Valvular heart disease, endocarditis

Question 1

Learning objectives

Answer 1

• Define the terms stenosis and incompetence
• Describe the common causes of cardiac valve stenosis and incompetence
• Define the term infective endocarditis
• Name some risk factors for infective endocarditis
• Describe the composition of a vegetation
• Name some probable causative organisms
• Describe the local and systemic complications of infective endocarditis
• Describe the principles of diagnosis, treatment and prevention of infective endocarditis

Question 2

How much of an issue is valvular heart disease?

Answer 2

• 10% of heart failure involves valve disease
• Four valves – all can be affected
• Primary and secondary problems

Question 3

Discuss the structure and function of the heart valves

Answer 3

Components:
Valve ring
Cusp
Chordae
Papillary muscles (mitral + tricuspid only)

Functions:
To allow forward flow but prevent back flow of blood

Question 4

What is a functional failure in valves?

Answer 4

Mitral stenosis
Mitral incompetence
Aortic stenosis
Aortic incompetence

Tricuspid and pulmonary valve as above but less common and less severe disease

Question 5

Define stenosis and incompetence

Answer 5

• Stenosis
Narrowing of the valve outlet caused by thickening of valve cusps, or increased rigidity or scarring.

• Incompetence
Or insufficiency or regurgitation (which is what happens) caused by incomplete seal when valves close, allowing blood to flow backwards

Remember vegetations

Question 6

Discuss the valves in relation to heart sounds and the signs you can pick up for valvular disease

Answer 6

• First: mitral and tricuspid - systole
• Second: aorta and pulmonary – diastole

Signs
• Aortic stenosis
• Aortic incompetence 
• Mitral stenosis
• Mitral incompetence

Question 7

What are common causes of cardiac valve stenosis and incompetence

Answer 7

• Congenital heart disease: bicuspid valve, atresia
• Cardiomyopathy (hypertrophic, dilated)

• Acquired
– Rheumatic fever
– Myocardial infarction
– Age related 
– idiopathic aortic calcific stenosis 
– Endocarditis

Question 8

What are the risks of aortic stenosis?

Answer 8

Left ventricular hypertrophy
Syncope
Sudden cardiac death

Question 9

What are the causes of aortic stenosis?

Answer 9

Calcification of congenital bicuspid valve

Senile calcific degeneration

Rheumatic fever

Question 10

What are the consequences of aortic stenosis?

Answer 10

Increases the work of the heart

Ventricular hypertrophy

Causes cardiac failure late in the clinical course

Clinical symptoms include:
Dyspnoea
Angina
Syncope

Question 11

What are causes of aortic incompetence?

Answer 11

Infective endocarditis
Rheumatic fever
Marfan’s syndrome

Question 12

What are the consequences of aortic regurgitation?

Answer 12

Increase the volume of blood to be pumped significantly
Increases the work of the heart
Cardiac hypertrophy
Cardiac failure
Can occur in the presence of aortic stenosis

Question 13

What are the causes of mitral incompetence?

Answer 13

• Cusp damage – for example
– Rheumatic heart disease – scarring, contraction
– Floppy valve & Marfan syndrome - stretch
– Infective endocarditis - perforation

• Chordae – as above
• Papillary muscle – eg post MI
• Valve ring – as above, age

Most often post-rheumatic fever

Question 14

What are the risks if mitral incompetence?

Answer 14

Pulmonary hypertension Right ventricular hypertrophy

Question 15

Discuss mitral stenosis

Answer 15

Congenital (rare)

Post rheumatic fever (rare in developed countries)

Restricts blood flow to the left ventricle

Atrial fibrillation

Back pressure results in pulmonary hypertension

Finally cause right hear t failure

Question 16

Define infective endocarditits

Answer 16

• Infection of valve with formation of
thrombotic vegetations
• Virulence of organisms determines damage and severity of the clinical illness
• Classified as acute and sub-acute
• Bacteraemia is common

Question 17

What are the risk factors for infective endocarditis

Answer 17

• Valve damage
– As before, especially after rheumatic fever

• Bacteraemia 
– Dental
– Catheterisation 
– 10% unknown 
– iv drug abuse

• Immunosuppression

Question 18

Discuss rheumatic fever

Answer 18

• Acute multisystem disease – heart (myocarditis, valvulitis, pericarditis), joints, connective tissue
• 3 weeks post Streptococcal infection (usually pharyngitis)
• Immune mediated rather than direct infection
• Occurs in children: 4-16 years
• May occur in recurrent episodes
• Chronic valve disease decades later

Question 19

What is the composition of a vegetation

Answer 19

Group D Streptococcus, gut commensals, skin Strep

Coxiella, fungi, Candida

Question 20

What are the local and systemic complications of infective endocarditis

Answer 20

many

Cerebral and retinal emboli

Bronchopneumonia 
Pulmonary infarct (tricuspid valve endocarditis)

Myocarditis

Renal infarcts
Glomerulonephritis

Splenomegaly +-infarcts

Anaemia

Clubbing
Splinter haemorrhages

Immune Infective Thrombotic

Question 21

Discuss acute native valve endocarditis

Answer 21

– valves may be normal
– aggressive disease
– virulent organisms, such as Staph. aureus and
group B streptococci

Question 22

Discuss subacute native valve endocarditis

Answer 22

– abnormal valves
– indolent but may deteriorate
– alpha-haemolytic streptococci, enterococci

Question 23

Discuss prosthetic valve endocarditis

Answer 23

– 10-20% of cases
– 5% of mechanical and bio-prosthetic valves become infected
– mitral are more susceptible than aortic
– early onset: Staph. aureus, gram-negative bacilli,
Candida species
– late onset: staphylococci, alpha-haemolytic streptococci, enterococci

Question 24

Discuss IV drug abuse in valvular heart disease

Answer 24

– 75% have no underlying valvular abnormalities
– 50% involve the tricuspid valve
– Staph. aureus most common

Question 25

What are the principles of diagnosis, treatment and prevention of infective endocarditis

Answer 25

• Treat Strep. infection with antibiotics
• Prophylactic cover for invasive procedures eg
dental work
• Replacedamagedvalves
• Clinical suspicion & signs
• Imaging – especially echocardiography
• BLOOD CULTURE
• IV ANTIBIOTICS