Valvular Heart Disease Pathology and Clinical Flashcards
What is the purpose of cardiac valves?
What are the different types of valves in the heart?
To maintain unidirectional flow of blood
There are
SEMILUNAR valves (aortic and pulmonary) and
ATRIOVENTRICULAR valves (mitral and tricuspid)
what are the two main categories of valvular heart disease? How do they usually occur?
Stenosis (failure of a valve to open completely):
- chronic process affecting a valve cusp
and
Insufficiency (failure to close completely):
- Functional regurgitation of valvular incompetence due to disruption of supporting structures
- Intrinsic disease of valve cusps
What are the major valvular diseases discussed?
Congenital: Bicuspid aortic valve (most common)
Acquired:
Aortic stenosis: senile calcific aortic stenosis
Aortic insufficiency: Dilation of ascending aorta related to HTN and aging
Mitral stenosis: Rheumatic heart disease
Mitral insufficiency: Myxomatous degeneration
What are different examples of calcific valvular diseases?
What is it?
Calcific aortic stenosis and Mitral annular calcification
Dystrophic calcification- damage causing wear and tear complicated by deposits of calcium phosphate?
Calcific Aortic Stenosis (AS)
When does it occur?
What are the clinical effects?
What is the treatment?
Calcific Aortic Stenosis (AS)
5th/6th decades-biscuspid, unicuspid valves (assoc w/ Notch gene)
8th/9th decades- normal valves (“senile”)
Clinical effects:
LV: increased pressure causes hypertrophy
Angina, ischemia, CHF
Syncope
Death for 50% within 2 years
Treatment: valve replacement
Mitral Annular Calcification
What is it?
Who gets it?
Why is it bad?
Mitral Annular Calcification
Degenerative calcific deposits on fibrous ring, at base of valve
Occurs in women older than 60 yo, increased in pt. with myxomatous valves or elevated LV pressure.
Usually does not affect fxn but calcifications are sites for thrombi/infection
Myxomatous Degeneration of Mitral Valve (prolapse)
What is it?
In who does it occur?
What are the complications?
How does it happen and Assoc w/ what?
Clinical features?
Myxomatous Degeneration of Mitral Valve (prolapse)
One or both leaflets enlarged, hooded, redundant, floppy (myxoid). Prolapse or balloon back into left atrium during systole
Occurs in Young women
Usually no serious complications but can have regurgitation. Infective endocarditis, mitral insufficiency, thrombi on atrial surfaces leading to stroke or other systemic infarcts due to emboli, arrythmias leading to sudden death.
Unknown pathogenesis but probably developmental anomaly of connective tissue. Associated with Marfan syndrome (fibrillin gene mutation) and other hereditary disorders.
Clinically presents with mid systolic click on auscultation when asymptomatic or late systolic/holosystolic mumur when regurgitation happens
Acute Rheumatic Fever
When does it occur?
Most important complication?
How does it present?
Acute Rheumatic Fever
Follows episode of Group A Beta-hemolytic Streptococcal (pyogenes) pharyngitis
Most important complication is the progression to chronic valvular dysfunction (mitral stenosis)
Presents as widely disseminated inflammatory lesions in many sites:
Pancarditis (all three layers)
Bread and butter pericarditis
Myocarditis w/ Aschoff bodies
Endocardium and left sided valves w/ fibrinoid necrosis and verrucae
Subendothelial (MacCallum) plaques: irregular fibrous thickening of endocardium)
What are Aschoff Bodies?
Classic lesion of Acute Rheumatic Fever
Foci of swollen eosinophilic collagen surrounded by T lymphocytes, plasma cells, and plump macrophages- Anitschkow cells (caterpillar cells)
What happens in Chronic rheumatic heart disease?
What is the major effect?
Organization of inflammation and fibrosis leads to>
Thickened valve leaflets
Fusion of commissures (fishmouth or buttonhole deformities)
Fusion/thickening of chordae tendinae
Major effect is mitral stenosis, leads to left atrial dilatation (someitmes thrombus formation). REDUCED CARDIAC OUTPUT b/c mechanical obstruction prevents filling of LV
Pulmonary congestion, eventual right ventricular hypertrophy, and right sided heart failure.
To what extent are the different valves affected by chronic rheumatic heart disease?
Mitral valve alone (65-70%)
Mitral and aortic (25%)
Tricuspid less often
Pulmonary rare
What is the pathogenesis behind Rheumatic heart disease?
What is the diagnosis for this?
Hypersensitivity reaction induced by group A streptococci
Antibodies against M protein cross react w glycoprotein antigens in heart, joints, and other tissues.
Diagnosis through Jones criteria:
Preceding Group A strep infection
2 major manifestations or 1 major and 2 minor
For diagnosis of Rheumatic heart disease, (2 major or 1 major 2 minor) and preceding Group A strep infection
What are the major manifestations?
and
What are the minor manifestations
Migratory polyarthritis (large joints)
Carditis- pericardial friction rub, weak heart sounds, tachycardia, arrhythmia
Subcutaneous nodules -rare (extensor surfaces of joints)
Erythema marginatum of skin- rare (trunk)
Sydenham chorea (involuntary purposeless, rapid movements)
Minor: non specific signs and symptoms of:
fever
arthralgia
elevated acute-phase reactants
What is a specific biomarker clinical feature of acute rheumatic fever in regards to gropu a beta hemolytic strep?
ASO titers and antibodies to DNAase B
(anti-Streptolysin O) and DNAase are protein produced by group a strep
Prognosis for acute rf?
Prognisis for chronic?
Acute: good for primary attack. increased vulnerability to reactivation
Chronic: Years or decades after initial episode. Valvulitis. Surgical repair of valves improves outlook
What are the two basic clinical forms of infective endocarditis?
Acute: Highly virulent organism, normal valve, 50% mortality
Necrotizing ulcerative invasive infection requiring surgery
Subacute: Low virulence, deformed valve
Less destructive lesions, respond to antibiotics