CR1.4 Heart valves and valvular pathology

Question 1

Describe the general anatomy of valves at a histological level.

Answer 1

Leaflets have a central core of collagen (i.e. fibrosa) and covered in a layer of loose fibroelastic tissue. The valve is covered in endothelium and is avascular.

Question 2

Each cusp of the aortic valve has a sinus called the ___________.

Answer 2

Each cusp of the aortic valve has a sinus called the sinus of valsalva (i.e. aortic sinuses).

Question 3

List four aetiology of aortic stenosis.

Answer 3

1. Congenital (cusps fused < 30 years old)
2. Rheumatic valve disease
3. Bicuspid valve (i.e. anatomical anomoly in 1% of population)
4. Calcification of trileaflet (> 70 years old)

Question 4

List the triad of symptoms for aortic stenosis.

Answer 4

1. chest pain (angina)
2. dyspnoea
3. syncopy

Question 5

Explain aortic regurgitation and list common causes.

Answer 5

Aortic regurgitation is when blood leaks back from aortic root to left ventricle. This is commonly due to an abnormal cusp or a distorted aortic root. Cusp abnormalities can be congenital, rheumatic, endocarditis or trauma. Distorted aortic root can be due to aortic root aneurysm (e.g. hypertension, Marfans syndrome), inflammation (e.g. syphilis) or dissection.

Question 6

Describe cusp / chordal abnormalities associated with mitral regurgitation.

Answer 6

Endocarditis destroys the cusp and ruptures chordae. Rheumatic valve scarring and retraction. Mitral valve prolapse and expansion, elongation/ruptured chordae.

Question 7

Explain the higher prevelance of rheumatic fever in Aboriginal and Torres Strait Islander peoples and common valvular disease presenting in this population.

Answer 7

Rheumatic fever is associated with environmental factors such as poverty and poor living conditions resulting in increased likelihood of acquiring bacterial infections. Socioeconomic disadvantage and barriers to health care access put Indigenous communities at a significantly greater risk of acquiring these conditions and not recieving adequate timely treatment. Mitral stenosis is almost exclusively related to rheumatic fever. Mitral stenosis is a reduced mitral orifice (i.e. <1cm²) and pulmonary hypertension is common.

Question 8

Define infective and non-infective endocarditis.

Answer 8

Infective: microbial infection of the lining of the heart and usually valves. Can be acute and subacute. Subacute is typically due to abnormal valve.

Non-infective: inflammation from systemic lupus arteriosis or acute rheumatic fever.

Question 9

Describe the features of subacute bacterial endocarditis.

Answer 9

Systemic infection including fevers, sweats, rigors, fatigue. Valve dysfunction and new murmurr, heart failure. Embolic complications including stroke, skin lesions, renal emboli. lung abcesses. Immune reaction (e.g. arthralgia and glomulonephritis).

Question 10

Briefly describe the pathophysiology of mitral regurgitation.

Answer 10

Defects in the mitral valve result in incomplete sealing during systole. During systole blood is regurgitated from the left ventricle into the left atrium. Stroke volume is increased to maintin cardiac output and the left ventricle adapts by dilating (i.e. eccentric hypertrophy). The left atrium dialtes in response to higher pressure.