Cardiovascular pathology 3 (2) Flashcards
What is a thrombus ?
solid mass formed from the constituents of blood which is found within the vascular system
Where can a thrombus be found?
Blood vessels or the heart
What causes a thrombus to from ?
change to Virchow’s triad
what is Virchow’s triad ?
Stasis (change in flow), endothelial damage (change in wall structure) and hypercoagulability (change in contents of the blood).
Describe the formation of a thrombus in the arteries
Arterial thrombosis is mainly caused by the rupture of an atheroma plaque which is an example of endothelial damage. Endothelial damage however can be caused by other things such as high cholesterol, smoking, trauma and hypertension. When a atheroma ruptures it causes a thrombus (mainly platelets and fibrin and is therefore white in colour) to form on the surface and this happens through the activation of the clotting cascade (See diagram). Lines of Zahn will then develop, where a thrombus causes a layer of clot to form which then causes a layer of thrombus to form etc.
What can the consequences of a arterial thrombus be ?
This thrombus can then embolise to the coronary vessels to cause a acute coronary syndrome or to the brain to cause a ischemic stroke.
Describe the clotting cascade
Damage occurs to the tissue.
Through a series of steps a clotting factor is produced which converts prothrombin to thrombin which then converts fibrinogen to fibrin
Describe thrombus in the veins
Venous thrombosis is mainly caused by a change in the stasis or hyperstability of the blood. Stasis/flow is altered when there is immobility i.e. when you are bed bound or on a long haul flight. Hypercoagulability can be caused by pregnancy, cancer, sepsis or genetics. In the veins the stasis or hypercoagulability result in a clot forming (mainly fibrin and red blood cells which is red in colour). Venous thrombosis often occurs in the deep veins of the legs and is called DVT. These clots can then embolise and often goes to the lungs and causes a PE. Some thrombus don’t embolise however some will resolve themselves or with medication or they will become organised and shrink over time.
Examples of things which cause stasis
immobility i.e. when you are bed bound or on a long haul flight.
Examples of things which cause hypercoagubility
pregnancy, cancer, sepsis or genetics.
What are the outcomes of venous thrombosis ?
These clots can then embolise and often goes to the lungs and causes a PE.
Some thrombus don’t embolise however some will resolve themselves or with medication
or they will become organised and shrink over time.
Describe normal flow through a vessel
laminar where the cells move in the centre of the vessel and the plasma flows around it.
What is blood flow controlled by ?
changing the pressure gradient, the resistance, the velocity and the compliance
What are the two main ways in which blood flow can be unusual
The first is stasis where there is stagnation of the blood flow i.e. the blood flows slowly (lack of movement due to sitting too long or not moving i.e. after an operation or in a aeroplane etc). The second is where there is turbulent blood flow i.e. flow is forceful and unpredictable.
What is a thromboembolism ?
When a thrombus or clot embolises
Name some other things which can cause an embolism
Fat gas tumours bone marrow foreign bodies parts of the trophoblast etc from the baby in pregnancy
How does fat cause embolism ?
Embolisms can be beads of fat caused when there are bone fractures and fat from the bone enters to the blood and causes confusion (if it enters the brain) or can lodge go to the kidneys or the skin.
How does gas cause embolism ?
Embolism can also be beads of gas. This is commonly caused when a driver rise to the surface to quickly and it causes N2 bubbles to form and lodge in the capillaries, this is called decompression sickness. Gas embolise can also be caused by injury to the head and neck, from surgery or from CV lines
How does bone marrow cause an embolism ?
Bone marrow can embolise after a bone fracture or even after CPR
Describe embolism in pregnancy
. In pregnant ladies an embolism is also caused when part of the Trophoblast from the baby, some Amniotic fluid embolism or foetal skin cells and keratin from the baby get into he maternal circulation.
What are the signs and symptoms of arterial thrombosis ?
Sudden onset
Signs of embolism i.e. strokes, ACS etc
What are the signs and symptoms of venous thrombosis ?
Slow onset
Signs of embolism i.e. PE
Evidence of DVT i.e. unilateral limb swelling, persistent discomfort, calf tenderness and to a lesser extent warmth, redness, prominent collateral veins and unilateral pitting oedema
What investigations should be carried out into thrombosis ?
The wells score
A D-dimer blood test
What is D-Dimer ?
the breakdown product of cross linked fibrin produced during fibrinolysis
What is fibrinolysis ?
The bodies natural process of trying to break down a clot
What other things can cause an elevated D-Dimer?
trauma, cancer sepsis, bleeding surgery
What should you do if the D-Dimer results are positive ?
An ultrasound
How can you be sure a patient does not have a Thrombus or embolism ?
Negative wells score and negative d-dimer
Describe the summary of the investigations for thrombosis and embolism ?
Do History Wells score and D-dimer test
if Wells and D-dimer are negative then not diagnosis
If both are positive do a compression ultrasound to confirm diagnosis
What is the wells score ?
-
How is thrombosis treated ?
Preventative: Prophylaxis before surgery, compression socks, encourage mobility.
Arterial thrombosis - Antiplatelet and anticoagulant therapy
Venous thrombosis - Anticoagulants.
Vascular surgery can also be offered for massive DVTs.
Treatment of the consequences.
What is chronic heart disease?
Dysfunction heart
What are the names of the two types of chronic heart failure ?
LVSD or HRrEF Left ventricular systolic dysfunction.
HRpEF left ventricular diastolic dysfunction
What is LVSD
Failure to pump
What is left ventricular diastolic dysfunction ?
Failure to fill with blood
What can cause left ventricular diastolic dysfunction ?
Thickening of heart muscle wall
What is a common consequence of having chronic left side heart failure ?
The failure of the left-hand side of the heart to function normally causes a build of blood trying to get into he heart and so there is a build up of blood in the lungs
What causes chronic heart failure ?
. Causes of chronic heart disease can be almost anything which causes a structural change to the heart. Common only, ischemic heart disease, valvular heart disease, hypertension and arrhythmias (commonly AF).
How is chronic heart failure classified ?
Using the new York association classification
What does the new York association classification system say ?
-
Risk factors for chronic heart failure
hypertension, MI, family history, alcohol, diabetes , being post partum, lyme’s disease
Signs and symptoms of chronic heart failure
Breathlessness which is worse on excretion,
cough sometimes with frothy white/pink sputum,
fatigue,
fluid retention i.e. oedema,
reduced exercise capacity,
raised JVP,
orthopnoea (shortness of breath which is worse when lying down),
Displaced apex beat,
paroxysmal nocturnal dyspnoea where patients wake up in the night with severe SOB and cough.
Bibasal capitations and crackles.
What is paroxysmal nocturnal dyspnoea?
Paroxysmal nocturnal dyspnoea is due to the
- fluid position in the lungs when lying down,
- the less responsive respiratory centres and
- the reduction in adrenaline when asleep.
How is chronic heart failure investigated ?
Cardiac function test (A BNP blood test)
Echocardiogram
ECG
Other tests that you could do to investigate chronic heart failure further
LVEF
coronary angiogram
What is a BNP blood test ?
A BNP blood tests which looks at amino acid peptides. It is released when there is a change in pressure in the heart. It can be done bedside and is cheap. An elevated BNP would suggest heart failure and the higher the BNP the greater the severity of the heart failure.
Why would you do an echocardiogram ?
cause of the failure
Why would you do an ECG ?
if it is normal then it is not going to be a LVSD
What is the scale of severity for an LVEF ?
A normal range is 55%-70%, mild if 44-55%, moderate is 30-40% and severe is < 30 %.
How is a chronic heart failure diagnosis made?
evidence of cardiac dysfunction and signs and symptoms
How is chronic heart failure treated ?
Get BNP
refer to specialist
Urgent referral if BNP > 2000 routen referral is BNP <2000
Get a heart failure nurse for the patient
Then ABEL
Describe what ABEL is
ACEI i.e. Ramipril. A ARB can be used instead if a patient is ACEI non-tolerant.
Beta blockers i.e. Bisoprolol which should only be given to stable patients without any acute presentation.
Aldosterone antagonist i.e. Spironolactone are not automatically started but if there is a reduced LVEF and poorly controlled symptoms them it is.
Loop diuretics i.e. Furosemide. A loop diuretic works by inhibiting the Na K and Cl transporters in the loop of Henle and therefore reduce re-absorption. If patients become resistant to furosemide then you can add in thiazide which is a very powerful combination. Loop diuretics should therefore be kept at the minimise does required to improve symptoms.
What are the ADRs of diuretics ?
dehydration, hypotension,
What is congestion ?
excess of blood in vessel, tissue or organs
What is primary congestion ?
it is the only pathology going on
What is secondary congestion ?
It is caused by another condition
What is acute local congestion caused by ?
a backlog of blood through the circulatory system
What can congestion result in ?
Stasis and DVT
Kidney and heart failure
Haemorrhage
Ischemia and infarction
Signs and symptoms of congestion
crepitations, tachycardia, cor pulomale, increased JVP, peripheral oedema
nutmeg liver which is red/brown and pale with spotty appearance because there is a build of fluid there as well as in the venous system.
What is blood flow controlled by in healthy tissue ?
hydrostatic pressure, oncotic pressure and the characterises and area of the endothelium.
What is oedema ?
the accumulation of abnormal amount of fluids in the extravascular compartments
Where does oedema occur ?
intercellular tissue compartments or in body cavities
Or intracellular spaces
What are the two types of oedema ?
Transudate
Exudate
What is a Transudate oedema ?
A transudate oedema is caused by a change to the haemodynamic forces which act across a capillary wall this is the case in cardiac failure and fluid overload. Transudate oedema does not contain much protein or album or cells but lots of water and electrolytes.
What is a Exudate oedema ?
A exudate oedema is where there is inflammatory response to increases vascular permeability. This can be caused by tumours, allergens etc. It has a high protein and album content as well as a high water and electrolytes content.
What type of oedema is peripheral oedema ?
transudate oedema
What is pitting oedema ?
A type of peripheral oedema
What is a congenital heart disease?
condition which a baby is born with
Are congenital condition genetic ?
Not always but yes often they are caused by an abnormal gene
What is a some things which can go wrong with genetics and result in an genetic mutation ?
CNVs are copy number variations which affect a whole or part of a chromosome
SNVs are single nucleotide variations which affect just one gene
If it is not genetic what else can it be ?
Caused by a teratogen
Multifactorial (Combination of risk factors)
Describe how down syndrome can result in cardiac disease
-In 15% of down syndrome patients there is a atrio-ventricular septal defects. Is where there is a defect of the interatrial or intraventricular septum.
what pathway is a group of conditions related to ?
MAPK pathway
What are the names of congeal conditions related to the MAPK pathway ?
Noonan’s,
leopard
Costello
