1. Confirm the diagnosis, using ambulatory (ABPM) or home blood pressure monitoring (HBPM)
Hypertension can be grouped into three stages using both clinic and ABPM/HBPM.
- Stage 1 – defined as a blood pressure greater than or equal to 140/90mmHg and subsequent ABPM daytime average or HBPM average 135/85 or greater.
- Stage 2 – clinic BP 160/100 or higher and average daytime ABPM/HBPM of 150/95 or greater.
- Severe – clinic systolic BP is 180 or higher or diastolic BP is greater than or equal to 110.1
For ABPM ensure patients know to take at least two measurements per hour during waking hours. The average value of at least 14 measurements will be calculated to give a final reading.
If using HBPM, ensure two measurements are taken, at least one minute apart, twice daily, preferably morning and evening, for a minimum of four days (ideally seven) and discard the first day’s measurements. In cases of severe hypertension (equal to or greater than 180/110), consider starting antihypertensive therapy immediately.
2. Refer for immediate admission for accelerated hypertension or phaemochromocytoma
Patients should be referred for admission on the same day if there are signs of accelerated hypertension (blood pressure >180/110 with signs of papilloedema and/or retinal haemorrhage) or there is suspicion of phaeochromocytoma (labile or postural hypotension, headaches, pallor, palpitations and diaphoresis).1
3. Those with ‘white-coat’ or ‘masked’ hypertension should be closely monitored
Those with ‘white-coat’ (clinic hypertension, but normal ambulatory monitoring) and ‘masked’ (hypertension on ambulatory monitoring but not clinical hypertension) are at a higher risk of developing sustained hypertension and asymptomatic target organ damage, such as left ventricular hypertrophy.2 Therefore, they should be investigated over a three to six-month period and followed up closely with repeated ambulatory or home monitoring.3 A link has also been shown between these groups and metabolic risk factors, including an increased risk of new-onset diabetes and associated increase in cardiovascular risk. Therefore lifestyle advice should be given to these individuals, with consideration of treatment for those at increased CV risk.3
4. Automated devices may not measure blood pressure accurately if the pulse is irregular
For all patients, palpate the radial or brachial pulse before checking the blood pressure. If the pulse is irregular, for example due to atrial fibrillation, an automated blood pressure device can give inaccurate readings due to beat-to-beat variation, so blood pressure should be measured manually with auscultation over the brachial artery.
5. Screen for treatable causes (secondary hypertension) and know when to refer
Suspect secondary hypertension in the presence of severe (systolic blood pressure >180 or diastolic >110) or resistant hypertension (uncontrolled blood pressure despite three antihypertensive medications) or where there is an acute rise in blood pressure, as well as malignant or accelerated hypertension (severe hypertension where end-organ damage is seen). Patients with stage 1 hypertension aged under 40, with no obvious identifiable risk factors for hypertension or family history, should also be investigated for an underlying cause. Secondary causes include renovascular disease, acute or chronic renal disease, endocrine disorders and drug-induced hypertension.4
6. Use the new guidelines as a guide for starting medical therapy
Antihypertensive therapy should be started in anyone with stage 2 hypertension (classified as a clinic blood pressure of greater than or equal to 160/100, and a subsequent average ABPM or HBPM of 150/95 or higher), those under 80 years with stage 1 hypertension (clinic blood pressure of 140/90 or greater and average ABPM/HBPM of 135/85) and any of the following:
- Target organ damage.
- Established CVD.
- Renal disease.
- Diabetes mellitus.
- A 10-year CV risk of 20% or higher.1
7. If considering diuretic treatment use a thiazide-like diuretic
If diuretic therapy is due to be initiated or changed offer a thiazide-like diuretic, such as chlortalidone (12.5–25.0mg once daily) or indapamide (1.5mg modified-release once daily or 2.5mg once daily), in preference to a conventional thiazide diuretic, for instance bendroflumethiazide or hydrochlorothiazide.1 However, for people already taking bendroflumethiazide or hydrochlorothiazide, with well controlled blood pressure, continue the same treatment.1
If a patient is on a ß-blocker as first-line treatment and needs a second agent, add in a calcium-channel blocker, rather than a diuretic to reduce their risk of developing diabetes mellitus. 5
8. For resistant blood pressure consider adding a fourth antihypertensive or seek expert advice
If a patient is already on three antihypertensive medications and still poorly controlled, start by ensuring that they are on optimal and best tolerated doses. If their clinical blood pressure remains >140/90 this is termed resistant hypertension, at which point consider a fourth antihypertensive drug and/or seek specialist advice. Consider further diuretic therapy with low-dose spironolactone (25mg once daily) if the serum potassium level is 4.5mmol/l or less (use with caution in those with renal impairment). If the serum potassium level is greater than 4.5mmol/l consider a higher-dose thiazide-like diuretic.
If further diuretic therapy for resistant hypertension is not tolerated, contraindicated or ineffective consider an alpha or ß-blocker. If blood pressure still remains uncontrolled seek expert advice, if not already sought.
9. Ensure drug compliance
Given the asymptomatic nature of hypertension, compliance can often be an issue. By counselling patients on the importance of adherence and the consequences of non-adherence, drug compliance rates can be improved.6 Time should be taken to both counsel patients about side-effects and monitor compliance at regular intervals. Simple regimens that can be tailored to patients’ daily activities are preferable. Observed improvement via a home monitor may help patient adherence.
10. Be careful of overtreatment in the elderly population
Monitor the response to lifestyle and drug therapy, aiming for a clinical blood pressure below 140/90 in those under 80 years and below 150/90 in those over 80 years, excluding patients with diabetes. Be sure to ask for symptoms of postural hypotension, especially in the elderly group, and adjust medications accordingly. In those aged 65 years or older with isolated systolic hypertension, caution needs to be taken not to reduce the diastolic blood pressure too low (to levels of 60 or below) as this has been associated with increased risk of stroke and myocardial infarction.7
Dr Ajay Jain is a consultant cardiologist at The London Clinic and Barts Health NHS Trust
References
