Valvular Disease Flashcards
1
Q
Describe cardiac valves in a disease state
A
- Stenotic valve tends to obstruct blood flow
- Incompetent valves allow back flow
- Incompetence, insufficiency and regurgitation are the same
2
Q
Briefly describe the anatomy of the atrioventricular valves
A
- Tricuspid mitral leaflets
- Function of AV depends on proper functioning on leaflets and tendinous cord or attached papillary muscle of ventricular wall
3
Q
What are the names of the semi-lunar valves?
A
- Aortic
- Pulmonary cusps
4
Q
Describe the histology of the valves
A
- Dense collagen core at outflow surface, connected valvular supporting structures (fibres)
- Central core of loose CT (spongiosa)
- Layer rich in elastin on inflow surface (ventricular)
5
Q
Describe the pathological changes that occur in valves
A
- Fibrotic thickening- rheumatic disease + infective endocarditis
- Damage to collagen that weakens the leaflets, e.g. mitral valve prolapse
- Nodular calcification beginning in interstitial cells, e.g. calcific aortic stenosis
6
Q
What is thematic fever (RF)?
A
- Acute, immunologically mediated, multi-system inflammatory disease
- Occurs a few weeks after an episode of group A stop, pharyngitis
7
Q
Describe the pathogenesis of rheumatic fever
A
- Acute RF- immune response to group A strep antigens cross react with host proteins (like antibodies)
- Can also recognise cardiac self-antigens- can activate complement and recruit Fc receptor cells
- Autoimmune
8
Q
Describe the diagnostics of acute rheumatic fever
A
- Fever and rash on examination
- On auscultation- pericardial friction rub
- Chest X-ray- dilated heart shadow
- Sore throat history
- Cross reaction
9
Q
What are the clinicopathological correlations in rheumatic fever?
A
- Synovitis –> migratory polyarthritis
- Pericarditis–> hearing friction rubs
- Myocarditis–> cardiac dilatation
- Dermatitis–> rash (erythema marginatum)
- Systemic inflammatory response–> cytokines and acute inflammation- pyrexia
- Destruction of ganglia basal cells–> Sydenham chorea
10
Q
What is Sydenham chorea?
A
Involuntary movements rapid arms and legs
11
Q
What is infective endocarditis?
A
- Microbial infection of valves or mural endocardium–> vegetation formation
- Thrombotic debris and organisms
- Often associated with destruction of underlying cardiac tissue
12
Q
Describe acute infective endocarditis
A
- Caused by highly virulent organism (e.g. staph aureus) rapidly producing necrotising/ destructive lesions
- Difficult to cure with antibiotics alone
- May need surgery
13
Q
What are the most etiological agents of infective endocarditis?
A
- Strep. viridans (normal component of oral flora)
- Staph. aureus
14
Q
What are the portals of entry of bacteria into the bloodstream?
A
- Mouth/ GI tract
- Any source of infection
- Injected of contaminated marterial
- Dental procedures
15
Q
Describe vegetations in IE
A
- Wart-like materials
- Projections
- Collections of thrombotic and inflammatory material together with micro-organisms
- Histology- infective, grain stain shows gram +ve cocci
16
Q
What are the clinical features of IE?
A
- Fever
- Malaise
- Weight loss
- New or changing heart murmur
17
Q
What embolic phenomena might be present in IE?
A
- Splinter haemorrhage (underneath nails)
- Osler’s nodes in hands
- Janeway lesions in feet
- Roth’s spots in retina
18
Q
What would be required to make a diagnosis of IE?
A
- Blood culture- usually 3 sets needed before AB therapy
- Echocardiogram- shows vegetation quite well
- Vegetations on imaging study
19
Q
What is the treatment for IE?
A
- Antibiotics
- Surgery (prosthetic valve)
- Valve replacement
20
Q
What are the potential complications of surgery for IE?
A
- HF, sepsis, multi-organ failure
- In-hospital mortality- 15-20%
- Patients who survive often have permanent scarred valves
21
Q
Are prosthetic valves a risk for IE and why?
A
- Yes
- Could have for another reason
- Vegetation might grow around prosthetic valve
- Very high risk of IE
- Antibiotic prophylaxis has to be considered
22
Q
Why are valve diseases associated with murmurs?
A
- Abnormal flow associated with valve defects may cause turbulence
- Turbulence can be heard as a murmur
- Damaged valve
23
Q
What causes valvular stenosis?
A
- Acquired valvular stenosis relatively few causes- usually consequence of remote/ chronic injury- declares itself over years
24
Q
What causes valvular insufficiency?
A
- Intrinsic disease- valve cusps, damage to supporting structures
- MI
- Many more causes and may appear acutely with cord rupture or chronically is disorders associated with leaflet scarring
- Acute MI- may only see post-morem
25
What are examples of supporting structures that could be damaged in valvular insufficiency?
- Aorta
- Mitral annulus
- Tendinous cords
- Papillary muscles
- Ventricular free wall
26
What are the major aetiologies of acquired mitral valve disease?
- Stenosis- post-inflammatory scarring from RD
- Regurgitation
- - Post-inflammatory scarring
- - IE
- - Mitral valve prolapse
- Rupture of chordal tendinae
27
What are the major causes of acquired aortic valve disease?
- Senile calcification of aortic stenosis
- Post-inflammatory scarring (RD)
- Calcification of congenitally deformed valve
28
What leads to regurgitation in acquired aortic valve disease?
- Post-inflammatory scarring (rheumatic heart disease)
- Aortic dissection- tear in wall of vessel
- IE
29
Describe aortic stenosis
- Most common valvular disease
- Age-related 'wear and tear'- either normal valves or congenitally bicuspid
- Calcification likely due to chronic injury- hyperlipidaemia, HT, inflammation- atherosclerosis
- Onset of symptoms (angina, CHF syncope)--> cardiac decompensation + CHD--> surgical valve replacement
- Abnormal ventricular emptying- ejection systolic normal due to obstruction to this
30
Describe mitral regurgitaton
- Malfunction of mitral valve
- Rheumatic fever of IE
- Myxoid degeneration of blood
- Blood regurgitates during ventricular contraction producing pan-systolic murmur
- can rupture papillary muscle
31
What is mitral valve prolapse?
- Myxomatous degeneration of mitral valve
| - One or both mitral leaflets floppy and prolapse/ balloon back into LA during systole
32
Describe the aetiology of mitral prolapse
- Unknown in most most cases
| - Uncommonly associated with Marfan's syndrome
33
What complications are associated with mitral valve prolapse?
- Usually asymptomatic
- IE
- Mitral regurgitation
- Stroke or other systemic infarct
- Arrhythmias- both ventricular and atrial
- MVP more common cause of mitral valve surgery
34
Describe the histology of mitral valve prolapse
- Key change in tissue is marked thickening of spongiosa layer with deposition mucoid material
- -> Myxomatous degeneration
35
How does mitral stenosis present and why?
- Diastolic murmur
| - Obstruction of ventricular filling during diastole
36
What is aortic regurgitation?
- Blood regurgitates during ventricular relaxation causing a diastolic murmur
- Common in aortic dissection
37
What are the consequences of valvular diseases?
- Hypertrophy of myocardium
- Heart failure
- Infective endocarditis
- Cardiac arrhythmias
