The Evaluation of blood pressure treatment stratified according to Central Aortic Systolic Pressure (CASP) in Young Hypertensive Patients - The TREAT CASP study

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High blood pressure (BP) is a leading cause of heart disease and strokes and the commonest chronic condition treated in primary care. In the UK, ~25% of all adults and 50% aged over 65yrs have high BP. NICE guidance recommends treatment when BP exceeds 160/100mmHg (called stage II hypertension). NICE also recommends treatment of lower pressures (140-159/90-99mmHg, i.e. stage I hypertension) in those with evidence of damage due to BP, those with diabetes and/or cardiovascular disease (CVD) or those calculated to be at higher risk. However, there is uncertainty what to do about treatment of younger people (aged 40yrs and under) with stage I hypertension because; i) younger people have rarely been included in clinical trials, ii) are unlikely to have developed CVD and iii) risk calculators do not apply to this younger age group. NICE has identified this group of over 1 million younger people as a key priority for research to better identify who would benefit from treatment. BP is routinely measured with a cuff wrapped around the arm and the assumption is made that pressure measured in the arm accurately reflects the pressure in the artery (aorta) close to the heart and the vital organs. We have developed a simple, non-invasive method to measure pressure in the aorta, next to the heart. This pressure is termed "central aortic systolic pressure" or CASP. Importantly, we have shown that pressure in the arm may not be an accurate measure of CASP, especially in younger people. Moreover, CASP is a better predictor of stress on the heart and may better predict stroke and CVD compared to BP measured in the arm. Our study will take place at the UCL vascular physiology unit and will recruit young men (aged 18-40 years) with stage I hypertension. We hypothesise that men with a low CASP (despite a high BP in the arm) actually have a normal BP, with no evidence of strain on the heart and do not need treatment. In contrast, those with a high CASP value will have early evidence of strain on the heart and arteries and will benefit from treatment. We will use MRI to sensitively measure the structure of the heart and the arteries. We will compare in men with high CASP, the effects of treatment for 1 year to lower BP versus no treatment, to see whether lowering CASP improves early heart and artery damage. Our study has no ethical issues as people recruited into the study would not normally receive treatment. We are well placed to conduct this study because of our experience in developing novel ways of measuring CASP, our experience in large clinical trials and in sensitive MRI measurements. The cost of our study is curtailed because of access to our research technology, including our research MRI scanner. Resources requested are to fund staff, clinical tests and consumables. Findings from our study may provide compelling evidence for a better way to stratify younger people with early hypertension who would benefit most from treatment and also avoid long-term treatment of those who would get no benefit.