AORTIC STENOSIS AND AORTIC REGURGITATION

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AORTIC STENOSIS
AND AORTIC REGURGITATION

• PRESENTED BY
• DR. Neeraj DR. Bikash
• MODERATER DR. Maya

www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
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AORTIC STENOSIS
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Aortic valve

• Normally - 3 cusps
• - May be bicuspid or unicuspid
• Normal AV diameter 1.9 to 2.3 cm
• Normal AV area 2 - 4 cm2
• (2.6 to 3.5 cm2 )
• Cusps are named according to their relation to
  coronary ostia -
• left ,right and non-coronary
• Normal diameter of LVOT 2.2 0.2 cm

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Incidence

• ¼ of all with patient chronic VHD
• Malegt female
• (80 of adult pt with symptomatic valvular
  AS are male )
• It is the most common form of VHD in US

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Classification

• SUPRAVALVULAR
• VALVULAR
• SUBVALVULAR- Discrete
• Tunnel
• VALVULAR
• Congenital (lt 30 yr)
• Bicuspid (40-60 yr )
• Secondary to inflammation
• (40-60 yr )
• Degenerative (gt70 yr )

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Etiology

• Congenital- Stenotic since birth
• Bicuspid 1-2 of population
• - Male gt female (3 1 )
• - 6 have coartation of aorta
• - Mechanical shear stress
• produce injury stenosis

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Cont.
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Cont.

• Secondary to inflammation-
• -Mainly rheumatic
• -MC cause of AS in India and world
• -Isolate rheumatic AS- rare
• (Rheumatic AS always associated with
  mitral valve
• involvement and AR )
• -Post inflammation -gt commissural
• fusion

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Cont.

• Degenerative-
• -MC cause of AS in US and EUROPE
• -gt30 people of gt65yr have AV
• sclerosis
• -Stenosis is due to sclerosis and
• calcification
• -Progress from the base of the cusp
• to the leaf-lets

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Risk factors of AS

• Bicuspid aortic valve
• Risk factors for atherosclerosis
• - age
• - male sex
• - smoking
• - DM, HTN
• - ? LDL , ? HDL , ? CRP
• Rheumatic fever
• Conditions with ?SV and altered calcium
  metabolism

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Pathophysiology

• Aortic stenosis
• ?
• Obstruction to LV ejection
• ?
• Pressure overload
• ?
• ?LV mass (?wall thickness)
• ?
• ? ? ? ?
  ? ?
• ?
  ?
• Compensated
  Decompensated
• ?LV compliance
  Fibrosis? contractility
• Normal contractility
• ?
  ?
• LV filling ?early
  LV dilatation
• ?late
• ?
  ?
• SV normal
  SV decreased

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Cont.

• The LVH is due to increase wall tension,in
  accordance with Laplaces law
• Wall tension PR/2H
• p -
  intraventricular pressure
• r inner radius
• h wall
  thickness

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Cont.

• Pressure overload
• ?
• ?Peak systolic pressure
• ?
• ?Wall tension
  
• ?
• Parallel replication of
  sacromeres (-)
• ?
• Increase wall thickness
• ?
• Concentric hypertrophy
• Concentric hypertrophy normalizes wall stress and
  thus preserve myocardial contractility

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Cont.

• Consequence of LVH
• - Alternation in diastolic compliance
• - Imbalance in myocardial
• supply/demand relationship
• - Possible deterioration of intrinsic
• contractile performance of
• myocardium

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Cont.

• Pressure volume loop in AS

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Cont.

• Increased chamber stiffness impedes early left
  ventricular filling
• Hence atrial systole is critical in maintaining
  ventricular filling and SV
• In AS atrial systole accounts for 40 of LVEDV.
  (Normally it contribute 15-20 of LVEDV )

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Cont.

• Although contractility is preserved,
  hypertrophied ventricle is sensitive to ischemia
  and LVF

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Natural history

• Prolonged latent period
• Once moderate stenosis present rate of
  progression is
• -0.3m/s jet velocity/yr
• -Mean pressure gradient
• 7 mm-hg/yr
• -?in valve area 0.1cm2 /yr

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Clinical presentation

• Asymptomatic with ES murmur
• Classical triad
• (angina, dyspnea, syncope )
• Sudden death
• (without symptoms it is lt1 )

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Cont.

• Symptoms/signs
• - Angina
• -Syncope
• -CHF

• Life expectancy
• 5 yr
• 2-3 yr
• 1-2 yr

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Cont.
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Physical findings

• Delayed sustain peak of arterial pulse
• (pulsus
  parvus et tardus )
• Bifid apical LV impulse
• Systolic thrill
• Late peaking SE murmur
• (2nd right
  intercostsl space )
• Paradoxical S2
• S4 (with LVH ) S3 (with LVF )
• (Thrill and intensity of murmur does not
  correlate with severity )

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Investigation

• CXR and ECG
• - LVH
• - Dilatation of ascending aorta
• - Aortic calcification

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Echocardiography

• 2D/Doppler TTE- test of choice
• Provide information about-
• - Etiology, location
• - Valve gradient and area
• - Systolic/diastolic LV function
• - Concomitant RWMA
• - Coartation associated with
• bicuspid valve

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Cardiac Catheterization

• Provide information about
• - Pressure gradient
• - AVA
• - Cardiac output

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Severity of AS
Severity Mean gradient (mm Hg) AV area (cm2)
Mild lt25 gt1.5
Moderate 25-50 1-1.5
Severe gt50 lt1.0
Critical gt80 lt0.7
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Cont.

• Gradient across valve normal until orifice area
  reaches less than half of normal
• Onset of symptoms
• 0.9 cm2 with CAD
• 0.7 cm2 without CAD

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Anesthetic consideration of AS in non-cardiac
surgery
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Risk assessment

• Increased peri and postoperative risk depend on
  both patient-related and procedure related
  factor.
• AS is MC VHD in elderly
• -2 to 9 of adult who are gt65 yr are affected
  by AS
• Stewart et al and Lindoos et al
• patients with severe AS face a17.3 risk of
  cardiac complication and 13 mortality rate
  during non-cardiac surgery.
• ( j.am coll
  cardiology)

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Cont.
Study/yr AS/ all pt Study type RR Perioperative cardiac events/death in pt with AS vs. pt without AS
Goldman et al (1977 ) 23/ 1001 Prospective 3.2 13 vs. 1.6
O keefe et al (1989 ) 48/NA Retrospective NA 14 only in pt with AS
Torsher et al (1998 ) 19/ NA Retrospective NA 11 only in pt with AS
Rohde et al (2001 ) 67/570 Prospective 6.8 8/ NA for all pt
Kertai et al (2004) 108/324 Retrospective case/control 5.2 14 vs. 2 for all event
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Cont.

• Adverse perioperative risk in patient with AS
  depends-
• - Severity of AS
• - Presence of concomitant CAD
• -Severity of surgical procedure
• -50 of patient with AS and angina have CAD ,
• - Patient lt40 yr with AS , with no chest
  pain and no
• coronary risk factor ,prevalence of CAD
  is 3-5
• ( Bonow et al,J Heart
  Valve Dis,19987 )

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How to deal with healthy patient with AS facing
noncardiac surgery

• Medical history and physical examination
  cornerstone of preoperative evaluation
• According to Michael et al
• (Chest
  2005128,2944-2953 )

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Cont.

• Non cardiac surgery can be safely performed 3
  months after CABG with an cardiac risk reduction
  from 3.3 to 1.7
• (Anesth Analg
  200294,)
• But paucity of data for timing of valve
  replacement prior to elective noncardiac surgery

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Role of echo and cardiac catheterization

• Current recommendation-
• TTE should be performed in every patient
  with suspected AS
• Cardiac catheterization? no extra role and is
  replaced by TTE.
• It is now performed-
• -When coronary angiography is required
• - There is any doubt in echo.
• (mochizuki et al., curr opin cardiol
  2003/18)

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Management of anesthesia in AS

• Anesthetic goal avoidance of event that may
  further decrease CO
• - Maintain normal sinus rhythm
• - Avoid Brady and tachycardia
• - Avoid sudden ? or ? in SVR
• - Fluid management to maintain
• venous return and LV filling

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Cont.

• Premedication
• - Adequate premedication to decrease
• undue preoperative excitement and
• tachycardia
• - Supplemental oxygen
• - Antibiotic prophylaxis

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Monitoring

• Routine monitoring
• Standard 5 lead ECG
• v4 and v5 for ischemia
• lead II for arrhythmia
• Use of intraoperative TEE is desirable -value is
  currently undetermined

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Cont.

• Invasive hemodynamic monitoring is -
  Controversial
• - Intra-arterial BP monitoring is
  desirable
• - CVP poor estimate of LV filling
  when
• compliance is reduced
• - Risk with PAC is arrhythmia
  induced
• hypotension or ischemia
• - But PAC also allow for measurement
  of CO, SVO2
• and possible trans-venous pacing
  when needed

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Cont.

• Induction
• - Few studies
• - But in severe AS narcotic based
• induction should be preferred
• - Preferred non-narcotic induction is
• by etomidate
• LMA should be preferred over ETT whenever possible

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Cont.

• Maintenance
• -In severe AS many prefer pure narcotic
• technique
• -In mild- moderate AS inhalational
  agents
• can be safely used
• disadvantage -negative inotrophy
• -risk of
  arrhythmia
• -Although N2O has potential of ?SVR
  discussion regarding this is less critical

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Cont.

• Intra-op hypertension and tachycardia-
• - ? conc. Inhalational agent
• - If B blocker- esmolol is preferred
• - Temptation to control intra-op
  hypertension with
• vasodilators should be resisted
  (Kaplan's )
• Intra-op hypotension-
• - Regardless of cause treat with
  alpha-agonist
• - Then address underline etiology
• 
  (Kaplan's)

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Regional anesthesia and AS

• Regional anesthesia decreases SVR ,hence not
  preferred over GA.
• Epidural is preferred over spinal
• Mild-moderate AS can tolerate spinal
• and epidural
• Severe AS spinal and epidural are
• contraindicated
• (stoelting coexisting diseases
  )

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Cont.

• Collard et al
• - Continuous spinal (.25 bupivacain )
• - 2 patients
• - Sever AS
• - Hip surgery
• - Invasive monitoring
• (Anesth.analg
  199585 )

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• THANK YOU

www.anaesthesia.co.in anaesthesia.co.in_at_gmail.co
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