IHD 2 - Coronary revascularisation Flashcards
What are the 4 main progressive steps involved in atherogenesis?
Normal -> fatty streak -> atheromatous plaque -> atherosclerotic plaque
What is atherosclerosis?
A disease of the arteries characterized by the deposition of fatty material on their inner walls causing progressive narrowing and hardening
What is an atheroma?
A fatty deposit in the intima
Risk factors for coronary heart disease?
Gender AgeDrug abusealcoholSmokingStressHypertensionHigh cholesterolObesityFamily history
What is chronic stable angina?
Chest pain caused by demand led ischaemia due to fixed stenosis which occurs in a predictable manner
What is the immediate treatment of chest pain due to chronic stable angina?
StopSitSpray
What is an acute coronary syndrome in general?
Any acute presentation of coronary artery diseaseOnly a provisional diagnosis that covers a spectrum of conditionsLike stable angina it is caused by ischaemia caused by atherosclerosis
What conditions are classified as acute coronary syndromes?
Unstable anginaNSTEMISTEMI
What are 2 older alternative names for a NSTEMI?
Non-Q waveSub-endocardial MI
What are 2 older alternative names for a STEMI?
Acute MI (not called this anymore)Q wave MI
What are the 2 types of MI?
ST elevation MI Non ST elevation MI
Does a fatty streak cause symptoms?
No - it is clinically silent
What is the pathogenesis surrounding unstable coronary syndrome?
Plaque rupture/ fissure and thrombosis
What can happen to the plaque which bridges between an atherosclerotic plaque and plaque rupture/ fissure and thrombosis?
Fibrous cap forms over the fatty core
What type of stenosis does acute coronary syndrome have?Type of ischaemia?
Dynamic stenosis (subtotal or complete occlusion)Supply led ischaemia
What are the stages of the platelet cascade?
InitiationAdhesionActivation
What causes initiation of the platelet cascade?
Spontaneous plaque rupture which leads to exposed tissue elements (sub endothelial collagen and Von Willebrand factor)
What are factors affecting plaque rupture/ fissure? (6)
Lipid content of plaqueThickness of fibrous capSudden changes in intraluminal pressure or toneBending and twisting of an artery during each heart contractionPlaque shapeMechanical injury
What is von willebrand factor?
A glycoprotein that plays an important role in stopping the escape of blood from vessels
What is involved in adhesion (platelet cascade)?
Platelet recruitment and adhesion at the site of injury forming a monolayer
What is involved in activation (platelet cascade)?
Activators are released (ADP and Thromboxane A2)They bind to surface receptors on plateletsPlatelet activation accelerates resulting in platelet aggregationActivated platelets express adhesion receptors for leukocytes (P-selectin and CD40 ligand) = inflammationOrganised fibrin-rich thrombus forms(This leads to vascular blockage = acute MI/ stroke)
How is ADP and other activators released during platelet cascade?
Through degranulation
How is thromboxane A2 generated?
Via cycloxygenase
What adhesion receptors for leukocytes do activated platelets express (2)?
P-selectinCD40 ligand
Difference between unstable angina and NSTEMI?
There is no elevation in cardiac enzymes in unstable angina where as there will be an elevation in cardiac enzymes in an NSTEMI (infarction does not occur- pre-MI which can lead to an MI)
Difference between a STEMI and NSTEMI?
There is only partial damage in heart muscle with an NSTEMI compared to full thickness damage to heart muscle with a STEMI - due to this full thickness damage ST elevation occurs on the ECG
What are ECG changes that are seen with a STEMI?
ST elevationT wave inversionPathological Q waves
What must be present on an ECG to confirm a STEMI? (either one of 3 of)
Greater than or equal to 1mm ST elevation in 2 adjacent limb leadsGreater than or equal to 2mm elevation in at least 2 adjacent precordial leadsNew onset bundle branch block (usually left bundle branch block)