A-V Valve Repair
1. The Perfect Valve
Excellent hemodynamics
Non-thrombogenic
Durable
Unrestricted availability
Easily implantable
Silent function
Low cost
2. Selection of Valve Prosthesis
Primarily based on hemodynamic need, risk of anticoagulation and required durability
Small aortic root
Elderly
Multiple medical conditions
Child-bearing female
Lifestyle precluding anticoagulation
Ability or desire to undergo reoperation
Hemodynamic performance
Aortic
Homograft / autograft
Stentless heterograft
Mechanical prosthesis
Stented heterograft
Mitral
Valve repair
Mechanical prosthesis
Stented bioprosthesis
3. Thromboembolism and Hemorrhage
Homograft / autograft
Bioprosthesis
Mechanical prosthesis
4. Durability
Mechanical prosthesis
Autografts
Homografts
Bioprosthesis
5. Infection
Important when operating on endocarditis
Homograft / autograft most resistant to infection
Stented bioprosthesis = mechanical prosthesis
6. Valve Repair
Successful valve repair is always more preferable than valve replacement
Aortic
Leaflet plication, commissure re-suspension
Mitral
Posterior quadrangular resection
Chordal transfer
Ring annuloplasty
Require training and experience for good result
7. Aortic Homograft
Sir Donald Ross- 1962
Performance
Freedom from failure 80-90%- 10 years
Risk of grade III/IV AI @ 7 years:
26% with subcoronary implant- 22% reoperation
12% with inclusion/root implant- 5% reoperation
Accelerated with younger age (Ann Thor Surg 1996 62:1069)
Freedom from thromboembolism 97% @ 14 years
Freedom from endocarditis 94% @ 14 years
71% actuarial survival @ 14 years (J Card Surg 1991 6:534)
Implant Techniques
Subcoronary
Inclusion
Root replacement
Immunologic responses
Cryopreservation maintains collagen but not cellular viability
Antibody production related to ABO type, HLA
Matching and immunosuppression
8. Pulmonary Autograft (Ross Procedure- 1967)
Advantages
Viable tissue, excellent hemodynamics
Near 0% thromboembolism, growth potential
Non-antigenic
Pulmonary valve equal in strength as aortic valve
Disadvantage
Creating 2-way valve pathology from single valve disease
Results
Freedom from re-operation 81% @ 8 years
5-10% annular dilatation and regurgitation
Pulmonary homograft deterioration
Technique
Root replacement preferred
Tailoring of aortic/pulmonary size mismatch
Bolstering ring with Dacron strip
Long-term follow-up still accruing
9. Porcine Bioprosthesis
Introduced in 1972
Indications
Elderly, child-bearance, intolerance of anticoagulation, bleeding diatheses
Disadvantages
Structural deterioration
Less common in older patients
Faster in mitral vs aortic positions (55% vs 37% @15 years)
Calcification
Children, adolescents, renal failure, pregnancy?
Obstructive in smaller sizes
19 mm: Porcine 0.8-1.2 cm2, Mechanical 1.6 cm2
Supra-annular: 2.1 cm2
10. Stentless Porcine Bioprosthesis
Stent is the major factor governing stress
Advantages
Better hemodynamics than stented prosthesis
Availability (full range of sizes)
Implant technique
Subcoronary/ inclusion/ root replacement
Long-term follow-up pending
11. Mechanical Prosthesis
Most commonly used prosthesis
Excellent durability
Higher incidence of anticoagulation related complications
Flow characteristics Flow Characteristics
ball/cage < tilting dic < bileaflet
Thrombogenic potential
ball/cage > tilting disc > bileaflet
Aortic < Mitral < both
12. Atrial Fibrillation and Valvular Disease
Anticoagulation substantially reduces stroke
Large immobile atrium with valve disease increases stroke risk
Anticoagulation should be maintained after valve replacement
No benefit to bioprosthesis
13. Antigcoagulation Management
TIA is most common event
Standardization of coagulation management (INR)
Narrow therapeutic range- balance between thrombolic and bleeding risk
ACCP recommendations: INR 2.5-3.5
Aortic: 2.5-3.0
Mitral: 3.0-3.5
Both: 3.5-4.0
Appropriate use of antiplatelet therapy
14. Moderate Aortic Stenosis with Coronary Artery Disease
Treatment plan
Life expectancy in the 7th decade
Male- 10 years
Female- 13 years
Valve area of 0.8
1.5 cm2 - moderate stenosis
>1.5 cm2- mild stenosis
Gradient
<25 mmHG is mild stenosis
15. Natural History
Moderate aortic stenosis- 10 years- 30% need or AVR
(0.8-1.5 cm2)- 15 years- 50% need AVR
Aortic gradient increases by 7 mmHg/ year when base gradient is 10 mmHg or more
Valve area decreases by 11 cm2/ year
Progression of moderate to severe stenosis mean duration is 5-7 years
EXTENDED OUTLINE
Surgical Anatomy of Cardiac Valves And Techniques of Valve Reconstruction
I. Mitral Valve
A. Anatomy
1. Leaflets - surface area is twice that of the MV orifice
a. anterior
- common attachment with left coronary and 1/2 of the noncoronary cusps
b. posterior
2. Commissures
- anterolateral
- posteromedial
- corresponding PM underneath
3. Annulus
- insertion of atrial and ventricular muscle
- attached to fibrous trigones
- right trigone junctions between the MV, TV, AV & membranous septum
- sphincter like function causing a 26% narrowing during systole
4. Chordae tendinae
- insert into the distal part of the valve on the rough zone
- anterior leaflet
- main, paramedian, paracommissural
- posterior leaflet
- basal , rough zone , cleft
5. Papillary Muscles
- anterolateral and posteromedial
6. Arterial Supply
a. leaflets
- anterior - Kugal's artery from the RCA or Circ.
b. PM
- anterolateral - LAD, Diagonal, Circ.
- posteromedial - Circ. and RCA
B. Mitral Valve Repair
1. leaflet motion is either normal, prolapsed, or restricted
2. if the leaflets move normally and there is MR then the annulus is dilated or there is leaflet perforation
3. goal is to improve movement of the leaflets and remodel the annulus
4. Repair of Prolapse
a. quadrangular resection
b. gap repaired by:
- annular plication
- sliding plication
5. Repair of Anterior Leaflet
a. chordal rupture
- fix to secondary chordae
- chordal shortening
- chordal transposition (post. to ant.)
- chordal replacement
b. chordal shortening
6. Papillary Muscle
- sliding plasty
- cuneiform resection
- concertina technique
7. Restricted Leaflet Motion
- resection of secondary chordae
- triangular resection of fused elements
C. Results
- 72 % 5 year survival
- 94 % freedom from embolic event
- 97 % freedom from endocarditis
- 87 % without reop @ 15 years
- 2. 5 % with signs of MR
II. Tricuspid Valve
A. Anatomy
1. Leaflets
- anterior, septal, posterior
2. Commissures
- anteroseptal, anteroposterior
3. Annulus
- attached only to the right fibrous trigone between the septal leaflet and the anteroseptal commissure, elsewhere the valve inserts directly into the myocardium
4. Chordae Tendinae
- similar to the MV with the addition of free edge @ deep chordae
5. Papillary Muscles
- anterior
- largest
- send chordae mainly to the anterior leaflet
- posterior
- may have more than one belly
- chordae of the posterior and a few to the septal
- septal leaflet supported with chordae directly from the septum
B. Tricuspid Valve Repair
1. indications for repair
a. annular size > 34 in women and > 36 in men
b. organic lesions
2. annuloplasty mainly works in the posterior leaflet
3. organic lesions
- division of fused commissures
- prolapse treated the same as MV
C. Results
- .6 % reop rate with ring vs. DeVega
III. Aortic Valve
A. Anatomy
1. leaflets
- tricuspid
- all insert into annulus
2. fibrous skeleton
- does not change during the cardiac cycle
3. sinuses of valsalva
B. Repair
1. Annular dilatation
- circular annuloplasty
- commissural annuloplasty
2. Repair of leaflets
a. prolapse
- triangular resection
- leaflet resuspension
b. restricted
- commissurotomy
C. Results
- 20 % reop rate
