Unit 3 - Valvular Heart Disease Flashcards
where is the best area to auscultate for aortic stenosis
2nd ICS at RSB
what do heart sounds coincide with
heart valve closure
what causes heart sounds
- closure of valve leaflets causes valve, intracardiac blood, and heart’s walls to vibrate
- mechanical energy transmitted throughout the chest, producing an audible sound
can valve opening be heard with a stethoscoepe?
nope
what does S3 suggest
heart failure (flaccid and inelastic heart)
what does S4 suggest
decreased ventricular compliance
S1 correlates with closure of which valves
mitral & tricuspid
which heart sound marks the onset of systole
S1
with S1, volume is proportionate to:
force of contraction
when is S1 louder or softer than normal
- louder: vigorously contracting ventricle
- softer: poorly contracting ventricle
S2 is caused by closure of what valves
aortic & pulmonary
which heart sound marks the onset of diastole
S2
heart sound that marks the end of LV ejection and beginning of isovolumetric relaxation
S2
in S2, volume is proportionate to:
LV pressure decrease at the end of systole
what makes S2 softer or louder
- softer: hypotension
- louder: HTN
when is S3 heard
during the middle 1/3 of diastole, after S2
which heart sound is described as a “gallop rhythm” or rumbling sound
S3
what is S4 caused by and when is it heard
- caused by atrial systole
- heard before S1
where is the aortic area located
right of sternal border at 2nd ICS
where is the pulmonic area
left sternal border at 2nd ICS
where is the tricuspid area
left sternal border 4th ICS (apex)
where is the mitral area located
left MCL 5th ICS (apex)
valvular diseases associated with eccentric hypertrophy
regurgitant lesions (mitral and aortic regurgitation)
valvular lesions associated with concentric hypertrophy
stenotic lesions (tend to produce pressure overload, compensates with thick wall + smaller chamber)
separates atria from ventricles
atrioventricular valves (mitral & tricuspid)
what anchors valve leaflets
chordae tendinae and papillary muscles anchor to interior of ventricles
what prevents AV collapse during ventricular systole
chordae tendinae and papillary muscles
valves that open to let blood exit ventricles
semilunar valves (aortic and pulmonary)
which valves are not anchored by chordae tendinae or papillary muscles
aortic & pulmonary
what propels blood forward when a valve opens
a pressure gradient created inside the cardiac chamber
what prevents blood from moving backward
valve closure
how do valves look on TEE
“mercedes benz” sign appearance
2 ways a valve can fail
- stenosis
- regurgitation
what causes stenotic valve failure
fixed obstruction to forward flow during systole
how does the heart overcome stenotic obstruction
requires higher transvalvular pressure gradient to push past stenotic valve
primary vs. secondary valve lesion
- primary: due to problem with valve itself
- secondary: due to supporting structures, such as ventricular dilation or papillary muscle infarction
how does the heart compensate for stenotic lesions
- adding sarcomeres in parallel
- chamber wall becomes thicker
- reduces chamber radius
velocity of blood traveling through stenotic lesion
increased
quantities of blood entering the chamber during diastole with regurgitant lesion
- blood returning from lesion
- regurgitant fraction
- results in volume overload
do stenotic lesions result in pressure or volume overload
pressure
how does the heart compensate for valvular regurgitation
- adding sarcomeres in series
- to accept a larger volume, chamber radius increases (dilates)
type of heart failure associated with stenotic valvular lesions
HF with normal EF
type of heart failure associated with regurgitant valvular lesions
HF with reduced EF
what happens to LVEDV following aortic valve replacement for aortic stenosis
decreased due to a reduction in impedence to ventricular ejection
where is afterload set in a patient with aortic stenosis
at the valve itself
primary regulator of afterload in a normal heart vs. a pt with aortic stenosis
- normal: SVR
- AS: valve itself
why does a patient with aortic stenosis who undergoes a valve replacement have a lower LVEDV
the new valve reduces impedence to LV ejection (afterload) and the heart naturally ejects a larger amount of blood with each beat (increased SV)
normal aortic valve orifice
2.5 - 3.5 cm2
aortic valve orifice in severe aortic stenosis
less than/equal to 0.8 cm2
mean transvalvular pressure gradient (Lv to aorta) diagnostic for severe AS
> 40 mmHg
4 etiologies of aortic stenosis
which is most common?
- bicuspid aortic valve
- calcification of valve leaflets
- rheumatic fever
- infective endocarditis
1&2 most common
why does a patient with aortic stenosis suffer from pressure overload and increased wall tension
the heart must generate more force to eject SV
what is CO dependent on in pts with aortic stenosis
HR
also preload dependent???
how does the pressure volume loop change in pt with AS?
- increased ventricular pressure increases the height of PV loop
- EDV and ESV also increase (shift to right)
law that explains why LV compensates with concentric hypertrophy
law of Laplace
key changes in the LV in pts with AS
- thicker LV wall
- decreased compliance
- smaller chamber radius
how does compensatory concentric hypertrophy with AS become maladaptive over time
- reduces myocardial O2 supply (subendocardial compression)
- increases MvO2 (increased heart mass)
what will pt with AS experience as concentric hypertrophy becomes maladaptive
- myocardial ischemia
- LV failure
- pulmonary edema
benefits of replacing a stenotic aortic valve
- decreased afterload
- decreased LV-Ao gradient
- decreased LVESV
classic triad of severe aortic stenosis
- syncope
- angina
- dyspnea
50% survival for the classic triad of AS symptoms
syncope = 3 years
angina = 5 years
dyspnea = 2 years
when do pts with aortic stenosis typically develop symptoms
when LV dysfunction develops
why is a spinal anesthetic contraindicated with severe AS
sympathectomy can cause CV collapse
associated disease in up to 90% of aortic stenosis patients
why
acquired von Willebrand disease - because von Willebrand molecule is damaged when it passes through stenotic valve
anesthetic management of which valve lesion is “full, slow, and constricted”
aortic stenosis
desired HR in aortic stenosis pt
slower side of normal with NSR
why is tachycardia dangerous in aortic stenosis
- decreased time for ventricular filling
- decreased LVEDV
= decreased SV, CO, ischemia
at a HR of ___ in a pt with aortic stenosis, further HR decrease should be avoided
70-80
why does a junctional rhythm or a fib require immediate treatment in a pt with aortic stenosis
properly timed atrial kick is required to prime non-compliant ventricle
loss of kick = decreased ventricular filling and SV
how does bradycardia affect pts with aortic stenosis
- decreased CO
- LV overdistention with compression of subendocardium
- decreased myocardial o2 supply
why is adequate intravascular volume important in a pt with aortic stenosis
- want increased preload
- adequate LVEDP required to fill non-compliant LV
LVEDP and PAOP in pts with aortic stenosis
overestimate LVEDV
treatment for LV dysfunction in pt with aortic stenosis
inotropes
consequences of hypotension in pts with aortic stenosis
- decreased aortic root pressure
- decreased coronary perfusion pressure
- myocardial ischemia
how should hypotension be treated in a pt with aortic stenosis
alpha-1 agonist - will increase SVR and coronary perfusion pressure without increasing HR
why is CPR ineffective in severe aortic stenosis
chest compressions won’t generate a sufficient intracardiac pressure to overcome stenotic aortic valve
SV and CO will be inadequate
results of diastolic failure in advanced aortic stenosis
- increased LAP
- pulmonary congestion and dyspnea
which neuraxial technique is preferred in aortic stenosis
epidural - slower LA onset, more gradual sympathectomy
lower block height is less likely to create HD instability
arterial tracing of aortic stenosis
- vs. normal, has a slower systolic upstroke (pulsus tardus) with delayed peak
- SV reduced, creates a narrow pulse pressure with waveform of small amplitude (pulsus parvus)
- dicrotic notch may not be present
valvular lesion associated with pulsus tardus
aortic stenosis
valvular lesion associated with pulsus parvus
aortic stenosis
why is CO reduced in aortic regurgitation
a portion of the SV returns to LV
etiologies of aortic regurgitation
incompetent valve or dilation of aortic root or supporting structures
why does the ESV get bigger during isovolumetric relaxation in aortic regurgitation
the regurgitant volume is added to the blood volume entering from LA
what happens to the pressure volume loop in aortic regurgitation
- wider (increased ESV)
- loop for acute is smaller than chronic
3 conditions that increase regurgitant volume (things to avoid)
- bradycardia (longer diastolic filling time)
- increased SVR (increased aorta-LV pressure gradient)
- large valve orifice (larger area for blood to return through)
will a pt with aortic regurgitation have pulmonary symptoms?
not if the mitral valve is intact
where should cardioplegia be injected into aorta when pt has aortic regurgitation
retrograde (throuh coronary sinus) or directly into each coronary ostia
how must cardioplegia be injected in aortic regurg
retrograde through coronary sinus or directly into each corornary ostia
(injection into aorta requires functional aortic valve)
causes of acute aortic regurgitation
- usually from endocarditis
- may be from aortic root dissection, aneurysm, trauma
why does acute aortic regurgitation lead to rapid CV instabiliy
LV becomes acutely dilated with increased wall tension and impaired contractility
may develop LV failure
how does LV compensate in chronic aortic regurgitation
- dilates (eccentric hypertrophy)
- chamber increases to greater degree than wall thickens
- normalizes wall tension, preserves SV and contractility
coronary perfusion pressure in chronic aortic regurgitation
reduced because of decreased aortic DBP and rise in LVEDP
what happens as LV continues to dilate beyond range of compensatory mechanisms in chronic aortic regurgitation
- wall tension and cardiac mass increase
- results in decreased compliance, contractility
- ultimately LV failure
why is the volume overloaded ventricle better able to compensate for chronic vs. acute aortic regurgitation
chronic develops slowly - can compensate for progressively increasing regurgitant fraction
conditions associated with chronic aortic regurgitation
- valvular calcification
- Marfan syndrome
- Ehler Danlos syndrome
- ankylosing spondylitis
anesthetic management of which valvular lesion is “full, fast, forward”
regurgitant lesions
preload goal in aortic regurgitation
maintain or increase
some SV is lost to LV, avoid hypotension
HR goal in aortic regurgitation
- increased with NSR
- faster HR reduces regurgitant volume and increases AoDBP and CPP
why is a slower HR not desired in aortic regurgitation
- gives more time for SV to flow back into LV instead of moving forward
- reduces CO, aortic root pressure, and can compromise CPP
treatment of LV failure in aortic regurgitation
inotrope and vasodilator
how does SVR affect aortic regurgitation
- increased afterload increases regurgitant volume
- lower afterload promotes forward flow into systemic circulation
why is phenylephrine not an ideal choice in aortic regurgitation
increased afterload increases regurgitant volume
PVR goal in aortic regurgitation
maintain
- acute LV dilation stretches mitral annnulus
- LV pressure will reflect to LA and pulm circulation
- pulmonary congestion will result
why is neuraxial anesthesia beneficial in pts with aortic regurgitation
sympathectomy reduces afterload and reduces regurgitant fraction
arterial waveform in aortic regurgitation
- sharp upstroke
- low diastolic pressure
- wide pulse pressure
- may have biphasic systolic peaks (bisferiens pulse)
valvular lesion associated with bisferiens pulse and why
aortic regurgitation - becuase of an additional reflective wave from the periphery
anesthetic goals for which valvular lesion - “full, slow, and constricted”
mitral stenosis
what causes increased LAP in pts with mitral stenosis
any condition that increases CO or HR
why should N2O be avoided in mitral stenosis
increases PVR, increasing workload of right ventricle
use of furosemide in pts with aortic regurgitation
minimizes pulmonary congestion by reducing preload and LA volume
normal area of mitral valve orifice
4-6 cm2
valve orifice in severe mitral stenosis
< 1 cm2
transvalvular pressure gradient and PA SBP in severe mitral stenosis
- LA to LV pressure gradient: > 10 mmHg
- PA SBP > 50 mmHg
most common cause of mitral stenosis
- in developing nations: rheumatic fever
- in the US: endocarditis and calcification of mitral annulus 2/2 atherosclerosis
6 etiologies of mitral stenosis (besides rheumatic fever and atherosclerosis)
- rheumatoid arthritis
- lupus
- congenital
- left atrial myxoma
- carcinoid syndrome
- iatrogenic following mitral valve repair
how is LV filling maintained in early mitral stenosis
increased LAP provides a sufficient pressure to maintain
what happens to the LV as mitral stenosis progresses
- pressure gradient (LA-LV) increases
- LV becomes chronically underfilled
- net result: overfilled LA, underfilled LV
- leads to lower EDV, SV, CO
how does the body compensate for chronic LV underfilling as mitral stenosis progresses
by increasing SVR to maintain BP
why can pts with mitral stenosis have pulmonary fluid overload
- increased LAP creates back pressure & contributes to increased pulmonary venous pressure
- promotes fluid movement into pulmonary interstituim, reduces pulm compliance, increased WOB
results of chronic pulmonary fluid overload in mitral stenosis
- causes anatomical changes in pulmonary vasculature, leading to pHTN
- increases workload of RV, eventually causing cor pulmonale
consequences of increased LA pressure and volume in mitral stenosis
- alters anatomy of atrial conduction system
- can precipitate A-fib (loss of atrial kick = reduced ventricular filling, CO)
surgical options for treating A-fib
- Maze procedure
- pulmonary vein isolation
why is tachycardia bad in mitral stenosis
- decreased diastolic filling time
- decreased time for blood to pass stenotic valve
- increased LAP
treatment of tachyarrythmias in mitral stenosis
- amiodarone
- beta blockers
- CCBs
- digoxin
- cardioversion
drugs to avoid in mitral stenosis
drugs that increase HR (anticholinergics, ketamine, atracurium)
clinical examples of conditions that increase CO or HR and may increase LAP/lead to pulmonary edema in a pt with mitral stenosis
- thyrotoxicosis
- infection
- autotransfusion during uterine contraction
effects of hypervolemia in pt with mitral stenosis
increases LAP, may cause pulmonary congestion
meds to decrease LAP in mitral stenosis
diuretics
what happens to the LA in mitral stenosis
undergoes concentric hypertrophy
PAOP measurement in mitral stenosis
overestimates LVEDV
PAOP waveform in mitral stenosis
- prominent a wave
- decreased y descent
effects of systemic vasoconstriction in the setting of low SV and CO in pt with mitral stenosis
increases SVR, preserves BP
why should a rapid increase in SVR be avoided with mitral stenosis
elicits a baroreceptor-mediated rise in HR
hypotension treatment in pt with mitral stenosis
vasoconstrictor such as phenylephrine or vasopressin (not ephedrine)
PVR goals in mitral stenosis
avoid conditions that increase (increases RV workload):
- acidosis
- hypercarbia
- hypoxia
- lung hyperinflation
- N2O
- Trendelenburg
considerations for neuraxial anesthesia in mitral stenosis patients
if the pt has Afib, likely anticoagulated and should not receive a neuraxial block
neuraxial is a safe option if INR is ?
< 1.5
why is ephedrine not a good choice for hypotension with mitral stenosis
it will increase HR
3 things that make regurgitant volume worse
- bradycardia
- increased LV to LA pressure gradient
- increased SVR
etiologies of mitral regurgitation
- rheumatic fever
- ischemic heart disease
- papillary muscle function
- ruptured chordae tendinae
- endocarditis
- mitral valve prolapse
- LVH
- lupus
- rheumatoid arthritis
- carcinoid syndrome
patho of mitral regurgitation
SV goes in 2 directions - towards the aorta and through the incompetent mitral valve towards LA
leads to volume overload of LA & LV
pressure volume loop of mitral regurgitation
- ventricular volume gets smaller during isovolumetric contraction
- acute loop always smaller than chronic
4 conditions that increase regurgitant volume of mitral regurgitation (things to avoid):
- slower HR
- increased pressure gradient between LV and LA
- increased SVR
- increased size of valve orifice
when does regurgitation occur with mitral insufficiency
during systole (isovolumetric contraction)
how does HR affect mitral regurgitation
faster HR reduces time spent in systole (when regurgitation happens) and reduces regurgitant fraction
why is a higher preload better in mitral regurgitation
helps compensate for SV lost to LA
is PAOP a reliable measure of LV filling pressure with mitral regurgitation?
no - overestimates LVEDP
PAOP waveform in mitral regurgitation
enlarged v wave (represents regurgitant volume passing through incompetent mitral valve)
how does SVR affect mitral regurgitation
- systemic vasodilation promotes forward flow
- systemic vasoconstriction increases regurgitant volume
risk after mitral valve repair
systolic anterior motion (SAM) of anterior leaflet - obstructs LV outflow tract during systole
treatment if SAM is suspected or verified with TEE
- increasing intravascular volume
- increasing afterload with alpha agonist
SAM is very similar to what other cardiac disease
hypertrophic cardiomyopathy
PVR considerations in pt with mitral regurgitation
avoid conditions that increase PVR (increases workload of RV)
- acidosis
- hypercarbia
- hypoxia
- lung hyperinflation
- N2O
- Trendelenburg
how can sympathectomy compromise coronary perfusion pressure in mitral regurgitation
if AoDBP is drastically reduced
valvular disorders assoc. with systolic murmur
- mitral regurgitation
- aortic stenosis
what phase of cardiac cycle is mitral regurgitation an issue
during isovolumetric contraction during systole
what phase of cardiac cycle is aortic regurg an issue
isovolumetric relaxation of LV during diastole
during what phase of cardiac cycle is mitral stenosis problematic
during atrial systole (atrial kick), which occurs during ventricular diastole
mnemonic for aortic stenosis murmur
ASSS
Aortic Stenosis is a Systolic murmur heard at right Sternal border
LV pressure in aortic stenosis
can exceed 350 mmHg
why might aortic stenosis murmur be confused with carotid bruit
sound is transmitted through upper aorta and carotid arteries
valvular disease with a systolic murmur that may be palpated as a thrill
aortic stenosis
murmur in severe AS
may decrease in intensity - not enough flow passes to make a sound
mnemonic for aortic regurgitation murmur
ARDS
Aortic Regurgitation is a Diastolic murmur heard at right Sternal border
high pitched “blowing” murmur
aortic regurgitation
which is louder - aortic stenosis or aortic regurgitation
aortic stenosis - less pressure gradient with regurg
mnemonic for mitral stenosis murmur
MSDA
Mitral Stenosis is a Diastolic murmur heard at the Apex and left Axilla
which murmur is an opening snap followed by low intensity rumbling murmur
mitral stenosis
holosystolic murmur characterized by loud “swishing” sound
mitral regurgitation
mnemonic for mitral regurgitation
MRSA
Mitral Regurg is a Systolic murmur heard at Apex and left Axilla
most common valves used in TAVR
- Edwards SAPIAN
- Medtroinc CoreValve
why are TAVR pts at risk for allergic reaction and renal injury
radiocontrast dye used
3 surgical approaches to TAVR
- transfemoral
- transaortic
- transapical (antegrade)
benefits of TAVR
sternotomy and CPB not required
aortic valve replacement that requires balloon valvuloplasty prior to deploying replacement valve
SAPIAN valve
unique feature of SAPIAN valve
need for rapid ventricular pacing
why is rapid ventricular pacing used in SAPIAN TAVR
promotes cardiac standstill during valvuloplasty and valve deployment (reduces motion caused by ventricular ejection, makes it easier to get the valve into correct position)
when should profound hypotension be anticipated with SAPIAN TAVR
rapid ventricular pacing (CO will be near 0 during this time)
anesthetic considerations for SAPIAN TAVR
- ensure MAP > 75 before rapid ventricular pacing helps patient restore BP after valve deployment
- consider prophylactic vasopressors before rapid ventricular pacing
- apnea required during valve deployment
why should radiotranslucent pads be placed prior to drapes in SAPIAN TAVR
if pt doesn’t resume NSR after rapid ventricular pacing, defibrillation may be required
CoreValve vs SAPIAN valve for TAVR
corevalve does not require valvuloplasty (the valve is self-expanding) or rapid ventricular pacing
methods to assess new valve function after a TAVR
TEE and fluoro
what are TEE and fluoro used to assess after TAVR
- valve function
- presence of aortic regurgitation
- perivalvular leak
- vascular injury
feared complication of TAVR
- mispositioned valve
- if the valve doesn’t deploy properly, patient will develop aortic regurgitation
treatment of a SAPIAN valve that doesn’t deploy correctly
another valve must be replaced through mispositioned valve
“valve-in-valve” procedure
treatment of a CoreValve TAVR that doesn’t deploy properly
can be retrieved and redeployed
complication to suspect with acute HD instability with TAVR
vascular injury
complication to rule out if pt has s/s myocardial ischemia after TAVR
coronary occlusion from native valve folds or mispositioned new valve obstructing coronary artery
complication of TAVR that may require aortic root repair or replacement
valvuloplasty can cause annular rupture (tamponade and CV collapse)
9 complications of TAVR
- malpositioned valve, acute aortic regurg
- vascular injury
- coronary occlusion
- annular rupture
- stroke
- perivalvular leak
- pericardial tamponade
- AV block
- LBBB
what is a critical acute complication of an improperly placed valve during TAVR
wide open aortic regurgitation
what are 2 unique needs when deploying a SAPIAN valve
- cardiac standstill via rapid ventricular pacing (160-200 bpm)
- balloon valvuloplasty
why might a pt have LV dilation after a TAVR
a malpositioned valve can cause acute aortic insufficiency - can cause LV dilation as a function of increased pressure and volume
what heart sounds are best using the bell of the stethoscope
S3, S4
(lower pitched sounds)
what heart sounds are best heard with the diaphragm
higher-pitched heart sounds such as S1 and S2
are diastolic murmurs best heard with diaphragm or bell
diaphragm
the presence of an S1 murmur at MCL 5th ICS most likely suggests:
mitral regurgitation
hallmark of HFrEF
decreased ejection fraction with increased EDV
what hypertrophies in mitral stenosis
the LA - must generate a higher pressure to push past stenotic mitral valve
how does the heart compensate for pressure overload in mitral stenosis
concentric hypertrophy of LA (parallel replication of sarcomeres)
CVP and PAOP goals in aortic stenosis
high/normal
why is it necessary to keep SVR high in pts with aortic stenosis
to help perfuse coronary arteries (afterload set by stenotic valve, CPP = AoDBP - LVEDP)
when is the risk of SAM after mitral valve replacement increased
when the anterior leaflet is longer than the posterior leaflet or when there is a narrow angle between mitral annulus and aortic annulus
pharmacologic treatment of SAM
(same as hypertrophic cardiomyopathy)
- made worse by vasodilators and inotropes
- improved by vasoconstrictors and volume expansion
best treatment for hypotensive patient with mitral stenosis
phenylephrine or vasopressin - want to avoid meds that increase HR
primary management goal of mitral valve prolapse
why
prevent excessive cardiac emptying
- large ventricle tends to reduce MVP
- small ventricle tends to increase MVP
things to avoid to keep the heart full in MVP
- SNS stimulation
- decreased SVR
- hypovolemia
- reverse Trendelenburg, sitting
why is ketamine avoided in mitral valve prolapse
activates SNS, increases contractility, augments LV emptying
consequence of increased LAP in severe mitral stenosis
pulmonary edema
which valve disease does this represent
aortic stenosis
which valve disease is seen
aortic stenosis
aortic regurg
mitral stenosis
mitral regurg
anesthetic goal for pts with mitral valve prolapse
prevent excesive cardiac emptying
things to avoid in pts with MVP
- SNS stimulation
- upright position
- hypovolemia
- decreased SVR
why should ketamine be avoided in pts with MVP
activates SNS, ↑ contractility, augments LV emptying
which valve disorder is assoc. with parallel replication of sarcomeres in left atrium
mitral stenosis
most common dysrhythmia assoc. with mitral stenosis
A-fib