high blood pressure: problems, solutions and research. dr martin schultz menzies research institute...
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High Blood Pressure:problems, solutions
and research.
Dr Martin SchultzMenzies Research Institute Tasmania
University of Tasmania, Hobart, [email protected]
Wednesday 23rd July 2014Glenorchy School For Seniors
Who am I?
• Postdoctoral research fellow – Menzies Research Institute Tasmania - Heart Foundation fellowship for 2014-2016.
• Exercise Physiologist• Menzies’ blood pressure research group member – led by
Associate Professor James Sharman
What do we do?
Our aim is to improve health outcomes related to high blood pressure. Clinical research in humans
• Currently undertaking research projects to:1) Determine the clinical value of new methods for the detection and management
of high blood pressure. e.g. Central BP.2) Understand the physiology of blood pressure in the human cardiovascular system
at rest and during exercise.3) Establish the role of low stress or ‘moderate’ physical activity blood pressure as a
clinical tool.
Blood Pressure (BP) – What is it?
Two BP values: 1. Systolic (e.g. 120) Maximal pressure exerted within the artery during cardiac
contraction (systole)2. Diastolic (e.g. 80) Minimal pressure during cardiac relaxation (diastole)
What are we measuring when assessing BP?
120 mmHg
80 mmHg
Systolic BP
Diastolic BP
Extremes of pulse pressure
Estimation of the ‘load’ imposed on the heart and other important organs
High blood pressure ‘hypertension’
Continuum of risk related to high BP
CV d
isea
se ri
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Blood pressure (mmHg)
Hypertension
#1 modifiable risk factor for cardiovascular disease
Hypertension
A major health problem in Tasmania• >30% of adult Tasmanians have high blood pressure – the most of any
Australian state• Many have uncontrolled or undiagnosed high blood pressure
Australian survey data• 40% of people with high blood pressure are obese, with a further 35%
overweight • One third of those with unmanaged or uncontrolled blood pressure also have
high cholesterol levels • Most complete no or very little physical activity
Significant action required!
BP is normally assessed in the clinic under conditions of rest.
How does a Dr normally assess BP?
Diagnosis of hypertension• Several measures over several visits• In conjunction with other risk factors
(absolute cardiovascular risk assessment)
Associated with stiff arteries: Elderly
Classification based on Clinic BP
Mancia G, et al Guidelines for the management of arterial hypertension J Hypertens. 2013;31:1281-1357.
Clinic BP problems: time and technique!
Recommendations
Allow patient to sit for 3 – 5 mins
No talking, back supported, feet on floor, legs uncrossed, appropriate cuff size, arm at heart level
Check BP in both arms; continue on arm with highest reading
Take at least 2 BP measures, spaced 1 – 2 mins apart
Take additional BPs if first 2 are ‘quite different’
Take after 1 and 3 mins standing (at first visit) in elderly, T2DM or when OH suspected
DefinitionHigh Clinic BP but normal outside clinic BP
Prevalence; o 13% (9 – 16% general population/practice)o 32% (25 – 46% hypertensive patients)1
More common in;o Older people, females, non smokers, glucose intolerance2
o People having BP measured by doctor (alarm response)
1. Fagard RH et al, J Hypertens. 2007;25:2193-2198. 2. Mancia G et al, J Hypertens. 2013;31:1281-1357.
Problem - White coat hypertension
What happens to BP classification?
True BP
Measured BP
Measured BP
Problem - Masked hypertension
DefinitionNormal clinic BP with high outside clinic BP(reverse white coat hypertension)
Prevalence; o 10 – 19% general population/practiceo >50% in patients with exercise hypertension1
o 29 – 46% patients with T2DM2
o Up to 50% in patients with treated hypertension3
Elevated CV risk - 3 x times greater risk compared to people with normal BP
1. Scott J et al, Am J Hypertens. 2008;21:715-721. 2. Franklin SS et al Hypertension. 2013;61(5):964-71. 3. Bobrie G et al, J Hypertens. 2008;26:1715-1725.
Masked Hypertension
Major problem:Given that those with masked hypertension have normal clinic (rest) BP readings, many individuals who may be at risk simply pass through the clinic without a diagnosis.
True BP
Measured BP
Measured BP
What happens to BP classification?
Solutions
Method Summary
Out of clinic BP 1. 7 day home BP – 2 readings morning and evening (averaged)
2. 24 hour ambulatory BP – 20 mins day, 30 mins night (average day, night and overall)
Automated in clinic BP Operator independent, average of repeat measures (15 mins), separate room
Menzies BP Clinic Open for referral of difficult BP cases
Solutions
Method Summary
Out of clinic BP 1. 7 day home BP – 2 readings morning and evening (averaged)
2. 24 hour ambulatory BP – 20 mins day, 30 mins night (average day, night and overall)
Automated in clinic BP Operator independent, average of repeat measures (15 mins), separate room
Menzies BP Clinic Open for referral of difficult BP cases
Automated Office BP
• Automated machine required• Quite room, no distractions or personal.• 3 measurements taken over 15 minutes (average)
• Removes ‘white coat effect’• Values more closely reflect that of home/self BP
measurements and may be a better representative of BP control.1
1. Myers et al. Hypertens. 2009 Feb;27(2):280-6.
Solutions
Method Summary
Out of clinic BP 1. 7 day home BP – 2 readings morning and evening (averaged)
2. 24 hour ambulatory BP – 20 mins day, 30 mins night (average day, night and overall)
Automated in clinic BP Operator independent, average of repeat measures (15 mins), separate room
Menzies BP Clinic Open for referral of difficult BP cases
Measuring Central BP Research technique with building clinical efficacy
Menzies BP Clinic Overview
o Specialist BP clinic (Prof’s Tom Marwick, Matthew Jose, Mark Nelson) – referral from GP
o Dedicated clinic co-ordinator - Talia Sleiterso Bulk billed service (within 2 weeks of referral)o Patients with ‘difficult to treat hypertension’o Comprehensive investigation & risk assessment with
plan for return to GP care o Summary letter with any relevant clinical results i.e.
24-hour or 7-day monitoring, pathology tests, ECHO/ECG reports
Menzies BP Clinic
Datao Clinic, home, 24ABPM, Auto in clinic BP (brachial and central),
aortic stiffness, CO, SVo Bloods/urine (DNA, white cells)o Anthropometryo Questionnaires (QOL, PA)o MoCA cognitive and frailty assessment o Retinal photographyo Clinical tests (echo, IMT)o Data linkage (hospitalisations, events, mortality)
Referralso Via GP software “Best practice”
Patient experience – discharge questionnaire
“Friendliness and professionalism of all staff and volunteers”
“I got confirmation that my blood pressure was not an immediate risk and that anxiety was a contributing factor in my condition”
“The information received put my mind at ease about my blood pressure problem”
Solutions
Method Summary
Out of clinic BP 1. 7 day home BP – 2 readings morning and evening (averaged)
2. 24 hour ambulatory BP – 20 mins day, 30 mins night (average day, night and overall)
Automated in clinic BP Operator independent, average of repeat measures (15 mins), separate room
Menzies BP Clinic Open for referral of difficult BP cases
Measuring Central BP Research technique with building clinical efficacyPredicts CV mortality independent of brachial BP
What are we measuring when assessing BP?
120 mmHg
80 mmHg
Systolic BP
Diastolic BP
Extremes of pulse pressure at the upper arm!
Central (aortic) BP May better predict adverse CV outcomes
Brachial BP 150/ 77 mmHg
Brachial BP 150 / 78 mmHg
Central BP 139 / 77 mmHg
Central BP 131 / 79 mmHg
Person A Person B
Schultz MG et al. 2012. Eur J Clin Invest, 42(4):393-401.
Central BP
Major discrepancies in central BP among people with similar brachial BP
Overlap in central SBP between brachial BP categories
Central BP bedside: non invasive measurement
Bo ne
Arte ry
Sensor
Sensor
Bo ne
Arte ry
Radial applanation tonometry (valid,1 reproducible2)
1. Sharman JE et al Hypertension. 2006 Jun;47(6):1203-8.2. Holland DJ et al. Am J Hypertens. 2008;21(10):1100-6.
Cuff central BP from brachial waveform analysis
BP GUIDE Study @ Menzies’= Less use of antihypertensive medication
Sharman JE et al. Hypertension. 2013 Dec;62(6):1138-45.
Lowering Central BP
• Lowering BP with medication improves outcomes, but…..• Even in populations with normal upper arm (brachial) BP there
remains considerable residual risk for CVD.1
• Much of this risk may be due to persistently elevated central BP.2,3
Despite this…..• There has never been a trial to determine the clinical value of
targeted central BP lowering. • Important study to be undertaken before central BP may be
routinely used as a clinical tool.
1. Cushman WC, et al. N Engl J Med.362:1575-1585.2. Schultz M et al. Eur J Clin Invest. 2012;42(4):393-401.3. Vlachopoulos C et al. Eur Heart J. 2010;15:1865-71.
The LOW CBP Trial @ Menzies
• Current NHMRC funded multi-centre (Hobart, Canberra, Brisbane) randomised trial over 2 years.
• 300 patients treated for hypertension who have controlled brachial BP (<140/90 mmHg) but relatively high central SBP.
• Randomised to receive a medication that selectively lowers central BP or usual care.
• Findings expected to open the way towards a new and refined target for BP control to lower CVD risk in the broad hypertensive community.
Brachial BP 150/80 mmHg
Person A
Targeting Central BP
Central BP 147/81 mmHg
Brachial BP 150/80 mmHg
Person B
Central BP 122/81 mmHg
LOWCBP study
How can I get involved?
• Always Talk to your GP first if you are concerned about your BP
• If you would like to find out if you are eligible to participate in the ‘LOW CBP Trial’ or other Menzies projects, please contact us.
Thanks For Listening!
Question’s?