Vascular Disease Flashcards
What is arteriolosclerosis
Thickening and hardening of wall of arteriole
What’s is arteriopath
Widespread disease of arteries
What are the three steps in hypertensive arteriosclerosis
1) hypertrophy of media
2) fibroelastic thickening of intima
3) elastic lamina replication
What are the stages in hypertensive arteriolosclerosis
Replacement of wall structures by amorphous hyaline material
Basement membrane how material = no smooth muscle
Perfusion failure and loss of function.
What are the consequences of hypertension
Reduction in vessel lumen
Reduced blood flow
Ischaemia
Increased rigidity ( loss of elasticity and contractility)
Unresponsive to normal vessel control agents ( vasodilators)
Where does atheroma not occur
Heart circ
Venous circ
What’ is atheroma initially a disease of
Tunica intima
What are the general four stages in development of an atheroma
Fatty stream
Lipid plaque
Fibrolipid plaque
Complicated atheroma
Explain a fatty streak
Smooth endothelial surface is damaged
LDLs enter intima through damaged area
Lipids are phagocytosed by macrophages
What is a the lipid plaque
Lipid released but macrophages
Macrophages secrete cytokines stimulating myofibroblasts to secret collagen
Early damage to elastic lamina and media
What is a fibrosis is plaque
Collagen covers lipid plaque
Media thins with replacement of muscle with collagen
Vessels susceptible to stretch
What is complicated atheroma
Lipids in intima become calcified and surfaces of fibrolipid plaque ulcerates exposing collagen with fibrin causes thrombosis
Activated coagulation cascade
What are the complications of atheroma
Expansion of intima - reduction in size of lumen = decreased blood flow and ischaemia
Ulceration of atheromatous intima- predisposition to thrombus formation and vessel occlusion
Plaque fissure- formation and haemorrhage
Aneurysm- thinning and stretching due to decreased muscle and elastic fibres
What does atheroma cause in coronary arteries
Angina
What does atheroma cause in leg arteries
Intermittent claudication (limp)
What does atheroma cause in mesenteric arteries
Ischaemic colitis (irritation and swelling)
What does atheroma cause in cerebral and vertebral arteries
TIA
or stroke
What is an aneurysm
Abnormal permanent focal dilation of an artery
What is aneurysm due to
Atrophy of media, muscle and elastic fibres replaced by collagen, collagen not capable of recoil, with each systolic pulse wall of artery stretches and thins
What types of aneurysms are there
Syphilitic- arch of aorta Developmental- cerebral vessels Dissecting- thoracic aorta Mycotic- endocarditis Bacterial septicaemia Infection of arterial wall
What are lifestyle risk factors for atheroma
Smoking Physical inactivity Obesity Unhealthy high salt diet Excess alcohol
What treatable non- lifestyle risk factors are there for atheroma
Hypertension High cholesteroleamia High lipideamia Diabetes Kidney dysfunction
What fixed risk factors are there for atheroma
Family history Make Male baldness Early menopause Age Ethnicity (India pakinstan Bangladesh and Sri Lanka)
What is thrombosis
Normal mechanism to prevent bleeding when a vessel wall is breached, solid mass d blood constituents ( fibrin and platelets) which have aggregated together in flowing blood in the lumen of a blood vessel
What is atheroma
Arteriosclerosis of large and medium arteries characterised by hardening of arteries
What is thrombosis limited by
Fibrinolysis
What happens in normal thrombosis
Vessel wall breached (damage/stasis/ change in blood)
Circulating platelet aggregates
Platelets release factors which trigger coagulation cascade
Fibrinogen converted to insoluble fibrin
Bind together platelets and entrapped red blood cells
Describe normal fibrinolysis
Plasma contains inactive proenzyme plasminogen, activated by tissue plasminogen activators secreted by endothelial cells -> plasmin
Fragments fibrin to form fibrin degradation products
What factors convert plasminogen to plasmin
Xla xlla
Tissue plasminogen activator
Urokinase
When is a thrombus pathological
When it enlarges beyond vessel healing requirements and continues to grow
Beyond a certain size and rate of development intrinsic fibrinolytic system is incapable of controlling size, is fibrinolysis fails thrombus grows by accretion
What initiates the intrinsic coagulation cascade
Vitamin k
What is involved in the extrinsic pathway
7a converts 10 to 10a
What predisposes to pathological thrombosis
Damage to vessel wall
Stasis
Change in blood character eg platelet increase, increases RBC, increased viscosity
What is most important for pathogical thrombosis in
A) heart ventricles
B) heart atrium
C) valves
A) chamber wall damage
B) stasis
C) valve surface damage
What are the possible outcomes for a thrombus
Lydia Occulsion Organisation as recanalisation Propagation Detach and travel in circ
What is recanalisation
Growth of new vessels into thrombus
development of vascular granulation tissue
Fibroblasts invade and deposit collagen
Fibrovascular granulation tissue develops
What are the consequences of a thrombosis embolism in an artery/left side of heart
Travels to Brain- stroke Leg- gangrene Mesenteric- bowel necrosis Renal- kidney infarct Splenic- spleen infarct
What are the consequences of a venous thrombo embolism
Pulmonary artery branch- small= peripheral lung infarct
Large= sudden death
What are 11 risk factors for VTE
Active cancer treatment Over 60 Dehydration Known thrombophilias Obesity Medical comorbidity Family history Hormone replacement therapy Oestrogen containing contraceptive therapy Varicose veins Pregnancy or
What are physical causes of a VTE
Thrombus Malignant tumour Fat and marrow Air Nitrogen Amniotic fluid
What does infarction mean
Term used to describe death of tissue due to lack of oxygen following abrupt cessation of the arterial supply or venous drainage
What are the cause of occulsion
Atheroma
Atheroma plus thrombosis
Atheroma with plaque fissure
By embolus
What are the outcomes of infraction
Sudden death
Death sure to complications during infarct healing
Survival with infarct replaced by granulation tissue- scar
In an arterial infarct what happens after 0-12 hrs 12-24 24-72 3-14 days 14-21 days 21-51 days
Invisible early cell death Necrotic muscle fibres- eosinophilic Acute inflammatory reaction Macrophagic removal of debris and vascular granulation tissue formation Fibrous granulation tissue Scar formation and cicatrisation
What is haemopericardium
Rupture of myocardium following an arterial infarct
Leads to acute valve failure
Give two examples of venous infarcts
Bowel (Volvulus or hernial strangulation) and testis (torsion)
What is the sequence of events after venous obstruction
Tissues venules Capps become engorged with blood
Pressure in venules and Capps increased so that they may rupture or cause hypoxia
Tissues become congested and necrotic
Chest pain on exercise is called…
Stable angina
Where’s is the most commend site of aortic aneurysm
Abdominal aorta just above bifurcation of iliac vessels
What and where is an intimal tear
Dissecting aneurysm, tunica media filled with blood
Haemopericardium
Stays near arch
Renal arteries descending
What is a common cause of a sub arachnoid haemorrhage
Berry aneurysm
What types of stroke are there
Ischeamic
Heamorrhagic
Cortical necrosis
What is the problem with reperfusion after a stroke
Red blood cells extravasate and tissue fluid from blood enters brain - swelling
What is a predisposing factor for rupture of blood into lateral ventricles
Warfarin
Hypotension
Atherosclerosis
What is an ECG with a big Q wave indicative of
Recent myocardial infarction
