Cardiac Valve Pathology Flashcards
When do valvular diseases become clinically significant?
when they produce a functional disorder
How are valvular diseases broadly classified?
as valvular stenosis or valvular insufficiency
*sometimes both disorders can occur in the same valve.
*What is a valvular disorder called if it is seen in one valve?
ISOLATED disease
*What is a valvular disorder called if it involves more than one valve?
COMBINED disease
What is valvular stenosis?
failure of a valve to open completely, impeding forward flow.
What is valvular insufficiency
regurgitation or incompetence, resulting from failure of a valve to close completely, allowing reversed flow.
Can you have valvular stenosis and insufficiency occurring together?
YES (can be purely one or the other or may be coexist in the same valve).
*One of the defects usually predominates.
What is functional regurgitation?
when a valve becomes incompetent because:
- dilation of the ventricle causes papillary muscles to be pulled down and outward.
- dilation of the aorta or pulmonary artery pulls the valve commissures apart, preventing full closure of AV or PV.
What dictates the severity of valvular disease?
depends on the valve involved, the degree of impairment, the rate of its development, and the rate of compensatory mechanisms.
It may also produce changes in other organs (heart, blood vessels, or lungs).
*What are the most frequent valvular diseases?
stenosis of the AV and MV
What usually causes valvular stenosis?
a primary cuspal deformity and is usually chronic
What causes valvular insufficiency?
either intrinsic disease of the cusps or damage to or distortion of the supporting structures without primary changes in the cusps.
What is calcified valvular degeneration?
valves can suffer cumulative damage with formation of calcium phosphate deposits: calcific aortic stenosis, calcification of bicuspid aortic valve or mitral annular calcification.
*What is dystrophic calcification?
normal serum calcium level with calcium deposited on abnormal tissue.
*What is metastatic calcification?
calcification occurring due to hypercalcemia.
*What is the most common of all valvular abnormalities?
acquired aortic stenosis
What is acquired calcific aortic stenosis?
heaped up masses of calcium build up within the aortic cusps preventing opening of the cusps due to age related wear and tear. This may be seen in normal or bicuspid valves.
This becomes symptomatic later in life and as the deposits distort the architecture they can cause LV pressure overload.
To what does left ventricular hypertrophy from calcific aortic stenosis lead?
ischemia, angina pectoris, and CHF can occur.
*Pulmonary back flow does not occur in early forms of disease.
What can result if the left ventricle begins to fail?
the lungs can become congested and COR PULMONALE can result= abnormal enlargement of the right side of the heart.
Asymptomatic pts have a good prognosis, but symptomatic patients need surgical intervention (valve replacement).
Usually begins with higher pitched murmur.
**What is the most frequent CONGENITAL cardiovascular malformation?
BICUSPID aortic valve (cusps usually of unequal size; one cusp usually has a partial fusion). This is generally asymptomatic at birth or early life, but predisposes you to progressive degenerative calcification (usually the larger cusp).
What problems can occur with calcific stenosis from congenitally bicuspid AV?
it may become incompetent from aortic dilation, cusp prolapse or infectious endocarditis.
What is important to know about mitral annular calcification?
this is when degenerative calcium deposits develop in the fibrous ring of the MV causing irregular hard stony nodules behind the leaflets.
It generally does not affect valvular function, but occasionally can result in REGURGITATION, STENOSIS, ARRHYTHMIA, or SUDDEN DEATH.
In whom is mitral annular calcification most seen?
women over 60 and those with mitral valve prolapse or elevated LV pressure.
What is myxomatous degeneration of the mitral valve (aka mitral valve prolapse)?
- one or both MV leaflets are floppy and prolapse or balloon into the left atrium.
- Often affects young women.
- Most asymptomatic, but can cause chest pain or syncope.
- Will hear a “midsystolic click”
What can happen to the tendinous cords in myxomatous degeneration of the MV?
- Elongate, thin out and may rupture.
- You may also see attenuation of the collagenous fibrosis layer of the valve, with thickened spongiosa layer and deposition of mucoid material making it edematous.
What are the secondary changes that can occur with MVP?
fibrous thickening of the valve leaflets and linear fibrous thickening of the LV and/or left atrium endocardial surface.
Thrombotic plaques can form where the valve contacts the atrium.
*In what syndrome may you see MVP?
Marfan due to mutations in fibrillin-1 gene, which dysregulates TGF-beta signaling.
What does MVP actually look like grossly?
a parachute or “hooding” of the mitral valve.
What are some complications that can occur with MVP?
infectious endocarditis, chordal rupture, emboli, arrhythmias…
**What is acute rheumatic fever?
systemic complication of pharyngitis due to GROUP A beta-hemolytic streptococci; affects children 2-3 weeks after an episode of streptococcal pharyngitis (step throat).
It is an immunologically mediated inflammatory disease. The bacteria initiate an IMMUNE REACTION, and these ANTIBODIES cross-react with glycoproteins on the heart valve and joints.
What will you see clinically with rheumatic fever?
elevated ASO (antistreptolysin-O) or anti-DNase B titers
What does rheumatic fever usually do to the mitral valve?
forms fibrotic disease (mitral stenosis). More commonly seen in areas of the world without access to antibiotics.
What are the MAJOR criteria for diagnosing acute rheumatic fever?
- migratory polyarthritis= swelling and pain in a large joint that resolves within days and migrates to inovled another large joint.
- Pancarditits= all 3 layers: endocarditis (small vegetations along the lines of closure), myocarditits with Aschoff bodies, and pericarditits.
- subcutatneous nodules
- erythema marginatum= annular nonpruritic rash with erythematous borders.
- Sydenham chorea= rapid involuntary muscle movements.
**What are Aschoff bodies?
fibrinoid necrosis of the MYOCARDIUM surrounded by chronic mononuclear cell inflammation, associated with acute rheumatic carditis.
Within these you will see ANITSCHKOW CELLS= large histiocytes with vesicular nuclei and basophilic cytoplasm (they have an owl-eye appearance in cross-section and caterpillar appearance in longitudinal sections).
What can fibrinous pericarditis of acute rheumatic fever cause?
a friction rub heard on auscultation
Can calcium nodules develop on valves in acute rheumatic carditis?
YES, distorting the valve and can form thrombi.
Can you develop right sided heart failure with acute rheumatic fever?
YES and liver congestion.
**What are MacCallum plaques?
subendocardial lesions that produce irregular thickenings (usually in the left atrium) associated with rheumatic fever.
**What is the trick to remembering clinical rheumatic fever?
STREP: Sydenham's chorea Transitory migratory arthritis Rheumatic subcutaneous nodules Erythema marginatum Pancarditis
What is the Jones criteria of rheumatic fever?
- evidence of prior group A streptococcal pharyngitis.
- presence of 2 of the major manifestations or presence of 1 major and 2 minor manifestation such as fever, arthralgias, or elevated blood levels of acute phase reactants or ESR.
When do heart abnormalities associated with acute rheumatic fever occur after an episode of pharyngitis?
10 days to 6 weeks, occurring more in children ages 5-15.
**What changes of the valve are associated with acute vs. chronic rheumatic heart disease?
acute= vegetations along the LINES OF CLOSURE. chronic= fibrous thickening and fusion of the chordae tendinae.
To what does chronic rheumatic heart disease lead?
stenosis of the mitral valve and occasionally the aortic valve with a classic “fish-mouth appearance.”
What is the most common cause of mitral stenosis?
mitral valvulitis from CHRONIC rheumatic heart disease
**What will you see on the valves in chronic rheumatic heart disease?
increased vascularity with focal lymphocytic infiltrates.
What commonly happens to the left atrium in chronic rheumatic heart disease?
it becomes dilated and hypertrophied
Does vulnerability for rheumatic fever increase after an initial attack?
YES. About 1% die, and damage to the valves is cumulative.
Are Aschoff bodies seen in CHRONIC rheumatic fever?
NO, only acute.
What is chronic aortic valvulitis?
aortic stenosis (valve cusps thick, firm and adherent to one another) leading to LVH or aortic regurg (fibrosis and retraction), and unlike rheumatic fever, this occurs more in men.
