Valvular Diseases - Cochran Flashcards
Describe the structure & function of normal cardiac valves.
Lined by endothelium and divided into leaflets. If AV valve, connected to ventricle via chordae tendineae & papillaries.
Function to allow unidirectional flow of blood.
What can cause valvular insufficiency?
Functional regurgitation (disruption of supporting structure, eg aortic dilation)
Structural disease affecting the valve cusps.
Which are more frequent: Stenoses of insufficiencies?
Stenoses.
What is the most common congenital valvular abnormality? What does this predispose to?
Bicuspid aortic valve, which is more prone to calcification.
Calcific Aortic Stenosis
Describe the pathophysiology.
Who does it generally affect?
“Wear & Tear” resulting in fibrosis and eventual calcification.
Wear & tear results in fibrosing and eventual calcification of the valves.
Occurs in normal valves in very late life (8th-9th decades), as well as in abnormal valves in the 5th-6th decades.
What is the signifiance of a Notch mutation in valvular heart disease?
Notch is involved in signaling during heart valve development; mutation predisposes to heart pathologies including CAS.
Calcific Aortic Stenosis
Describe its morphology.
Calcific Aortic Stenosis
Calcified masses in cusps, rarely involving the cuspal edges.
No fusion of commissures.
Mitral Annular Calcification
Describe the pathogenesis.
Who does it affect?
What are its complications?
Mitral Annular Calcification
Wear & tear degeneration resulting in calcification on the base of the valve (fibrous ring).
Usually women >60, especially with myxomatous valves or increased LV pressure.
Doesn’t affect function, but forms sites for thrombi/infection.
Mitral Degeneration
Describe the pathogenesis.
Who does it affect?
What are its complications?
Mitral Degeneration
Myxoid changes weaken the mitral valve, causing it to prolapse back into the left atrium during systole.
Young women, and those with connective tissue disorders (Marfan, Ehler-Danlos).
Usually asymptomatic. Sometimes IE, regurgitation, formation of thrombi and arrhythmia.
What is the auscultatory finding of mitral prolapse, and why does it occur?
Holosystolic “blowing” murmur. During systole, left ventricular contraction causes the valve to prolapase into the Left atrium, creating a “blowout” sound akin to a parachute inflating.
What valve is most typically affected chronic rheumatic fever?
What is the trigger for ARF?
Usually mitral valve, but may also involve the aortic.
Preceding group A Strep pharyngitis infection.
Acute Rheumatic Fever
Describe the 3 components of its pericarditis.
Acute Rheumatic Fever
“Bread & Butter” pericarditis.
Myocarditis with Aschoff bodies (eosinophilic foci with lymphocytes, plasma cells, & anitschkow cells).
Endocarditis with formation of MacCallum plaques (irregular fibrous thickening), fibrinoid necrosis & verrucae.
A patient presents with aortic stenosis. How could you distinguish calcific stenosis from that caused by rheumatic fever based on the heart findings alone?
Aortic stenosis due to rheumatic fever would be accompanied by mitral stenosis.
Involvement of the cusp edges.
Fusion of the commissures.
Describe the findings seen in chronic rheumatic heart disease.
Valve leaflet thickening
Commissure fusion (“Fishmouth” or “Buttonhole” deformities)
Thickening of chordae tendineae
Rheumatic Heart Disease
Describe the pathogenesis.
Rheumatic Heart Disease
GAS pharyngitis generates antibody response against M protein, which is then directed against an unknown heart antigen. (Type II HSR)
(some genetic predisposition to this molecular mimicry response)
