clinical knowledge summaries cks hypertension (not people with diabetes) diagnosis and initial...

Clinical Knowledge Summaries

CKS Hypertension (not people

with diabetes)Diagnosis and initial management of hypertension in primary care

Does not cover hypertension in pregnancy

Educational slides based on the CKS topic Hypertension – not diabetic (April 2012), and NICE guidance (2011); Hypertension: clinical management of primary hypertension in adults.

Key learning points and objectives• To be able to:

o Outline how blood pressure should be measured.o Describe when to use ambulatory and home

monitoring and why. o Recognise people who require hypertensive

treatment. o Recognise people who require referral or

admission.

Hypertension• Hypertension is persistently raised arterial

blood pressure (BP).• Arbitrary thresholds are used to define when a

person becomes hypertensive. • The threshold for suspecting hypertension in

clinic is:o Systolic BP sustained above or equal to

140 mmHg, oro Diastolic BP sustained above or equal to

90 mmHg, or o Both.

Based on the CKS topic Hypertension – not diabetic (April 2012), and NICE guidance (2011); Hypertension: clinical management of primary hypertension in adults.

Hypertension• Hypertension is not a disease, but is a significant risk factor

for diseases such as:o Coronary heart disease.o Stroke.o Peripheral vascular disease.o Retinopathy.o Aortic aneurysm.o Heart failure.o End-stage renal disease.

• The greater the systolic or diastolic BP, the greater the risk of mortality and morbidity, for example: o The risk of stroke, myocardial infarction, and peripheral vascular

disease is 2–3 times greater in people with hypertension.Based on the CKS topic Hypertension – not diabetic (April 2012), and NICE guidance (2011); Hypertension: clinical management of primary hypertension in adults.

Prevalence • About 30% of adults have blood pressure

that is at least 140/90 mmHg.• The proportion of people with

hypertension increases with age.• About:

o30% of people 45–54 years of age have hypertension.

o70% of people 75 years of age or older have hypertension.


Hypertension - types• Primary (or essential) hypertension

o No identifiable cause - most common form and accounts for 95% of people with hypertension.

• Secondary hypertensiono Has a known underlying cause (accounts for 5%). Caused

by: o Renal disorders (e.g. chronic pyelonephritis, diabetic

nephropathy).o Vascular disorders (e.g. coarctation of the aorta).o Endocrine disorders (e.g. primary hyperaldosteronism).o Drugs (e.g. alcohol, cocaine).o Miscellaneous causes (e.g. scleroderma, obstructive sleep

apnoea).


When measuring BP• Always use a device that:

o Has been validated to the British Hypertension Society (BHS) standard, and

o Is properly maintained and calibrated.

• Use the correct cuff size:o Using too large a cuff can cause the BP to be

underestimated.o Using too small a cuff can cause the BP to be

overestimated.

• Make sure the person is:o Sitting for at least 5 minutes.o Relaxed and not moving or speaking.


When measuring BP

• Ensure the arm is supported at the level of the heart, and no tight clothing is constricting the arm.

• Information on validated BP measuring devices can be obtained from the BHS website:o www.bhsoc.org/


Diagnosing hypertension• Initially measure BP in clinic.• Take a BP reading in both arms.

o There can be large differences between arms in some people.

• If the difference in readings between arms is more than 20 mmHg:o Repeat BP measurements in both arms.

• If the second measurement confirms a difference of more than 20 mmHg.o Use the arm with the higher values for subsequent

measurements.o Consider secondary causes of hypertension (e.g. coarctation of

the aorta) and possible referral if a difference of more than 20/10 mmHg persists.


Diagnosing hypertension• If the first blood pressure measurement is

140/90 mmHg or greater, measure BP again after 1 minute.

• If the second measurement is substantially different from the first, take a third measurement after 1 minute.

• Use the lower of the last two measurements as the recorded clinic blood pressure.


What if BP is very high in clinic? • Arrange same-day admission if:

o BP is 220/120 mmHg or higher.o BP is 180/110 mmHg or higher with signs

of accelerated (malignant) hypertension (papilloedema and/or retinal haemorrhage).

• Start antihypertensives immediately if no signs of accelerated hypertension and:o Systolic BP is 180 mmHg or higher, or o Diastolic BP is 110 mmHg or higher.


Diagnosing hypertension• For everyone else, if clinic blood pressure

remains 140/90 mmHg or greater:o Recheck blood pressure on 2–3 occasions over the

next few weeks or months.o The interval depends on clinical judgement.


Diagnosing hypertension

• If blood pressures are persistently above 140/90 mmHg in clinic:o Arrange ambulatory BP monitoring (ABPM) to

confirm the diagnosis. o If ABPM is not available or the person cannot

tolerate ABPM use home blood pressure monitoring (HBPM).

• ABPM and HBPM are not suitable for people with atrial fibrillation or other significant pulse irregularity.


Why use ABPM?• ABPM is recommended because it:

o Is a more accurate reflection of BP.o Is better at predicting clinical events (e.g.

mortality, stroke) than clinic BP monitoring. o It reduces the risk of misdiagnosis and

unnecessary drug treatment for people who have ’white coat hypertension’.

• When ABPM readings are averaged, they are usually lower than readings made in clinic. o The difference is about 10–20 mmHg for systolic

BP and 5–10 mmHg for diastolic BP.Based on the CKS topic Hypertension – not diabetic (April 2012), and NICE guidance (2011); Hypertension: clinical management of primary hypertension in adults.

How to use ABPM

• The ABPM is normally set up to take readings:o Every 30 minutes during usual waking hours (e.g.

between 8am and 10pm).

• A record of the readings is stored on the device.o An average of at least 14 readings is required.


How to use ABPM

• When the readings are being taken, the person should:o Sit (if possible).o Keep the cuff at the level of the heart.o Keep still.

• Ask the person to fill in a diary card to note whenever particularly restful or stressful situations occur, and when medications are taken.


Why use HBPM?

• HBPM is recommended because:o Frequent measurements produce average

values that can be more reproducible and reliable than traditional clinic BP readings.

o Self-monitoring might:• Improve blood pressure control by improving

compliance.• Predict cardiovascular outcome better than clinic

measurements.


How to use HBPMAdvise the person to:

o Sit comfortably and rest for 5 minutes before taking a reading.

o Take a BP reading twice daily, in the morning and evening, for 7 days ideally (or at least 4 days).

o Take two consecutive measurements at least one minute apart for each reading.


Interpreting ABPM or HBPM results• ABPM

o Use the average value of at least 14 ABPM readings.

• HBPMo Discard the measurements taken on the first day, as they

might not be representative.o Average all the measurements from the remaining days.

• If clinic BP is above or equal to:o 140/90 mmHg and ABPM or HBPM is above or equal to

135/85 mmHg, diagnose stage 1 hypertension.o 160/100 mmHg and ABPM or HBPM is above or equal to

150/95 mmHg, diagnose stage 2 hypertension.Based on the CKS topic Hypertension – not diabetic (April 2012), and NICE guidance (2011); Hypertension: clinical management of primary hypertension in adults.

Criteria for diagnosing hypertension


Category Clinic blood pressure(mmHg)

Subsequent ABPM or HBPM average blood pressure (mmHg)†

Stage 1 hypertension >=140/90 >=135/85

Stage 2 hypertension >=160/100 >=150/95

Stage 3 hypertension >= 180 systolic or* >=110 diastolic

—

Isolated systolic hypertension

>= 160 systolic —

* When systolic and diastolic blood pressure readings fall into different categories, use the higher pressure category to determine the class. If stage 3 hypertension, do not wait for results of ABPM or HBPM before starting antihypertensive treatment.

† ABPM (Ambulatory Blood Pressure Monitoring) daytime average; HBPM (Home Blood Pressure Monitoring) average blood pressure.

What if hypertension is not diagnosed?• Measure the BP every 5 years.• Consider measuring BP more often if the

person's clinic blood pressure is close to 140/90 mmHg.


Initial management following ABPM and HBPM

• Offer antihypertensive treatment if the person is:o Younger than 80 years with stage 1 hypertension

and has one or more of the following:o Target organ damage, established cardiovascular

disease, renal disease, diabetes, and/or a 10 year cardiovascular risk of 20% or more.

o Any age with stage 2 hypertension.


Initial management• For all people with hypertension:

o Assess and manage cardiovascular risk.o Reinforce lifestyle advice such as:• Stopping smoking.• Moderation in alcohol, salt, and caffeine consumption.

o Give advice on weight loss (if appropriate).


Summary• Primary (or essential) hypertension accounts for 95% of

cases.o Secondary hypertension (known cause) accounts for 5%.

• Initially measure BP in clinic. • BP should be measured with immaculate technique using

calibrated equipment.• Always use a device that:

o Has been validated to the British Hypertension Society (BHS) standard, and

o Is properly maintained and calibrated.

• Arrange same-day admission if:o BP is 220/120 mmHg or higher.o BP is 180/110 mmHg or higher with signs of accelerated hypertension.

Summary• Start antihypertensives if no signs of accelerated

hypertension and:o Systolic BP is 180 mmHg or higher, or o Diastolic BP is 110 mmHg or higher.

• For everyone else, if clinic BP is persistently greater than 140/90 mmHg, arrange for ABPM or HBPM. If:o ABPM or HBPM is above or equal to 135/85 mmHg, diagnose stage 1

hypertension.o ABPM or HBPM is above or equal to 150/95 mmHg, diagnose stage 2

hypertension.

clinical knowledge summaries cks hypertension (not people with diabetes) diagnosis and initial...

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