Pathology of Valvular Diseases Flashcards
What is the main etiology of valve defects in children & adolescenrs
primarily congenital
What is the main etiology of valve defects in adults
Primarily Degenerative Disease,
e.g. Calcific, Myxomatous, etc., or Inflammatory e.g. Rheumatic HD
What are risk factors of valvular dieases
- Congenital Heart Defects,
- Ageing (40 million cycles per year),
- Rheumatic Heart Disease,
- Immunosuppression
- Invasive Techniques
What are the types of valvular diseases
- stenosis
- regurgitation
- mixed
What is stenosis
narrowed valve
failure of a valve to open completely, thereby impeding forward flow
What is regurgitation
incompetency or insufficiency-
failure of a valve to close completely, thereby allowing back flow
What is a mixed valvular defect
Double Valve Disease;
stenosis and incompetence
What causes a mixed valvular disease
Sometimes due to healing, the cusps of the vlaves may fuse but at the same time certain parts may retract and in that condition you will get what we call DOUBLE VLAVE DISEASE, which includes both stenosis and incompetence.
What are the features of valvular diseases
- Degree of severity: mild to severe
- Course: Acute or Chronic
- All valvular diseases have Characteristic Murmur
- Secondary Changes in the Heart, Blood Vessels, and other Organs e.g. Lungs
Which valves are most commonly affected
Acquired Mitral and Aortic Stenoses account for 2/3 of ALL Valve Disease
What is RHD
Inflammatory process that may affect the Pericardium, Myocardium and Endocardium (PANCARDITIS)
Usually results in distortion and scarring of the valves
What is rheumatic fever
Immunologic reaction induced by group A b-hemolytic strep
What is the pathophysiology of rheumatic fever
Antibodies against M proteins of certain strep cross-react with antigens in the heart, joints, skin and brain
What is the possible causes of rheumatic fever
- Genetic susceptibility
- Autoimmune response against self-antigens
What causes chronic rheumatic fever
chronic sequelae are due to progressive fibrosis and normal hemodynamic turbulence
What is the epidemiology of rheumatic fever
- May develop 2-3 weeks after a Group A strept infection e.g. strept. sore throat
- Repeated untreated infection (RF in 50%)
- Rare in Kuwait and Western countries
- Children 5-15 yrs (uncommon below 3 yrs)
What is used to diagnose RHD
Jones criteria
- 2 major criteria, or 1 major + 2 minor, with evidence of strept. infection
- Chorea and inactive carditis, each by itself can indicate Rheumatic Fever
What are the major jone’s criteria
- Migratory polyarthritis
- Carditis
- Subcutaneous nodules
- Erythema marginatum
-Sydenham’s chorea
What is migratory polyarthritis
– affects large joints
– temporary inflammation
– usually start in the legs and migrate upwards
What are the features of carditis
– pericarditis
– myocarditis
– a new heart murmur
What are the features of subcutaneous nodules
– painless, firm over bones or tendons
– back of wrist, elbow, front of knees
What are the features of erythema marginatum
– Trunk or arms
– Macules with central clearing
What are the features of sydenham’s chrorea
a series of rapid (involuntary) purposeless movements of the face and arms
What are the minor jone’s criteria
- Fever
- Arthralgia
- Raised ESR or C-reactive protein
- Leukocytosis
- ECG: heart block, prolonged PR interval
- Streptococcal infection: elevated Antistreptolysin O titer (ASOT) or DNAase
- Previous episode of rheumatic fever
What is the pathology of acute rheumatic carditis
- pericarditis
- myocarditis
- endocarditis
How does pericarditis present
Fibrinous/ Bread and butter appearance
How does myocarditis present
Aschoff Bodies (Paravascular)
How does endocarditis present
- Fibrin and platelets valvular vegetations
-Aortic and Mitral are most commonly affected
What are the features of the vegetaions
- sterile
- do not detach/embolize
What can happen as a consequence of the vegetations
fibrous thickening and fusion of the chordae tendineae
What are the features of aschoff bodies
- only in acute stage
- core of fibrinoid necrosis with inflammatory cells
- giant cells with single/multiple nuclei
‘interstitium has a circumscribed collection of large histiocytes and central necrosis’
What is a an anitschkow cell
modified large macrophages
oval caterpillar nucleus
What is the pathology of chronic rheumatic carditis
Endocarditis heals by progressive Fibrosis
valve leaflets: fuse/stenosis, or retract/incompitence
chordae tendinae: pull –> incompitence
What happens to the leaflets in chronic rheumati carditis
- thickened, fibrotic, shrunken
- often with Commisural Fusion (can cause stenosis)
- secondary deposition of Ca++
Gross appearance of chronic rheumatic carditis
– Fish mouth (Button Hole) appearance
– Funnel shape (chordae tendineae)
– 70% have mitral involvement (Mitral Stenosis)
– 25% have both Mitral and Aortic involvement
Microscopic appearance of acute rheumatic carditis
- No Aschoff bodies (acute phase only)
- Diffuse Fibrosis and Neovascularization
What are the complications of mitral stenosis in the chronic phase
- Left atrium dilatation
- Pulmonary Vascular Changes and Pulm. Hypertension
- Right Ventricular Hypertrophy
- May not become clinically significant until several decades later
What is mitral valve prolapse
(floppy mitral valve)
Myxomatous degeneration of the mitral valve,
What causes mitral valve prolapse
Developmental defect of connective tissue (Marfan Syndrome)
0.5-3% of adults in USA
How does mitral prolapse appear clincally
Usually an incidental finding during physical examination (asymptomatic) or autopsy
- chest pain, palpitations or exercise intolerance
- dizziness, syncope or Sudden Death
- audible mid-systolic click murmur
What is the pathology of mitral valve prolapse
Valvular leaflets are enlarged, floppy(soft and loose), and prolapsed(balloon back) into left atrium during
systole
What are the complications of mitral valve prolapse
– Infective endocarditis
– Mitral insufficiency
– Stroke (Thrombo-embolism)
– Arrhythmias
– Sudden death (rare)
gross appearance of mitral valve prolapse
Hooding with prolapse of the posterior mitral leaflet into the left atrium
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What is an infective endocarditis
Infection of heart valve or mural endocardium by organism leading to formation of Bulky Friable Vegetations and destruction of underlying cardiac tissue
What are the characteristics of the infective vegetation
necrotic debris, thrombus and organisms (commonly bacteria)
( fibrin + platelets + RBCs + colonies of bacteria)
What can cause infective endocarditis
- Bacteria, Fungi, Rickettsia, Chlamydia
Organisms enter bloodstream through Dental/Surgical procedures, IV Drug Abuse (Rt. side valves), or Bacteremia - A serious disease; prompt diagnosis and effective treatment are life saving
What are the classifications of infective endocarditis
- acute
- subacute
Many cases fall somewhere along the spectrum between the two forms
What is acute infective endocarditis
– Virulent Organisms e.g. S. aureus, Enterococci
– Normal valves
– Necrotizing, ulcerative, invasive infection
– Often needs surgery, fatal in 50%
What is subacute infective endocarditis
– Less virulent organisms e.g. Strep. Viridans
– Abnormal valves
– Treatable with antibiotics
What are the predisposing valvular factors of RHD
- RHD (previously)
- Myxomatous Mitral Valve (FMV)
- Degenerative Calcific Valve Stenosis
- Prosthetic Valves - ICD
What are host factors related to IE
- Immunosuppression
- Malignancy
- Diabetes
- Alcohol Abuse
- I/V Drug Abuse (Right - side Valves e.g. Tricuspid)
- Dental/Surgical procedures transient bacteremia
- Post -Covid-19 IEC
What are the pathologic criteria of IE
- Vegetations contain Microorganisms,
- Large, dark and friable,
- Septic Emboli from Vegetations,
- Intracardiac Abscess
Gross appearance of infective endocarditis
Aortic Valve with large irregular reddish vegetations on the destroyed valve cusps
Microscopic appearance of infective endocarditis
Blue bacterial colonies extending into the pink connective tissue of the valve.
Inflammatory infiltrate
What is used to diagnose infective endocarditis
Duke criteria
– 2 major, or
– 1 major + 3 minor, or
– 5 minor
What are the major duke criteria
- positive blood culture
- ECG findings
- new valvular regurgitation
What do the ECHO findings of infective endocarditis include
valve-related or implant-related mass or abscess, or partial separation of artificial valve
What are the minor duke criteria
- Predisposing Heart Lesion or I/V Drug Abuse
- Fever
- Vascular Lesions: mostly embolic, including
- Subcutaneous petechiae
- Splinter hemorrhages
- Septic emboli
- Septic infarcts
- Mycotic aneurysm
- Intracranial hemorrhage
- Janeway lesions
petechial hemorrhage
splinter hemorrhage
Tiny blood spots underneath the nails-
Due to microemboli
Janeway lesions
Irregular, painless hemorrhagic lesions on palms and soles
Due to septic microemboli
What are the immunologic phenomena of IE
Circulating immune complex deposition e.g. Glomerulonephritis , Osler nodes, Roth spots
What are the minor ECHO findings of IE
new valvular regurgitation, or pericarditis
Osler’s nodes
Painful immune-mediated lesions on hand and feet
Roth spots
White centered retinal hemorrhages
immune mediated
Types of non-infected vegetations
- Nonbacterial thrombotic endocarditis
- Endocarditis of SLE (libman-sacks endocarditis)
Describe the vegetations in nonbacterial thrombotic endocarditis (NBTE)
- Deposition of small (1-5 mm), masses of fibrin, platelets, and RBCs on cardiac leaflets (sterile)
- Debilitated patients, e.g. cancer or sepsis
- Endothelial injury in a hypercoagulable state
- May produce emboli causing infarcts in brain, heart, or kidney
Describe the vegetations in Libman-Sacks endocarditis
Mitral and tricuspid valvulitis with small, sterile vegetations that rarely embolize
Can occue on both sides
What is calcific valvular degeneration
Slow cumulative damage (wear and tear) with dystrophic calcification
– Tissue deformation at each cycle
– Calcific deposits (calcium phosphate)
What can occur as a result of calcification
- Calcific Aortic Stenosis
- Calcification of a Congenital Bicuspid Aortic Valve
- Mitral Calcification
- Mitral Senile Calcification
Causes and Epidemiology of calcific aortic stenosis
- Most common of all valvular abnormalities.
- Acquired, Senile/age-associated “wear and tear”
- Accounts for 8-10% of aortic stenosis in USA.
- Normal valve or congenital bicuspid valve
- Rheumatic Aortic Calcification
Pathology of Calcific Aortic Stenosis
– Calcific masses in aortic cusps
– Senile Calcification: No commissural fusion
– Rheumatic Calcification: Commissural fusion
