Pathophysiology of Atheroma

Question 1

process of atherogenesis

Answer 1

injury to endothelial lining of artery and then chronic inflammatory (macrophages) and healing response of vascular wall to agent causing injury. chronic exposure of arterial wall to these processes leads to formation of atheromatous plaques

Question 2

atheromatous plaques formation

Answer 2

fatty streaks that develop into atheromatous plaques. collagens provide the structural strength. central lipid core with fibrous tissue cap covered by arterial endothelium. inflammatory cells reside in fibrous cap which are recruited from arterial endothelium

Question 3

components of atheromatous plaques

Answer 3

soft, highly thrombogenic, often rim of “foamy” macrophages. yellow plaques that make vessels lumen smaller. form at arterial branching points/ bifurcations

Question 4

role of lipids in the aetiology of atheroma.

Answer 4

hypercholesterolaemia is most important risk factor. causes plaque formation and growth. LDL cholesterol which doesn’t bind to cell membrane receptors due to genetic mutation which means elevated plasma ldl cholesterol levels

Question 5

signs of major hyperlipidaemia.

Answer 5

biochemical evidence, corneal arcus (premature), tendon xanthomata (knuckles, achilles), xanthelasmata, family history of heart disease

Question 6

atheroma

Answer 6

formation of focal elevated lesions (plaques) in intake of large and medium sized arteries. complicated by thromboembolism

Question 7

complicated atheroma

Answer 7

features of established atheromatous plaque plus haemorrhage into plaque, plaque rupture/fissuring thrombosis

Question 8

risk factors for atheroma

Answer 8

smoking, hypertension, male, elderly, diabetes

Question 9

causes of endothelial injury

Answer 9

haemodynamic disturbances (turbulent flow) and hypercholesterolaemia

Question 10

injured endothelial cells are functionally altered eg

Answer 10

enhanced expression of cell adhesion molecules, high permeability for LDL, increased thrombogenicity

Question 11

Advanced plaque formation

Answer 11

large numbers of macrophages and T lymphocytes, lipid laden macrophages die through apoptosis which puts lipid into lipid core, chronic inflammatory response, growth factors, fibrous cap encloses lipid rich core

Question 12

clinical issues with atheroma

Answer 12

develop over lifetime many clinically unnoticed, relatively benign to life threatening, acute changes in plaques lead to serious consequences

Question 13

clinical signs of severe stenosis

Answer 13

ischaemia (stable or unstable angina) due to reduction of blood flow in distal arterial bed

Question 14

atheroma in peripheral arterial disease

Answer 14

ill, femoral or political artery stenosis leads to intermittent claudication which is peripheral arterial disease

Question 15

acute atherothrombotic occlusion

Answer 15

rupture of plaque. exposes thrombogenic contents to blood stream which triggers activation of coagulation cascade and thrombotic occlusion in very short time this leads to irreversible schema and necrosis of tissues eg myocardial infacert, stroke, lower limb gangrene

Question 16

embolisation of distal arterial bed

Answer 16

detachment of small thrombus fragments from thromboses atheromatous arteries which embolise distal to ruptured plaque. leads to arrhythmia, cholesterol emboli in kidney, leg, skin, stroke, TIA

Question 17

ruptured atheromatous abdominal aortic aneurysm

Answer 17

seen in elderly and usually asymptomatic. media beneath atheromatous plaque gradually weaken which leads to dilation of vessel and can cause sudden rupture, retroperitoneal haemorrhage, aneurysms, mural thrombus.

Question 18

vulnerable atheromatous plaques

Answer 18

thin fibrous cap, large lipid core, prominent inflammation

Question 19

prevention and therapy

Answer 19

smoking cessation, control blood pressure, weight loss, cholesterol lowering drugs, aspirin, surgery