CVS 15: Hypertension Flashcards
Define hypertension and give the value which is considered abnormal
Abnormally elevated blood pressure
140/90 mmHg = abnormal
What does the updated guidelines state as the difference between ambulatory bp and office bp/ white coat bp?
- Ambulatory (home bp) the threshold tends to be 5-10 mmHg lower than of that taken at a clinic
What happens to bp with age?
- Systolic bp rises
- diastolic bp plateaus into extreme old age and then begins to decline
- PP increases (SBP- DBP)
- Mean bp rises with age
- almost everyone over 80yrs is hypertensive
What is the classification of hypertension?
- Primary/ essential (90-95% of cases): Unidentifiable cause
- Secondary (<5% of cases): Identifiable cause
Name some causes of secondary hypertension
- RENAL DISEASE
- Tumours secreting aldosterone (Conn’s)
- Tumours secreting catecholamines
- Oral contraceptive pill
- Pre-eclamsia
- Rare genetic causes
What could be some of the causes of primary hypertension?
- GENETICS
- Monogenic- Liddle’s or mineralocorticoid excess
- Complex polygenic
- ENVIRONMENT
- dietary salt
- obesity/ lack of exercise
- alcohol
- pre-natal environment
- Pregnancy
Give an equation for Blood pressure
BP= CO x PVR
What are the haemodynamic properties associated with hypertension (think about the equation for BP)
- increased TPR
- reduced arterial compliance (higher PP)
- normal cardiac output
- Normal blood volume
- central shift in blood volume- secondary to venous compliance
What causes elevated PVR in hypertension?
- Active narrowing of arteries- Vasoconstriction
- Structural Narrowing of arteries- Vasoconstriction accompanied by remodelling of the arteries, lumen gets smaller, resistance increases
- Loss of capillaries- Rarefaction= reduction in capillary density-> increase in resistance
What is isolated systolic hypertension? And which age group is it most common in?
SBP> 140 and DBP< 90
tends to occur in people over 60 because of divergence of SBP and DBP
What causes isolated systolic hypertension?
- Increased stiffness of medium/ large arteries
- pulse wave reflected and is greater by the time it reaches the brachial artery
What is the treatment for this?
- No drugs specific to this
- normal antihypertensives will reduce already normal DBP
What are the possible mechanisms causing primary hypertension?
- Kidney- key role in BP regulation, evidence mostly associated with salt intake
- Sympathetic Nervous system- high activity=> hypertension
- Endocrine/ paracrine factors => inconsistent evidence
Give 5 pieces of evidence for the kidney being the cause of hypertension
- kidney regulates bp through regulation of Na+/ H2O and EC fluid volume
- impaired renal function/ blood flow= commonest cause of hypertension
- Monogenic causes of hypertension affect kidneys
- Salt intake = high correlation with bp
- excess salt intake in many animals ==> hypertension
- in rats hypertension can be transplanted with the kidney
State some of the major risks caused by an increase in blood pressure
- CHD
- Stroke
- Peripheral vascular disease/ atheromatous disease
- Heart failure
- Atrial fibrillation
- Dementia/ cognitive impairment
- Retinopathy