Mzantsi Medics

S.S.V. Siko.

31 July 2023

Download PDF summary: TOPICS – Mzantsi Medics

Scope

This summary will cover the following items:

• Definition of hypertension.
• Classification of hypertension.
• Risk factors for hypertension.
• How to correctly measure blood pressure.
• Blood pressure measuring devices.
• Out-of-office BP measurements.
• White coat hypertension definition.
• Masked hypertension definition.

Definition of hypertension

According to the 2017 guidelines from American College of Cardiology (ACC) and American Heart Association (AHA) guidelines; hypertension is defined as a systolic blood pressure (SBP) of 130 mmHg or more, or a diastolic blood pressure (DBP) of 80 mmHg or (1,2,3). The 2017 ACC/AHA guidelines replaced ≥ 140/90 mm Hg as the definition of hypertension. However, in the context of Mzantsi Africa (South Africa) if the 2017 ACC/AHA guidelines were to be applied the incidence of hypertension would increase to great proportion. The 2017 ACC/AHA guidelines also place substantial administrative and financial burden on a health system. The European Society of Cardiology (ESC) and European Society of Hypertension (ESH) published hypertension guidelines in 2018 and they defined hypertension as SBP of 140 mm Hg and/or DBP of 90 mm Hg and more (4). The definition of hypertension according to Mzantsi Africa guidelines is ≥ 140/90 mm Hg (5).

Classification of hypertension

The categorical classification for hypertension in Mzantsi Africa is similar to that of ECS and ESH guidelines of 2018 (6). The classification system has the following categories:

• Normal blood pressure
• Optimal blood pressure 
• High normal blood pressure 
• The three grades of hypertension 
• Isolated systolic hypertension

Normal BP is defined as SBP below 120 mm Hg and DBP below 80 mm Hg (See Table 1). Optimal BP is a SBP from 120 to 129 mm Hg and DBP below 80 mm Hg (See Table 2). High normal BP is a SBP from 130 – 139 mm Hg or DPB from 80 – 89 mm Hg (See Table 3). Grade 1 Hypertension is a SBP from 140 to 159 mm Hg or DBP from 80 – 89 mm Hg. Grade 2 Hypertension is a SBP from 160 to 179 mm Hg or DBP from 90 to 99 mm Hg. Grade 3 Hypertension is a SBP of 180 mm Hg and higher and DBP from 110 mm Hg and higher (See Table 4). Isolated systolic hypertension is defined as SBP of 140 mm Hg and higher and DBP below. Take note the usage of words such as “and” and “or” in order to classify blood pressure.

Normal blood pressure	SBP	+ DBP
	<120	<80

Optimal blood pressure	SBP	DBP
	120-129	+ < 80

High normal  blood pressure	SBP	DBP
	130-139	Or 80-89

Hypertension	SBP	DBP
Grade 1	140–159	Or 80 – 89
Grade 2	160 – 179	Or 90–99
Grade 3	≥180	Or 100–109

Isolated Systolic hypertension	SBP	DBP
	≥140	+ <90

Risk factors for hypertension

Hypertension risk factors can be differentiated in various ways. The following are known modifiable and non-modifiable risk factors for hypertension (7,8,9):

• Smoking.
• Dyslipidaemia.
• Diabetes mellitus.
• Old age of more than 55 years in males and more than 65 years in females.
• Positive family history of early onset cardiovascular disease.
• Excessive alcohol consumption.
• Excessive sodium (salt) intake and sodium sensitivity.
• Insufficient potassium intake resulting in sodium-potassium imbalance.
• Abdominal obesity / large waist circumference.
• Lack of physical activity / sedentary lifestyle.

BP Measuring technique

The technique used to measure blood pressure can influence the blood pressure readings and management of the patient; it is therefore important that a correct technique be used at all times. It is important to measure blood pressure multiple times at multiple times at rest because certain factors can affect blood pressure measurements (10). The following are guidelines for measuring blood pressure (11):

• The patient must not smoke tobacco or ingest any caffeine for at least 30 minutes before the blood pressure is measured.
• The patient must be seated for 5 minutes or longer before blood pressure is measured.
• The patient must be seated in a relaxed position in a quiet room, not slouching forward and there should be no talking while blood pressure is being measured.
• Remove tight clothing around the patient’s arm.
• In order to avoid an auscultatory gap the SBP should first be estimated by palpation.
• Inflate the cuff to 30 mm Hg above the palpated systolic level. Deflate the cuff slowly and note the BP reading when the Korotkoff sounds appears, this systolic BP, and note when Korotkoff sounds, disappear this is diastolic BP. Round off to the nearest 2 mm Hg.
• A correct size cuff must be used. The bladder portion of the cuff must cover 80% of the circumference of the upper arm but should not cover more than 100% circumference of the arm.
• Measure the blood pressure in both arms and use the arm with a higher blood pressure reading as a baseline comparison for subsequent visits.

Blood pressure measuring devices

There are numerous blood pressure measuring devices and they are grouped as follows (12,13,14):

1. Automated electronic device.
2. Manual-auscultatory blood pressure measurement devices.

Currently automated electronic devices are preferred over manual devices. Blood pressure devices are validated for use by various protocols and the two commonly used validation protocols are the British Hypertension Society (BHS) and US Association for the Advancement of Medical Instrumentation (AAMI). This document does not cover which devices are validated.

Out-of-office BP measurements

Out-of-office BP refers to home BP monitoring and Ambulatory BP monitoring. Out-of-office BP monitoring offers more prognostic value than office blood pressure monitoring (15,16). Even when correctly performed, office BP measuring is not always a true reflection of the patient’s BP. Office BP monitoring may underestimate (masked hypertension) or overestimate (white coat hypertension) hypotension.

White coat hypertension

White coat hypertension is defined as an elevated clinic BP or office BP with normal ambulatory or home BP in a patient who is not on treatment (17,18). In essence the patient has normal out-of-office BP readings. White coat hypertension occurs in approximately 30% of the patients with a high office blood pressure. This summary does not discuss prevalence, causes, effects and management of white coat hypertension. Although noted in all the grades of hypertension; white coat hypertension most commonly occurs with grade 1 hypertension.

Masked hypertension

Masked hypertension is defined as a normal clinic or office blood pressure measurements, but high BP’s out-of-office in environments such as ambulatory daytime BP or home BP (19,20,21). Masked hypertension is found in approximately 15% of the patients with a high office blood pressure (22).  This summary does not discuss prevalence, causes, effects and management of masked hypertension.

Environment of BP measuring	White coat hypertension	Masked Hypertension
Doctor’s office (Office BP)	Patient BP is elevated	Patient BP is normal
Other environment (Home / Ambulatory)	Patient BP is normal	Patient BP is elevated

References

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2. Unger, T. et al. (2020) “2020 international society of hypertension global hypertension practice guidelines,” Hypertension, 75(6), pp. 1334–1357. doi: 10.1161/hypertensionaha.120.15026.
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7. Olack, B. et al. (2015) “Risk factors of hypertension among adults aged 35-64 years living in an urban slum Nairobi, Kenya,” BMC public health, 15, p. 1251. doi: 10.1186/s12889-015-2610-8.
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10. What is blood pressure and how is it measured? (2019). Institute for Quality and Efficiency in Health Care (IQWiG).
11. NATIONAL HEALTH AND NUTRITION EXAMINATION SURVEY III CYCLE 2 PULSE AND BLOOD PRESSURE PROCEDURES FOR HOUSEHOLD INTERVIEWERS prepared by (1989) Cdc.gov. Available at: https://wwwn.cdc.gov/nchs/data/nhanes3/manuals/pressure.pdf (Accessed: July 26, 2023).
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13. Points, K. (no date) Blood pressure 1: key principles and types of measuring equipment, Emap.com. Available at: https://cdn.ps.emap.com/wp-content/uploads/sites/3/2020/05/200624-Blood-pressure-1-key-principles-and-types-of-measuring-equipment.pdf (Accessed: July 28, 2023).
14. (No date) Researchgate.net. Available at: https://www.researchgate.net/publication/12101789_Blood_pressure_measuring_devices_Recommendations_of_the_European_Society_of_Hypertension (Accessed: July 28, 2023).
15. Asayama, K., Ohkubo, T. and Imai, Y. (2021) “In-office and out-of-office blood pressure measurement,” Journal of human hypertension, pp. 1–9. doi: 10.1038/s41371-021-00486-8.
16. Baguet, J.-P. (2012) “Out-of-office blood pressure: from measurement to control,” Integrated blood pressure control, 5, pp. 27–34. doi: 10.2147/IBPC.S30409.
17. Holland, K. (2017) White coat syndrome: Causes, treatment, diagnosis and more, Healthline. Available at: https://www.healthline.com/health/white-coat-syndrome (Accessed: July 30, 2023).
18. Johnson, J. (2018) White coat syndrome (hypertension): Causes and treatment, Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/320861 (Accessed: July 30, 2023).
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20. Nichols, H. (2023) Masked hypertension: Definition, symptoms, treatment, and more, Medicalnewstoday.com. Available at: https://www.medicalnewstoday.com/articles/masked-hypertension (Accessed: July 30, 2023).
21. Ogedegbe, G., Agyemang, C. and Ravenell, J. E. (2010) “Masked hypertension: evidence of the need to treat,” Current hypertension reports, 12(5), pp. 349–355. doi: 10.1007/s11906-010-0140-4
22. ESC/ESH guidelines on Arterial Hypertension (management of) (no date) Escardio.org. Available at: https://www.escardio.org/Guidelines/Clinical-Practice-Guidelines/Arterial-Hypertension-Management-of (Accessed: July 31, 2023).