Cardiovascular Systems 11 - Hypertension Flashcards
Discuss the epidemiology of hypertension
- Mean blood pressure rises with age
- Most people over 60 are expected to be hypertensive
- As blood pressure increases, stroke mortality increases
Define hypertension
A level of blood pressure where investigation and treatment does more good than harm
How is hypertension classified?
- Secondary hypertension has an identifiable cause (eg. tumours, renal disease, contraceptive pill, genetic causes)
- Primary/essential hypertension has an unidentifiable cause (majority)
List the genetic and environmental causes of high blood pressure
- Monogenetic/polygenetic causes (monogenetic is very rare)
- Dietary salt
- Obesity
- Alcohol
- Birth weight
- Pregnancy
List the monogenic diseases that cause hypertension.
- Liddles syndrome (mutation in amiloride-sensitive tubular epithelial Na channel)
- Mineralocorticoid excess (mutation in 11b-hydroxysteroid dehydrogenase)
What is established hypertension associated with?
- Increased TPR
- Decreased arterial compliance
- Normal cardiac output
- Normal blood volume
- Central shift in volume
What causes elevated total peripheral resistance in hypertension?
- Active narrowing of arteries
- Structural narrowing of arteries (growth and remodelling)
- Capillary loss
What is isolated systolic hypertension?
- Systolic blood pressure is over 140mmHg
- Diastolic BP is less than 90mmHg
What causes isolated systolic hypertension?
- Increasing stiffness in medium/large arteries in those over 60
- The pulse wave is reflected and greater by the time it reaches the brachial artery
- TPR does not increase
What parts of the body are responsible for causes of primary hypertension?
- Kidneys have a key role in BP regulation (evidence in relation to salt intake)
- Sympathetic nervous system (high SNS hypertension)
Describe some evidence of the kidneys being important in hypertension.
Rats can have a transplanted healthy kidney to remove hypertension.
List the increased risks caused by high blood pressure?
- Coronary heart disease
- Stroke
- Peripheral vascular disease
- Heart failure
- Atrial fibrillation
- Dementia
- Retinopathy
- Aneurysm
How much does hypertension increase risk of CHF?
2-3 fold
How does hypertension and the eye?
- The retina has microvasclar damage
- There is thickening of the wall of small arteries, arteriolar narrowing, vasospasm, impaired perfusion and increased leakage into surrounding tissue
What is microaluminurea?
- Albumin loss in the urine
- Caused by hypertension
- Hypertension causes a reduced glomerular filtration rate
