Hypertension

Question 1

• BP levels are continuously distributed in a population
• Increased BP is associated with increased risk of cardiovascular disease – (strokes, myocardial infarction (heart attacks), heart failure and atheromatous disease)
• The definition of hypertension is arbitrary and is based on the balance of the risks of elevated BP versus the risks of investigation and treatment
• 90-95% of cases of hypertension have no identifiable cause (primary or essential hypertension).
• Secondary hypertension is rare, but important causes include renal disease, tumours secreting aldosterone (Conn’s syndrome), and tumours secreting catecholamines (pheochromocytoma)
• Established hypertension is due to elevated peripheral vascular resistance, mostly
• The increased peripheral resistance in hypertension is due to active vasoconstriction and structural narrowing of small arteries and loss of capillaries (rarefaction)
• Hypertension is associated with left ventricular hypertrophy, increased wall thickness in large arteries, remodelling in smaller arteries and rarefaction of the microvasculature

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•Antihypertensive drugs will not be discussed

Answer 1

Question 2

Answer 2

Question 3

Genes and Environment in Etiology of Primary Hypertension

Genetics

Monogenic (rare) - causes <1% of hypertension

Liddle’s Syndrome - mutation in amiloride-sensitive tubular epithelial Na channel

Apparent mineralocorticoid excess - mutation in 11b-hydroxysteroid dehydrogenase

Complex Polygenic (common)

Environment

Dietary Salt

Obesity/Overweight/Lack of Exercise

Alcohol

Pre-natal Environment (underweight babies have a higher risk of cardiovascular disease and diabetes)

Pregnancy (pre-eclampsia)

Answer 3

Question 4

Typically, established hypertension is associated with:

list 5 things

Answer 4

Question 5

What accounts for the elevated PVR in hypertension?

List 3 things

Answer 5

•Active narrowing of arteries

– vasoconstriction (probably short-term)

•Structural narrowing of arteries

–growth and remodelling (adaptive?)

•Loss of capillaries

–rarefaction (adaptive/damage?)

Question 6

Isolated Systolic Hypertension- what causes it?

Read LAZ notes

Answer 6

•Systolic BP ≥ 140, diastolic BP ≤ 90

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•Condition of people over age 60

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• Due to increasing stiffness of medium/large arteries

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• Pulse wave reflected and is greater by the time it reaches brachial artery

Question 7

Candidate causes of primary hypertension

Answer 7

•Kidney

–Key role in BP regulation (Guyton)

–Best evidence especially in relation to salt intake

•Sympathetic nervous system

–Evidence linking high sympathetic activity to the development of hypertension

•Endocrine/paracrine factors

–Inconsistent evidence

Question 8

LOOk at lecture and laz notes

Answer 8

LOOk at lecture and laz notes