Dyslipidemia & CVD 1 Flashcards
Guidelines to consult for dyslipidemia in Canada
The Canadian cardiovascular Society’s Dyslipidemia Guidelines
Trend of mortality from CVD in past decade
40% decrease in mortality from CVD
Why decrease in mortality from CVD
- improvement in control of CVD risk factors
- medical management of patients with CVD
2nd cause of death
CVD (1st= cancer)
Role of cardiovascular system
- regulates blood flow to tissues
- thermoregulation
- hormone transport
- maintenance of fluid volume
- regulation of pH
- gas exchange
How the cv system regulates blood flow to tisses
- delivers oxygenated blood and nutrients
- retrieves waste products
Major forms of cardiovascular disease
- hypertension
- atherosclerosis
- coronary heart disease
- peripheral vascular disease (cerebrovascular disease; deep vein thrombosis)
- congestive heart failure
Atherosclerosis =
Thickening of the blood vessel walls caused by presence of atherosclerotic plaque
Atherosclerosis results in :
restriction of arterial blood flow (due to the plaque)
Atherosclerosis is associated with :
- myocardial infarction (MI°
- cerebrovascular accident (CVA or stroke)
- peripheral vascular disease (PVD)
- coronary heart disease (CHD)
- congestive heart failure (CHF) when severe CHD or MI occurs
Cells involved in atherosclerosis
- endothelial cells
- smooth muscle cells
- platelets
- leukocytes
How atherosclerosis begins
Begins as a response to endothelial lining injury that results in an inflammatory process
Symptoms of atherosclerosis
asymptomatic until it progresses to ischemic heart disease
3 steps of formation of atherosclerotic plaque
1) Injury of endothelial wall, monocytes respond to injury and infiltration under the lining
2) Monocytes slip under blood vessel cells and engulf LDL cholesterol, becoming foam cells. Fatty streaks develop.
3) fatty streak thickens and forms plaque as it accumulates additional lipids, smooth muscle, CT, cellular debris
Key cells that react to endothelial injury
monocytes = phagocytic WBC
What are fatty streaks
the thin layer of foam cells that develop on artery walls
Primary causes of endothelial wall damage
- high blood pressure
- chemicals from tobacco
- oxidized LDL
- glycated proteins
- low nitric oxide
- angiotensin2
In which disease would you have glycated proteins
Uncontrolled diabetes leads to chronic hyperglycaemia in circulation
Consequence of decreased nitric oxide
vasoconstriction
2 hypothesis that used to describe the atherogenesis (discovered they are linked)
- Endothelial-Injury hypothesis
2. Lipid-infiltration hypothesis
Endothelial-Injury hypothesis
endothelial injury -> adherence of platelets -> release of platelet-derived growth factor-> cell proliferation -> advanced lesion (atheroma)
Lipid-infiltration hypothesis
high plasma LDL level -> LDL infiltration into intima -> oxidised LDL plus macrophages -> foam cells -> fatty streak
How are the 2 theories linked?
Oxidized LDL + macrophages and fatty streak both cause endothelial injury
T/F
High LDL causes foam cells and thus atherosclerosis
F
Need an injury to contribute to atherosclerosis
Biomarker of atherosclerosis
CRP
Risk factors for developing atherosclerosis
- family history
- age and sex (more in men, 65+)
- obesity (+ly associated with dyslipidemia, HTN, physical inactivity, diabetes)
- dyslipidemia
- hypertension
- physical inactivity
- diabetes mellitus
- impaired fasting glucose/metabolic syndrome
- cigarette smoke
- obstructive sleep apnea
Typical patient at high risk for atherosclerosis
- man
- 65+
- obese
- smokes
- physically inactive
Atherosclerosis less prevalent in women, why
Because estrogen is protective against atherosclerosis (post menopausal women have a risk similar to men)
Which risk factor for atherosclerosis can be revered?
Physical inactivity
How can hypertension be a risk for developing atherosclerosis
- may initiate an atherosclerotic lesion
- can cause plaque to rupture
Chylomicrons
lipoproteins formed by intestine after we ingest a meal with fat, are carriers of ingested TG
Enzyme that lines blood vessels and hydrolyses TG
Lipoprotein lipase
Apoprotein on VLDL
ApoB-100 (from liver)
Apo E
Apo C
Apoprotein on CM
Apo B-48 (from intestine) Apo A-I Apo A-IV Apo C-II Apo C-III
Apoprotein on HDL
Apo A-1
Apo A-II
Apo C
Apo E
Lipoprotein with the most TG
CM
Lipoprotein with the least TG
HDL