OxBP
Research type
Research Study
Full title
OxBP: Arterial Pulsatility in Small Vessel Diseases – Measurement of Arterial Pulsatility on MRI
IRAS ID
238848
Contact name
Alastair Webb
Contact email
Sponsor organisation
University of Oxford
Duration of Study in the UK
3 years, 0 months, 1 days
Research summary
Chronic vascular injury to the small vessels of the brain (small vessel disease) is associated with increased pulsation of blood flow to the brain, but this can only currently be measured with ultrasound, which is not widely available. This study aims to develop and test an equivalent method during an MRI scan.
15 patients will be recruited from participants in the TREAT-SVDs randomised controlled trial in Oxford, which already requires 4 clinic visits on different medications and an MRI scan. At each of these visits, participants in OxBP will undergo 5-10 minutes of continuous monitoring of blood pressure and blood flow to the brain by ultrasound (as used for babies in the womb). In addition, the stiffness of their blood vessels will be measured by pressing a small pencil-like probe gently on their wrist, upper leg and neck, as this effects how the blood pressure transmits to blood flow in the brain. Then, during the MRI scan they are having as part of the TREAT-SVDs trial, they will have a short period of concurrent, continuous blood pressure monitoring via partially inflated standard blood pressure cuffs around the upper arm, to compare to the MRI measure of blood flow on a beat-to-beat basis. These tests pose no additional risk to the participants. To test the accuracy of the BP monitoring method adapted for use in the MRI scanner, we will carry out the same monitoring method outside the MRI scanner in 5 healthy volunteers, with concurrent non-invasive blood pressure monitoring using the standard method (Finometer).
Development of a novel method of assessing cerebral arterial pulsatility on MRI imaging will enable future clinical studies to test this measure in greater numbers of patients and assess its role in the pathogenesis of small vessel disease.
Lay summary of study results: OxBP was a single-centre study in participants of the multicentre TREAT-SVDs crossover randomised controlled trial, carried out in Oxford. TREAT-SVDs compared the effects of three common antihypertensive medications (amlodipine, losartan, atenolol) on cerebrovascular reactivity to inhalation of carbon dioxide on MRI in patients with cerebral small vessel disease. This substudy included additional measures of cerebrovascular function with transcranial Doppler ultrasound and a novel MRI imaging sequence to measure pulsatility of blood flow to the brain.
OxBP demonstrated that cerebral pulsatility on ultrasound was significantly increased when participants were taking atenolol compared to the other two medications, and that this effect was likely mediated by the reduction in heart rate on this beta-blocker.REC name
North East - Tyne & Wear South Research Ethics Committee
REC reference
18/NE/0012
Date of REC Opinion
3 Jan 2018
REC opinion
Favourable Opinion