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SpC Surgery > Interactive Tutorial: Surgery For Heart Valve Disease > Flashcards

Interactive Tutorial: Surgery For Heart Valve Disease Flashcards

1
Q

Heart valve problem in general

A
  1. Stenosis
    - Limited blood pass through —> Pressure overload
  2. Regurgitation
    - Large amount of blood going back —> Volume overload
Causes of Valve disease:
1. Chronic rheumatic heart disease (2nd most common)
2. Degeneration (most common)
3. Infective endocarditis
4. IHD
5. Congenital disease
Etc.
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2
Q
  1. Chronic rheumatic heart disease
A
  • Group A beta haemolytic streptococcal pharyngeal infection
  • Ab cross-reactivity attacking body own tissue
  • Fibrosis of leaflet, ***Commissural (connection points between leaflets) fusion + annulus
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3
Q
  1. Degeneration
A
  • Actual pathophysiology pathway unknown (Multifactorial)
    —> Degeneration of leaflet + chordae
    —> Aging
    —> ?Genetic
    —> ?Same process of atherosclerosis of vessels
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4
Q
  1. Infective endocarditis
A

Usually in patients with predisposed valve problem

Causative agents:

  • Streptococcus viridans
  • Staphylococcus aureus / epidermidis
  • Enterococci

Diagnosis:
- Modified Duke’s criteria

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5
Q
  1. IHD
A
  • Mainly cause problem of ***Mitral valve (particularly posterior LV —> ischaemic LV distortion —> papillary muscle displacement —> tethered chordae —> restricted leaflet closure of MV + annular dilation of AV)
  • ?AV, TV
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6
Q
  1. Congenital disease
A
  1. Marfan syndrome
    - Aortic problem (e.g. dissection / aneurysm) —> number 1 cause of death
    - Valvular problem (e.g. AV / MV regurgitation)
  2. Bicuspid aortic valve
    - common in chinese: 2-3% normal population
    - sustain higher pressure —> earlier degeneration
  3. Mitral valve prolapse syndrome
    - longer mitral valve leaflet —> easier prolapse
  4. Ebstein’s anomaly (Atresia of tricuspid leaflet + Atrialised RV)
  5. Others
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7
Q

Natural history of heart valve disease

A

Normal heart function
—> Dilated atrium / ventricle
—> AF (worsening of all symptoms ∵ drop in 20% CO) + Other valves affected
—> Heart failure (∵ Volume / Pressure overload)
—> Life-threatening events

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8
Q

Symptoms of Heart valve disease

A
  1. SOB (esp. on exertion)
  2. Tiredness, dizziness, LOC
  3. Chest tightness, discomfort, pressure
  4. Edema (from foot —> knee —> abdomen)
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9
Q

Diagnosis of Heart valve disease

A
  1. Stethoscope
  2. CXR
  3. ECG
  4. Echocardiogram (gold standard, easy, non-invasive, accurate)
  5. Angiogram
  6. MRI
    Etc.
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10
Q

Treatment of Heart valve disease

A
  1. Medical (Palliative)
    - ACE inhibitors
    - Diuretics
    Etc.
  2. Trans-catheter treatment
  3. Surgery
    - Valve repair
    - Valve replacement
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11
Q

Valve repair vs replacement

A

Native valve ***better than Artificial valve —> Repair first before replacement whenever possible

  1. ***Less endocarditis
  2. ***Less affect heart function
  3. Better QoL
    - no need long term anticoagulant if in sinus rhythm
    - less risk of thromboembolism / bleeding
    - less risk of prosthetic endocarditis
  4. Repair as first choice

Replacement:
- Require cutting out major native heart tissues
—> Including chordae, papillary muscle (subvalvular apparatus)
—> Alter LV **geometry (Elliptical to Spherical shape) + **function
—> Change LV **outflow direction + **Larger size (Laplace’s law: greater volume of ventricle —> more energy required for contraction)

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12
Q

Mechanical vs Tissue heart valve

A

Long term complication rate:
- SAME

Mechanical:

  • More durable (>20 years)
  • Require life long warfarin (X NOAC)
  • Risks: Bleeding due to warfarin

Tissue:

  • Less durable (~15 years —> 50% chance to re-do)
  • Only need short period of warfarin (~3 months)
  • Risks: Redo operation
Choice depends on patient preference:
Towards Tissue valve:
- Pregnancy (∵ warfarin: teratogenic in 3rd trimester, high abortion rate in 1st trimester —> need to switch to heparin)
- Old age patient (>65)
- History of severe bleeding

Towards Mechanical valve:

  • Mechanical valve in-situ
  • Long term renal replacement therapy (esp. peritoneal dialysis ∵ ***HyperCa in renal failure patients —> tissue valve calcify much faster)
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13
Q

Atrial Fibrillation

A
  • Rhythm + Rate problem
  • Most have no cause ?Degeneration
  • Can due to IHD, valve disease, infection, thyroid problem
  • Longer time having valve disease —> higher chance of AF
  • ~30% of patient have AF before valve operation

Problems:
1. Additional symptom to valve problem (∵ decreased in CO)

  1. Long term risk
    - Blood clot —> Stroke (5x)
    - Poor control can lead to cardiomyopathy
  2. Impact on cardiac surgery
    - Higher risk for surgery
    - Higher early + late mortality
    - Only a small proportion of patient can converted back to sinus after surgery if they have AF pre-op

Concomitant AF surgery:
- Maze procedure
—> break down “reentry wave form” + “ectopic foci” by RFA / Cryo
—> allow normal signal run in near normal manner
—> highest success rate 65-90% in literatures (better than Drugs, Catheter ablation)
—> confirmed long term benefits: less stroke, better QoL, less cardiac complications, probably better survival
—> recommended as a ***concomitant procedure to cardiac surgery

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14
Q

Common valve diseases

A
  1. Mitral regurgitation
  2. Mitral stenosis
  3. Aortic stenosis
  4. Aortic regurgitation

Prognosis: AS > AR > MS/MR

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15
Q
  1. Mitral regurgitation
A
  • Volume overload —> Higher requirement for EF to be normal (>60% ∵ higher preload)
  • Dilatation of LA + LV —> Increased C:T ratio
Natural history:
- Asymptomatic for many years
- Progression is slow
- Once become severe —> NOT benign
—> Develop symptoms
—> AF
—> Mortality / Surgery in 10 years

Indications for surgery:

  1. Severe MR + symptom
  2. Severe MR + LV dysfunction but asymptomatic
  3. Severe MR + asymptomatic
    - if valve likely repairable
    - unfavourable features present: AF, pulmonary HT
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16
Q
  1. Mitral stenosis
A
  • Pressure overload of LA —> LA enlargement —> Pulmonary HT —> Dilated pulmonary artery (shown on CXR) —> Early TR

Causes:

  • Rheumatic (99%)
  • Congenital

Natural history:

  • Progression from Rheumatic fever to Symptomatic MS require 20-40 years
  • Asymptomatic: Good survival >80% at 10 years
  • Symptomatic: Poor survival 10% at 10 years
  • Pulmonary HT: <3 year survival

Treatment:
1. Percutaneous mitral balloon valvuloplasty (PMBV)
- Less severe cases
- Less calcified
- No MR
—> will still progress + need surgery eventually due to ongoing autoimmune disease process

  1. Surgery (repair / replacement —> repair treatment of choice for all etiologies)
    - More severe cases
17
Q

Mitral repair / replacement techniques

A 
Repair:
Treat: Annulus + Leaflet + Chordae
1. Quadrangular resection
2. Annuloplasty
3. Triangular resection
4. Chordal shortening
5. Chordal transfer
6. Chordal replacement
7. Double orifice technique
8. Leaflet extension

Replacement:

  • Excise all leaflets + chordae —> Larger space for prosthesis
  • Preserving leaflets (esp. posterior leaflet): To preserve LV geometry + function
18
Q

Open heart surgery

A
  1. Median sternotomy
    - Most common approach to perform MVR / MR repair
  2. Cardiopulmonary bypass
    - Motionless + Bloodless surgical field

Potential problem:

  1. Need 10 weeks for bone healing —> No weight bearing exercise
  2. Larger wound
  3. Wound infection
19
Q

General results after MV surgery

A
  • Mortality: 1-5%
  • Morbidity: 5%
    —> General: severe infection, bleeding, multi-organ failure, CVA
    —> Specific: heart block (require pacemaker), heart failure (require inotropic support), peri-op MI
  • Progressive improvement of symptom + heart function after 3 months of surgery
20
Q

Transcatheter treatment for mitral valve

A
  • Developing stage
  • Mainly for high risk patients / research purpose
  • Repair / Replacement
21
Q
  1. Aortic stenosis
A

Pressure overload —> LV hypertrophy

Natural history:
- Most lethal
- Prolong latent period + slow progression
- Asymptomatic: Good prognosis
- Symptomatic: 2-3 year survival + high risk of sudden death
- Poor prognostic factor:
—> Heavily calcified valve
—> Jet velocity >4m/s

Symptoms:

  • SOB
  • Chest pain
  • LOC

Indications for surgery:

  1. Severe AS + symptomatic
  2. Severe AS + LV dysfunction
  3. Severe AS + asymptomatic / normal LV
    - Heavily calcified
    - Vmax >4m/s
    - Rapid rate of deterioration
22
Q
  1. Aortic regurgitation
A
  • Volume overload —> LV dilatation —> Increased C:T ratio

Natural history:
- Mild / Moderate: Progress slowly + unlikely to have symptoms
- Severe:
—> Asymptomatic: Progression to symptom / LV dysfunction 5% per year
—> Symptomatic / LV dysfunction: 10-20% per year of mortality

Indications of surgery:

  1. Severe AR + symptoms
  2. Severe AR + LV dysfunction
    - EF <50% / ESD >55mm / EDD >75mm
23
Q

Treatment options for Aortic valve disease

A
  1. **Aortic valve replacement (vs Mitral: **repair mainly) (∵ mainly stenosis —> valve too calcified to be repaired)
  2. Aortic valve repair
  3. Pulmonary valve autotransplant
  4. Homograft
  5. LV to descending aorta shunt
24
Q

General results after AV surgery

A

Operative mortality:
- 1-5% depending on pre-morbid, cardiac, operative condition

Complications:

  • ~5%
  • General: bleeding, infection, multi-organ failure, CVA
  • Specific: heart block, heart failure, peri-op MI
25
Q

New treatment options for AV valve

A
  1. Surgical AVR
    - Small incision: Hemisternotomy / Thoracotomy
  2. Transcatheter AVR (TAVI)
    - Femoral approach
    - Transaortic / Transapical approach
    —> patients with access problem

How to choose between treatments?

  • Low risk patients (young, good past health) —> Surgical AVR
  • Moderate risk patients (some comorbidities, older age) —> Surgical AVR
  • High risk patients —> TAVI
  • Inoperable patients —> TAVI

Surgical AVR: Higher durability

26
Q

Summary

A
  • Increasing patients with valve disease, esp. AS, MR
  • Key symptoms: SOB, Chest discomfort, Dizziness, Tiredness, Edema
  • Once symptomatic —> most valve problem have ***poor prognosis
  • Treatment: Surgery / Transcatheter based
  • General indication for surgery: **Severe valve problem + **Symptom / ***Ventricular dysfunction
  • Surgery for valve disease: Repair > Replacement
  • Traditional approach: Median sternotomy
  • Recent development of surgery for valve: Minimally invasive surgery, Robotic assisted surgery, TAVI, Other trans-catheter instruments

SpC Surgery (11 decks)

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