None listed
Conditions
Brief summary
Hypertension is a major risk factor for cardiovascular disease and the most frequent problem managed by General Practitioners (GP’s) in Australia. Blood pressure is traditionally measured by inflating a cuff around the upper arm, and doctors rely on this information when making treatment decisions. However, individuals with the same, or similar, brachial blood pressure may have very different central blood pressure (>30 mmHg difference). This difference is important because central blood pressure has been shown to have greater relevance to the structure and function of the heart and arteries. Moreover, several longitudinal trials show that central blood pressure indices are independently associated with severe cardiovascular events and mortality. When all these data are considered, relying solely on the measure of brachial blood pressure has severe limitations for assessing patient risk and determining the effect of treatment. Indeed, the evidence points toward an expectation that patient care will be improved by tailoring medical treatment based on central, rather than upper arm, blood pressure. However, there is no data to show that using central blood pressure changes decision-making or outcomes and, therefore, doctors continue to rely on brachial blood pressure to make therapeutic decisions. The technology is now available to measure central blood pressure non-invasively by radial applanation tonometry. This methodology should improve patient care by providing the treating clinician with a greater understanding of the “true” risk relating to blood pressure control and, therefore, make more appropriate treatment decisions. This research program aims to bridge the gap between the current method of managing patients with hypertension (focus on upper arm blood pressure) and the theoretical improvement in the quality of patient care that may be achieved with the use of new technology and consideration of central blood pressure. The research should provide the foundation model for a new way to undertake management of patients with hypertension. It is hypothesised that patients randomised to have treatment decisions based on central blood pressure will have no significant change in left ventricular mass; will have less use of medication and improved quality of life scores.
Interventions
Patients with essential hypertension treated by their General Practitioners will be randomised to have treatment decisions (i.e. titration of antihypertensive therapy) based on central blood pressure measures (intervention) versus usual care (control). Central blood pressure will be measured non invasively by radial tonometry using commercial equipment. The duration of intervention is 12 months. All participants will be receiving oral antihypertensive medication upon entry to the study as part o
Patients with essential hypertension treated by their General Practitioners will be randomised to have treatment decisions (i.e. titration of antihypertensive therapy) based on central blood pressure measures (intervention) versus usual care (control). Central blood pressure will be measured non invasively by radial tonometry using commercial equipment. The duration of intervention is 12 months. All participants will be receiving oral antihypertensive medication upon entry to the study as part of their usual medical care. The dose and frequency of drug administration at study entry will be at the discretion of each participants attending General Practitioner. Recommendations about changing antihypertensive therapy (maintain, decrease or increase medication) will be made throughout the course of the study. These recommendations will be made on the basis of central or brachial blood pressure and the clinical presentation of each individual participant. Recommendations will be provided to each participants attending General Practitioner (there is no standard dose). A data and safety monitoring committee has not been appointed because we have determined the study to be extremely low risk. Indeed, 1768 patients would be required in each group in order to detect a significant change in 2D LV mass over the course of one year (p=0.001 and 80% power). These calculations are based on an expected change in LV mass of 4.747 g per year, with a standard deviation of 35 at baseline and 37 at one year, as per Framingham data (Lieb W et al. Circ. 2009; 119:3085-3092).
Sponsors
The University of Queensland
Study design
Allocation
Randomised controlled trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Open (masking not used)
Eligibility
Sex/Gender
All
Age
18 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
Essential hypertension
Exclusion criteria
Brachial blood pressure >180/100 mmHg. Taking more than 3 antihypertensive drugs. Clinical history of coronary artery disease. Clinical history of renal disease (or serum creatinine >140 umol). Left ventricular hypertrophy (>59 g/m2.7; women and >64 g/ m2.7; men). Secondary causes of hypertension. Aortic valve stenosis or upper limb obstructive atherosclerosis. Pregnant females.
Outcome results
None listed