non-invasive) and direct intra-arterial measurement (the gold standard).

Study Overview

• Status: Completed
• Conditions: Vascular Disease

• Study Type: Observational
• Enrollment (Actual): 80

Contacts and Locations

Study Locations

• United Kingdom
  • London, United Kingdom, E2 9JX
    • London Chest Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Non-interventional cardiology clinic. Patients undergoing elective angiography.

Description

Inclusion Criteria:

• Age 18 years and above
• Patients eligible for coronary angiography
• Informed consent obtained
• Able to complete experimental protocol

Exclusion Criteria:

• Refusal of consent
• Age below 18 years
• Breast feeding
• Known or suspected pregnancy
• Patient participating in another study at time of study entry or previous participation in this registry
• diagnosed but untreated hypertension

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
Angiography high risk; Patients with multiple risk factors, positive non-invasive test, or known pre-existing coronary artery/vascular disease. Patients with diabetes mellitus will be identified, and subject to a sub-group analysis.
Angiography Low Risk; Patients with chest pain symptoms, minimal risk factors, and inconclusive evidence of myocardial ischaemia on non-invasive testing.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Quantitative agreement between intra-arterial measurement of aortic pulse wave velocity and transcutaneous values: a) Contact PPG from probes on the skin of the back in the intercostal spaces and b) non-contact from infra-red camera imaging the back.	Single measurement to be made between January 2010 and June 2010

Secondary Outcome Measures

Outcome Measure	Time Frame
Assessment of differences in aPWV and between low and high risk groups of patients undergoing elective coronary angiography.	Single measurement to be made between January 2010 and June 2010

Collaborators and Investigators

• Sponsor: Barts & The London NHS Trust
• Collaborators: National Institute for Health Research, United Kingdom
• Investigators: Principal Investigator: Stephen E Greenwald, PhD, Queen Mary University of London, Barts & The London School of Medicine & Dentistry

Publications and helpful links

General Publications

• Wang X, Keith JC Jr, Struthers AD, Feuerstein GZ. Assessment of arterial stiffness, a translational medicine biomarker system for evaluation of vascular risk. Cardiovasc Ther. 2008 Fall;26(3):214-23. doi: 10.1111/j.1755-5922.2008.00051.x.
• Cohn JN, Duprez DA, Grandits GA. Arterial elasticity as part of a comprehensive assessment of cardiovascular risk and drug treatment. Hypertension. 2005 Jul;46(1):217-20. doi: 10.1161/01.HYP.0000165686.50890.c3. Epub 2005 May 2.
• Greenwald, S.E., Denyer, H.T., and Sobeh, M.S., Non Invasive Measurement of Vascular Compliance by a Photoplethysmographic Technique. SPIE Proc., 1997. 2970: 89-97.
• Loukogeorgakis S, Dawson R, Phillips N, Martyn CN, Greenwald SE. Validation of a device to measure arterial pulse wave velocity by a photoplethysmographic method. Physiol Meas. 2002 Aug;23(3):581-96. doi: 10.1088/0967-3334/23/3/309.
• Zheng, J., Hu., S., Azorin-Peris, V., Echiadis, A., Shi, P., Chouliaras, V., "A remote approach to measure blood perfusion from the human face", Vol. 7170. 7170-4., Proc. of SPIE BiOS
• Greenwald SE. Ageing of the conduit arteries. J Pathol. 2007 Jan;211(2):157-72. doi: 10.1002/path.2101.
• Mitchell, G.F., Pulse Wave Velocity Measuring Device, USA, 2001, 6331162 B1.
• Rajzer MW, Wojciechowska W, Klocek M, Palka I, Brzozowska-Kiszka M, Kawecka-Jaszcz K. Comparison of aortic pulse wave velocity measured by three techniques: Complior, SphygmoCor and Arteriograph. J Hypertens. 2008 Oct;26(10):2001-7. doi: 10.1097/HJH.0b013e32830a4a25.

Study record dates

Study Major Dates

• Study Start: September 1, 2010
• Primary Completion (Actual): June 1, 2012
• Study Completion (Actual): March 1, 2013

Study Registration Dates

• First Submitted: September 15, 2009
• First Submitted That Met QC Criteria: September 29, 2009
• First Posted (Estimate): September 30, 2009

Study Record Updates

• Last Update Posted (Estimate): February 23, 2015
• Last Update Submitted That Met QC Criteria: February 20, 2015
• Last Verified: February 1, 2015

More Information

Terms related to this study

• Keywords: Photoplethysmography; Non-invasive; Pulse wave velocity; Non contact; Doppler flow velocimetry
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases
• Other Study ID Numbers: II-FS-0109-11005; i4i Track 1