L43 Valvular Heart Disease and Cardiac Neoplasms Flashcards
What are the two types of semilunar valves in the heart and how many cusps do they have?
Aortic and pulmonary; three
Upon what does the function of semilunar valves depend?
Integrity and coordinated movement of cusps and attachments
What are the two types of atrioventricular valves in the heart?
Tricuspid and mitral
Upon what does the function of AV valves depend?
Integrity of valve apparati (including leaflets, annulus, chordae tendinae, papillary muscles, ventricular wall)
Describe the basic histology of a valve.
Lined by endocardium with a connective tissue core of variable density
What is the difference between regurgitant and stenotic valvular heart disease?
Regurgitant: insufficient, allows backflow of blood
Stenotic: tight valve
What is the most common congenital valvular heart disease?
Biscupid aortic valve
Describe the etiology of a bicuspid aortic valve.
Normally, the aortic valve has three cusps. Here, there is incomplete embryonic separation, leading to 2 cusps
What does bicuspid aortic valve cause?
Aortic stenosis and increased pressure load on L ventricle
Any kind of abnormal valve can be predisposed to developing what infection?
Endocarditis
What is the most common cause of aortic stenosis?
Calcific aortic degeneration
What happens in calcific aortic degeneration?
Dystrophic calcification - deposition of calcium at sites of cell injury and necrosis
Discuss the development of calcific aortic stenosis.
Over time, calcified masses develop within aortic cusps. This prevents the cusp from opening, which obstructs outflow, increases pressure gradient across the valve, and leads to concentric LVH development.
What are the symptoms of calcific aortic stenosis?
Congestive heart failure, angina due to myocardial ischemia, and syncope
What happens in mitral valve prolapse?
Mitral valve leaflets are enlarged, redundant, and floppy; they balloon into the atrium during systole. This can injure the atrium.
What can be seen histologically in mitral valve prolapse?
Expansion of the spongiosa via deposition of myxomatous (mucoid) material; this makes the valve more floppy.
What is the pathogenesis of mitral valve prolapse?
Unknown; some patients have a developmental defect of connective tissue (Marfan Syndrome), but not all patients
Describe the epidemiology of mitral valve prolapse.
Occurs in 3% of the population, particularly in young women
What are the symptoms of mitral valve prolapse?
Majority are asymptomatic, midsystolic click (snapping of chorda tendinae); minority of patients have non-specific symptoms such as chest pain, dyspnea, fatigue, depression, and anxiety
What are the rare, serious complications of mitral valve prolapse seen in 3% of patients?
- Infective endocarditis
- Mitral insufficiency (regurgitation)
- Stroke/systemic infarction (due to embolism of thrombi formed in atria due to ballooning)
- Arrhythmia
What is infective endocarditis?
Destructive inflammation of cardiac valves and endocardium caused by infection (most commonly bacterial)
What is a hallmark of infective endocarditis?
Vegetation
What is vegetation?
Warty excrescences on the valves of the heart composed of various tissue elements including fibrin and collagen
Describe the vegetations of infective endocarditis.
- Composed of thrombotic debris, fibrin, inflammatory cells, microorganisms
- Large and bulky
- Destructive and erosive
- Friable, apt to embolize
What are the two types of infective endocarditis?
- Acute
2. Subacute
Describe acute infective endocarditis.
Involves highly virulent microorganisms (classically S. aureus), usually involves a previously normal valve with rapid, severe destruction; patients present as very sick (50% mortality)
Describe subacute infective endocarditis.
Involves low virulence organisms (classically S. viridans), usually involves a previously deformed valve, recovery with appropriate treatment
Who is at risk for infective endocarditis?
Patients with valvular disease and prosthetic valves, immune deficient patients, patients with diabetes, people who use IV drugs, people with alcohol use disorder
What are portals of entry for infective endocarditis?
- Injection of contaminated material into bloodstream
- Infections elsewhere (bacteremia, goes to heart)
- Dental or surgical procedures with bacteremia
- Occult source (gut, oral cavity, trivial injury)
How do we diagnose infective endocarditis?
- Clinical suspicion
- Blood cultures (infection)
- Echocardiogram (can see vegetation)
What are the cardiac complications of infective endocarditis?
Valve insufficiency, abscess, and injury to prosthetic valves
What are the other complications of infective endocarditis?
Emboli (brain, kidney, spleen, lungs)
Glomerulonephritis (immune complex depositions)
How is infective endocarditis treated?
IV antibiotics (prolonged course), surgery sometimes; can give antibiotics prophylactically to those at high risk
What diseases involve non-infected vegetations?
- Acute rheumatic fever
- Endocarditis of systemic lupus erythematosus (Liebman-Sacks endocarditis)
- Nonbacterial thrombic endocarditis (marantic endocarditis)
What is Rheumatic fever?
A disease that occurs a few weeks after Group A streptococcal pharyngitis; it has acute systemic manifestations and can develop into chronic rheumatic heart valve disease
What is the pathogenesis of acute rheumatic fever?
Patients have an immune response to GAS which cross-react with host tissues; Ab directed against M proteins of strep cross-react with self-antigens in the heart. CD4+ T cells specific for strep peptides react with cardiac self proteins. This produces cytokines to activate macrophages.
What are the major manifestations of acute rheumatic fever?
- Migratory polyarthritis (large joints)
- Carditis
- Subcutaneous nodules
- Erythema marginatum of skin
- Sydenham chorea (involuntary purposeless, rapid movements - St. Vitus’ danse)
What are the minor manifestations of acute rheumatic fever?
Fever, arthralgia, elevated acute-phase reactants
What are the Jones Criteria for acute rheumatic fever?
Preceding GAS infection + 2 major manifestations or 1 major + 2 minor manifestations
What is pancarditis?
Inflammation of all three parts of the heart (pericarditis, myocarditis, endocarditis)
Describe the vegetations of rheumatic fever endocarditis grossly and histologically.
Gross: tiny little vegetations on the heart valves (typically mitral, L side)
Histology: Aschoff bodies (T cells, plasma cells, macrophages, multinucleated giant cells)
What is the special name for macrophages in Aschoff bodies?
Antischkow cells/caterpillar cells
After the formation of Aschoff bodies, what happens next?
Inflammatory injury to the valve, fibrosis during healing, deformation of the normal leaflet structure; this induces turbulence, which leads to further injury and additional fibrosis
What can happen years after rheumatic fever?
Chronic rheumatic valvular disease
What are the hallmarks of chronic rheumatic valvular disease?
Fibrosis of valve leaflets, fusion of leaflets (fish mouth stenosis), thickening of chordae tendinae
Which valve is most commonly involved in chronic rheumatic valvular heart disease?
Mitral valve (65-70%)
Aortic and mitral valves - 25%
Triscuspid/pulmonary - rare
Describe the vegetations seen in Libman-Sacks endocarditis (SLE).
Small, sterile, found on mitral and tricuspid valves and chords; caused by immune complex deposition, leads to valvulitis, fibrosis, deformity
Describe the vegetations seen in non-bacterial thrombotic endocarditis (marantic endocarditis)
Small, non-destructive, loosely attached, sterile thrombi
What type of patients get marantic endocarditis?
Patients who are very sick and wasting away; they are in a hypercoagulable state due to sepsis, cancer, burns, indwelling catheters
What happens in marantic endocarditis?
The vegetations have little effect on the valve itself, but can embolize and cause infarctions. They can also serve as a nidus for bacterial colonization, leading to infective endocarditis.
___ occurs in people who are ill and hypercoagulable.
Nonbacterial thrombotic endocarditis
___ incidence increases with age.
Calcific aortic stenosis
___ is a result of post-inflammatory scarring.
Chronic rheumatic valve disease
___ develops earlier with bicuspid aortic valve.
Calcific aortic stenosis
Embolization is the most important complication of ___.
Nonbacterial thrombotic endocarditis
What is a myxoma?
Most common primary benign tumor of the heart in adults
The myxoma involves which part of the heart in 90% of cases?
Atria (L»_space; R)
Describe a myxoma grossly and histologically.
Gross: mucoid, gelatinous
Histology: mucopolysaccharide, various other types of cells
How does myxoma present?
Ball-valve obstruction can block the flow of blood, particularly in a position-dependent fashion; fever and malaise (IL-6), embolization
