Valvular Heart Disease and Anesthesia

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Valvular Heart Disease and Anesthesia

• Wayne E. Ellis, Ph.D., CRNA

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Replacement Valves
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Valvular Heart Disease

• Definition An acquired or congential disorder
  of a cardiac valve characterized by stenosis
  (obstruction) or regurgitation (backward flow) of
  blood

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Valvular Heart Disease

• Common findings of the history and physical exam
  in patients with valvular disease
• A history of rheumatic fever, IV drug abuse, or
  heart murmur
• Decreased exercise tolerance
• May exhibit S/S of CHF (dyspnea, orthopnea,
  fatigue, pulmonary rales, JVD, hepatic
  congestion, and dependent edema)
• Compensatory increases in SNS tone manifest as
  resting tachycardia, anxiety, and diaphoresis

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Valvular Heart Disease

• Mitral stenosis
• Mitral insufficiency
• Mitral valve prolapse
• Aortic insufficiency
• Aortic stenosis

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What Information is Required?

• Clinical history
• Angina
• Syncope
• Dyspnea
• Orthopnea
• Physical exam
• Increased JVP a wave, sustained PMI
• Midsystolic ejection murmur at the base

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Tests to be performed?

• CXR
• Cardiomegaly
• Post-stenotic dilation of the ascending aorta
• Calcification of the aortic valve
• ECG
• LVH
• Pseudoinfarction pattern

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Tests to be performed?

• Echo
• M-mode
• Thickened leaflets, diminished orifice, calcific
  size
• 2-D
• Severity- wall thickness and chamber size
• Doppler
• Flow, severity of stenosis

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Tests to be performed?

• Nuclear imaging
• CAD
• Cardiac catheterization
• Valve area, ventricular function, CAD
• Gradient across aortic valve 50 torr or more
  indicates severe AS
• Except in CHF patients
• A gradient of 30 torr may signify severe AS due
  to poor LV function

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Murmurs

• Memory aid for murmurs
• MR. ASS mitral regurgitation/aortic stenosis
• systolic murmurs
• MS. ARD mitral stenosis/aortic regurgitation
• diastolic murmurs

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Typical murmurs
S1 Closure of mitral and tricuspid valves
S2 Closure of aortic and pulmonic valves
Diastole
Systole
Diastole
S1
S2
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Typical murmurs
Mitral stenosis
Opening snap
S2
S1
Mitral insufficiency
S2
S1
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Typical murmurs
Mitral valve prolapse
S1
S2
Click
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Typical murmurs
Aortic insufficiency
S2
S1
Aortic stenosis
S2
S1
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Orifice sizes

• Mitral
• Normal 4 - 6 cm2
• Mildly stenotic 1.5 - 2.5 cm2
• Moderately stenotic 1.1 - 1.5 cm2
• Severely stenotic lt 1 cm2
• Usually have symptoms when area is decreased by
  50

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Orifice sizes

• Aortic
• Normal 2.6 - 3.5 cm2
• lt 1 cm2
• Marked increase in LVEDP
• lt 0.75cm2
• DOE, angina, syncope
• If gt 1 cm2
• Cath findings and pressures are normal

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Mitral stenosis
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Valvular Lesions Mitral Stenosis

• Etiology
• Delayed complication of rheumatic fever
• 66 of patients are female

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Valvular Lesions Mitral Stenosis

• Pathophysiology
• Valve leaflets thicken, calcify and become
  funnel-shaped
• Left atrium dilates (pressure)

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Valvular Lesions Mitral Stenosis
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Valvular Lesions Mitral Stenosis

• Signs and symptoms
• 90 of patients present with CHF and Atrial
  fibrillation
• 10-15 develop chest pain
• Hoarseness caused by enlarged left atrium putting
  pressure on left recurrent laryngeal nerve
• Pulmonary hypertension from chronic increased
  pulmonary vascular resistance
• Hemoptysis often occurs

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Valvular Lesions Mitral Stenosis

• Treatment
• Anticoagulation
• Sodium restriction
• Diuretics
• Valve replacement
• Onset to incapacitation averages 5-10 years and
  most patients die within 2-5 years of onset

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Valvular Lesions Mitral Stenosis

• Anesthesia concerns
• Maintain sinus rhythm
• Avoid tachycardia, large increases in CO
• Avoid both hypovolemia and fluid overload
• Avoid increases in pulmonary vascular resistance

• Phenylephrine is preferred over ephedrine
• Epidural is preferred over spinal due to gradual
  onset of sympathetic block with epidural

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Mitral Stenosis

• Mitral stenosis- is characterized by mechanical
  obstruction to left ventricular diastolic filling
  secondary to a progressive decrease in the
  orifice at the mitral valve
• 90 of patients present with CHF with A-fib
• Increase left atrial pressure eventually impedes
  blood flow return form the lungs and causes
  pulmonary congestion (Trendelenburg position or
  IV bolus during induction)
• Thrombi form in the left atrium

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Mitral Stenosis

• Management
• HR- keep slow to allow for diastolic filling
  avoid sinus tachycardia
• Rhythm- sinus rhythm if A-fib, control rate
• Preload- Maintain or slightly increase to help
  with left ventricular filling excess preload may
  cause pulmonary edema
• Afterload- SVR should be maintained avoid
  decreases in SVR avoid increases in PVR
• Contractility- Maintain to provide adequate
  cardiac output
• epidural preferred over spinal

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Mitral Stenosis

• Characterized by
• Normal ventricular function
• Obstruction to left atrial emptying decreases
  cardiac output
• Pulmonary congestion from elevations in LA and
  pulmonary venous pressure
• Pulmonary hypertension and RVH over time

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Hemodynamic Goals for the Patient with MS

• P - Enough to maintain flow across stenotic valve
• A - Avoid increased RV afterload
• C - LV usually ok until after CPB, with
  longstanding pulmonary hypertension RV may be
  impaired
• R - slow to allow time for ventricular filling

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Hemodynamic Goals for the Patient with MS

• Rhythm - Often atrial fibrillation, control
  ventricular response
• MVO2 - Not a problem
• CPB - Vasodilators may help post-CPB RV failure,
  control of ventricular response may be difficult

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Obstruction to LA emptying
Difficulty in LV filling
LA pressure
Change in LA function
Mitral stenosis
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Obstruction to LA emptying
Difficulty in LV filling
Change in LA function
LA pressure
Pulmonary venous pressure
Perivascular edema Luminal narrowing
Pulmonary artery pressure
Mitral stenosis
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Obstruction to LA emptying
Difficulty in LV filling
Change in LA function
LA pressure
Pulmonary venous pressure
Perivascular edema Luminal narrowing
Pulmonary artery pressure
Reversal of pulmonary blood flow Pulmonary
compliance Work of breathing
Mitral stenosis
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Obstruction to LA emptying
Difficulty in LV filling
Change in LA function
LA pressure
Pulmonary venous pressure
Perivascular edema Luminal narrowing
Pulmonary artery pressure
Stable with mild symptoms
Cardiac output
Reversal of pulmonary blood flow Pulmonary
compliance Work of breathing
Severe pulmonary Htn
Mitral stenosis
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Obstruction to LA emptying
Difficulty in LV filling
Change in LA function
LA pressure
Pulmonary venous pressure
Perivascular edema Luminal narrowing
Pulmonary artery pressure
Stable with mild symptoms
Cardiac output
Reversal of pulmonary blood flow Pulmonary
compliance Work of breathing
Severe pulmonary Htn
Pulmonary vascular resistance
Mitral stenosis
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Obstruction to LA emptying
Difficulty in LV filling
Change in LA function
LA pressure
Pulmonary venous pressure
Perivascular edema Luminal narrowing
Pulmonary artery pressure
Stable with mild symptoms
Cardiac output
Reversal of pulmonary blood flow Pulmonary
compliance Work of breathing
Severe pulmonary Htn
Pulmonary vascular resistance
RV overload
Mitral stenosis
Tricuspid regurgitation
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Anesthetic Considerations

• Prevent rapid ventricular increases
• Minimize increases in central blood volume
• Avoid marked decreases in SVR
• Prevent increase in PA pressure

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Mitral Insufficiency
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Mitral Regurgitation

• Mitral regurgitation- A portion of the LV volume
  is ejected back into LA during systole because of
  an incompetent valve. This leads to
• Increased left atrial pressure, but the atrium
  usually does not enlarge
• Increased pulmonary artery pressure
• Pulmonary edema/HTN
• Left ventricular hypertrophy occurs due to the
  increased workload required to maintain volume
  output

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Mitral Regurgitation

• Management
• HR- maintain or increase avoid bradycardia which
  worsens regurgitant flow
• Rhythm- sinus rhythm
• Preload- Maintain or slightly increase an
  elevated preload will cause an increase in
  regurgitant flow, and low preload causes
  inadequate cardiac output
• Afterload- Decrease to improve forward cardiac
  output avoid sudden increases in SVR
• Contractility- Maintain or increase to decrease
  left ventricular volume
• spinal epidurals well tolerated, but
  bradycardia must be avoided

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Valvular LesionsMitral Regurgitation

• Etiology
• ACUTE
• Myocardial ischemia or infarctions
• Infective endocarditis
• Chest trauma

• CHRONIC
• Rheumatic fever
• Incompetent valve
• Destruction of mitral valve annulus

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Valvular LesionsMitral Regurgitation

• Pathophysiology
• Reduction in forward SV due to backward flow of
  blood into left atrium during systole (can be as
  much as 50 of SV)
• Left ventricle compensates by dilating and
  increasing end-diastolic volume
• Regurgitation reduces left ventricular afterload,
  but may enhance contractility
• End-systolic volume remains normal, but
  eventually increases as disease progresses

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Valvular LesionsMitral Regurgitation
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Valvular LesionsMitral Regurgitation

• Signs and symptoms
• Degree of atrial compliance will determine the
  clinical manifestations
• Normal or reduced atrial compliance (acute MR)
  will result in pulmonary vascular congestion and
  edema
• Increased atrial compliance (chronic MR) will
  demonstrate signs of decreased cardiac output
• Chronic weakness and fatigue
• Blowing pansystolic murmur best heard at the
  cardiac apex and often radiating to left axilla

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Valvular LesionsMitral Regurgitation

• Treatment
• Medical Tx digoxin, diuretics and vasodilators
• Surgical valvuloplasty
• Usually reserved for those with moderate to
  severe symptoms (regurgitant volume 30-60 or
  gt60, respectively, of SV)

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Valvular LesionsMitral Regurgitation

• Anesthesia concerns
• Avoid slow heart rate (ideally 80-100 bpm)
• Avoid increase in afterload
• WATCH IV FLUIDS
• excess fluids will dilate the LV and worsen
  regurgitation
• Need adequate volume to maintain forward SV

• Preload reduction with vasodilators and diuretics
  
• Minimize drug-induced myocardial depression
• Spinal and epidural are well tolerated (avoid
  bradycardia)
• Give prophylactic antibiotics

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Mitral Regurgitation

• Characterized by
• Chronic volume overload similar to AI
• Increased ventricular compliance without change
  in LVEDP
• May mask signs of impaired ventricular function

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Hemodynamic Goals for the Patient with MI

• P - Usually pretty full, may need to keep that
  way, although preload reduction may reduce
  regurgitant flow
• A - Decreases are beneficial, increases augment
  regurgitant flow
• C - Unrecognized myocardial depression possible,
  titrate myocardial depressants carefully

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Hemodynamic Goals for the Patient with MI

• R - A faster rate decreases ventricular volume
• Rhythm - Atrial fibrillation is occasionally a
  problem
• MVO2 - only if associated with CAD, then caution!
• CPB - New valve will increase afterload,
  unmasking impaired ventricle

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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Mitral Regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Early
LV filling Fiber size
Stroke volume
Cardiac output and BP maintained
Mitral regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Early
Late
LV filling Fiber size
Contractility
Stroke volume
BP and CO
Cardiac output and BP maintained
Mitral regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Late
Early
LV filling Fiber size
Contractility
Stroke volume
BP and CO
Cardiac output and BP maintained
Reflexive arteriolar constriction
SVR
Mitral regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Early
Late
LV filling Fiber size
Contractility
Stroke volume
BP and CO
Cardiac output and BP maintained
Reflexive arteriolar constriction
SVR
Regurgitation
Mitral regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Early
Late
LV filling Fiber size
Contractility
Stroke volume
BP and CO
Cardiac output and BP maintained
Reflexive arteriolar constriction
SVR
Regurgitation
LA pressure Pulmonary congestion
Mitral regurgitation
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Volume overload of LA Volume overload of LV
LA dilation Normal LA pressures
Early
Late
LV filling Fiber size
Contractility
Stroke volume
BP and CO
Cardiac output and BP maintained
Reflexive arteriolar constriction
SVR
Forward flow
Regurgitation
LA pressure Pulmonary congestion
Mitral regurgitation
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Anesthetic Considerations

• Prevent peripheral vasoconstriction
• Avoid myocardial depressants
• Treat acute atrial fibrillation immediately
• Maintain a normal or slightly elevated heart rate
• Monitor PCW pressure or intensity of murmur

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Mitral Valve Prolapse Anesthetic Considerations

• Avoid decreases in preload
• Continue antiarrhythmic therapy
• With MVP and moderate to severe mitral
  insufficiency the same considerations as listed
  for mitral insufficiency alone apply