Vascular Disease

Question 1

Define arteriosclerosis

Answer 1

Thickening and hardening of the wall of an artery

Question 2

Define Artheroma

Answer 2

Important disease of medium and alrge arteries in high-pressure systems, never venous

Question 3

Define artherosclerosis

Answer 3

Arteriosclerossis due to artheroma

Question 4

Development of hypertensive arteriosclerosis

Answer 4

1. Hypertrophy of media
2. Fibro-elastic thickening of smooth muscle intima
3. Elastic lamina reduplication

Question 5

Development of hypertensive Arteriolosclerosis

Answer 5

Replacment of wall structures by amourphous hyaline material causing decreased lumen size and lessening response to endocrine stimulus

Question 6

Consequences of hypertensive vascular changes

Answer 6

1. Reduction of vessel lumen; reduced flow; ischaemia
2. Increased rigidity of vessel walls; loss of elasticity and contractility; unresponsive to control agents e.g. vasodilators

Question 7

Stages of artheroma

Answer 7

Initially effects tunica intima, later tunica media, worsens with age

1. Blood lipids enter intima by damaged epithelium
2. Macrophages phagocytose lipids to make araise fatty streak
3. Some lipid released forming a lipid plaque. M secrete cytokines, stimulate myofibroblasts to secre collages-> early damage of elastic lamina
4. Collagen covers plaque forming fibrolpid plaque, muscle fibres replaced by collagen
5. Lipids in intima calcified. plaque surface ulcerates, initates coagulation cascade leading to blood clot

Question 8

How does ischaemic damage occur by artheroma?

Answer 8

Intima expansion; reduced lumen size; reduced blood flow; reduced oxygenation; ischaemic damge

Coronary arteries - Angina

Legs - Intermittent claudation

Mesenteric - Iscaehmic colitis

Cerebral/vertebral - Cerebral sichaemic event

Question 9

Layers of artery from inner to outer

Answer 9

Lumen

Intima - connective tissue

Internal elastic lamina

Media

Adventia

Question 10

Dietary cause of Artheroma

Answer 10

High LDL diet

Question 11

Mechanism for developing aneurysms from artheroma

Answer 11

= Abnormal permanent focal dilation of an artery

• Enlarging intimal artheroma plaque leads to atrophy of media, elastic fibres replasced by collagen
• Collagen incapable of elastic recoil; arterial wall stretches with systolic pulse
• Most common in abdominal aorta

Question 12

Main cause of mycotic aneurysm

Answer 12

Endocaritis or bacterial sepicaemia

Question 13

Risk factors for artheroma

Answer 13

• High fat diet
• High LDL:HDL ration
• Smoking
• High BP
• Diabets
• Obesity

Question 14

Define Thrombosis

Answer 14

The process leading to formation of a thrombus

Can be physiological; preventing bleeding in breached vessel wall. Limited by fibrinolysis

Or pathological: not limited by fibrinolysis

Question 15

Define thrombus

Answer 15

A solid mass composed of blood constituents which have aggregated together in flowing blood in the lumen

Question 16

Events in physiological thrombosis

Answer 16

1. Vessel wall is breached
2. Circulating plateletes aggreagte and plug
3. Platelets release factors which trigger coag cascade
4. Cascade converts fibrinogen to large molecule sof insolube fibrin
5. Fibrin binds platelets together and traps RBC/WBCs

Fibrinolysis

1. Plasminogen activated
2. Converted to plasmin
3. Fragments fibrin; dissolves thrombus

Question 17

Events in pathological thrombus

Answer 17

1. Normal thrombosis
2. Reduced fibrinolysis
3. Thrombus continues to enlarge over capacity of fibrinolysis
4. Red/brown mass produced in lumen

Question 18

Virchows triangle

Answer 18

3 categories contributing to thrombosis

1. Vessel: Disturbance/damage of the blood vessel
   
   • Exposes collagen in intima
2. Blood Flow: Reduction in blood flow/stasis
3. Blood: Disturbance of blood properties/character
   
   • Increased platelets, RBS numbers, Viscosity

Question 19

Consequences of arterial thrombosis

Answer 19

Stops flow of blood; cuts off oxugen; infarction

Question 20

Consequence of venous thrombosis

Answer 20

Prevents drainage; blood pools; congestion(+infarction)

e.g. DVT

Question 21

Define Thromboembolism

Answer 21

Thrombus fragments or detaches completely (breaks off) and travels elsewhere in the circulation (passes into bloodstrem) to a distal site where it occludes the vessel

Question 22

Circumstances under which a pulmonary thromboembolism can occur

Answer 22

• Thromboembolism in a systemic vein
  
  • Eventually embolises to a pulmonary artery branch
  • large enough embolus will cause sudden death

Question 23

Risk factors in venous thromboembolism

Answer 23

• Active cancer treatment
• 60+
• Dehydration
• Obesity
• HEart disease
• hormone replacement therapy
• Oestrogen contraception

Question 24

Other material than thrombosis that can embolise

Answer 24

Cancer cells/tumour

Air

Nitrogen(diving)

Amniotic fluid

Question 25

Define Infarct

Answer 25

An area of ischaemic necrosis due to abrubt cessation of the arterial supply

Question 26

Stages of venous infarction

Answer 26

1. Veins become obstructed 2. Tissues become congested with blood 3. Pressure rises in capillariea and venules * Rupture * Pressure too highg for arterial blood to enter e.g. hernial strangulation

Question 27

Causes of arterial infarction

Answer 27

* 95% thrombotic or embolic * Arterial spasm * Arterial trauma

Question 28

Stages of arterial infarction

Answer 28

1. **0-12H** Swelling of cells; some death 2. **12-24** Necrotic muscle fibres apparent 3. **24-72** AIR to dead muscle 4. **3-14D** Macrophagic removal of debris 5. Vascular granulation 6. Fibrous grnulation 7. Scar formation by mature fibrous tissue

Question 29

Common cause of renal infarct

Answer 29

Emboli from left side of heart

Question 30

Cerebral infarction

Answer 30

Emolisms Liquefactive necrosis, heals by astrocytic gliosis Commonly death

Question 31

Complication of MI

Answer 31

**early** * Sudden death by LV failure or dysrhytmia * Ruoture of myocardium * Rupture of papillary muscle; acute valve failure **Late** * Chronic LVF * Ventricular aneurysm