L14-15 Valve Pathology Flashcards
Define incompetent valve
Insufficiency results from failure of valve to close completely allowing regurgitation of blood
Define stenotic valve
is failure of a valve to open completely obstructing forward flow
What causes murmers
Turbulent flow through diseased valves typically produces murmurs
Describe bicuspid aortic valve
▪️1% of population has a congenital bicuspid valve
▪️aortic valve is replaced by complete fibrous tissue or unicommisural
What is aortic valve stenosis
Blood is unable to flow freely from left ventricle to the aorta during aortic stenosis
Describe aortic valve incompetence
intrinsic abnormality (like endocarditis) or dilation of aortic root due to accumulation of mucus in wall of aorta
Where can dilation of atrial root be seen
Idiopathic
Marfan’s syndrome
Describe mitral valve incompetence
▪️Floppy mitral valve where the cusps are larger than normal,dome shaped and the chordae tendinae are elongated
Define rheumatic valvular disease
Acute, immunologically mediated inflammatory disease that occurs after group A b-hemolytic streptococcal throat or skin infections
Clinical features of rheumatic valvular disease
Pan carditis
Valvular inflammation and scarring
What does valvular disease principally take the form of
Fibrotic mitral stenosis
Pathogenesis of acute rheumatic fever
▪️Hypersensitivity reaction
▪️Antibodies against group A streptococcal molecules that cross react with host myocardial antigens
▪️ab against m proteins of certain streptococcal strains bind to proteins in the myocardium and cardiac valves and cause injury through the activation of complement and Fc receptor-bearing cells
What is acute rheumatic fever characterized by
Discrete inflammatory foci called Aschoff bodies
What do the Aschoff bodies contain
Collections of lymphocytes (mostly t cells)
Scattered plasma cells
Plump activated macrophages called anitschkow cells associated with zones of fibrinoid necrosis
How is the pericardium affected
Fibrinous exudate which can be resolved on its own
How is the myocardium involved in rheumatic fever
Myocarditis
Scattered aschoff bodies within interstitial CT
Valve involvement in rheumatic fever
Results in fibrinoid necrosis and fibrin deposition along lines of closure forming vegetations
What is rheumatic chronic heart disease characterized by
Organization of acute inflammation and subsequent scarring
Aschoff bodies or replaced by fibrous scar so that these regions are rarely seen
Valve cusps and leaflets become permanently thickened and retracted
What happens to the mitral valve in chronic rheumatic heart disease
Exhibits leaflet thickening commissural fusion and shortening and thickening and fusion of chordae tendinae
Fibrous bridging across the valvular commissures and calcification create fish-mouth stenosis
Most important functional consequence of rheumatic heart disease
Valvular stenosis and regurgitation
What happens in tight mitral stenosis
Left atrium progressively dilates causing pressure overload ,precipitating atrial fibrillations formation of large mural thrombi
Clinical features of chronic rheumatic heart disease
▪️Acute rheumatic fever in children manifestation is carditis
▪️Symptoms begin 2 to 3 weeks after streptococcal infection
▪️Symptoms are fever and migratory polyarthritis

What are usually elevated in acute rheumatic fever
Cultures are negative for streptococci but serum titers of antibodies against one or more streptococcal antigens are elevated
What are the Jones criteria
Carditis migratory polyarthritis of large joints subcutaneous nodules erythematous annular rash Sydenham chorea
What is Sydenham chorea
Neurologic disorder characterized by involuntary purposeless rapid movements
What are the minor criteria
Fever
arthralgias
EKG changes
elevated acute phase reactants
What is ineffective endocarditis
Inflammatory condition affecting the endocardium particularly on the heart valves
What does ineffective endocarditis lead to
Leads to the development of large Friable vegetation on the heart valves fragments of these Thrombi split from the main mass and embolize around the breadstream and may impact in distant vessels causing infraction and spread of infection
Clinical manifestation of ineffective endocarditis
▪️Patient is feverish and becomes rapidly
▪️the classic organism is Staphylococcus aureus
▪️Usually in intravenous drug abusers because they inject dirty drug solutions affecting the right sided valves
What is subacute infective endocarditis
Slow disease that occurs on top of disease valves by rheumatic heart disease or prosthetic
The organism is streptococcus viridian
Vegetations are smaller firmer and embolization is less common 
What is the morphology of infective endocarditis
▪️Vegetations are usually 0.5 to 1 cm in subacute and 1 to 2 in acute
▪️Vegetation may be a single or form a merging valve destroying Mass
▪️In acute IE perforation of valve cusp maybe seen or infiltration of the myocardium with abscess formation
▪️Vegetations are on the upper aspect of tricuspid and mitral valves and on the ventricular surface of pulmonary and aortic valves
What are the consequences of ineffective endocarditis
▪️Embolus formation: may travel along coronary artery or systemic circulation after impaction,infection weakens the wall of the vessel leading to a weak dilated artery
▪️Valve perforation and destruction leading to spread of infection into the myocardium which may lead to heart failure
▪️ immune complex tissue injury which may cause glomerulonephritis in kidney, vasculitis of skin or Arthralgia in joints
