5: Rheumatic valvular heart disease Flashcards
purpose of valves, and how damage results
- 4 cardiac valves:
- Tricuspid
- Mitral
- Pulmonic
- Aortic
- Maintain unidirectional blood flow
- Suffer from high levels of repetitive mechanical stress
which valve is described as following?
- 3 thin, delicate cusps
- Coronary artery orifices above it
- Smooth, shiny
AORTIC VALVE
which valve is described as following?
- 3 thin, delicate leaflets
- Thin chordae tendineae attaching leaflet to papillary muscles of ventricular wall
TRICUSPID VALVE
2 types of valvular disease?
STENOSIS or INSUFFICIENCY
Type of valvular disease associated w/ the following?
- Failure to open completely
- Obstructs forward flow
- Due to primary cuspal abnormality from a chronic process
- Leads to pressure overload cardiac hypertrophy
STENOSIS
Type of valvular disease associated w/ the following?
- Failure to close completely
- Regurgitation of blood
- Due to intrinsic disease of cusps (endocarditis) or secondary (disruption of supporting structures)
- Leads to volume overload
INSUFFICIENCY
pathophys of mitral stenosis?
postinflammatory scarring (rheumatic heart disease)
pathophys of mitral regurgitation?
-
abnormalities of leaflets and commissures
- postinflammatory scarring
- ineffective endocarditis
- mitral valve prolapse
- “Fen-phen”- induced valvular fibrosis
-
abnormalities of tensor apparatus
- rupture of papillary muscle
- papillary muscle dysfunction (fibrosis)
- rupture of chordae tendineae
-
abnormalities of left ventricular cavity and/or annulus
- left ventricular enlargement
- myocarditis, dilated cardiomyopathy
- calcification of mitral ring
pathophys of aortic stenosis?
- postinflammatory scarring (rheumatic heart disease)
- senile calcific aortic stenosis
- calcification of congenitally deformed valve
pathophys of aortic regurgitation?
-
intrinsic valvular disease
- postinflammatory scarring (rheumatic heart disease)
- infective endocarditis
-
aortic disease
- degenerative aortic dilation
- syphilitic aortitis
- anklylosing spondylitis
- rheumatoid arthritis
- marfan syndrome
what accounts for 2/3 of all valvular disease?
acquired stenosis of Aortic valve and Mitral valve
what infection causes rheumatic fever?
- acute, immunologically mediated multisystem inflammatory disease occurs after group A β-hemolytic streptococcal infection (usually pharyngitis)
- Incidence declined in the Western world
what is rheumatic heart disease (RHD)?
what is the characteristic lesion associated?
cardiac manifestation of rheumatic fever
- Acute & chronic
- Characteristic lesion – fibrotic valvular disease (MV)
what is the pathogenesis of rheumatic fever and heart disease?
- results from a hypersensitivity reaction –> antibodies directed against M proteins of certain Strep strains cross-react w/ host myocardial antigens
- Antibody binding –> activates complement, recruits macrophages, & neutrophils, cytokine production by T-cells leads to macrophage activation
Genetic susceptibility (~3% will develop RF)
the hypersensitivity reaction of Rheumatic fever/ heart disease causes pancarditis of which valves?
- Mitral valve alone - 70% of cases
- Mitral valve + aortic valve - 25% of cases
what are the key morphological features of acute rheumatic fever?
- Anitschkow cells - (pathognomonic for RF); plump, elongated macrophage with slender wavy central, condensed chromatin (caterpillar cells)
-
Aschoff bodies -
- collections of primarily T lymphocytes, plasma cells, and plump activated macrophages
- aka mononuclear cells, histiocytes w/ abundant cytoplasm, central nucleoli, can be binucleated (image)
what are the features of pancarditis associated w/ Acute Rheumatic Fever?
- Pericarditis – fibrinous exudate–> friction rub
- Myocarditis – scattered Aschoff bodies –> arrhythmias, heart failure
- Valvular disease – verrucous vegetations (1-2 mm) along the lines of closure
what are caterpillar cells?
Anitschkow cells: plump, elongated macrophage with slender wavy central, condensed chromatin (caterpillar cells)
what are the morphological changes of chronic rheumatic fever?
- Replace acute lesions with scarring
- leaflet thickening
- commissural fusion and shortening
- thickening and fusion of chordae tendineae
- MV virtually always involved –> mitral stenosis –> “fish mouth” appearance
what is this gross anatomical finding associated with?
fibrous thickening, commissural fusion (fishmouth);
associated w/ CHRONIC Rheumatic Fever
what is this gross anatomical finding associated with?
Neovascularization of valve, thickened, fused chordae;
associated w/ Chronic Rheumatic Fever
clinical features of acute rheumatic fever
- Timing: appears 10 days to 6 weeks after infxn in 3% of patients
- Clinical sxs:
- Pharyngeal cultures are usually negative
- Antibodies against strep are elevated (streptolysin O or DNAase)
- After 1st attack, patient has increased vulnerability to reactivation of disease with subsequent pharyngeal infection
what is the following auscultation finding? what condition is it associated with?
“opening snap followed by diastolic rumble”
- mitral stenosis
- associated w/ acute rheumatic fever
To diagnose: serologic evidence of a previous Strep infection + 2/- Jones Criteria
(Jones Criteria includes what?)
- Carditis
- Migratory polyarthritis of large joints
- Subcutaneous nodules
- Erythema marginatum
- Sydenham chorea
what are the minor criteria associated with Rheumatic Fever?
- fever,
- arthralgias,
- EKG changes,
- elevated acute phase reactants
what is the most common cause of aortic stenosis?
what causes this?
- Calcific Aortic Stenosis;
- Result of recurrent chronic injury (hyperlipidemia, hypertension, inflammation) , due to age-related “wear and tear”
Calcific Aortic Stenosis:
epidemiology
- Incidence increases with age (70s-80s, but 40s-50s in those with bicuspid AV)
- Bicuspid aortic valve – 1-2% of all live births, 2 cusps of unequal size (NOTCH1 mutations)
what are the complications of aortic stenosis?
- Concentric LV hypertrophy - may progress to HF
- Angina and syncope with exercise - limited ability to increase blood flow across stenotic valve
- Microangiopathic hemolytic anemia - RBCs damaged while crossing the calcified valve
describe the pathology of mitral valve prolapse (MVP)?
- Myxomatous Degeneration –> One/both leaflets are “floppy” and prolapse
- Etiology is unclear (likely disorders of connective tissue - Marfan syndrome)
- Primary MVP: F >>> M
- Secondary MVP: M=F
mitral valve prolapse (MVP) - morphology
Ballooning of the leaflets
- Chordae can be elongated, thinned, and may rupture
- Valve leaflets undergo fibrotic thickening (<–rubbing against each other)
- LV endocardial surface undergoes linear fibrous thickening (<–long cords rub against surface)
- Mural endocardium of LV/LA thickens
- Atrial surfaces of the leaflets/ atrial walls develop thrombi
which histo slide is normal?
what is the characteristic sign of a myxomatous mitral valve?
- Left side is normal
- Right side is myxomatous mitral valve:
- collagen in the fibrosa is loose & disorganized
- **proteoglycan deposition (mucoid/myxoid material) in the spongiosa is
markedly expanded - elastin in the atrialis is disorganized
what are the clinical features of mitral valve prolapse associated w/ Myxomatous degeneration?
- Most are asymptomatic
- Palpitations, dyspnea, chest pain
- *Midsystolic click* on ausculation
- 3% of patients will develop complications
- Infective endocarditis
- Mitral insufficiency with chordal rupture
- Stroke
what is: Microbial infection of the heart valves or endocardium that leads to formation of vegetations often assoc. with destruction of underlying cardiac tissue
Infective endocarditis
which bacteria is associated w/ Acute Infective Endocarditis?
- (Staph aureus)
- destructive infections, highly virulent organism attacking a previously normal valve
- substantial morbidity and mortality, even with appropriate antibiotic therapy and/or surgery.
which bacteria is associated w/ Subacute Infective Endocarditis?
- (Strep viridans)
- infections by organisms of low virulence affecting a previously abnormal valves (scarred/deformed)
- follows a protracted course of weeks to months; most patients recover
after appropriate antibiotic therapy.
- follows a protracted course of weeks to months; most patients recover
pathogenesis of infective endocarditis?
- Starts with seeding of the blood with microbes
- Develops on normal, damaged, or prosthetic heart valves
- RHD, MVP, bicuspid AV, calcific valvular stenosis
10% culture negative endocarditis
most of the damaged/defomed valves are affected by which bacteria?
- 50-60% of cases affecting damaged/deformed values
- Streptococcus viridans (part of normal oral flora)
most of the normal/damaged valves are affected by which bacteria?
- 10-20% normal/damaged valves
-
Staph. aureus
- Major cause in IV drug users
which causative organism causes infective endocarditis in prosthetic valve?
Staphylococcus epidermidis
what are the HACEK group of organisms associated w/ infective endocarditis?
- Haemophilus
- Actinobacillus,
- Cardiobacterium
- Eikenella
- Kingella
what is the key morphology of Infective Endocarditis?
- Friable, bulky, destructive vegetations that contain fibrin, inflammatory cells, microorganisms
- Ring abscess – vegetations erode into underlying myocardium and form an abscess cavity
- Aortic and mitral valves are most commonly infected
- Tricuspid valve frequent target in IV drug users
symptoms associated with Infective Endocarditis?
- Fever, fatigue, weight loss, flu-like symptoms
- Murmurs in 90% with left-sided lesions
What are the microscopic pathological features in infective endocarditis?
what clinical presentation does this cause?
- Microemboli –> petechiae, splinter hemorrhages, retinal hemorrhages (Roth spots), painless palm or sole erythematous lesions (Janeway lesions), painful fingertip nodules (Osler nodes)
- Glomerulonephritis
- Fatal if untreated
two families of noninfected vegetations?
- Nonbacterial thrombotic endocarditis
- Endocarditis of systemic lupus erythematosus (SLE)
Nonbacterial Thrombotic Endocarditis:
pathology
- Deposition of sterile thrombi on valves (underlying hypercoagulable state)
- Mucinous adenocarcinoma
- Also by indwelling catheters (endocardial trauma)
Nonbacterial Thrombotic Endocarditis:
describe the vegetations; location, etc
- Vegetations are non-destructive and small (1-5 mm)
- Located along the line of closure of leaflets/cusps
- Usually occurs on previously normal valves
- Vegetations can also be a nidus for bacterial colonization –> infective endocarditis
Endocarditis of Systemic Lupus Erythematosus (SLE) aka. Libman-Sacks Endocarditis:
describe the pathology and vegetations,
- Path: Immune complex deposition –> inflammation –> can lead to fibrosis and scarring, similar to chronic RHD
-
Sterile, small (1-4 mm) vegetations on valves of patients with SLE
- Mitral and tricuspid valves
- Located on valve undersurface, cords, endocardial surfaces
Endocarditis of Systemic Lupus Erythematosus (SLE) aka. Libman-Sacks Endocarditis:
histo, and epidemiology
- Histology – fibrinous, pink material with cellular debris, valvulitis (fibrinoid necrosis of valve substance)
- Epi: 10% of SLE patients
what % of pts will develop serious prosthesis-related problems w/ prosthetic valves?
60% will develop serious prothesis-related problems within 10 years of surgery (thromboembolism, infective endocarditis, etc)
