Valvular Diseases - Cochran Flashcards
Describe the structure & function of normal cardiac valves.
Lined by endothelium and divided into leaflets. If AV valve, connected to ventricle via chordae tendineae & papillaries.
Function to allow unidirectional flow of blood.
What can cause valvular insufficiency?
Functional regurgitation (disruption of supporting structure, eg aortic dilation)
Structural disease affecting the valve cusps.
Which are more frequent: Stenoses of insufficiencies?
Stenoses.
What is the most common congenital valvular abnormality? What does this predispose to?
Bicuspid aortic valve, which is more prone to calcification.
Calcific Aortic Stenosis
Describe the pathophysiology.
Who does it generally affect?
“Wear & Tear” resulting in fibrosis and eventual calcification.
Wear & tear results in fibrosing and eventual calcification of the valves.
Occurs in normal valves in very late life (8th-9th decades), as well as in abnormal valves in the 5th-6th decades.
What is the signifiance of a Notch mutation in valvular heart disease?
Notch is involved in signaling during heart valve development; mutation predisposes to heart pathologies including CAS.
Calcific Aortic Stenosis
Describe its morphology.
Calcific Aortic Stenosis
Calcified masses in cusps, rarely involving the cuspal edges.
No fusion of commissures.
Mitral Annular Calcification
Describe the pathogenesis.
Who does it affect?
What are its complications?
Mitral Annular Calcification
Wear & tear degeneration resulting in calcification on the base of the valve (fibrous ring).
Usually women >60, especially with myxomatous valves or increased LV pressure.
Doesn’t affect function, but forms sites for thrombi/infection.
Mitral Degeneration
Describe the pathogenesis.
Who does it affect?
What are its complications?
Mitral Degeneration
Myxoid changes weaken the mitral valve, causing it to prolapse back into the left atrium during systole.
Young women, and those with connective tissue disorders (Marfan, Ehler-Danlos).
Usually asymptomatic. Sometimes IE, regurgitation, formation of thrombi and arrhythmia.
What is the auscultatory finding of mitral prolapse, and why does it occur?
Holosystolic “blowing” murmur. During systole, left ventricular contraction causes the valve to prolapase into the Left atrium, creating a “blowout” sound akin to a parachute inflating.
What valve is most typically affected chronic rheumatic fever?
What is the trigger for ARF?
Usually mitral valve, but may also involve the aortic.
Preceding group A Strep pharyngitis infection.
Acute Rheumatic Fever
Describe the 3 components of its pericarditis.
Acute Rheumatic Fever
“Bread & Butter” pericarditis.
Myocarditis with Aschoff bodies (eosinophilic foci with lymphocytes, plasma cells, & anitschkow cells).
Endocarditis with formation of MacCallum plaques (irregular fibrous thickening), fibrinoid necrosis & verrucae.
A patient presents with aortic stenosis. How could you distinguish calcific stenosis from that caused by rheumatic fever based on the heart findings alone?
Aortic stenosis due to rheumatic fever would be accompanied by mitral stenosis.
Involvement of the cusp edges.
Fusion of the commissures.
Describe the findings seen in chronic rheumatic heart disease.
Valve leaflet thickening
Commissure fusion (“Fishmouth” or “Buttonhole” deformities)
Thickening of chordae tendineae
Rheumatic Heart Disease
Describe the pathogenesis.
Rheumatic Heart Disease
GAS pharyngitis generates antibody response against M protein, which is then directed against an unknown heart antigen. (Type II HSR)
(some genetic predisposition to this molecular mimicry response)
Rheumatic Heart Disease
Describe the criteria used to diagnose this disease.
Rheumatic Heart Disease
JONES criteria (major manifestations; Joint pain, heart involvement, Nodules, Erythema marginatum, Sydenham chorea)
Minor criteria: Fever, elevated ESR/ARPs.
Positive ASO or Anti-DNAse B titers.
Rheumatic Heart Disease
When does chronic rheumatic disease develop, relative to an acute GAS infection?
What role do recurrent infections play?
Rheumatic Heart Disease
Can take years or decades to develop.
Recurrent infections & relapses increase the risk of developing chronic disease.
Infectious Endocarditis
Distinguish between acute and subacute infections.
Infectious Endocarditis
Acute endocarditis involves highly virulent organisms affecting a normal valve. Infection is necrotizing & ulcerative, requiring surgery and resulting in high mortality.
Subacute preferentiallya ffects deformed valves, is less destructive and may be managed by antibiotics alone.
Infective Endocarditis
Who is predisposed to IE?
What organisms are generally responsible?
Infective Endocarditis
Those with cardiovascular abnormalities, or with immunosuppression (eg diabetics, alcoholics, cancer patients). IV drug users.
Strep viridans > Staph Aureus* > commensals (eg staph epidermidis)
*SA highest in IVDUs.
Infective Endocarditis
What valves are most commonly affected? Why is this different in IVDUs?
Describe the lesion.
Infective Endocarditis
Usually mitral and aortic. IVDUs contract endocarditis from venous inoculation, so tricuspid valve is involved.
May range from mild fibrosis & granulation tissue reaction, to formation of bulky, friable vegetations at the bases of valves. May erode the myocardium.
Infective Endocarditis
What should be present on histology?
Infective Endocarditis
Abundant neutrophils, dense regions of bacteria corresponding with the vegetations.
Infectious Endocarditis
Describe the criteria used in the diagnosis of this disease.
Infectious Endocarditis
Duke criteria: Major (positive culture, echo findings, & valvular insufficiency), Minor (predisposing lesion or IVDU, fever, & septic emboli)
Recall the names given to of septic embolization to the following sites:
Nail bed
Palms & soles
Digits
Retina
Nail bed: Splinter hemorrhages
Palms & soles: Janeway lesions
Digits: Osler nodes
Retina: Roth spots
Infectious Endocarditis
What are its complications?
How is it treated?
Infectious Endocarditis
Valvular stenosis/insufficiency, myocardial abscess/perforation, septic emboli, glomerulonephritis.
IV antibiotics and possibly valve replacement.
Nonbacterial Thrombotic Endocarditis
What are the valve findings?
Describe its pathogenesis & etiology.
Nonbacterial Thrombotic Endocarditis
Deposition of fibrin, platelets, & other blood products (thromboses!). May result in emboli & infarcts. Small, noninflammatory & nondestructive lesions lining the cusp edges.
Results from hypercoagulable states. Associated with mucin producing adenocarcinomas & endocardial trauma.
Libman-Sacks Endocarditis
What is it associated with?
Describe its morphology.
Libman-Sacks Endocarditis
Systemic Lupus Erythematosus (Anti-PL antibodies present).
Forms intensely inflamed verrucae on valve leaflets & endocardium. Targets mitral, tricuspid valves.
Carcinoid Syndrome
Describe its etiology & pathogenesis.
What impact can this have on the heart?
Carcinoid Syndrome
A result of carcinoid tumors in tissues such as lung and GI, which produce vasoactive products resulting in flushing, nausea, vomiting, etc.
50% of carcinoid syndrome results in carcinoid heart disease: “plaque-like fibrosis of right-heart endocardium & valves” probably due to endothelial damage.
Carcinoid Heart Disease
Why is the right heart preferentially affected?
Where do the carcinoid tumors have to be located?
When can the left heart be affected?
Carcinoid Heart Disease
Many of the vasoactive agents are inactivated by MAO, which is highly concentrated in the lungs.
GI with metastasis to liver, or anywhere that dumps to non-portal venous system.
In primary lung carcinoids, or tumors that secrete extremely high levels of vasoactive produces.
Carcinoid Heart Disease
Describe the changes found in the heart.
Carcinoid Heart Changes
Thickening of the endocardium. Expansion of smooth muscle cells & collagen. May result in tricuspid insufficiency or pulmonic stenosis.
What problems are associated with both mechanical and biological heart prosthesis?
What problems are distinct to either?
Both are more prone to infectious endocarditis.
Mechanical prosthesis are a possible substrate for thromboembolus formation.
Cow & Pig valves are prone to deterioration; half need replacement by 15 years.
