CHD Flashcards
What is tissue ischaemia and what can it be due to?
Reduced blood flow to an organ or tissue due to:
- lack if O2 and nutrients supply
- lack of washout of metabolic
Describe Myocardial ischaemia.
- Reduced blood flow to the heart.
- Ischaemia as an imbalance between myocardial demand and supply.
- Concept of exertional demand and ischaemia and non-exertional supply ischaemia.
Define CHD
Pathological conditions and characterised by a reduced or inadequate blood flow to the heart.
Usually due to an obstructive/constrictive disease of coronary arteries
What are the characteristic of CHD?
- Incurable
- High morbidity and mortality
- Highly dependent on environmental and cultural factors.
- Preventable
Describe the process of CHD.
- Coronary artery obstruction or constriction.
- Reduced regional blood flow to the heart
- Oxygen and nutrient deprivation and accumulation of toxic waste.
- Leading to: metabolic and contractile dysfunction, electrical instability and myocardial cell death (infarction).
What are the clinical manifestations of CHD?
- Angina pectoris - stable, variant and microvascular.
- Immediate or sudden cardiac death.
- Acute coronary syndromes (ACS) - unstable angina, acute myocardial infraction (NSTEMI, STEMI).
What are the pathological factors of CHD?
- Atherosclerosis
- Coronary thrombosis
- Coronary artery spam
- Coronary microvascular dysfunction
Define Atherosclerosis.
A progressive, degenerative arterial disease characterised by asymmetric deposition of lipids and fibrous tissue on the inside wall of arteries
Describe the disease process of Atherosclerosis.
- LDL deposition in sub-endothelial space.
- LDL oxidation + monocyte recruitment into sub-endothelial space.
- Macrophage differentiation + uptake of oxidised LDL.
- Foam cell formation
- SMC migration, proliferation and de-differentiation.
- Fibrous plaque or atheroma
What are the consequences of Atheroclerosis?
Impact on coronary function:
- Partial coronary occlusion - stable angina
- Endothelial/ vascular dysfunction - coronary artery spasm.
- Ulceration/ rupture - coronary thrombosis
Define Coronary Thrombosis.
Unwanted formation of a haemostatic plug or thrombus or blood clot within coronary arteries
What is the disease process of Coronary thrombosis?
- Rupture or ulceration of atherosclerotic plaque.
- Contact of blood elements with collagen and tissue factor.
- Platelet adhesion and activation - platelet aggregation - thrombus/ clot.
Activation of coagulation cascade - fibrin formation and deposition - thrombus/clot
What are the consequences of Coronary Thrombosis?
Impact on coronary function:
- Complete and permanent occlusion of coronary artery - ACS (STEMI).
- Subtotal or intermittent occlusion of coronary artery- ACS (UA/NSTEMI).
- Thromboembolism in a distal artery
Define Coronary artery spasm.
A transient, spontaneous coronary vasoconstriction.
- May occur in normal coronary arteries
- May occur at mildly atherosclerotic sites or during ongoing coronary thrombosis.
- The underlying cause of variant angina.
What are the disease mechanisms coronary artery spasm?
- Local endothelial injury - increase reactivity to vasoconstriction.
- Abnormal release of vasoconstrictors or local imbalance in release of vasodilators and constrictors.
- Smooth muscle cell hyper-contraction/ hyper-reactivity