Coronary Heart Disease Flashcards
What are modifiable risk factors for Atherosclerosis?
Smoking - Smoking cessation
Lipids intake - Statins, injection with pcsk9 antibody
Blood pressure - ABCDE
Diabetes - Dietary advice, weight loss, Metformin
Obesity - Dietary advice, Gastric surgery
Sedentary lifestyle - advice.
Risk factors multiply.
What are non-modifiable risk factors for Atherosclerosis?
Age
Sex
Genetic Background
What is the ABDCE approach in treating blood pressure?
Ace inhibitors first followed by,
Beta blockers
Converting enzyme inhibitors
Diuretics
What have been the epidemiological change in coronary heart disease?
Reduced hyperlipidemia
Reduced hypertension
Increased Obesity - Diabetes
New improvements in diabetes treatment have a doubtful effect on macro vascular disease.
What would happen if you inhibited the endothelium?
Rise in blood pressure
What are the stages of Atherosclerosis?
Type II - Macrophage foam cells
Type III - Macrophages die, forming small pool of lipids.
Type IV - Atheroma, lipids coalesce to form a big core
Type V - fibro-atheroma, Inflammatory reaction that triggers smooth muscles to form fibrous thickening.
Type VI - complicated lesion, collagen becomes weaker, breaks allowing formation of a thrombus, fissure & hematoma
At what point is the window for primary intervention (Lifestyle changes, risk factor management)?
Intermediate lesions
Advanced lesions
At what point is there need for clinical intervention?
Stenosis, plaque rupture.
What is the role of vascular endothelial cells?
Barrier function via lipoproteins
Leukocyte recruitment
What is the role of platelets
Coronary, cerebral artery thrombosis.
Carotid embolism,
Activation means a lot of cytokine secretion
What is the role of Monocytes & Macrophages?
Lipid rapping - foam cell formation.
Secrete cytokines & growth factors.
Major source of free radicals and Metalloproteinases ( enzymes that degrade collagen).
What is the role of vascular smooth muscle cells?
Migrate from the media into the plaque, strengthening it through collagen synthesis as well as narrowing the lumen slightly. However this protects you from getting an MI.
What is the role of T-Lymphocytes?
Macrophage activation
Why are patients at high risk of atherosclerosis complications injected with antibodies to Interleukin-1?
Atherosclerosis has an inflammatory basis.
What are the two main classes of Macrophages?
Inflammatory Macrophages
Resident Macrophages
What is the role of Inflammatory macrophages?
Adapted to kill microorganisms
What are the roles of Resident Macrophages?
Homeostasis - suppress inflammatory activity
Alveolar resident macrophages - surfactant lipid homeostasis.
Osteoclast - Calcium and phosphate homeostasis
Spleen - iron homeostasis
What is LDL?
‘Bad’ cholesterol - Synthesised in liver.
Carries cholesterol from liver to rest of the body, including arteries.
What is HDL?
‘Good’ cholesterol
Carries cholesterol from ‘peripheral tissues’ including arteries back to liver (=“reverse cholesterol transport”
How is LDL modified in atherosclerosis?
LDL’s leak through endothelial barrier & bind to proteoglycans, making them susceptible to modification. Modification involves oxidation (partial burning). Free radicals oxidise LDL.
Oxidised LDL is phagocytosed by macrophages, which form foam cells that lead to chronic inflammation
What happens in familial hyperlipidemia?
Autosomal genetic disease (main form dominant with gene dosage)
Massively elevated cholesterol (>~20 mmol/L). (effective ‘normal’ ~1-5 mmol/L)
Failure to clear LDL from blood.
Xanthomas and early atherosclerosis; if untreated fatal myocardial infarction before age 20
What does increased LDL in the liver do?
switches off cholesterol synthesis in a negative feedback loop.The enzyme that is the rate limiting step in cholesterol synthesis is the same one that is regulated by cholesterol itself. HMG-CoA reductase inibitors - statins.
What is Macrophage scavenger receptor A?
Known as CD204
Binds oxidised LDL
Binds to gram positive bacteria, e.g. staphylococci & Streptococci.
Bind to dead cells
What in Macrophage scavenger receptor B?
Known as CD36
Bind to oxidised LDL
Binds to malaria parasites
Binds to dead cells