Hypertension Flashcards
What is hypertension?
Is that blood pressure at which benefits of treatments with antihypertensive agents in reducing cardiovascular, cerebrovascular and peripheral vascular risk outweighs the risk of treatment
When does a person have hypertension?
140/90
What happens when there is a 2 mmHg rise in BP?
7% increase risk of mortality in IHD
10% increase mortality from stroke
What does an increase in BP of 20mmHg systolic and 10mmHg diastolic?
Doubles risk of CVD death regardless of age
What is hypertension a risk factor for?
MI, Heart failure, stroke, cardiovascular disease
What organ does hypertension affect?
Damages every organ
End-organ damage
What can make BP fluctuate during the day?
Physical and mental stress
What is stage 1 hypertension?
140/90 mmHg
ABPM daytime average of 135/85 mmHg or more
What is stage 2 hypertension?
160/100 mmHg
ABPM daytime average of 150/120 mmHg or higher
What is stage 3 or severe hypertension?
180/120 mmHg or higher
What is ABPM measurements?
30 measurements over the day or so
More accurate reflection of BP
What is primary hypertension?
No cause is identified - 80-90% of cases
What is secondary hypertension?
Can have chronic renal disease, renal artery stenosis or endocrine disease
More common in younger patients
What is the risk factors for hypertension?
Cigarette smoking, Diabetes, Renal disease, Male (2x), hyperlipidaemia, previous stroke and LV hypertrophy (2x)
Low fitness is main factor
What are the primary contributors to BP?
Cardiac output - CO=SV x HR
Peripheral vascular resistance
What does sympathetic system activation produce?
Vasoconstriction
Reflex tachycardia
Increased stroke volume
What does renin stimulation produce?
Produces angiotensin II and aldosterone
Angiotensin II - vasoconstrictor
Aldosterone - salt and water retention which increases the circulating blood volume
What is the RAAS responsible for?
Maintenance of sodium balance
Control of blood volume
Control of blood pressure
What is RAAS stimulated by?
Fall in BP
Fall in circulating volume
Sodium depletion
These stimulate release of renin from the juxtaglomerular apparatus
Explain the aetiology of hypertension?
Polygenic - major genes and poly genes
Polyfactorial - environment, individual and shared
What is the likely causes of hypertension?
Increased reactivity of resistance vessels and resultant increase in peripheral resistance
Sodium homeostatic effect - kidneys unable to secrete appropriate amounts of Na for any given BP. Fluid is then retained so BP increases
What are other factors that can cause hypertension?
Age, genetics and FH, environment, weight, alcohol intake and race
Explain hypertension and age
BP tends to rise with age due to decreased arterial compliance
Treatment will reduce stroke and MI risk
Pragmatic approach as elderly more susceptible to adverse effects
Explain hypertension and genetics
Hypertension can run in families
Closest correlation is between siblings
Environmental factors have a role in the development
Explain environment and hypertension
Mental and physical stress increase BP
True stress - tend to be highly resistant to treatment
White coat hypertensives are at risk of CVD
Explain alcohol and hypertension
Common causes in young men
Large amounts of alcohol increase BP
If reduce alcohol intake then BP will fall
Explain weight and hypertension?
Obese patients have increased BP
Weight loss can produce a fall in BP
Most important non- pharmacological measure
Explain birth weight and hypertension
Low birth weight is associated with higher likelihood of developing hypertension and heart disease in adulthood
Each Kg lost, 1-2mmHg higher
Explain race and hypertension?
Caucasians have lower BP then African populations in same environment
Reasons are unclear
African populations seen as salt retainers so more sensitive
What are the steps in treatment for hypertension?
Confirm diagnosis
Assess risk factors - calculator/ Q risk
Assess end organ damage
How do you assess end organ damage?
ECG, Echocardiogram, proteinuria, renal ultrasound, renal function
What are some treatable causes for hypertension?
Obesity, renal artery stenosis, endocrine causes, coarctation of aorta, drug induced and sleep apnoea
Explain treatment for stage 1 hypertension?
Antihypertensive - if under 80 with one of: target end organ damage, renal disease, CVD, Diabetes
Under 40s - look for causes
Elderly - offer antihypertensive taking into account of co-morbidities
What is the treatment for stage 2 hypertension?
Antihypertensive to people of any age
What is step 1 of choosing antihypertensive?
Aged over 55 or black people f African/Caribbean descent - calcium channels blocker or thiazide like diuretic
Under 55 - ACE inhibitor or ARB. Careful with women of child bearing age
What is step 2 and 3 of choosing antihypertensive drug treatment?
2 - add thiazide type diuretic to step 1 (Indapamide)
3 - Add CCB, ACEi and diuretic together
What is step 4 for choosing an antihypertensive drug treatment?
Resistant hypertension
Unable to achieve target BP despite 3 or more agents
Consider compliance issues, high dose thiazide, or further diuretic therapy (spironolactone)
What are some antihypertensive drugs?
Angiotensin converting enzyme inhibitors
Competitively inhibit the action of ACE - ACE converts angiotensin I to II which is a vasoconstrictor
What are some contradictions to ACEi?
Renal artery stenosis
Impaired renal function
Hyperkalaemia
Fertile female
What are some drug-drug interactions that can occur?
NSAIDs - precipitate acute renal failure
Potassium supplements/ potassium sparing diuretics - hyperkalaemia
Explain angiotensin II receptor blockers
ARB ex. losartan, valsartan, candesartan
Inhibit action of angiotensin II at AT1 receptor
Advantage of ACEi - fewer side effects
Describe some calcium channels blockers
Vasodilators - reduce peripheral vascular resistance. >55 and women of child bearing age
Rate limiting Ca2+ blockers - reduce HR and produce some vasodilation
Both block the L type Ca2+ channels in myocytes
What are some adverse drug reactions to calcium channel blockers?
Flushing, headaches, ankle oedema, indigestion
Can be rate limiting as can also cause bradycardia and constipation
What are some contraindications for CCB?
Acute MI
Heart failure
Bradycardia
Describe thiazide type diuretics
Ex. Indapamide
First line therapy usually in people of African/ Caribbean origin
Can be used in combination with antihypertensive
Benefit in reducing risk of stroke and MI
Low doses so don’t cause significant diuresis
What is thiazide type diuretics mechanism of action?
Enhances urinary excretion of sodium
Resistance vessel dilation - reduced resistance
Effect may take weeks
Side effects include gout and ED
What are some less commonly used agents?
Alpha adrenoreceptor antagonist - Doxazosin which opposes smooth muscle contraction
Centrally acting agents - methylopa and moxonidine which can be used in pregnancy
Vasodilators - hydralazine and minoxidil
Explain common treatment regime for age >55 or African/ Caribbean origin
Start CCB
Add thiazide diuretic
Add ACEi or ACE
Add beta blocker or alpha blocker
Add less commonly used agent
Explain a common treatment regime for an under 55?
Start ACEi
Add thiazide diuretic
Add CCB
Add beta blocker
Add less commonly used agent
