Duplex-CVR
Research type
Research Study
Full title
The feasibility of assessing Cerebrovascular Reactivity with Carotid Duplex Ultrasound
IRAS ID
282086
Contact name
Alastair Webb
Contact email
Sponsor organisation
Clinical Trials and Research Governance, The University of Oxford
Duration of Study in the UK
0 years, 7 months, 31 days
Research summary
Research Summary
An ultrasound assessment is commonly used to assess the blood vessels in the neck. This assessment can determine how much blood is flowing through the vessel, or how many fatty deposits exist within the blood vessel and if they may be interfering with the blood flow to the brain. This study will first determine if patients who require this type of assessment can perform a series of breathing manoeuvres whilst having an ultrasound assessment on the neck. Different breathing manoeuvres, such as holding your breath or breathing very quickly, will help promote small changes in the blood vessels by making them larger or smaller. The brain is continuously working to regulate blood flow so that a constant supply of blood can be provided to the brain. However, this control system is susceptible to failure in people with cardiovascular disease or following an injury such as a stroke, when a blood clot in the blood vessel prevents blood from reaching a part of the brain. This study will assess whether these breathing manoeuvres can be performed without affecting the quality of the images taken during the ultrasound assessment on the neck, and whether they demonstrate measurable changes in the blood flow to the brain. By doing so, this study will evaluate whether these tests could be used during routine clinical ultrasound scans to assess whether small blood vessels in the brain are working properly.
Summary of Results
Fifty patients (15 female, mean age of 68 ± 13 years old) were recruited for this study, where the aim was to determine if carotid ultrasound can be used to perform an assessment in cerebrovascular reactivity (changes in blood flow to a given stimuli) using different types of breathing manoeuvres. A range of patients undergoing carotid Duplex ultrasound for clinical reasons (such as symptoms of cerebrovascular disease or pre-surgery surveillance) were recruited within a 6 month period. Recordings included measures of blood flow velocity, blood vessel diameter and expired carbon dioxide. Recordings at rest were of good quality in 96% of the data. During a Breath-Hold manoeuvre and Rapid Breathing manoeuvre, physiological recordings were of good quality in 86 and 84% of the data respectively. As such, Duplex-CVR can be performed in patients undergoing a routine carotid Duplex assessment and can provide high-resolution imaging of changes in blood flow that occurs in relation to changes in expired carbon dioxide. This data can be used to provide measurements of cerebrovascular reactivity within this cohort of patients, which may indicate how well the small blood vessel are working within the brain. This outcome supports further studies to determine whether this technique is useful in the clinical setting. We thank the study participants for their contribution in helping us to gather this valuable information that will support future research in this field.
REC name
North West - Haydock Research Ethics Committee
REC reference
20/NW/0406
Date of REC Opinion
8 Oct 2020
REC opinion
Favourable Opinion