Surgical Management of Valve Disease

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Surgical Management of Valve Disease
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Aortic Stenosis

• Obstruction to the blood flow leaving the left
  ventricle
• Classified into
• Rheumatic--- Pancarditis
• Rheumatic Fever
• Non-Rheumatic Congenital
• Degenerative

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Physiology

• RHEUMATIC AORTIC STENOSIS
• Least common cause usually associated with mitral
  stenosis
• Inflammatory changes affect the aortic valve
• Causes scarring and degeneration in the valve
  leaflets

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Physiology

• Resulting in a stenotic valve or destruction of
  the soft tissue in the aortic annulus resulting
  in dilatation and aortic regurgitation
• Decreased incidence in the developed world

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Degenerative Aortic Stenosis

• Occurs in the normal Aortic Valve
• The Calcific deposit develops as part of the
  atheromatous process of the leaflet and causes
  the leaflet to remain closed
• Developes in the 6th 7th and 8th decades in life

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Degenerative Aortic Stenosis

• Clinical Risk Factors
• Age
• Male
• Diabetes
• Hypertension
• Renal Failure
• Hyperlipidaemia
• Hypercalcaemia

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Congenital Bicuspid Valve

• Bicuspid Aortic Valve, the valve has 2 instead of
  3 cusps or leaflets
• - Is progessive and produces significant
  stenosis by the 5th and 6th decades in life
• Causes fusion of the commissural leaflet
• Usually the valve orriface is fixed

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Symptoms

• CLASSICAL TRIADE
• Angina
• Syncope
• Congestive Heart Failure

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ANGINA

• Is the initial symptom in 50-70 of patients
  with severe aortic Stenosis
• Life Expectancy lt 5 years
• Occurs on exertion
• Angina at rest would be associated with coronary
  disease

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SYNCOPE

• Is the presenting symptom in 15-30 off
  presenting Patients
• Occurs during exercise as a consequence of
• Reduction of the systematic vascular resistance
  without the ability to increase the cardiac
  output across the stenotic valve

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CONGESTIVE HEART FAILURE

• Symptoms include.
• Pulmonary Hypertension.
• Dyspnoea.
• Orthopnoea.
• Paroxismal Noctural Dyspnoea.
• Pulmonary Oedema.
• End Stage Right Ventricular Failure.

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Cause Of Diastolic Dysfunction.

• Increase LV wall thickness reduces ventricular
  compliance
• The Atrium needs higher pressure to fill the
  ventricle
• Development of symptoms of pulmonary congestion

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CXR

• Normal Heart size with inceased convexity of the
  left ventricular silouette due to ventricular
  hpertrophy
• Calcification of the Aortic Valve
• Cardiomegaly at end stage

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ECG

• Sign of Left ventricular hypertrophy
• Sign of left atrial enlargement
• Bundle Branch Block
• Complete Heart Block
• Atrial Fibrillation

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ECHOCARDIOGRAPHY

• Motility of the Leaflet
• Gradient across the valve
• Measure of the valve ares
• EF
• Regional Ventricular Motion
• Ventricular Hypertrophy
• Left Atrial Enlargement

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ANGIOGRAM

• Mainly indicated in patients over 40yrs to
  exclude CAD
• Identifies Coronary Anomalies
• Aortogram to identify post stenotic dilatition
• Calcium deposits in the Aortic wall

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PATHOPHYSIOLOGY

• The natural progresion of Aortic Stenosis is from
  
• Mild
• Moderate
• Severe
• Development of symptoms indicate
• Moderate Aortic Stenosis
• Critical Aortic Stenosis

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Moderate Aortic Stenosis

• Valve area of 0.7-1.2cm2
• LV hypertrophy
• Compromised LV contractility causing reduced EF

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CRITICAL AORTIC STENOSIS

• Valve Area lt0.7cm2
• Increase LVEDP
• Decreased EF
• Decreased Stroke Volume

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Atrial Fibrillation

• SYMPTOMS MAY APPEAR as ATRIAL CONTRACTION
  SUPPLIES UP TO 40 OF THE VENTRICULAR FILLING
  DURING DIASTOLE IN AORTIC STENOSIS (20 IN A
  NORMAL HEART)
• AF MAY CAUSE RAPID DETERIORATION

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Natural History

• Long Asymptomatic period
• When symptoms develop duration of life is
  markedly reduced
• After angina occurs survival approx 4yrs After
  Syncope approx 2yrs
• Congestive Heart Failure Less than 1 yr

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Natural History

• Valve ares not the only prognostic factor
• Absence of symptoms does not guarantee absence of
  L V dysfunction
• Sudden Death gt10 in symptomatic Patients

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Bacterial Endocarditis

• Staphylococcus Aureus most common organism
• Infection most commonly causes valvular
  incompetence (regurgitation) from destruction of
  the valve and supporting structures
• Virulent cases can be seen in IV drug abusers who
  use unsterile needles

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Pre-op Care

• Diuretics for Heart Failure
• Nitrates and Beta Blockers for Angina
• No proven preventative treatment ? Use of Lipid
  Lowering Therapy may slow the progression on
  Calcific Aortic Stenosis

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Indications and Timing of Surgery

• Surgery indicated for all symptomatic patients
• Early detection with regular follow up advised

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Aortic Regurgitation

• Leakage of Blood from the Aorta back into the
  Left Ventricle
• Valve fails to close due to damage in the valve
  leaflets or changes in the valve annulus
• Acute or Chronic

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Aortic Regurgitation

• Acute
• Infective endocarditis
• Prosthetic Valve Dysfunction
• Chronic
• Dilated Aortic Root
• Rheumatic Fever
• Bicuspid valve
• Hypertension
• Degenerative or inflammatory process (Marfans
  syndrome)

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Aortic Regurgitation

• Large volume of blood is regurgitated into the
  Left Ventricle in each diastole
• Left Ventricular output may be more than doubled
  causing
• Left Ventricular Hypertrophy

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Aortic Regurgitation

• Symptoms
• Dysponea especially on exertion or lying flat
• Fatigue
• Dizziness and awareness of vigorous heart action
• Angina infrequent

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Aortic Regurgitation

• ECG Evidence of LV Hypertrophy
• CXR LV enlargement ,Dilation of the Ascending
  Aorta

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Aortic Regurgitation

• Clinical Course
• Mild Regurg compatible with normal lifestyle
• Symptom less
• Risk of endocarditis
• Treatment with diuretics and vasodilators for
  heart failure

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Aortic Regurgitation

• Moderate Severe
• Dysponea on exertion or when lying flat
• Fatigue
• May be associated with Aortic Stenosis

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Aortic Regurgitation

• Chronic Aortic Regurg can be better tolerated
  than Aortic Stenosis if compensatory mechanisms
  occur
• Condition unlikely to improve in the long term
• Surgery should be performed before LV dysfunction
  occurs
• Acute Aortic Regurg requires emergency surgery

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Mitral Stenosis

• The narrowing of the valve orifice which reduces
  blood flow leaving the left atrium and entering
  the left ventricle.
• Left Atrial pressure rises, enlarging the left
  atrium causing pulmonary congestion.
• Left ventricular filling becomes dependant on
  left atrial contraction.
• Normal MV area is 4.0-5.0cm2.

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Mitral Stenosis

• When valve narrows to lt 2.5cm2 patients become
  symptomatic.
• Causes.
• Degenerative disease.
• Rheumatic Heart Disease.

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Degenerative Disease

• Associated with aging
• Diabetes, hypertension and aortic stenosis
• Occurs most often in patients over 70
• Affects women more (41)
• Can appear in 10 of patients over 50

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Effects

• Calcification occurs where the posterior leaflet
  meets the left ventricle and impairs leaflet
  mobility
• As calcification progresses the annulus becomes
  stenotic and blood has a harder time moving
  forward through the narrowed valve
• Thrombi can form on these areas predisposing
  patients to stroke and bacterial endocarditis

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Rheumatic Heart Disease

• Attributed to Rheumatic Fever which causes
  inflammation in various body tissues including
  the heart, where the most serious damage occurs
• The predominant cause of Mitral Stenosis

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Causes

• Strep infection, occurs most commonly in children
  5-15yrs, less common now in industrialized
  nations
• Disease follows a stable course initially but in
  later years there is a more progressive
  acceleration of the disease

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Effects

• Translucent vegetations appear along the free
  margins of the leaflets , causing then to become
  inflamed and fuse together
• Creating a valve orifice that is stenotic
• Left atrium has difficulty emptying through a
  narrow orifice

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Mitral Stenosis

• Complications
• Atrial Fibrillation an important complication
  because it contributes to the development of
  Cardiac Failure and is responsible for atrial
  stasis risk of thrombosis and embolism
• Pulmonary Embolism
• Systemic Embolism cerebral, mesenteric or renal
• Respiratory congestion makes the patient liable
  to attacks of acute bronchitis and the
  development of chronic bronchitis
• Infective endocarditis rare in pure mitral
  stenosis, more associated with mixed mitral
  stenosis and mitral regurg

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Mitral Stenosis

• Symptoms
• Symptom free for many years
• Eventually develop features of left sided failure
  progressing o right sided failure
• Various factors such as Pregnancy or the onset of
  Atrial Fibrillation may suddenly precipitate the
  patient from one stage to another
• Most significant symptom Shortness of Breath
• Strenuous exercise initially progressing to
• Orthopnea
• Paroxysmal Dyspnoea
• Acute Pulmonary Oedema

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Mitral Stenosis

• ECG A fib common, Evidence of R ventricular
  hypertrophy develops in late stages
• CXR Classical Feature selective enlargement
  of the left atrium
• Calcification of the mitral Valve
• Upper pulmonary veins are usually prominent

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Mitral Stenosis

• Indications for surgery
• Surgery or Balloon valvuloplasty are eventually
  required in most cases
• Post relief of the stenosis treatment is still
  required for control of arrhythmias and the
  prevention of emboli
• Balloon Valvuloplasty is useful if the leaflets
  are pliant and mobile
• Relieve symptoms for 5-10yrs but restenosis
  usually occurs

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Mitral Regurgitation

• Occurs when a valve does not close properly,
  causing blood to leak back from the left
  ventricle to the left atrium
• Increases the workload of the left side to clear
  the regurgitated blood
• May occur in conjunction with mitral stenosis

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Causes

• Mitral Valve Prolapsed congenital or acquired
• Congenital disease, rheumatic fever
• Connective tissue disorders Marfans
• Structural factors- disproportion between the
  chordae tendane and papillary muscle
• Disproportion between mitral leaflet and valve
  orifice area often due to cardiomyopathy
• More common in young to middle aged women

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Endocarditis

• Infection of the valve by direct invasion of
  bacteria
• Untreated always fatal
• At risk are patients with congenital valve
  defects
• Rheumatic heart disease
• 10-15 of nosocomal endocarditis with cardiac
  surgery

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Ischemia

• Complication of Coronary Heart Disease and Acute
  MI
• Poor perfusion to the papillary muscle
• Necrosis and fibrosis formation causing papillary
  muscle dysfunction

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Effects

• With systole the blood shunts back through the
  mitral orifice into the left atrium
• Left Atrial pressure rises
• During diastole additional blood returns to the
  LV increasing volume

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Effects

• Both the LA and LV hypertrophy over time
• With LA compensation pulmonary congestion and
  dyspnea occur
• With LV compensation pulmonary venous pressures
  elevate and pulmonary hypertension occur
• Ventricular function is compromised and C.O
  decreases, consequently L atrial enlargement
  causes Afib which further decreases C.O

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Mitral Rergurgitation

• Acute
• Myocardial ischaemia and Mi
• Endocarditis
• Idiopathic chordae rupture
• Chronic
• Progressive
• Lv dysfunction in spite of normal EF
• patients may remain asymptomatic well after LV
  decompensation

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Mitral Regurgitation

• Indications for surgery
• Acute MR with CCF or Cardiogenic shock
• Acute endocarditis
• CHF due to valvular dysfunction
• Unstable valve prosthesis
• Uncontrolled infection
• Persistent bacterimea
• Fungal infections
• Vegetations in situ

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Mitral Regurgitation

• Mitral Valve Reconstruction in possible in a
  percentage of cases with degenerative disease
• Mitral Valve replacement indicated when repair
  not possible

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Types and Choices Prosthetic Valves

• Mechanical
• Better Durability
• Require Long-term Anticoagulation Therapy
• 3 main types
• Ball valves (Starr-Edwards)
• Tilting disc valves (Shiley)
• Bi-leaflet valves (St Jude)

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Tissue Valves

• Autologous valves made from the patients own
  pericardium
• Autograft valves diseased aortic valve
  removed and replaced with the pulmonary
  valve which is then replaced with a
  homograft

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Tissue Valves

• Homograft Human cadavers
• Porcine Specially treated porcine tissue
• Shorter Lifespan may require replacing within
  10yrs
• Useful for younger childbearing women

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Complications of Prosthetic Valves

• Thromboembolism anticoagulant therapy
• Haemorrhagic Complications
• Primary Valve Failure
• Endocarditis

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Pre Operative Considerations

• Nutritional Support
• Aggressive Diuresis
• Measures to prevent Resp Failure
• Atrial Fibrillation

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Pre Operative Considerations

• Dental Checks
• Cardiac catheterisation
• Selection of valve type
• Counseling
• Asymoathomatic patients question the need for
  such dramatic surgery
• Valve choice
• Lifestyle changes relating to warfarin therapy
• Education re endocarditis

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Post-operative Considerations

• Routine complications post cardiac Surgery
• Fluid and haemodynamic monitoring and management
• Education re anticoagulation therapy
• Arrhythmias, complete heart block, need for
  permanent pacemaker
• Dyspnoea reduction may take time to improve
• Prophylactic antibiotic therapy prior to dental
  work and other invasive procedures

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Antibiotics Prophylaxis

• Dental/oral/resp/oes procedures
• Standard regimen Ampicil 2grm po 1hr
• Unable to take po Ampicil 2grm iv/im 30min
• Pen allergic Clindamycin 600mg or Cefazolin
  igrm iv 30mins

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