Management of Valvular Heart Disease

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Management of Valvular Heart Disease

• Diagnosis (predominant valve disease, severity)
• Related symptoms and functional capacity.
• Co-morbidities (CAD, LV RV fx, A Fib, age, non
  cardiac disease)
• Expected Natural history.
• Expected interventional risk (EuroSCORE).

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Case 1. Valvular heart disease

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Physical examination
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ECG

• Regular sinus rhythm, incomplete right bundle
  branch block, non-specific ST- and T-wave changes

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• normalmild calcification in aorta

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Echocardiography

• Echocardiography has emerged as the principle
  method of establishing the diagnosis of aortic
  stenosis.
• Valve anatomy and calcifications
  (morphology).
• Severity of stenosis.
• Concomitant valvular or nonvalvular
  conditions (aortic dilatation, aneurysm).
• Left ventricular response to the
  pressure overload.
• Echocardiographic interpretation requires special
  skill and expertise - investigator dependent.

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Morphology
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Rheumatic
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Calcific
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Aortic Stenosis Echocardiography

• The severity of stenosis can be represented by
• Aortic jet velocity
• Estimated maximum and mean transaortic
  pressure gradients
• Estimated aortic valve area

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Aortic Stenosis - Echocardiography

• The pressure difference (gradient) that causes
  blood to flow between two chambers can be
  estimated using a modification of the Bernoulli
  equation
• Pressure difference P2 - P1 (4 x Velocity of
  flow)2
• P2 is the upstream pressure
• P1 is the downstream pressure.

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Aortic Stenosis - Echocardiography

• The maximum gradient can be determined from the
  maximal velocity, and the mean gradient can be
  determined by integrating the instantaneous
  pressure gradients over the systolic ejection
  period.

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Aortic Stenosis - Echocardiography

• The velocity of a moving column of fluid
  increases through areas of narrowing according to
  a basic principle of fluid mechanics known as the
  continuity equation.
• This principle can be applied to determine the
  area of the aortic valve.

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Aortic Stenosis Continuity Principle
The stroke volume (SV) at the level of the aortic
valve (AV) equals the stroke volume at the level
of the left ventricle outflow tract (LVOT). The
velocity time integral (VTI) is measured with
pulsed Doppler in the outflow tract and with
continuous wave Doppler in the narrowed orifice.
The cross-sectional area (CSA) at the LVOT is
measured on two-dimensional echocardiography, and
the equation is solved for the CSA of the aortic
valve. LA, left atrium LV, left ventricle.
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Aortic Stenosis Continuity Principle
LVOT diameter
AV velocity
LVOT velocity
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Aortic Stenosis - Echocardiography

• Left ventricular hypertrophy may result in LV
  diastolic dysfunction, which can be evaluated by
  echocardiographic measurements.
• Echocardiography also allows evaluation of other
  potential causes of a systolic murmur, such as
  mitral regurgitation, hypertrophic
  cardiomyopathy, coarctation of the aorta and
  ventricular septal defect.
• A large number of patients (approximately 80)
  who have aortic stenosis also have some degree of
  aortic regurgitation that should be quantified.

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Aortic Stenosis Crdiac Catheterization

• Invasive measurements of the transaortic valve
  gradient and calculation of the aortic valve area
  by the Gorlin formula are needed when
  good-quality echocardiographic data are not
  available.
• AVA Cardiac Output
• (delta P)1/2
• Patients at risk of coronary artery disease
  require coronary angiography so that bypass
  grafting can be performed at the time of valve
  replacement (gt 45 years).

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Aortic Stenosis Crdiac Catheterization

• The peak-to-peak gradient is the difference
  between the peak left ventricular pressure and
  the peak aortic pressure.
• The peak instantaneous gradient corresponds to
  the maximum gradient measured by Doppler
  echocardiographic methods.
• The mean gradient is average transaortic gradient
  during the systolic ejection period

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Aortic Stenosis Severity by Echo
Normal cardiac output
AHA/ACC Guidelines - 2006
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Velocity / Gradient
Dynamic obstruction

• Moderate AS

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Velocity / Gradient
Severe
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• Left ventricular outflow tract (LVOT) velocity
  1.0m/secMaximum aortic jet velocity
  4.2m/secLVOT/aortic velocity ratio 0.25

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Q1 How severe is this patient's aortic stenosis
(AS)?

• Mild
• Moderate
• Severe
• Need more information

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Severe

• The AHA/ACC Guidelines define an area lt1.0cm2 as
  severe stenosis.
• However a given valve area has different
  implications depending on the size of the
  patient.
• The new ESC Working Group Report recommends that
  valve area be indexed to the patient's body
  surface area, and defines an area lt0.6cm2/m2 as
  severe AS.
• Echocardiography shows that this patient's aortic
  valve area is 0.4cm2/m2.
• Severe asymptomatic calcied aortic stenosis with
  good LV function (echocardiography).

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Management of Valvular Heart Disease

• Diagnosis (predominant valve disease, severity)
• Related symptoms and functional capacity.
• Co-morbidities (CAD, LV RV fx, A Fib, age, non
  cardiac disease)
• Expected Natural history.
• Expected interventional risk (EuroSCORE).

27
Aortic Stenosis Natural History

• Prospective studies have shown that the average
  rate of increase in maximum aortic jet velocity
  is 0.30.3m/s per year, with an increase in mean
  gradient of 77mmHg per year and a decrease in
  aortic valve area of 0.120.19cm2 per year.

However, the rate of hemodynamic progression in
an individual patient may be more variable.
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Aortic Stenosis Natural History

• Death with severe AS occurs most commonly in the
  seventh and eighth decades.
• The average time to death after the onset of
  angina pectoris, 3y syncope, 3y dyspnea, 2y
  congestive heart failure, 1.52 y.

• gt80 of patients who died with AS, had symptoms
  for lt4 y.
• Sudden death, which presumably resulted from an
  arrhythmia, occurred in 1020.
• Most sudden deaths occurred in patients who had
  previously been symptomatic very uncommon (lt1
  per year) in asymptomatic adult patients with
  severe AS.

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Aortic Stenosis - Management

• The treatment of patients who have aortic
  stenosis is dictated by the presence or absence
  of symptoms.
• Asymptomatic should be provided with education
  regarding expected symptoms and the time course
  for disease progression.

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Aortic Stenosis - Management

• Modification of risk factors (hypertension,
  smoking, diabetes, elevated low-density
  lipoprotein cholesterol), should also be a major
  focus of treatment to prevent concurrent coronary
  artery disease.
• Statines and aortic stenosis
• Several retrospective studies have demonstrated
  that statin treatment is associated with lower
  haemodynamic progression of AS.
• However, prospective studies using statins to
  reduce progression of AS showed inconsistent
  effects.

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Aortic Stenosis - Management

• In patients with severe AS (lt1.0 cm2), strenuous
  physical activity should be avoided, even in the
  asymptomatic stage.
• Care must be taken to avoid dehydration and
  hypovolemia to protect against a significant
  reduction in cardiac output.
• Medications used for the treatment of
  hypertension or CAD, including beta blockers and
  ACE inhibitors, are generally safe for
  asymptomatic patients with preserved left
  ventricular systolic function.

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Surgical considerations
Aortic Stenosis - Management

• Operative mortality is ideally in the range of
  23, however, it may be as high as 10 in the
  elderly and even higher in the presence of
  significant co-morbidity.
• Prosthetic valve related long term morbidity and
  mortality must be taken into account.
• Thromboembolism, bleeding, endocarditis, valve
  thrombosis, paravalvar regurgitation, and valve
  failure occur at the rate of at least 23 per
  year.
• Approximately 30 of bioprosthetic valves
  evidence primary valve failure in 10 years,
  requiring re-replacement, and an approximately
  equal percentage of patients with mechanical
  prostheses develop significant hemorrhagic
  complications as a consequence of treatment with
  anticoagulants.

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Additional Risk AssessmentQ2 Which examination
would you choose next?

• Transoesophageal echocardiography (TEE)
• Exercise test
• Left heart catheterisation with coronary
  angiography
• Left heart catheterisation without coronary
  angiography
• Coronary angiography

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Aortic Stenosis Risk Stratification

• Risk stratification by echocardiography
• Peak aortic jet velocity and LV ejection fraction
  as well as the rate of hemodynamic progression
  have been identified as independent predictors of
  outcome (retrospective).
• Aortic valve calcification has turned out to be a
  powerful independent predictor of outcome.
• The combination of a notably calcified valve with
  a rapid increase in velocity of gt 0.3 m/s from
  one to the following visit within one year has
  been shown to identify a high risk group of
  patients. Approximately 80 of them required
  surgery or died within two years

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Aortic Stenosis Risk Stratification

• Risk stratification by exercise testing
• Exercise testing is primarily helpful in
  physically active patients younger than 70 years
  and A normal exercise test indicates a very low
  likelihood of symptom development within 12
  months

• Symptom development on exercise testing in
  physically active patients younger than 70 years
  indicates a very high likelihood of symptom
  development within 12 months and valve
  replacement should be recommended.

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Exercise test in asymptomatic AS

• An exercise test uncovers functional and
  haemodynamic impairments, which may be clinically
  silent, in about 30-40 of asymptomatic patients
  with AS.
• These include
• Unexpected hypotension
• Inadequate rise (20mmHg) in blood pressure
  during exercise.
• Arrhythmias, bradycardia or conduction
  disturbances during or after exercise.
• Signs or symptoms of myocardial ischaemia such as
  angina pectoris, ST-segment depression 0.2mV
• Inadequate exercise tolerance.
• Dyspnea or other symptoms at low workloads.

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Exercise test in asymptomatic AS

• Exercise testing is safe in asymptomatic patients
  with AS. In contrast, it may be hazardous (and
  unnecessary) in patients with symptoms.
• TEE provides accurate planimetry of the aortic
  valve, and it is useful if preliminary tests give
  discordant results but it need not be performed
  in every patient.
• As this patient is asymptomatic, it is not
  appropriate to proceed to cardiac catheterisation
  and coronary angiography without first obtaining
  additional information on cardiac function.
• Cardiac catheterisation should be confined to
  cases where there is a discrepancy between
  clinical and echocardiographic findings in
  defining the severity of AS, and should also be
  performed prior to surgery in patients aged gt45y
  and/or those with coronary risk factors.

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Stress Test Results / Supine Bicycle Exercise
Asymptomatic, 94 HR predicted (220-age)
100 146 exercise tolerance predicted 2.1 W/ kg
body weight HR x BP 30870
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Q3 What do you think is this patient's risk of
sudden death?

• lt 0.1 / year
• 0.3 / year
• 5 / year
• 10 / year
• 20 / year
• Need more information

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Case 1. Valvular heart disease

• An overview of several studies (about 500
  patients with moderate/severe aortic stenosis)
  showed an incidence of sudden death of about 0.3
  / year.
• The risk is increased in the presence of
  extensive valve calcification and is much higher
  (about 6/year) in patients with severe AS and a
  positive exercise test.
• The prognosis is significantly worse in patients
  with symptoms.

For this patient, with a very good exercise test
result, the risk of sudden death is probably
about 0.3/year.
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Q4 Would you consider valve surgery at this time?

• Yes
• No

If LV function, exercise tolerance and exercise
hemodynamics are normal and no extreme LV
hypertrophy is present, the prognosis for a
patient with asymptomatic AS is good, with a risk
of sudden death lt1 / year. In this situation
surgery can be deferred.
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Q5What do you think will be the event-free
survival of this patient (survival without death
or development of symptoms requiring surgery)
over the next year?

• lt30
• 30-50
• 60-70
• gt 80
• Need more information

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Case 1. Valvular heart disease

• In asymptomatic patients with AS the degree of
  calcification strongly influences event-free
  survival (EFS).
• In a study of 126 initially asymptomatic patients
  EFS at 1 year was 925 in those with no or mild
  calcification and 606 in those with
  moderate/severe calcification.
• Within the group with moderate/severe
  calcification, an increase of aortic jet velocity
  0.3m/sec per year predicted a particularly poor
  prognosis (EFS 206 at 2 years).

• This patient's probability of EFS at 1 year is
  probably gt60 because of his preserved cardiac
  function and good exercise test result.
• Re-examination in a few months' time could give
  valuable information about his prognosis (e.g.
  the rate of increase of aortic jet velocity).

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Q6 What would you decide concerning
cholecystectomy?

• AS is not a contraindication
• AS is not a contraindication however special
  requirements are needed
• Perform cholecystectomy only after aortic valve
  replacement.

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Case 1. Valvular heart disease

• AS is a major predictor for cardiovascular events
  with non-cardiac surgery, but only in symptomatic
  patients.
• The surgical risk of the non-cardiac procedure
  should also be considered. Cholescystectomy is an
  intermediate-risk operation when performed
  conventionally, and low-risk if performed
  endoscopically.
• The anaesthesiologist can be told that
  cholecystectomy can proceed with standard
  anaesthesia and intubation, but the patient
  should be carefully monitored for cardiac
  arrhythmias, and hypotension or volume depletion
  must be avoided.
• Inotropic agents should be avoided in a patient
  with AS because over-contraction of the
  myocardium is dangerous (LVOT obstruction).
• If low cardiac output occurs, cautious volume
  loading should be considered.

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Q7Would you consider aortic valvuloplasty before
cholecystectomy for this patient?

• Yes
• No

There is no place for aortic valvuloplasty in an
elderly patient with asymptomatic calcific AS.
The surgical outcome and long-term mortality are
not acceptable.
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Q8 What medical treatment should this patient
receive?

• No medication
• Lipid lowering therapy
• Anti hypertensive therapy
• Bacterial endocarditis prophylaxis

This patient has elevated blood pressure and
total cholesterol, so he should receive
lipid-lowering and antihypertensive therapy.
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Q 9 Do you think this patient should be listed
for elective AVR? (risks associated with active
sports (e.g. tennis, skiing) will be lower after
surgery)

• Yes
• No

The risk of sudden death for this patient was
less than 0.3/year. It might be possible to
delay AVR for many years at this low risk, and
postpone the hazards of anticoagulant therapy,
which would be needed after AVR.
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Q 10 Would you allow the patient to continue
active sports?

• Yes
• No

Allow the patient to continue playing active
sports, but not at a competitive level
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Case 1. Valvular heart disease

• After cholecystectomy the patient was treated
  with a statin, antihypertensive therapy.
• This man is at high risk of progression of AS. He
  must be reviewed every 6 months with physical
  examination, Doppler echocardiography (to measure
  the rate of increase of peak velocity) and
  exercise testing.
• He must be taught to recognize any signs or
  symptoms that suggest progression of AS, and to
  report them immediately.

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Aortic Stenosis

• SYMPTOMATIC AORTIC STENOSIS
• The prognosis of symptomatic patients is
  extremely poor without surgical treatment.
• In recent studies, symptomatic patients with
  aortic stenosis who have refused surgery have had
  5-year survival rates of only 1550.
• Options for valve replacement include
  bioprosthesis and mechanical valves, the
  pulmonary autograft procedure, and recently
  percutaneous aortic valve replacement.

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Aortic Stenosis with LV dysfunction

• Subnormal LV ejection fraction stems from
  afterload axcess, contractile dysfunction or
  both.
• When afterload excess is the primary cause, AVR
  relieves obstruction to flow, afterload falls and
  ejection fraction increases strikingly.
• However when muscle dysfunction prevents cardiac
  output from generating a mean gradient of more
  than 30 mmHg, prognosis is greatly impaired.

Survival low EF low gradient
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Aortic Stenosis with LV dysfunction

• Although such patients have poor outlook, some do
  get better after surgery.
• The first issue is to decide whether severe AS
  led to LV dysfunction, low gradient and a small
  calculated valve area or whether a LV weakened by
  independent cardiomyopathy (CAD) is unable to
  open the valve.
• In the first situation we can reasonably
  postulate that AVR will be of benefit.
• In the second situation AVR is associated with
  increased mortality.

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Aortic Stenosis with LV dysfunction

• Currently the best indicator of outcome in
  patients with sever AS low EF and low gradient is
  the presence or absence of inotropic reserve.
• Operative mortality is reduced and long term
  survival increased in patients whose stroke
  volume rose more than 20 during dobutamine
  infusion.

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CoreValve prosthesis
Percutaneous AVR
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The balloon-expandable prosthesis (Cribier
Edwards)
Percutaneous AVR

• Stainless steel stent with an attached equine
  pericardial trileaflet valve and fabric sealing
  cuff (Two sizes 23- and 26-mm).

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Percutaneous transfemoral AVR (TAVI)
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Percutaneous AVR (transapical)
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Aortic Stenosis- Summary (1)

• Symptomatic sever AS is a fatal disease when
  treated medically, but after AVR lifespan returns
  to near that of unselected population.
• Even individuals with advance disease and LV
  dysfunction can have good outcome especially when
  the reason for dysfunction is a large
  transvalvular gradient.
• With low gradient severe AS prognosis is worse
  but still favorable when inotropic reserve is
  present.

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Aortic Stenosis- Summary (2)

• The asymptomatic individual with severe AS
  remains a management challenge, most have good
  results with careful follow-up and urged AVR when
  symptoms. develop. Some should go AVR especially
  if exercise tolerance is reduced, exercise
  testing produces worrisome outcome ar rate of
  progression is high.
• Surgical treatment is the proven effective
  treatment for severe AS.
• Medical approaches for retarding progression of
  mild disease are likely to come to fruition.
• Percutaneous placed valves hold promise for
  future effective non-surgical treatment.