3 microscopic layers of each valve leaflet
1. fibrosa: back surface of valve (aortic side of aortic valve, ventricular side of mitral) in continuitry with annulus fibrosa 2. spongiosa : central layer comprised of loose CT 3. ventricularis/atrialis: closest to the inflow surface and rich in elastic fibers
Normal valves are __________.
Most important etiologic associations with valve defects: AS, MS, AR, MR
AS: dystrophic (wear and tear, aka senile) calcification -MS: chronic rheumatic heart disease -AR: dilation of aortic root (old age, HTN, atherosclerosis, Marfan) -MR: myxomatous degeneration, dilation of mitral valve ring with LV dilation due to LV failure
Dystrophic calcification most often affects ________ and _________. Discuss the cause.
-aortic valve leaflets, and mitral valve ring -turbulent blood flow leads to wear and teardamage to leaflets, esp. where pressuregradients and turbulence are greatest,leading to amorphous (dystrophic)calcification (notatherosclerosis of valves, but shares some risk factors)
Aortic valve calcification results in ______ in the _____ of leaflets, protruding into the __________. There is no ____________. Functionally this most often results in ________, but regurgitation as well. There is associated LV ____________.
-nodular deposits -middle, protruding into sinuses of Valsalva -no fusion of valve commissures (vs. Rheumatic heart disease) -most often results in stenosis -assoc with concentric LVH
Clinical sxs of dystrophic calcification. When does it tend to reach clinical significance.
-angina, syncope, CHF -8-9th decades (senile calcific AS) when aortic valve orifice is reduced to <1 cm2
dystrophic calc of tricuspid aortic valve
nodular fibrosis and calcification in dystrophic calcification
Timing of clinical sxs due to aortic valve calcification
-previously nl heart valve: 8-9th decade
-congenitally deformed aortic valves= earlier sxs onset
-bicuspid valves at 5-6th decade (unequal with raphe on large or equal without raphe)
-unicuspid valves: 2-4th decades : unicommmissural or acommmisural
-trend: greater deformity= greater turbulence= sooner calcification
bicuspid aortic valve with raphe (not calcified here) but can also be born without raphe
left is unicommissural
-right is acommissural
Calcification of MV annulus
-elderly, more often in women, more often in patients with myxomatous degernation or chronically increased LV pressures
-commonly detected on CXR or US; usually asymptomatic but can cause mitral regurg
-rarely erods into conduction system
calcification of MV annulus
calc of mitral valve annulus! not leaflets!!
Acute rheumatic fever vs chronic rheumatic heart disease
-ARF: systemic disease! whichc an affect all layers of the heart as well as extracardiac sites (joints, skin, CNS); inflammatory disease triggered by an abnormal immune reaction to pharyngitis caused by Group A B hemolytic strep
-CRHD: affects cardiac valves, years after 1 or more attacks of ARF; mitral valve affected with or without aortic valve (less common)
Chronic RHD occurs _______________. Affect which valves? What does chronic injury cause?
-years to decades after 1 or more episodes of ARF
-affects mostly cardiac valves on LH esp mitral or mitral + aortic
-chronic injury causes scarring of valve leaflets with thickening, retraction, and neovasc. of leaflets as well as fusion of commissures. Shortening, thickening, and fusion of chordae tendonae
Gross path of chronic rheumatic heart dz
chronic injury causes scarring of valveleafletswith thickening, retraction, andneovascularization of leaflets, as wellasfusion of commissures. Also causesshortening, thickening and fusion of chordae tendineae (may also cause regurg)
The valvular changes in CRHD can produce function _____, ______ or both.
Pure MS from CRHD results in ___________________ . Added MR produces ____________, as does AS or AR.
-left atrial dilation, atrial fibrilation, atrial thrombbus which possible embolization
-added MR produces LVH, as does AS or AR
Scarred valves from CRHD are predisposed to ________.
MS secondary to CRHD
-view from above: fish mouth,; thickened leaflets and fused commissures
-side view: shortened, thickened fused chordae
Aortic regurgitation due to CRHD looks like what?
-shortened, rolled up leaflets
Chronic rheumatic heart disease on microscopy
-bland fibrosis of leaflets with loss of 3 layers
arrow pointing out neovasc in CRHD
Causes of AR, which is the most common? and what is end result?
-dilation of aortic root is by far the most common cause (old age, medial degeneration, marfan's)
-perforation or tear of leaflet (infectious endocarditis)
-retraction of valve leaflets: scarring due to CRHD
-fixation of valve leaflets: scarring or calcification
-results in eccentric LVH
AR due to dilation of aortic root
-can also be due to shortened rolled upleaflets from CRHD!
Myxomatous degeneration of MV
-increased deposition of mucopolysaccharides in spongiosa with associated attenuation of fibrosa
-leaflets thicken, stretch, chordae elongate, and leaflets can billow upward into LA (prolapse) functionally producing regurg
-Pathogenesis is unknown, but may involve a subtle,
sometimes inherited disorder of structural proteins, so that normal physical stresses on the valve result in
increased deposition of extracelllular matrix, as well as stretching of the chordae..
What does MV prolapse sound like?
-mid systolic click
myxomatous degeneration: spongiosa layer is blue with polysaccharides
myxomatous degeneration of valve: looks like clouds on long stems!
Acute complication on top of MV prolapse within myxomatous degeneration
-rupture of chordae
Myxomatous degeneration clinical lesions
1. asxs systolic click
2.mitral regurg: annulus dilation, chordal lengthening, misaligned leaflets, resulting in gradual regurg; chordae rupture resulting n sudden regurg
3. thrombus formation on leaflets or atrium: systemic embolization, endocarditis
4. dysrhythmia: syncope or sudden death
-Similar changes can be seen in cardiac valvesof patients with underlying connectivetissue disorders, e.g. Marfan’ssyndrome,suggesting there may be underlying (? hereditary) connective tissueabnormalitiesthat predispose allpatients with this disorder to valvedamage by hemodynamic stress
Elevation of LAP in MS or even moreso in MR or chronic LV failure of any cause can affect __________.
-acutely: inc LAP transmitted back to pulm veins, leading to venous congestion +/- still lung and inc venous P transmitted to alveolar caps which may lead to interstitial and/or alveolar edema (SOB, orthopnea, PND); 3. severe inc pressure goes to pulm arterioles which lead to pressure overload on RV and may cause RHF
-chronically: inc LAP can lead to fibrosis in wall of pulm veins, increase in pulm arteriolar pressure can lead to structural changed in them leading to fixed pulm arterial resistance and PHTN
-concentric intimal thickening in small pulm artery due to MS leading to pulm HTN
Acute vs chronic LAP effects
-acute increase in LAP can lead to pulm congestion +/- edema +/- transient increase in pulm vascular resistance
-chronic LAP can result in persistent PHTN +/- RHF
-infection of a heart valve (less commonly non-valvular endocardium)
-most often bacterial, but can be fungal, rickettsial, chylamydial, or viral
Non-bacterial thrombotic endocarditis (NBTE)
-aka non-infectious endocarditis
-occurs in pts with injury to the endocardium, often due to turbulent blood flow often in setting of underlying disorder of hypercoagulability
Bacterial endocarditis pathogenesis requires...
-pre-existing fibrin depostion on a heart valve (ex. NBTE) followed by bacteremia, which allows bacteria to enter the fibrin deposit. progressive growth of bacteria with more fibrin, polys, and possible invasion of valve
-shedding of bacterial antigens into blood alongside with development of antiboides allow intravascular immune complex formation
Bacterial endocarditis clinical spectrum
1. acute bacterial endocarditis: virulent bacteria which can attack normal or abnormal valves; acute cataclysmic onset; if untreated, lethal within weeks; Staph aureus or gram negative enteric bacteria
2. subacute BE: less virulent bacteria, usually attacking previously damaged valve; more subtle onset (FUO); untreated lethal >6 weeks; most commonly streptococcus, esp viridans
Predisposing valve abnormalities to BE
1. dystrophic calc (AV>MV)
2. congenitally abnormal walves
3. myxo degeneration
4. chronic RHD
5. previous BE
6. artifical valve
Factors other than valves predisposing to BE
1. infection elsewhere with bactermia, esp virulent ones like staph
2. IV foreign bodies: caths, pacemakers
3. Immunosuppression: pharm, AIDS, lymphoma
4. IV drug abuse left or RIGHT SIDED valves
If a patient comes in with BE of right-sided valves, what are you suspicious of?
-IV drug use
Effects of BE
-embolism: to brain, kidney, spleen, gut, heart, lungs if R sided; septic emboli leading to abscesses elsewhere
-valve regurg: perforation of leaflet, rupture of chordae
-immune complex disease: glomerulonephritis, small vessel vasculitis
-may pierce conduction system causing arrhythmias
top left: crescent, bottom right: segmental necrosis
-acute necrotizing glomerulonephritis (immune complex) in BE
Infective endocarditis causative organisms
-most often bacterial, but 10% have no organism identified
-on normal vales: staph aureus, gram -s
-abnormal valves; strep, esp viridans
-prosthetic: staph epidermidits, staph aureus, strep
-IV drugs: staph aureus, fungi (candida, aspergillus); RIGHT SIDED!
NBTE: Non-bacteria thrombotic endocarditis
-occurs in pts with injury to the endocardium, often due to turbulent flow, often in setting of underlying hypercoag disorder
-coag disorders include low grade DIC, sepsis, burns, or malignant neoplasms esp mucin producing adenocarcinomas esp pancreas; can be assoc with DVTs
Outcomes of NBTE
-vegetations usually small, asxs, but can embolize: bland organizing fibrin, with NO bacteria
-usually no destruction of underlying valve
-can resolve by organization, leaving small fibrous nodules on leaflets
-can predispose to superimposed infection!!!!!