Treatment of hypertension Flashcards
What is blood pressure?
The pressure exerted by blood on blood vessles
Short term regulation of blood pressure
Baroreceptors, Sympathetic and parasympathetic outflow
Long term regulation of blood pressure
Hormonal control of total body sodium
MABP
Mean Arterial Blood pressure
Equation for MABP
CO x TPR
Control of blood volume
Degree of vasoconstriction
Stage 1 hypertension
> /= 140/90
Stage 2 hypertension
> /=160/100
Stage 3 hypertension
> /= 180/110
What are the risk factors with hypertension
- Stroke,
- Ischemic heart disease
- Left ventricular hypertrophy
- Heart failure
- Renal failure
- Retinopathy
Secondary causes of hypertension
(<10%)
Renal disease
Vascular - e.g. renal artery stenosis
Hormonal- e.g. Conn’s syndrome, Cushing’s syndrome
Monogenic genetic diseases - e.g. Liddle’s
Primary causes of hypertension
(90%)
Genetic predisposition and environmental factors are proposed to cause essential hypertension through many mechanisms
Essential hypertension
- Increased sympathetic nervous system
- Increased renin-angiotensin-aldosterone system
- Endothelial dysfunction
- Defect in vascular smooth muscle contraction
- Defects in renal Na handling increased salt intake
- Obesity/ insulin resistance
- Age (increases with age)
- Ethnicity (e.g. more common in Afro-Caribbean groups)
- Family history
Why treat hypertension?
reduce risk
- reduce strokes by 42%
- Reduce heart attacks by 16%
- Reduce vascular mortality by 21%
Goals of anti-hypertensive treatment
Adequate blood pressure control -< 140/90 mmHg, alter relative risk
Prevention of target organ damage
Controlling other cardiovascular risk factors
Treatment pathways
Nonpharmacological: lifestyle modifications
Pharmacological treatment
Surgical (e.g. Conn’s syndrome)
Lifestyle
- Quit smoking
- Weight control
- Eat less salt
- Regular exercise
- Reduce alcohol intake
- Behavioral therapies, e.g. CBT
Major classes of antihypertensive drugs
ACE inhibitors Angiotensin 2 receptor blockers Diuretics Drugs acting on Sympathetic Nervous system Vasodilators
ACE inhibitors and AT1 receptor blockers side effects
- Cough (common) due to decrease in bradykinin breakdown
- Angioedema (rare but serious)
Side effects of both ACEi and ARBs
Hyperkalaemia - so cardiac issues
Diuretics
Increase in sodium and water excretion
Reduce blood volume - reduces CO - reduce BP
Sympathetic neural effects on CVS
Beta 1 - increase HR and contractility- increase CO and increase BP
Alpha 1- vasoconstriction - TPR- increase BP
Beta-blockers
Reduction in CO and renin release
Vasodilators (hint k channels)
Are K channel openers - Arterioles normally have significant smooth muscle tone - scope for relaxation
