Management of Primary Hypertension

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Hypertension affects a large selection of the population and is one of the most important preventable causes of premature morbidity and mortality. It usually is only detected on routine examinations or as a result of a complication which has arisen as a result of hypertension. Having high blood pressure increases your risk of stroke (haemorrhagic and ischaemic), myocardial infarction, heart failure, chronic kidney disease, cognitive decline and premature death.

There is a variety of guidelines for defining and categorising hypertension. According to the World Health Organisation (2018) International classification of disease, hypertension is categorised into 4 descriptions:
  • Normal: systolic blood pressure (BP) <120mmHg and diastolic BP <80mmHg
  • Elevated: systolic BP 120-129mmHg and diastolic BP <80mmHg
  • Stage 1 Hypertension: systolic BP 130-139mmHg or diastolic BP 80-89mmHg
  • Stage 2 Hypertension: systolic BP >140mmHg or diastolic >90mmHg
However, according to the National Institute for Health and Care Excellence (NICE)(2011) and the definition currently accepted in practice (within the UK) is:
  • Stage 1 Hypertension: clinic BP is >140/90mmHg and subsequent ambulatory blood pressure monitoring (ABPM) daytime average or home blood pressure monitoring (HBPM) average blood pressure is >135/85mmHg.
  • Stage 2 Hypertension: clinic BP is >160/100mmHg and subsequent ABPM daytime average or HBPM average blood pressure is >150/95mmHg.
  • Severe Hypertension: clinic systolic blood pressure is >180mmHg, or diastolic is >110mmHg.

Red Flags

Coarctation of Aorta
Coarctation of the aorta is the congenital narrowing of the aorta, commonly referred to as aortic narrowing. The narrowing usually occurs at the aortic arch.
Pre-eclampsia
Phaeochromocytoma
Illicit Drug Use

Emergencies Vs Urgencies

A hypertensive emergency is a blood pressure >180/110 mmHg (Severe Hypertension) with evidence of new or worsening target organ damage; this can result in an immediate risk to the cardiovascular system and the patient. Hypertensive emergencies include:
  • Hypertensive encephalopathy
  • Hypertension left ventricular failure
  • Acute aortic dissection
Hypertensive urgencies is a blood pressure >180/110 mmHg (Severe Hypertension) in a patient who is otherwise well with no acute or impending change in target organ damage. Hypertensive urgencies include:
  • Malignant or accelerated hypertension
  • Asymptomatic high blood pressure
  • Pre-eclampsia

Initial Investigations

To assess the patient for the potential complications it is useful to undertake some screening. The initial investigations include:
  • ECG
  • Chest x-ray
  • Routine blood tests including random sugar
  • Urine dip to identify glycosuria and proteinuria

Treatment

The effects of chronic hypertension on the organ systems of the body are called the target organ damage. These include nephropathy, hypertensive retinopathy, cerebrovascular disease, cardiovascular disease and left ventricular hypertrophy. Therefore, early diagnosis and treatment of hypertension result in a reduction of the risks above.

Offer treatment for individuals aged <80years with Stage 1 Hypertension who have one or more of the following:
  • target organ damage
  • cardiovascular disease
  • renal disease
  • diabetes
  • a 10-year cardiovascular risk equivalent to 20% or higher (can use QRISK®2 calculator)
Offer treatment for individuals of any age with Stage 2 Hypertension.

For individuals <40 years with Stage 1 Hypertension and no evidence of target organ disease, cardiovascular disease, renal disease, or diabetes should be considered for referral to a specialist to exclude secondary hypertension and detailed assessment of target organ damage. The main reason for this is due to an underestimate in the 10-year cardiovascular risk in this age group.