Atherosclerosis Heart Disease and MI PDF

Atherosclerosis and Heart Disease What carries the highest risk for cardiovascul ar disease? What is ApoB/ApoA1 ratio It is the ratio of good HDL and bad LDL in your body ApoA1 = HDL ApoB = LDL Name the A = Endothelium B = Internal elastic lamina structures C = Smooth muscle...

Atherosclerosis and Heart Disease What carries the highest risk for cardiovascul ar disease? What is ApoB/ApoA1 ratio It is the ratio of good HDL and bad LDL in your body ApoA1 = HDL ApoB = LDL Name the A = Endothelium B = Internal elastic lamina structures C = Smooth muscle cells D = External elastic lamina E = Mast cell  1) Circulating LDL gains access to subendothelial space where it is oxidised 2) Cytokines IL-1 & MCP-1 attract circulating monocytes that cross intima to become How does a macrophages 3) Macrophages phagocytose LDL to form foam cells thrombus form? 4) Smooth muscle cells migrate and proliferate under the influence of smooth muscle mitogens 5) A primitive plaque is formed of foam cells, smooth muscle , Lipid and necrotic cells 6) The plaque enlarges, develops a fibrous capsule and protrudes in vessel lumen What is Familial Hypercholesterolaemia It is the reduction in receptor mediated clearance of LDL, due to a mutation of LDLR, APOB or PCSK9 gene Prevalence is 1/250 people Its lipid profile is elevated LDL-cholesterol, TC 9-12mmol/L and Low normal fasting triglycerides Physical signs: Tendon Xanthomas, corneal arcus, homozygotes – also planar digital and natal cleft cutaneous xanthomas and aortic stenosis CHD risk: Very high (symptomatic 50% of males by the age of 50 and 50% of females by the age of 60  Ischaemia: An inadequate supply of blood to a tissue resulting in insufficient supply of oxygen and other metabolic needs What is Infarction: Cell/Tissue Necrosis (death) caused by inadequate supply of blood carrying oxygen and other metabolic needs It can be caused by atheroma, thrombus, spasm, embolus and vasculitis ischaem Atheroma: A build-up of fatty substance in your arteries over time Thrombus: Formation of blood clot inside one of your blood vessels or a ic heart chamber of your heart Spasm: Coronary artery spasm – temporary tightening of the muscles in the artery wall, can decrease or even prevent blood flow to part of the heart muscle, causes MI disease? Embolus: Is when a thrombus breaks off from the blood vessel and moves around the bloodstream and blocks a vessel Vasculitis: Inflammation of blood vessel walls can lead to stenosis, occlusion, aneurysm or rupture What factors determine myocardial oxygen supply?  What happens in a patient that has angina? - When a normal person is at rest – artery constricts as there is no need for oxygen and blood flow is normal - When a normal person exercises the blood vessel dilates as it needs more oxygen and blood flow increases. - In a person who has stable angina, there artery has an atherosclerotic plaque that partially is blocking the blood flow in the artery. At rest their blood flow and requirement for oxygen is low, however when they exercise, there demand for oxygen increases but their artery is dilated, but blood flow decreases because of the plaque.  How do you treat stable angina? - Glyceryl trinitrate is used, isosorbide mononitrate is longer acting - It relax vascular smooth muscle by reducing afterload and relaxes veins by reducing the central venous pressure and pre-load - However, in healthy individuals it reduces stroke volume, venous pooling when standing and postural hypotension and dizziness - Therapeutic doses have less effect on small resistance arteries than on veins - It reduces oxygen demand as nitrates metabolised releasing NO, activating guanylyl cyclase, increases cGMP, Dephosphorylation of myosin light chains, reduces cytoplasmic Ca2+ and relaxation of smooth muscle - It is given by sublingual administration, effect happens in minutes and rapidly inactivated by hepatic metabolism - Adverse effects are postural hypotension and headache  Relieve hypoxia à Can give oxygen, but not used How can Relieve routinely, only used if oxygen saturation is reduced we treat Pain Pain relief à Morphine/Diamorphine with an antiemetic myocardi as it relieves pain and nausea and causes vasodilation al Reduce cardiac Reduce cardiac workload and improve perfusion à Nitrates (GTN) are vasodilators and reduce cardiac infarction workload work ? Reduce clot Reduce risk of another infarction à Antiplatelet drug, such as Aspirin, Clopidogrel is used to prevent another clot from forming What are the drug treatments to treat myocardial infarction? - Beta blockers are given to improve myocardial perfusion and reduce risk of arrythmias. Improves myocardial perfusion by lengthening diastole and is a class 2 antiarrhythmic drug - ACE inhibitor – Captopril is used to improve survival in risk of heart failure and left ventricular dysfunction - Anticoagulants are used as protection from thrombus in at risk patients, heparin may prevent reinfarction - Other useful drugs are Nitrates, Antiarrhythmics and Statins (lipid lowering drugs)