Valvular Heart Disease II: The Aortic Valve

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Valvular Heart Disease IIThe Aortic Valve

• Laura Wexler, M.D.
• 475-6383
• wexlerl_at_ucmail.uc.edu

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Reference Sources for Valvular Heart Disease

• Reading Harrison, 14th Edition p 1311-1323
• Computer
• Umedic Aortic stenosis, aortic regurgitation,
  mitral stenosis, mitral regurgitation
• Instructional Programs
• Heart Sounds and Murmurs

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• Case
• An active 75 yo farmer comes to your office
  after experiencing a fainting spell while baling
  hay. The episode occurred without warning and he
  had no symptoms following the episode. However,
  on close questioning he admits to some
  breathlessness and vague chest heaviness with his
  usual heavy exertion over the past few months. He
  has been healthy all his life, doesnt smoke and
  has not seen a doctor in 30 years. He served in
  the army in 1942 no abnormalities were reported
  during his induction physical.

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Physical Exam

• Robust looking older man.
• BP 135/90 P 68 bpm, regular RR-12
  T-98.6? F
• JVP 6 cm with normal a and v waves
• Carotids Difficult to palpate, delayed
  upstroke
• Lungs Clear
• Heart Palpation Palpable thrill over the
  mid LSB. PMI 5 ICS, 2 cm lateral to the MCL.
  Palpable presystolic impulse followed by a
  sustained ventricular lift.
• Auscultation Loud S4. S1 is normal. A
  single S2 (P2) is heard at the upper left sternal
  border but no A2 is heard at the lower left
  sternal border. There is a 4/6 systolic ejection
  murmur (crescendo-decrescendo) heard best at the
  R 2nd interspace that radiates widely to the LSB,
  and to the neck. No diastolic murmurs.
• Abdomen and extremities are unremarkable.

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Aortic Stenosis
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Aortic Stenosis Etiology
Norma Burns

• Congenital bicuspid aortic valve
• Rheumatic aortic valve disease
• Calcific (senile) aortic stenosis

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Pathophysiology of Aortic Stenosis

• Left ventricular outflow obstruction
• LV systolic pressure aortic pressure
• Concentric left ventricular hypertrophy
• Sustains high LV pressures
• Normalizes wall stress (radius x pressure/wall
  thickness)
• Eventually results in impaired LV diastolic
  compliance
• LA hypertrophy and enlargement
• Severe stenosis Limits ability to increase
  stroke volume on demand
• Critical aortic stenosis fixed cardiac output

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Key Physical Findings in SevereAortic Stenosis

• Carotid impulse parvus et tardus
• JVP Prominent a wave
• Heart Systolic thrill
• Palpable presystolic impulse (S4)
• Sustained apical systolic impulse S4
• Coarse late peaking systolic ejection murmur
  (may radiate to neck and/or LSB)
• Attenuated/absent aortic component of S2

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Natural History of Aortic Stenosis

• Long asymptomatic latent period
• Cardinal symptoms of severe aortic stenosis
• Dyspnea
• Angina
• Syncope
• Sudden death
• Left ventricular dilatation and contractile
  failure
• Endocarditis
• Arrhythmias
• Ventricular tachycardia
• Conduction system disease
• Atrial fibrillation

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Natural History of AS
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Mechanisms of Dyspnea inAortic Stenosis

• LVH ? diastolic dysfunction
• Progressive LV dilation and contractile failure ?
  systolic dysfunction

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Mechanisms of Anginal Chest Pain inAortic
Stenosis

• Increased wall stress ? increased myocardial O2
  demand, exceeds ability to coronary flow to meet
  demand
• Associated coronary artery disease

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Mechanisms of Syncope in Aortic Stenosis

• Fixed cardiac output Vasodilation (exercise,
  vagal stimulation, drug induced), inability to
  augment CO, drop in cerebral perfusion pressure.
• Heart block Ca deposits in aortic ring
  encroach upon conduction tissue
• Ventricular arrhythmias (LVH, ischemia)

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Diagnostic Studies in Aortic Stenosis

• ECG LVH with repolarization changes strain
  pattern
• Chest X-Ray Aortic root dilation
  (aortic valve Ca)
• Echo Aortic valve thickening and restricted
  motion
• Doppler Gradient across aortic valve and aortic
  valve area can be estimated from increased flow
  velocity across aortic valve
• Cath Measure gradient across aortic valve and
  calculate valve area

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Aortic Stenosis
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Treatment of Aortic Stenosis

• Mild to moderate asymptomatic aortic stenosis
• Close follow up History and physical exam,
  serial echocardiograms
• Endocarditis prophylaxis
• Severe, symptomatic aortic stenosis (1 year
  survival 57)
• Aortic valve replacement with either mechanical
  or bioprosthetic valve
• - Ten year survival 75
• - Complications of prosthetic heart valves
  infection, thromboembolism, mechanical
  failure
• Severe, symptomatic aortic stenosis NOT
  surgically treatable
• Palliative option aortic balloon valvuloplasty

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• CASE
• A 52 yo salesman is referred to you for
  evaluation of a heart murmur. He had applied for
  a pilots license and was denied because of the
  murmur. He is asymptomatic and physically
  active. He denies chest pain, dyspnea or dizzy
  spells and gives no history of a murmur being
  mentioned during his last physical exam five
  years ago. He has no family history of heart
  disease. He has never had high blood pressure or
  diabetes, doesnt smoke, and takes no
  medications. A lipid profile done five years
  ago was reported to be OK.

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Physical Exam

• BP - 145/45 P - 78 reg RR
  - 12 Temp98.6F
• Carotids Very brisk with sharp collapse
• JVP 5 with normal a and v waves
• Lungs Clear
• Heart Palpation PMI is enlarged (4fb), in the
  anterior axillary line
• Auscultation S1 normal, S2 soft. A 2/6 early
  peaking systolic ejection murmur at the upper
  RSB and a 3/6 holodiastolic blowing murmur,
  heard best at the lower LSB when you ask the
  patient to hold his breath in expiration and
  lean forward. There is a different 2/6
  low-pitched diastolic murmur at the apex.
• Pulses are all very prominent and brisk audible
  pulse over
• the femoral arteries

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Additional Testing

• ECG LVH with massive voltage in the lateral
  precordial leads (V4-V6)
• Chest X-Ray Large heart, predominant left
  ventricular enlargement. No congestive heart
  failure.
• Echo Marked left ventricular dilation, estimated
  EF 65. The end diastolic dimension is 65 mm
  and the end diastolic dimension is 55 mm.
  Aortic valve bicuspid and thickened.
• Doppler Severe aortic regurgitation. The aorta
  is slightly enlarged (4.2 mm).
  
  

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Major Causes of Aortic Regurgitation

• Leaflet Dysfunction Aortic Root Dilation
• Rheumatic fever Systemic hypertension
• Endocarditis Dissecting aneurysm
• Trauma Aortitis (syphilis)
• Bicuspid aortic valve Reiters syndrome
• Rheumatoid arthritis Ankylosing spondylitis
• Myxomatous degeneration Ehlers-Danlos
• Ankylosing spondylitis Osteogenesis imperfecta
• Marfans syndrome Pseudoxanthoma elasticum
• Fenfluramine-phentermine Marfans syndrome
• Annulo-aortic ectasia

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Aortic regurgitation
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Physical Findings in Aortic Regurgitation

• Wide pulse pressure
• Bounding pulses
• Soft aortic second sound (A2)
• Early diastolic murmur (blowing) immediately
  after A2
• Upper RSB with root dilation
• Mid to lower LSB with leaflet dysfunction
• Systolic murmur at base (similar to aortic
  stenosis)
• Austin Flint murmur mid to late diastolic
  rumble at apex
  

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Some Really Neat Physical Findings in Severe
Chronic Aortic Regurgitation

• deMussets sign Head bob with each systolic
  pulsation
• Corriganss pulses Pistol shot pulses over
  femoral artery
• Muellers sign Pulsation of the uvula
• Duroziezs sign Systolic/diastolic bruit over
  femoral artery
• Quinckes pulses Capillary pulsations seen in
  the nailbeds
• Beckers sign Pulsation of retinal arteries and
  pupils
• Hills sign Popliteal BP exceeds brachial BP by
  60 mmHg

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Acute vs. chronic aortic regurgitation
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Pathophysiology of Chronic Aortic Regurgitation

• Slowly progressive diastolic volume overload
• Augmented stroke volume with rapid runoff
• Increased systolic pressure with low
• diastolic pressure wide pulse pressure
• Progressive left ventricular dilation, some
  hypertrophy
• Increased diastolic compliance with maintenance
  of normal diastolic pressures initially
• Late systolic failure with reduced ejection
  fraction and CHF

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Acute Aortic Regurgitation

• Sudden diastolic volume overload without LV
  dilation
• - Acute elevation in left ventricular
  diastolic pressure? pulmonary edema
• - Acute LV systolic failure ? hypotension
• Provide inotropic support, vasodilator therapy if
  tolerated, urgent valve replacement.

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Natural History of Chronic Aortic Regurgitation

• Long asymptomatic phase may be decades long.
• Left ventricular systolic dysfunction ( decline
  in EF)
  NOTE!! LV dysfunction may
  occur in the absence of symptoms
• Symptoms associated with LV dysfunction
• - Exercise intolerance
• - Dyspnea on exertion
• Angina (rare)
• Sudden death (rare)

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Natural history of aortic regurgitation
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Factors Influencing Severity ofAortic
Regurgitation

• Size of regurgitant orifice
• Gradient across aortic valve in diastole (i.e.
  worse AR with high diastolic BP)
• Duration of diastole

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Management of Chronic Aortic Regurgitation

• Close follow up of left ventricular size and
  function with serial echocardiograms (Every few
  years with mild AR, every 6-12 months with severe
  AR)
• Endocarditis prophylaxis
• Medical therapy
• Vasodilator therapy reduces blood
  pressure?reduces
  regurgitant volume
• Delays need for aortic valve
  replacement
• Digoxin (enhance systolic function)
• Diuretics (reduce LA pressure)
• Do NOT slow heart rate!
• Aortic valve replacement with mechanical or
  bioprosthetic valve

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Criteria for Aortic Valve Replacement in Chronic
Aortic Regurgitation

• Symptoms
• Congestive heart failure
• Declining exercise tolerance on exercise
  testing
• Angina
• Anatomy, regardless of symptoms
• Left ventricular dysfunction EF
• Progressive left ventricular dilation or
  decline in EF on serial studies
• Severe dilation (echo)
• - Left ventricular diastolic dimension 75
  mm
• - Left ventricular systolic dimension 55
  mm
• Aortic root dimension 50 mm

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Right Sided Valve DiseaseRead Harrison, 14th
Edition Pages 1322-1323

• Tricuspid stenosis
• Tricuspid regurgitation
• Pulmonic stenosis
• Pulmonic regurgitation