Physiology - Vessels Lecture 5

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Physiology - Vessels Lecture 5
2011-03-04 20:42:11

Cardiovascular Disease: Atherosclerosis and Hypertension
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  1. Cardiovascular Disease: Atherosclerosis and Hypertension study topics
    • 1. Identify risk factors for cardiovascular disease
    • 2. Describe the basic events of atherosclerosis
    • 3. Define hypertension and differences between systolic and diastolic hypertension
    • 4. Distinguish between primary and secondary hypertension
  2. CVD: Risk Factors
    • Controllable: smoking, obesity, sedentary lifestyle, untreated hypertension
    • Uncontrollable: sex, age, family history
    • genetics are uncontrollable but lifestyle is modifiable
    • blood lipids lead to atherosclerosis ( HDL-C versus LDL-C)
    • Diabetes mellitus: metabolic disorder contributes to developement of atherosclerosis
  3. LDL and Plaque types: (low density lipoproteins)
    • normal wall: healthy blood vessel
    • fatty streak: little strip of fat depoited in vessel wall
    • stable fibrous plaque: fat deposited in vessel wall taht contains calcifications
    • vulnerable plaque: over accumulation of plaque leading to endothelium tear then being attacked by macrophages and repaired by platelets
    • tears lead to creation of scar tissue
  4. Definition of Hypertension:
    • generally defined as blood pressure > 140/90
    • chronically elevated
    • need to differentiate physiological (natural) from pathophysiological (disease)
    • BP may be transiently elevated in normal people (exercise/stress/ “White Coat” syndrome)
    • higherBP is more likely to be pathophysiological/ more likely to require treatment
  5. Hypertension
    • is very common (35-50% of Canadian adult population affected) and increases in occurence with age, significant morbidity and mortality.
    • Untreated HTN shortens life by 10-20 years and over 50% will develope end organ damage despite treatment. (heart kidney eyes brain)
    • The symptoms (fatigue, blurred vision, headache) are often clinically silent and will often go untreated as patients feel well despite HTN.
    • Those who do detect it may have issues of compliance with their treatment.
    • The risk of developing cardiovascular disease doubles with each 20/10 mm Hg increase in blood pressure
    • Essential hypertension has no clear cause other than hereditary
    • Carotid and aortic baroreceptors adapt
  6. Risk factor for atherosclerosis
    • • Heart muscle hypertrophies
    • • Pulmonary edema (build up of fluid)
    • • Congestive heart failure
  7. Treatment
    • Calcium channel blockers
    • Diuretics
    • Betablocking drugs
    • ACE inhibitors
    • predominantly an increase in systolic pressure
    • associated with: wide pulse pressure / increased stroke volume
    • predominantly an increase in diastolic pressure
    • associated with: usually reflects elevated TPR / rarely occurs without elevated systolic pressure
  10. Classification of Hypertension - PRIMARY (essential hypertension)
    • - most common
    • - no clearly defined cause
    • - majority of hypertensive patients (90-95%)
    • ~35-50% of Canadian population affected
    • - unknown cause but genetic susceptibility
    • - salt sensitivity? (only60% are)
    • arteriolar constriction can lead to increased TPR (leading to increased systolic pressure and increased diastolic pressure), decreased renal blood flow, or increased renin, angiotensin, and aldosterone (which can further lead to increased arteriolar constriction.
  11. Classification of Hypertension SECONDARY
    • - occurs secondary to a disease
    • - more likely if onset of ↑BP occurs at <25 or >50 years old
    • - usually a symptom of another condition/disease
    • - ~5-10% of all cases of hypertensioncauses:
    • • renal disease
    • most common ~3-5% of all cases of hypertension (nephrosclerosis)
    • • endocrine diseases
    • hyperaldosterone secretion – leads to increased blood volume
    • pheochromocytoma - catecholamine secreting tumour
  12. - OTHER
    • - malignant hypertension
    • - hypertension associated to pregnancy
  13. Prolonged hypertension can lead to:
    • - damage to retinal bloodvessels (blindness)
    • - damage to arterial walls(atherosclerosis)
    • - damage to cerebralarteries (stroke)
    • - damage to renal bloodvessels (kidney failure)
    • - increased work load ofheart
    • • hypertrophy
    • • heart failure