Title: Developing the Blood Pressure Index for improved blood pressure control
Funder: Department of Health and Social Care

Abstract: Although blood pressure (BP) is the strongest biomarker of stroke and heart disease, current methods of managing BP are limited because they only present the highest and lowest measurements (ie the systolic and diastolic BP). There are a number of other parts of the arterial BP waveform that are already routinely recorded by most commercially available BP devices, which could be better at predicting cardiovascular risk. We have unique patient datasets, which we plan to apply our AI expertise to, in order to produce better, patient friendly, BP data from home BP machines and smartwatches. This will empower patients to self-manage their lifestyle and BP treatments more effectively. This Phase 1 innovation uses AI to discover and interpret intercorrelated factors derived from the arterial BP waveform. A model will be generated using unique datasets, including patient’s arterial pressure waveforms and their 12-16-year cardiovascular outcome data, collected by our group from over 5000 patients. The data has been cleaned and pilot data has already been published showing the high quality of the waveform recordings. The algorithm will find which measurements within the waveform are better predictors of cardiovascular events compared to systolic BP, and which are less susceptible to variation errors across heartbeats. The AI would condense the complex mathematical analysis into an index that would be easily understood by non-experts. With a substantial public involvement project, this index will present the most useful and user-friendly measurements to the public. The exit point will be the definition and presentation of the explainable ‘Blood Pressure Index’ on a prototype smartphone app that connects to existing automated cuff devices. The outcomes from this phase 1 study will generate the necessary information to design and deliver a clinical trial to compare the ‘Blood Pressure Index’ to systolic BP.

Lay abstract: Raised blood pressure, or hypertension, is the most important cause of strokes, heart disease and deaths, and it can be prevented. We measure blood pressure using an arm blood pressure machine, and this provides us with the highest (systolic) and the lowest (diastolic) numbers. However, blood pressure varies in a wave-like pattern during one heartbeat. We know that there are useful measurements that can be taken from the wave pattern and not just the highest and lowest numbers. However, we still do not know which of these numbers are the most useful for the public for understanding and improving their health. We will use artificial intelligence to discover which measurements within the wave pattern give us the best prediction of a person s risk in the long-term. In order to do this, we will create software to analyse the wave pattern data of over 5000 participants of White European, South Asian and African and Caribbean ethnicity. We will compare the wave pattern from the artery from each person to whether that person experienced a stroke, heart attack or a fatal event over the last 16 years. All the data that is required for this project has already been gathered from previous trials and we have consent to use it. Therefore, this study makes incredibly cost-effective use of previously public-funded research data. Drawing upon a wealth of high-quality patient and public involvement and engagement activity within our team, we will explore which wave measurements are the most useful to the public. We will organise a series of workshops for adults from different socioeconomic backgrounds, women, adult members of Black ethnicity, for whom high blood pressure is more common and where inclusion in blood pressure research has previously been limited, and young adults, because high blood pressure rates are rapidly rising in this group. Our artificial intelligence analysis of the wave pattern data and our public engagement activities will decide which measurements are the most accurate, acceptable and helpful for improving blood pressure in every-day life. This combination and presentation of measurements will be an application called a Blood Pressure Index . Previous research using the same data gives us confidence that there will be statistically important findings from this research. The development of public involvement in this project over the last year, the role of a member of the public who is a co-applicant, and the support and recommendation of the NIHR Biomedical Research Centre Patient Experience Research Centre and the Societal Engagement Team at Imperial College London gives us confidence that this project will have a significant and positive impact on the future of the health of the public in the UK.

Research activity codes: 4.1 DISCOVERY AND PRECLINICAL TESTING OF MARKERS AND TECHNOLOGIES;7.3 MANAGEMENT AND DECISION MAKING
Health categories: CARDIOVASCULAR