High Blood Pressure:problems, solutions

and research.

Dr Martin SchultzMenzies Research Institute Tasmania

University of Tasmania, Hobart, Australia.Martin.Schultz@utas.edu.au

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

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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?