Pathophysiology of Atheroma Flashcards
Atheroma/atherosclerosis
Formation of focal elevated lesions (plaques) in intimacy of large and medium-sized arteries
Serious consequence of atheroma
Atheroma can result in myocardial ischaemia which can lead to angina
Angina
Chest pain due to restricted blood supply to the heart
Atheroma can be complicated by
Thromboembolism
Arteriosclerosis
Age-related
Smooth muscle hypertrophy, apparent reduplicate of internal laminae and intimal fibrosis
Arteriosclerosis results in
Decrease in vessel diameter
Arteriosclerosis can cause
Cardiac, cerebral, colonic and renal ischaemia
Earliest significant lesion of atheroma
Fatty streak
Fatty streak
Yellow linear elevation of intimal lining
Fatty streak comprises
Masses of lipid-laden macrophages
Early atheromatous plaque
Smooth yellow patches in intima
Fully developed atheromatous plaque
Central lipid core with fibrous tissue cap, covered by arterial endothelium
What provides fibrous tissue cap of plaque with structural strength
Collagens
What resides in fibrous cap of plaque
Inflammatory cells (recruited from arterial endothelium)
Central lipid core of plaque contains
Cellular lipids and debris from macrophages
What occurs late in plaque development
Extensive dystrophic calcification
Atheroma tend to form in areas of
Turbulent flow
Areas of turbulent flow
Arterial branching points/bifurcations
Late stage plaques
Confluent and cover large areas
Complicated atheroma
Established atheromatous plaque plus haemorrhage into plaque (calcification), plaque rupture/fissuring and thrombosis
Most important risk factor of atheroma
Hypercholesterolaemia
Hypercholesterolaemia
High cholesterol in blood
Hypercholesterolaemia can be a result of
Lack of LDL cell membrane receptors
Signs of major hyperlipidaemia/hypercholesterolaemia
Familial vs acquired Biochemical evidence Corneal arcus Tendon xanthomata Xanthelasmata Risk/premature/family history MI/atheroma
Risk factors for atheroma
Hyperlipidaemia/hypercholesterolaemia Smoking Hypertension Diabetes mellitus Male Elderly
Two-step process of formation of atheromatous plaque
- Injury to endothelial lining of artery
2. Chronic inflammatory and healing response of vascular wall to agent causing injury
Chronic inflammation results in
Accumulation of lipids and inflammatory cells in the intimal layer which results in plaque formation
Causes of endothelial injury
Heamodynamic disturbances (turbulent flow) Hypercholesterolaemia
Altered function of injured endothelial cells
Enhanced expressed of cell adhesion molecules
High permeability for LDL
Increased thrombogenicity
Clinical manifestation of consequences of atheroma
Lumen stenosis
Acute atherothrombotic occlusion
Embolisation of distal arterial bed
Aortic aneurysm and rupture
Vulnerable atheromatous plaque
Thin fibrous cap with large lipid core and prominent inflammation
Result of pronounced inflammatory activity on plaque
Degradation and weakening of plaque, increasing the risk of plaque rupture
Preventative and therapeutic approaches to atheroma
Stop smoking Control blood pressure Weight loss Regular exercise Dietary modifications
Secondary prevention of atheroma
Cholesterol lowering drugs
Aspirin - decrease risk of thrombosis
Surgical options
