The SA Journal Diabetes & Vascular Disease Vol 11 No 4 (November 2014)

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140 VOLUME 11 NUMBER 4 • NOVEMBER 2014
REVIEW SA JOURNAL OF DIABETES & VASCULAR DISEASE
guidelines leads to significant errors in BP measurement. BP should
be recorded using an approved and calibrated electronic device
or mercury sphygmomanometer (Table 2). Repeat measurements
should be performed on at least three separate occasions within
four weeks unless BP is ≥ 180/110 mmHg.
Self- and ambulatory measurement of BP
Self BP measurement (SBPM) and ambulatory BP measurement (ABPM)
are recommended in selected circumstances and target groups:11
• suspected white-coat HTN (higher readings in the office
compared with outside) or masked HTN (normal readings in
office but higher outside)
• to facilitate diagnosis of HTN
• to guide antihypertensive medication, especially in high-risk
groups, e.g. elderly, diabetics
• refractory HTN
• to improve compliance with treatment (SBPM only).
Masked HTN should be suspected if, despite a normal BP in the
clinic, there is evidence of target-organ damage.
All devices used for SBPM and ABPM should be properly
validated in accordance with the following independent websites:
or .
In general, only upper-arm devices are recommended, but these
are unsuitable in patients with sustained arrhythmias. For SBPM
the patient should take two early morning and two late afternoon/
early evening readings over five to seven days, and after discarding
the first day readings, the average of all the remaining readings is
calculated.
Wrist devices are recommended only in patients whose arms are
too obese to apply an upper arm cuff. The wrist device needs to be
held at heart level when readings are taken.
The advantages of SBPM measurement are an improved
assessment of drug effects, the detection of causal relationships
between adverse events and blood pressure response, and possibly,
improved compliance. The disadvantages relate to increased patient
anxiety and the risk of self-medication.
ABPM provides the most accurate method to diagnose HTN,
assess BP control and predict outcome.12 Twenty-four-hour ABPM
in patients with a raised clinic BP reduces misdiagnosis and saves
costs.13 Additional costs of ABPM were counterbalanced by cost
savings from better-targeted treatment. It can also assess nocturnal
BP control and BP variability, which are important predictors
of adverse outcome. However the assessment is limited by
access to ABPM equipment, particularly in the public sector, and
impracticalities of regular 24-hour ABPM monitoring.
The appropriate cut-off levels for diagnosis of HTN by SBPM and
ABPM are listed in Table 3. 11
Automated office BP measurement
Despite efforts to promote proper techniques in manual BP
measurement, it remains poorly performed. Automated office BP
measurement offers a practical solution to overcome the effects of
poor measurement, bias and white coating.14 It is more predictive
of 24-hour ABPM and target-organ damage than manual office BP
measurement. Six readings are taken at two-minute intervals in a
quiet room. The initial reading is discarded and the remaining five are
averaged. The appropriate cut-off level for HTN is 135/85 mmHg.14
CVD risk stratification
The principle of assessing and managing multiple major risk factors
for CVD is endorsed. However, because the practical problems in
implementing previous recommendations based on the European
Society of HTN (ESH) and the European Society of Cardiology (ESC)
HTN guidelines, it has been decided to use a modification of this
approach.9
Once the diagnosis of HTN is established, patients with BP ≥
160/100 mmHg should commence drug therapy and lifestyle
modification. Patients with stage 1 HTN should receive lifestyle
modification for three to six months unless they are stratified as
high risk by the following criteria: three or more major risk factors,
diabetes, target-organ damage or complications of HTN (Table 4).
Routine baseline investigations
Table 5 lists recommended routine basic investigations. The tests
are performed at baseline and annually unless abnormal. Abnormal
results must be repeated as clinically indicated.
Table 3. Definitions of hypertension by different methods of BP
measurement
Office
Automated
office Self Ambulatory
Predicts
outcome
+ ++ ++ +++
Initial diagnosis Yes Yes Yes Yes
Cut-off BP
(mmHg)
140/90 Mean
135/85
135/85 Mean day
135/85
Mean night
120/70
Evaluation of
treatment
Yes Yes Yes Limited, but
valuable
Assess diurnal
variation
No No No Yes
Table 4. Major risk factors, target-organ damage (TOD) and
complications. Adapted from the ESH/ESC guidelines9
Major risk factors TOD Complications
• Levels of systolic and
diastolic BP
• Smoking
• Dyslipidaemia:
– total cholesterol
> 5.1 mmol/l, OR
– LDL > 3 mmol/l, OR
– HDL: men < 1 and
women < 1.2 mmol/l
• Diabetes mellitus
– Men > 55 years
– Women > 65 years
• Family history of early
onset of CVD:
– Men aged < 55 years
– Women aged
< 65 years
• Waist circumference:
abdominal obesity:
– Men ≥ 102 cm
– Women ≥ 88 cm
The exceptions are
South Asians and
Chinese:
men: > 90 cm and
women: > 80 cm.
• LVH: based on
ECG
– Sokolow-Lyons
> 35 mm
– R in aVL
> 11 mm
– Cornel
> 2 440 (mm/
ms)
• Microalbuminuria:
albumin creatine
ratio 3–30 mg/
mmol, preferably
spot morning
urine and eGFR
> 60 ml/min
• Coronary heart
disease
• Heart failure
• Chronic kidney
disease:
– macroalbuminuria
> 30 mg/mmol
– OR eGFR
< 60 ml/min
• Stroke or TIA
• Peripheral arterial
disease
• Advanced
retinopathy:
– haemorrhages OR
– exudates
– papilloedema