C7: AV Regurg Flashcards
4 groups of mechanisms that cause AI
cuspal abnormalities
AO root dilation
AO root distortion
loss of commissural support
4 causes of cuspal abnormalities
congential
rheumatic AV disease
AV prolapse
infective endocarditis
…. eg, any congenital disorder or disease process that affects the Av cusps
which congenital, cuspal, abnormalities can commonly cause AR
bicuspid, uni or quadricuspid AV
is a quadricuspid AV rare?
what other abnormality is it associated with?
yes
anomalous coronary artery origin
describe how rheumatic AV disease causes cuspal abnormalities which lead to AR
-cusp tissue is infiltrated w/ fibrous tissue which causes them to contract and shorten, this prevents cuspal apposition which leads to AI
is rheumatic AV disease usually also associated w/ some degree of AS
other associations
yes
MR and MS
causes of AV prolapse leading to cuspal abnormalities and AR
myxomatous degeneration
rheumatic disease
Ao root dilation
trauma
what type of AR jet would you get w/ AV prolapse
eccentric
how does AO infective/bacterial endocarditis cause cuspal abnormalities that lead to AR
vegetation destroys AV and can cause perforations/holes in the cusps
how does AO root dilation lead to AR
prevents leaflet coaptation during diastole
list some causes of AO root dilation
systemic HTN atherosclerosis c-tissue disorders (marphans) bicuspid AV sinus of valsalva aneurysms idopathic
how does AO root distortion occur and lead to AR
root becomes distorted due to infammation that can eb cause by:
ankylosing spondylitis
takayasu’s arteritis
rheumatoid arthritis
what 3 things might cause a loss of commissural support
VSD
AO dissection
AO trauma
causes of acute, severe, AI
does it cause an increase in filling pressures?
trauma, infective endocarditis, AO dissection
yes, mainly LVEDP
describe the pathophysiology of acute, severe, AI
why does acute, severe, AI cause an increase in LVEDP
- regurgitant volume (RV) leaks back into the LV as well as the norm blood volume entering from the LA….
- because his is acute, LV hasn’t had time to dilate yet to accommodate the extra volume so LVEDP increase dramatically
how does acute, severe, AI effect the MV
may cause early closure, press is rising faster due to regurg volume
describe the pathophysiology of chronic, severe, AI
what will filling pressure be like
- regurgitant volume causes the LV chamber volume to increase due to dilation which may lead to increase ejection volume through the AO (starlings principle)
- filling press may by norm or slightly elevated
how will LV mass change w/ chronic, severe, AI
increase - eccentric hypertrophy
what will happen to the LV over time w/ chronic, severe, AI
will start to fail, and then the LVEDP will increase at this point
symptoms of AI (acute and chronic)
dizziness syncope fatigue, SOBOE CHF signs diastolic murmur, w/ S3 and S4 heard
complications of AR
- increase LV and LA size due to press and volume overload
- pulm venous congestion…. leading to pulm edema, RH faliure, systemic venous congestion and edema
- embolization
- death
what is the pulse press
SBP-DBP
4 roles of echo w/ AR
- determine etiology
- assess LV function and size
- measure AO dimensions
- estimate severity of AI
etiologies of AR
congenital, degenerative, rheumatic
what will the direction of AR often be if the cause is due to a bicuspid AV
eccentric… regurg will get worse over time
how does a bicuspid AV effect the commissure lines
they calcify earlier
most common cause of acute severe AI
how will it appear
infective/bacterial endocarditis
hypermobile mass on the underside of the AV (LV side) that will have different echo characteristics than surrounding tissue
how does infective/bacterial endocarditis cause AR
by destroying one or more of the valve cusps
why does the mass causes by infective/bacterial endocarditis grow on the LV side
mass always grows on the low pressure side of the valve
how can a VSD lead to AR
the defect affects the supporting structures of the AO root, leading to AR
(Especially if a membranous VSD)
how can a proximal AO dissection lead to AR
stretched out the annulus so leaflets don’t coapt
when the LV is severely dilated, what shape does it take on
what should you look for when this happens
spherical instead of conical…
-look for eccentric hypertrophy and calculate LV mass
what is jet height
When is it less accurate for severity of AI
the height of the regurg jet on the LVOT of the AV
With eccentric jets
what is the vena contracta width
in what view is it measures
the height of the regurg jet at the narrowest point, usually just on the LV side
PLAX, LVOT zoom
which is more accurate, jet height or vena contracta width
why
vena contracta width, its less influenced by loading conditions than jet height
what ratio can be used to determine the severity of AR
what does it measure
jet height/LVOT diameter ratio, measures how much of the LVOT diameter the jet covers
jet height/LVOT diameter ratio for mild AR
severe AR
mild: <25%
severe: >/= 65%
when will the jet height/LVOT diameter ratio underestimate the AR jet severity
when its eccentric
in what view do you measure jet area/LVOT area ratio
what does it measure
in the PSAX AV/BASE view, w/ zoom, w/in 1 cm of the vena contracta width
measures/estimates the regurgitant orifice area
jet area/LVOT area ratio w/ mild AR
severe AR
mild: < 5%
severe: >60%
when may the jet area/LVOT area ratio be in accurate
may be inaccurate based on the direction of the jet
when is the vena contract width/zone the most accurate
for single, central jets
vena contract width for mild AR
severe AR
mild: <3mm
severe: >/= 6mm
how does brightness of the CW AR tracing related to severity of AR
how do you determine brightness
brighter = more significant AR (more RBCs moving at a that velocity)
compare it to the brightness of the AO outflow
if flow reversal is seen in the Abdo AO what does this usually indicate for severity of AR
severe
if flow reversal is seen in the descending AO what does this usually indicate for severity of AR
moderate
if flow reversal is seen in the ascending AO what does this usually indicate for severity of AR
mild
what is pressure half time (PHT or P1/2)
time it takes for the press gradient to fall by 1/2
how do measure the PHT
which window is usually best
use CW, align to the AR and measure the deceleration rate of the AR
Apical
what does the steepness of the AR slope tell you about severity of the regurg
what determines this steepness
steeper = more severe
press gradient b/w LV and AO….. higher LVEDP and relatively low AO press will create a steeper slope
at what severity does AR become hemodynamically significant
if it moderate or greater
PHT value for mild AR
severe
mild: >500 ms
mod: 200-500
severe: <200 ms
regurgitant volume measurement principle
in the abscence of regurg, SV across any valve in the heart should be the same….. but if there is regurg, the SV of the RV will be higher than the SV of a non-regug valve
regurgitant volume and regurgitant fraction can be calculated using which 2 methods
stroke volume or PISA
SV formula for regurgitant volume
RVolume = SV of regurg valve - SV of control valve
or
RVolume = RV (pie (r^2) x VTI) - CV (pie (r^2) x VTI)
units = cm^3 or ml
what does PISA stand for
proximal isovolocity surface area
AV regurgitant fraction % for mild AR
severe
mild: <30%
severe: >/=50%
AV regurgitant fraction
formula
% of blood leaking back across the valve
RF = [ (SV of RV - SV of CV) / SV of RV ] x 100
effective regurgitant orifice area (EROA) value for mild AR
severe
mild: <0.1 cm^2
severe: >/= 0.3 cm^2
2D and Mmode finding of the MV w/ severe AR
- AML reverse doming due to a severe AR jet hitting the AML
- may lose double bump in severe cases
- AML fluttering during diastasis
if the vena contracta is > 6mm and flow reversal is seen in the descending AO, do you need to measure more parameters to grade AR
no, automatically severe
if central jet width was < 25% and the LVOT CW is not intense, how would you grade the AR
mild
regurgitant volume value for SV and PISA, for mild AR
severe
mild: <30 ml
severe: >/=60ml
order of assessment for AR
AR colour flow images
vena contracta
abdo AO PW (if moderate-severe is seen)
