Indications for Aortic Valve Replacement

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Indications for Aortic Valve Replacement

• Tim Brinker

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Overview

• Anatomy
• Aortic Stenosis and Aortic Insufficiency
• -Etiology
• -Signs/Symptoms
• -Diagnostic Studies
• -Indications for Surgical Intervention

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Normal Anatomy

• 3 semilunar valve leaflets (right, left, and
  posterior)
• Normal Aortic valve has cross sectional area of
  2.5 to 3.5 cm2.

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Aortic Stenosis

• Etiology
• Degenerative calcific disease
• Congenital Stenosis
• Bicuspid Aortic Valve
• Rheumatic Heart Disease

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Signs and Symptoms

• Most patients remain asymptomatic for years.
• Classic Triad
• Angina Pectoris
• Syncope
• Congestive Heart Failure
• Other symptoms include hypertension and dyspnea.

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NYHA Classification

• Class I Symptomatic only with greater than
  normal activity.
• Class II Symptomatic with ordinary activity.
• Class III Symptomatic with minimal activity.
• Class IV Symptomatic at rest.

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Physical Exam

• High pitched systolic crescendo-decrescendo
  murmur at RUSB and radiates to the carotids.
• Decreases with Valsalva maneuver.
• Increases with passive leg raise
• Ejection click with bicuspid aortic valve

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Diagnostic Studies

• CXR Normal size or cardiomegaly. May see
  calcification of the valve in older individuals.
• EKG Demonstrates LVH.
• ECHO Can evaluate calcification and mobility of
  aortic valve leaflets, anatomy and aortic valve
  area, LVH, EF, transvalvular gradients, and
  aortic regurgitation.

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• Cardiac Catheterization Reveals coronary
  anatomy, CO, transvalvular gradients, LV
  function, presence of other valvular lesions.
  Indicated in patients suspected of having CAD in
  preparation for AVR.
• Exercise Testing May elicit exercise-induced
  symptoms and abnormal bp responses in
  asymptomatic patients.

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Bonow, RO, Carabello, BA, Chatterjee, K, et al.
ACC/AHA 2006 guidelines for the management of
patients with valvular heart disease. A report of
the American College of Cardiology/American Heart
Association Task Force on Practice Guidelines
(Writing committee to revise the 1998 guidelines
for the management of patients with valvular
heart disease). Journal of the American College
of Cardiology 2006 48e1.
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Low Gradient Aortic Stenosis

• AVA
• TVPG
• Dobutamine or Nitroprusside can distinguish
  between true stenosis and psuedostenosis.

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Operative Indications

• Surgery (Aortic Valve Replacement)
• Symptomatic Severe Aortic Stenosis
• Asymptomatic severe Aortic Stenosis with
  decreased EF (
  4m/s, or decreased BP with exercise
• Asymptomatic moderate-severe Aortic Stenosis and
  undergoing CABG.

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Medical Treatment

• Antibiotic prophylaxis for infective endocarditis
  and recurrent rheumatic fever.
• If patient is symptomatic and not an operative
  candidate
• Gentle Diuresis, control of HTN (ACEI,dig,statin)
• Avoid venodilators (nitrates) and neg ionotropes
  (BB, CCB) in severe AS

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Prognosis

• Angina 5 year survival
• Syncope 3 year survival
• CHF 2 year survival

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Aortic Insufficiency

• Etiology
• Degenerative diseases
• Inflammatory or infectious disease (endocarditis,
  rheumatic fever)
• Congenital diseases (bicuspid valve)
• Aortoannular ectasia
• Aneurysm of the aortic root
• Aortic dissection

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Signs and Symptoms

• May be asymptomatic
• Dyspnea on exertion, decreased exercise capacity
• Palpitations
• Angina
• Pulmonary edema
• Right heart failure

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Physical Exam

• Diastolic decrescendo murmur at LUSB
• Severity proportional to duration of murmur.
• Wide pulse pressure (decrease in diastolic
  pressure)
• Austin Flint murmur diastolic rumble at apex

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Diagnostic Studies

• CXR cardiomegaly ,/- aortic dilation
• EKG may show LVH or A-fib
• ECHO Measures degree of valvular insufficiency,
  LV size and function.
• Exercise test assess functional capacity and
  symptomatic response.
• May perform aortic root angiography or MRI if
  aneurysmal disease is suspected.

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Bonow, RO, Carabello, BA, Chatterjee, K, et al.
ACC/AHA 2006 guidelines for the management of
patients with valvular heart disease. A report of
the American College of Cardiology/American Heart
Association Task Force on Practice Guidelines
(Writing committee to revise the 1998 guidelines
for the management of patients with valvular
heart disease). Journal of the American College
of Cardiology 2006 48e1.
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Operative Indications

• Surgery (Aortic Valve Replacement)
• Symptomatic severe AI
• Asymptomatic severe AI and EF diameter 55mm or diastolic diameter 75mm
• Asymptomatic severe AI and undergoing CABG.

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Medical Therapy

• Vasodilators (nifidepine, ACEI, hydralazine) if
  severe AI, HTN, or patient is not an operative
  candidate.
• Diuretics and Digoxin if patient with CHF.

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Operative Techniques

• Aortic Valve Replacement
• Median sternotomy incision
• Cardiopulmonary bypass is used.
• Aortic valve is excised totally.
• Mechanical valves (single tilting or bileaflet
  disk). Patients require lifelong
  anticoagulation.
• Tissue valves (have projected durability of 15
  years or longer with no anticoagulation).

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• Ross Procedure
• Involves replacement of the aortic valve with an
  autograft from the patients native pulmonary
  valve. The pulmonary valve is then replaced with
  a pulmonary homograft.
• Patients do not require long term anticoagulation.

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Take Home Points

• In symptomatic AS patients, AVR improves symptoms
  and improves survival
• AVR is indicated in virtually all symptomatic
  patients with severe AS.
• AVR is indicated in patients with symptomatic AI
  or with LV dysfunction (EF
• AVR is not indicated in asymptomatic patients
  with normal LV function (EF0.50) and LV dilation
  in AI