CV valvular heart disease Flashcards
What do the heart sounds coincide with
Heart valve closure
What are the 4 heart sounds (S)
What do they represent
S1 = closure of mitral and tricuspid valve S2 = closure of aortic and pulmonic valve S3 = suggests CHF S4 = suggests poor ventricular compliance
Where is each valve best auscultated Aortic valve Pulmonic valve Mitral valve Tricuspid valve
Aortic valve = right sternal border at 2nd ICS
Pulmonic valve = left sternal border at 2nd ICS
Mitral valve = left midclavicular line at 5th ICS
Tricuspid valve = left sternal border at 4th ICS
When is S3 and S4 heard
During diastole when MV is open
When are S1 and S2 heard
S1 = onset of systole S2 = onset of diastole
What type of hypertrophy do regurgitant valves tend to produce.
Why
eccentric hypertrophy
(thin wall + dilated chamber)
Sarcomeres added in series
due to volume overload during diastole
What type of hypertrophy do stenotic valves tend to produce.
Why
concentric hypertrophy
(thick wall + small chamber)
sarcomeres added in parallel
due to pressure overload during systole
Definition of valvular stenosis
fixed obstruction to forward flow requiring higher pressure to overcome transvalvular pressure gradient
Definition of valvular regurgitation
incompetent valve allows blood to flow forward and backward during diastole. chamber radius increases to allow for greater volume
Normal size of aortic valve
What size is the AV valve to be considered severe
normal = 2.5 - 3.5 cm^2
Severe = <0.8 cm^2
3 common etiologies of aortic stenosis
Bicuspid aortic valve
Rheumatic fever
Infective endocarditis
What are 3 compensatory mechanisms of the LV in the presence of aortic stenosis
Increased LV wall thickness
Decreased compliance
Small chamber radius
50% survival rate for AS when pt presents with syncope, angina, or dyspnea, respectively
syncope = 3 yrs angina = 5 yrs dyspnea = 2 yrs
Anesthetic goals for aortic stenosis HR Rhythm Preload Afterload Contractility PVR
HR = avoid tachycardia Rhythm = NSR (atrial kick) Preload = Increase (to overcome pressures) Afterload = maintain or increase Contractility = maintain PVR = normal
What type of anesthesia should be avoided in pts with aortic stenosis? Why?
spinal anesthesia b/c increased risk for CV collapse d/t sympathectomy
What type of arterial waveform is noted with aortic stenosis
pulsus tardus (slow systolic upstroke and delayed peak) or pulsus parvus (narrow pulse pressure with small amplitude waveform)
What is the mean transvalvular pressure gradient that qualifies as severe AS
> 40 mmHg between LV and aorta
What is CO dependent on in the patient with AS
CO is HR dependent
What happens to SVR in pts with AS and how does this affect CPP
SVR is decreased
This reduces CPP
What type of hypertrophy occurs with AS?
What are the characteristics of this type of hypertrophy
concentric hypertrophy
Thick LV wall
Decreased compliance
Smaller chamber radius
How does the pressure-volume loop change in the patient with AS
Loop height increases
ESV shifts right
EDV shifts right
How is the subendocardium at risk in the patient with AS
Reduced O2 supply d/t compression
Increases risk for MI, LV failure, pulmonary edema
What benefits does aortic valve replacement produce in patients with AV stenosis
- decreases afterload
- decreases LV-Ao gradient
- Decreases LV-ESV
Why is NSR important in patients with AS
Atrial kick allows for adequate ventricular filling and stroke volume
Tachycardia decreases LV filling time and SV/CO
How can tachycardia be treated in patients with AS
Synchronized cardioversion
Beta-blockade
Avoid medications that produce tachycardia
How can bradycardia be risky in patients with AS
decreased HR allows for LV over-distension from volume. This causes compression of subendocardium and decreases O2 supply
Why is preload important in the patient with AS? What measures are used to increase preload?
Adequate LVEDP is required to fill the non-compliant LV
Give IVF to ensure adequate intravascular volume
Why is it important to maintain or increase SVR in patients with AS
Stroke volume is fixed d/t the stenotic aortic valve
This means CO is dependent on HR
If pt becomes hypotensive, Ao root pressure drops and decreases CPP leading to MI
What medications are best for HoTN in patients with AS? Why
Alpha-1 agonist
This increases SVR and CPP but not HR
What effect does CPR have in patients with AS
Chest compressions won’t generate sufficient intracardiac pressure to overcome stenotic valve
When is increased PVR concerning in patients with AS and why
Late in the disease process
Diastolic failure leads to increased LAP, pulmonary congestion and dyspnea
Define:
Pulsus tardus
Pulses parvus
Pulsus tardus = arterial waveform with slow systolic upstroke and delayed peak
Pulsus parvus = narrow pulse pressure with small amplitude waveform
When a patient with aortic regurgitation is receiving cardioplegia, how is this given
Retrograde, via the coronary sinus
Describe the anesthetic goals for each in the patient with aortic insufficiency HR Rhythm Preload Afterload Contractility PVR
HR = increased Rhythm = NSR Preload = maintain or increase Afterload = decrease (improves forward flow) Contractility = maintain PVR = maintain
How does the arterial waveform appear in patients with aortic insufficiency
Increased pulse pressure with bisferiens pulse
What are 2 etiologies of aortic regurgitation
Incompetent valve
dilation of the aortic root
What happens to stroke volume in patients with aortic regurgitation
it is decreased because a portion returns to the LV instead of forward into the aorta
How is ESV affect in patients with aortic insufficiency
It increases during isovolumetric relaxation
How does the pressure-volume loop change in patients with aortic regurgitation
The loop becomes wider
How does the pressure-volume loop compare for acute vs chronic aortic regurgitation
the acute loop is smaller and shifted right
the chronic loop is larger and wider
What conditions increase regurgitant volume and how
Bradycardia (longer diastolic filling time) Increased SVR (Ao-LV pressure gradient) Large valve orifice (larger area for blood to return)
How does each factor increase regurgitant volume in aortic insufficiency
Bradycardia
Increased SVR
Large valve orifice
Bradycardia = longer diastolic filling time for more volume
Increased SVR = increased aorta-LV pressure gradient
Large valve orifice = larger area for blood to return through
How does the LV compensate in patients with aortic insufficiency
Through eccentric hypertrophy aka LV dilation.
The chamber radius increases to preserve stroke volume and contractility
How is CPP altered in patients with aortic insufficiency
Decreased
d/t decreased aortic DBP and increased LVEDP
What conditions are associated with chronic aortic regurgitation
Valvular calcification
Marfan syndrome
Ehler-Danlos syndrome
Ankylosing spondylitis
Why should preload be maintained or increased in patients with aortic insufficiency
Because some of the stroke volume is lost to the LV
Avoid hypovolemia, fluid resusitate
Why is a faster HR preferred in patients with aortic regurgitation
Increased HR = less time for regurgitant volume backflow, increased AoDBP and CPP
Why should low HR be avoided in patients with aortic regurgitation
Low HR allows more time for volume backflow into LV
Reduces cardiac output
Decreases CPP d/t decreased Ao root pressure
How should SVR be maintained in patients with aortic regurgitation and why
Decrease SVR
Allows for forward flow d/t decreased afterload pressure
Which medications are used to reduce SVR in patients with aortic insufficiency
Phenylephrine or vasopressin (???)
Can regional anesthesia be used in patients with aortic regurgitation. Why or why not
Yes
Sympathectomy reduces afterload and will reduce regurgitation fraction
Define bisferiens pulse seen on arterial waveform
Which valvular conditions is this seen with
Sharp upstroke
Low diastolic pressure
Wide pulse pressure
Possible biphasic systolic peak
Seen with aortic regurgitation
What is the normal size of the mitral valve?
What size valve is considered severe for mitral stenosis?
Normal = 4 - 6 cm^2
Severe <1 cm^2
What are the 3 most common causes of mitral stenosis
Endocarditis
Mitral calcification
Rheumatic fever
How is BP maintained in patients with mitral stenosis
Increased SVR
What pulmonary problem can result from mitral stenosis
Pulmonary HTN d/t increased left atrial pressures
What are anesthetic goals for patients with mitral stenosis HR Rhythm Preload Afterload Contractility PVR
HR = LOW side of normal Rhythm = NSR Preload = maintain Afterload = maintain Contractility = maintain PVR =avoid increase
In patients that have pulmonary HTN as a result of mitral stenosis, what physiologic states should be avoided (4)
Hypoxia
Hypercarbia
Hypothermia
Acidosis
These all increase pulmonary vascular resistance
Why are patients with mitral stenosis at increased risk for thrombus formation
Blood stasis in the left atrial appendage causes thrombus formation
How does the possibility of thrombus formation in mitral stenosis impact an anesthetic
Pts may be on anticoagulants. Neuraxial blocks may need to be avoided
Regional anesthesia effects on mitral stenosis
Epidural anesthesia is preferred over spinal
Rapid BP declines with spinals can cause significant CO reduction
Which heart chambers are affected by severe mitral stenosis
left atrium has increased pressure
Left ventricle has decreased pressure and volume which affects CO
What is a normal mitral valve transvalvular gradient?
When is it considered severe?
Normal = 10 mmHg Severe = 50 mmHg
What are less common etiologies of mitral stenosis (5)
SLE Congenital defect LA myxoma Carcinoid syndrome Problem following MV repair
Which heart rhythm may result with mitral stenosis and why
Atrial fibrillation
Due to stretch of conduction system from increased LAP and volume altering anatomy
Mitral stenosis cause what type of hypertrophy in which heart chamber
Concentric hypertrophy of left atrium
What signs and symptoms are noted with severe mitral stenosis
S/S related to pulmonary HTN
- Dyspnea
- Increased RV workload
How are stroke volume and LV-EDV affect in patients with severe mitral stenosis
LV is underfilled decreasing SV and LV-EDV
How is the pressure-volume loop altered in patients with mitral stenosis
Left shift
Shorter height
Describe the pulmonary effects of mitral stenosis
Pulmonary HTN Promotes fluid movement into pulmonary interstitium Reduces pulmonary compliance Increases WOB Chronic fluid overload
How is pulmonary compliances affected by mitral stenosis
Compliance is reduced
What are the right heart effects of severe mitral stenosis
Increased workload of RV RV failure (cor pulmonale)
Goal for HR in mitral stenosis and why
Goal = slow side of NSR
Allows for increased filling time of LV
tachycardia decreases diastolic filling time and allows less time for blood to pass through stenotic valve
What medications are used for tachyarrhythmias in mitral stenosis
Amiodarone
Beta-blockers
CCBs
Digoxin
What types of drugs should be avoid in patients with mitral stenosis
Medications that increase HR
- anticholinergics
- Ketamine
- Atracurium
- ephedrine
How should preload be maintained in patients with mitral stenosis
NORMAL
Low preload causes decreased SV/CO
High preload increases LAP and pulmonary congestion
What medications can be used to adjust LAP in patients with mitral stenosis
Diuretics can decrease LAP by decreasing preload
Is PAOP accurate in patients with mitral stenosis? Why or Why not?
It’s inaccurate
PAOP overestimates LVEDV d/t increased LAP from concentric hypertrophy
How is the PAOP waveform altered in patients with mitral stenosis
a wave = prominent
y descent = decreased
What medications should be used to treat hypotension in patients with mitral stenosis? Why?
Vasoconstrictors
-phenylephrine or vasopressin
they constrict without affecting HR
What is the result of rapid drop in SVR in patients with mitral stenosis
SVR is increased to maintain BP
A rapid drop will elicit baroreceptor mediated increase in HR which should be avoided (keep HR slow)
How should PVR be managed in patients with mitral stenosis? Why?
Avoid increase
Any increase in PVR increases the workload of the RV
What physiologic conditions increase PVR
Acidosis Hypercarbia Hypoxia Hyperinflation Nitrous oxide T-burg
What type of hypertrophy does mitral insufficiency cause and to which chamber
Eccentric hypertrophy to the left atrium
What are common causes of mitral valve regurgitation?
MV prolapse Myxomatous of MV Ischemic heart disease Ruptured cordae tendineae Papillary muscle dysfunction LV hypertrophy
What hemodynamic and valve conditions should be avoided in the patient with mitral valve regurgitation? Why?
Slow HR
Increased LV-LA pressure gradient
Increased SVR
Increased size of valve orifice
These conditions increase regurgitant volume
What are anesthetic goals for patients with mitral insufficiency HR Rhythm Preload Afterload Contractility PVR
Full, fast, forward HR = increased Rhythm = NSR Preload = maintain or increase Afterload = decrease Contractility = maintain PVR = avoid increase
What are patients with MV repair at risk for following surgery?
At risk for systolic anterior motion of anterior leaflet which leads to outflow obstruction
How is systolic anterior motion of the anterior leaflet treated after MV repair
Increase intravascular volume Increase afterload (phenylephrine)
How is sympathectomy useful in patients with mitral insufficiency
It can facilitate forward flow by reducing SVR which reduces regurgitant fraction
In the patient with mitral regurgitation, what happens to flow during isovolumetric contraction
Flow becomes bidirectional between LV-LA
How does the pressure-volume loop change in patients with mitral insufficiency? Acute vs chronic
Chronic
- Loop widens, ESV moves right and EDV moves right
- The loop height is shorter (lower pressure)
Acute
- Height is shorter
- Width is smaller and moved right
- ESV moves significantly right
- EDV moves right
How should HR be maintained in patients with mitral insufficiency? Why
INCREASED NSR
Regurg happens during systole
Faster HR decreases systolic time and decreases regurgitation fraction
How should preload be maintained in patients with mitral insufficiency? Why
Maintain or INCREASE
Higher preload compensates for lost volume by increasing pressure forward
How is PAOP affected by mitral regurgitation? How does this reflect LVEDP?
PAOP overestimates LVEDP
Unreliable measure of LV filling pressure
How is the PAOP waveform altered in patients with mitral valve regurgitation
V wave = enlarged
representing regurgitant volume passing through incompetent valve
How should SVR be maintained in patients with MV insufficiency
DECREASE
Vasodilation promotes forward flow because the pressure gradient is decreased
What effect does vasoconstriction have on flow in patients with mitral valve regurgitation
It increases SVR and will increase regurgitant volume because the higher pressure
How should PVR be maintained in patients with MV regurgitation? Why
Avoid increase
Pulmonary HTN increases workload of the RV
Which valvular disorders are associated with systolic murmur
Mitral insufficiency
Aortic stenosis
Where is a murmur heard associated with AS?
When in cardiac cycle
Right sternal border
(ASSS = AS systolic sternal border)
Systolic
Where is a murmur heard associated with aortic regurgitation?
When in cardiac cycle
Right sternal border
(ARDS = AR diastolic sternal border)
Diastolic
Where is a murmur heard associated with Mitral stenosis?
When in cardiac cycle
Apex and left axilla
(MSDA = MS diastolic apex/axilla)
diastolic
Where is a murmur heard associated with mitral regurgitation?
When in cardiac cycle
Apex and left axilla
(MRSA = MR systolic apex/axilla)
systolic
Where can a murmur associated with AS be transmitted?
Confused with what sound?
Transmitted to upper aorta and carotid arteries
confused with carotid bruit
Anesthetic considerations when a valve is deployed during a TAVR
Rapid ventricular pacing to produce cardiac standstill
Anticipate profound HoTN due to no CO during this time
When is apnea required during a TAVR
When the valve is being deployed
Preoperative considerations for patients undergoing TAVR in preparation for possible complications
Have T&C with 4 units of blood in room
2 large bore IVs
If valvuloplasty causes annular rupture during TAVR, what are the implications
Causes pericardial tamponade
Pt may require aortic root repair/replacement
What are some risks of the TAVR procedure
stroke perivalvular lead pericardial tamponade AV block Left BBB CHB w/ presence of RBBB
