L66: Valvular Heart Disease Flashcards
Structure of heart valves
Mitral and Tricuspid valve:
- Spongiosa
- loose CT
- atrial / blood vessel side of each valve
- covered by endothelium - Fibrosa
- fibrous core
- dense irregular CT
- fibres from cardiac fibrous skeleton - Ventricularis
- dense CT
- covered by endothelium
- many layers of elastic fibres
- continues into Chordae tendineae (in AV valves)
Aortic and Pulmonary valve: spongy core with 2 outer fibrous core
***Valve response to injury
- Mechanical injury
- Superficial fibrous thickening - Inflammation
- Vascularisation, Fibrosis (↓ size, ↓ SA) - Degenerative
- Distortion (↑ size due to deposition of Ca, cholesterol)
Effects of valvular disease
- Stenosis —> tightening of opening —> ↓ Outflow
- Incompetence —> incomplete closure —> Regurgitation of blood
- Mixed
Mitral stenosis
Mitral stenosis —> ↓ outflow —> ↑ atrial volume + P —> atrial dilatation —>
- ↑ blood volume in lungs —> congestion of lungs —> pulmonary hypertension —> right heart hypertrophy —> right heart failure
- atrial thrombus —> systemic embolisation
Aortic stenosis
Aortic stenosis —> LV outflow obstruction
- ↑ LV systolic pressure —> ↑ LV hypertrophy —> ↑ oxygen consumption —> myocardial ischaemia —> LV failure
- ↑ LV ejection time —> ↓ diastolic time —> ↓ coronary blood flow —> myocardial ischaemia —> LV failure
- ↓ Aortic pressure —> ↓ coronary blood flow —> myocardial ischaemia —> LV failure
***Common valvular disease
- Degenerative
- Calcific aortic stenosis (most frequent)
- Mitral annular calcification
- Myxomatous degeneration of mitral valves / Mitral valve prolapse - Rheumatic fever / heart
- Infective endocarditis
Calcific aortic stenosis
- Calcification induced by wear and tear
- heaped up calcified masses
Signs:
- small amplitude pulse
- systolic ejection murmur
- systolic thrill
- displaced apex beat
Symptoms:
- palpitations, fatigue, dyspnea, congestive heart failure
Mitral annular calcification
- Calcific deposits on ring of mitral valve
- Mitral regurgitation
- thrombus + emboli formation
- prone to infective endocarditis
- common in women > 60
Signs:
- hypertension
- heart failure
- systolic murmur
Myxomatous degeneration of valve / Mitral valve prolapse
- Ballooning / tenting of valvular cusps (floppy valve)
- thickened and rubbery leaflets
- developmental anomaly of CT (Marfan’s syndrome)
Symptoms:
- fatigue
- palpitation
- chest pain
Rheumatic fever (Autoimmune)
- Acute immunologically mediated
- multi-system inflammatory disease post-streptococcal group A infection
- acute vs chronic phase
Acute phase:
- fibrinoid degeneration surrounded by lymphocyte —> Aschoff bodies
- Pancarditis: Valvulitis, Myocarditis, Percarditis, Verrucae vegetation (small spots)
Chronic phase:
- Inflammatory deformation of heart valves (esp mitral valves)
—> Vascularisation + Fibrosis (↓ size)
- Leaflet thickening
- Commissure fusion
- Chordae tendineae shortening, thickening and fusion
Infective endocarditis
- Colonisation of heart valves of microorganism
- Friable vegetation (thrombotic debris + microorganism)
- Destruction of underlying cardiac tissue
- Infective embolism
- mainly left heart valves, tricuspid valve involved in IV drug user
- Antibiotics prophylaxis
Complications:
- Sepsis
- Embolism
- Abscess
- Destruction of valves
Cardiac vegetation
- Verrucae vegetation (Rheumatic heart disease)
- Friable vegetation (Infective endocarditis)
- Nonbacterial thrombotic endocarditis (Thrombus platelet aggregation)
- Libman-Sacks endocarditis (mitral and tricuspid valvulitis in SLE)
Treatment of damaged / stenosed valves
- Prosthetic valves (risk of bacterial endocarditis, thrombosis, structural failure)
- mechanical
- tissue
—> need to be maintained on anticoagulant therapy - Balloon valvuloplasties
