Hypertension Part 3: When to intervene

High Blood pressure is a major risk factor for cardiovascular disease. None the less it is important to consider any individual risk factor in the context of overall cardiovascular risk.
treatment is influenced by

• pre-existing vascular disease
• other risk factors
• associated conditions (diabetes and renal disease) & target organ damage

Treatment Goals

• improve long term survival and quality of life
• reduce blood pressure
• reduce overall cardiovascular risk
• minimise end-organ damage

"Remember to remove, revise, or substitude drugs which may be causing hypertension (eg NSAIDs, corticosteroids, oral contraceptives)" Murtagh's General Practice 5th edition.


Individual and population interventions to reduce blood pressure, stroke and vascular disease (From Medicine Today sept 2009 vol 10 number 9 p 62; and Guidelines for the management of absolute cardiovascular disease risk p 39)

• decrease weight (ideal weight is BMI <25 and waist circ < 94 cm in men (<90 Asian men) and < 80cm in women (including Asian women).
• physical exercise (minimum 30 mins 5 to 7 times a week)
• reduce salt < 6 grams a day (= 2300 mg sodium)
• reduce alcohol (<2 drinks a day and 2 alcohol free days)
• increase unsaturated fat intake
• increase fresh fruit and vegetable intake
• use drug therapy in high risk individuals
• no smoking 

Immediate treatment to lower blood pressure is recommended in the following situations:

• Systolic blood pressure 180 mmHg or greater (grade 3 hypertension) and or
• Diastolic blood pressure 110 mmHg or greater
• Systolic blood pressure 160 mmHg or greater and diastolic blood pressure 70 mmHg or less (isolated systolic hypertension with widened pulse pressure)
• Patients with associated conditions (for example, stroke or myocardial infarction) or evidence of end-organ damage (for example, microalbuminuria, left ventricular hypertrophy) also need urgent treatment (see the tables below)
• Patients assessed as being at "high risk" following 5 year absolute risk assessment

Any pharmacotherapy should always be used in conjunction with lifestyle modification, and management of associated conditions.

 

 

Associated clinical conditions
Diabetes	Ø  > age 60 Ø  With urine ACR >2.5 male or > 3.5 female
Cerebrovascular disease	Ø  Ischaemic or haemorrhagic stroke Ø  TIA
Coronary heart disease	Ø  MI Ø  Angina Ø  Stent/ angioplasty
Chronic heart failure
Chronic kidney disease	Ø  Diabetic nephropathy Ø  GN Ø  Hypertensive kidney disease
Aortic disease	Aneurism (dissecting or fusiform)
Peripheral Arterial Disease	Clinically or ABI < 0.9
Hypercholesterolaemia	>7.5 total
Family history of:	Premature cardiovascular disease
Previous diagnosis of:	Familial hypercholesterolaemia

End Organ Disease
LVH	Diagnosed on ECG or echo (see previous blog)
Microalbuminuria
Chronic kidney disease	Presence of either Ø  Proteinuria Ø  eGFR < 60
Vascular disease	Ø  Atherosclerosis evident on ultrasound or radiology Ø  Hypertensive retinopathy grade II or higher

From Heart Foundation Guide to Management 2010 guide

The most up to date guidelines on blood pressure that I can find are the "National Vascular Disease Prevention Alliance Guidelines for the management of absolute cardiovascular disease risk". 2012.

In contrast to the 2008 (updated 2010) guidelines from the Heart Foundation "Guide to the Management of Hypertension", the former, more recent guidelines, recommend immediately treating anyone who is over age 45, at low or moderate risk (based on the Australian cardiovascular risk charts) with blood pressure ≥ 160/100.

Treatment should begin with any of the following

• ACEi or ARB
• CCB (dihydropyridine)
• Low dose thiazide or thiazide like diuretic (in patients > age 65)*

* Note that thiazide diuretics have been associated with increased risk of new onset diabetes therefore use cautiously in patients with "pre-diabetes" or metabolic syndrome. The Heart foundation recommends reserving these agents as first-line for older patients in whom the benefits of managing isolated systolic hypertension and preventing stroke are likely to outweigh the risk of diabetes onset.

Always begin with the LOWEST recommended dose (e.g. ACEi or ARB).

If target not reached after 6 week trial

suggest ACEi (or ARB) + CCB (dihydropyridine)

If target not reached at 3 months

suggest ACEi (or ARB) + CCB + Thiazide

ACEi/ ARB are recommended in a number of settings for cardiac and renal benefit, they must be used cautiously/ avoided in patients with renal artery stenosis.

Beta Blockers are recommended post MI and in the setting of angina. Exercise caution in patients with depression, uncontrolled heart failure, bradycardia/ AV block and asthma/ COPD.

Combinations to avoid:

X ACEi (or ARB) + potassium sparing diuretic (spironolactone, amiloride)

= hyperkalaemia

X Beta blocker + verapamil 

= heart block

X ACEi + ARB

= hypotension and lack of efficacy

Common Adverse Effects

 ACEi (and ? ARB) can cause cough
CCBs may cause constipation (especially verapamil), flushing, headache and oedema
Thiazide diuretics can cause gout
Beta blockers can cause depression, lethargy, erectile dysfunction

If blood pressure is not responding to medication, reassess for;

• non adherence
• undiagnosed secondary cause
• hypertensive effects of other drugs
• treatment resistance due to sleep apnoea
• hidden use of alcohol or recreational drugs
• unrecognised high salt intake
• white coat hypertension
• technical factors affecting measurement
• volume overload in CCF

Which of the following  combinations would you avoid?

• Lisinopril 20mg daily and Olmesartan 30mg once daily
• Eplerenone 50mg and Captopril 25mg
• Atenolol 50mg daily and Verapamil CR 240mg once daily
• Carvedilol 50mg and Amlodipine 10mg in a patient with CHD

Following blogs will cover management of hypertension in particular situations such as pregnancy, diabetes, stroke etc