Pathology of Valvular Heart Disease

Question 1

What can go wrong with heart valves? (2)

Answer 1

Stenosis - valves dont open far enough, so only a small amount of blood can pass through the valve.

Incompetence - valves dont close fully so blood that has already travelled through valves can come back down again (backflow)

Some can have a combination of being stenotic and incompetent

Question 2

What causes the problems with valve disease? (3)

Answer 2

Rheumatic fever

Calcific aortic valve disease

Age-related degeneration

Question 3

What does rheumatic fever start as?

Answer 3

A sore throat (streptococcal pharyngitis) - caused by streptococcal bacteria

Pus can form on the tonsils

Rheumatic fever is a reaction to this sore throat

Question 4

How does streptococcal pharyngitis lead to rheumatic fever?

Answer 4

The sore throat triggers an immune reaction from the body.

There is then a cross-reaction of the immune reaction with self antigens

These antigens are inside the lining of the heart (causes endocarditis), in heart muscle (myocarditits), around the heart (pericarditis).

Can also get it in joints (polyarthritis), subcutaneous nodules and a skin rash

Question 5

What happens after valve inflammation?

What valves are most often affected?

Answer 5

After valve inflammation, the patient will get fibrosis

In 90% of cases the mitral valve is affected

In 40% of cases the aortic valve is affected

Question 6

What is calcific aortic valve disease?

Answer 6

Valves have almost calcified - would feel very hard.

This stops them from opening = stenotic valves.

Question 7

Which valve does calcified aortic valve disease most commonly affect?

What are the effects of calcified aortic valve disease?

Answer 7

Aortic valve most affected

Causes rigid valve cusps, LVH (left ventricular hypertrophy as the ventricle has to work harder), and inadequate coronary artery perfusion (not enough blood going through coronary arteries)

Question 8

What is age-related degeneration of the mitral valve?

Answer 8

Can involve ‘floppy’ mitral valves - will close fully but are weak

Mainly age-related - unknown reasons why

Question 9

What are the different types of prosthetic heart valves?

Answer 9

Biological - can be human or porcine (pig)

Artificial (made of metal or plastic)- tilting disc or ball and cage

Question 10

What are the possible problems of using prosthetic valves?

Answer 10

haemolysis

coagulation

anti-coagulation therapy (needed for the rest of life)

mechanical failure (can break due to stress)

calcification

infective endocarditis

Question 11

What is the link between infective endocarditis and rheumatic fever?

Answer 11

NO LINK except that it can cause heart valve damage

Rheumatic fever often occurs in childhood years as an autoimmune reaction to a sore throat.

This valve damage due to rheumatic fever predisposes to infective endocarditis.

Question 12

Where can infective endocarditis occur? (2)

Answer 12

• any abnormal heart valve - rheumatic fever damage, mitral valve degeneration, aortic stenosis, prosthetic valves
• tricuspid valve - in intravenous drug users

Question 13

What is infective endocarditits?

Answer 13

A bacterial infection of the heart valves

Question 14

What are the complications of infective endocarditis?

Answer 14

• LOCAL (if valve is destroyed by the I.E) - valve incompetence, myocarditis
• SYSTEMIC - embolisms, general effects of systemic infection, glomerulonephritis (immune complex deposition)

Question 15

What are the causative organisms of infective endocarditis?

Answer 15

Often caused by microorganisms living in the oral cavity

• streptococcus viridans (from the oral cavity)
• staphylococcus aureus (in drug users)
• aspergillus (fungi) - in immunocompromised people

Question 16

Why is infective endocarditis relevant to dentistry?

Answer 16

Because prodding around in the gums can sometimes release streptococcus viridans, which can be the cause of infective endocarditis.

If this bacteria gets into the bloodstream it may cause I.E