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AV Valve Repair

A-V Valve Repair

1. The Perfect Valve

A. Excellent hemodynamics
B. Non-thrombogenic
C. Durable
D. Unrestricted availability
E. Easily implantable
F. Silent function
G. Low cost

2. Selection of Valve Prosthesis

A. Primarily based on hemodynamic need, risk of anticoagulation and required durability
B. Small aortic root
C. Elderly
D. Multiple medical conditions
E. Child-bearing female
F. Lifestyle precluding anticoagulation
G. Ability or desire to undergo reoperation

3. Hemodynamic performance

A. Aortic
1) Homograft / autograft
2) Stentless heterograft
3) Mechanical prosthesis
4) Stented heterograft
B.Mitral
1) Valve repair
2) Mechanical prosthesis
3) Stented bioprosthesis

4. Thromboembolism and Hemorrhage

A. Homograft / autograft
B. Bioprosthesis
C. Mechanical prosthesis

5. Durability

A. Mechanical prosthesis
B. Autografts
C. Homografts
D. Bioprosthesis

6. Infection

A. Important when operating on endocarditis
B. Homograft / autograft most resistant to infection
C. Stented bioprosthesis = mechanical prosthesis

7. Valve Repair

A. Successful valve repair is always more preferable than valve replacement
B. Aortic
1) Leaflet plication, commissure re-suspension
C. Mitral
1) Posterior quadrangular resection
2) Chordal transfer
3) Ring annuloplasty
D. Require training and experience for good result

8. Aortic Homograft

A. Sir Donald Ross- 1962
B. Performance
C. Freedom from failure 80-90%- 10 years
D. Risk of grade III/IV AI @ 7 years:
1) 26% with subcoronary implant- 22% reoperation
2) 12% with inclusion/root implant- 5% reoperation
3) Accelerated with younger age (Ann Thor Surg 1996 62:1069)
E. Freedom from thromboembolism 97% @ 14 years
F. Freedom from endocarditis 94% @ 14 years
G. 71% actuarial survival @ 14 years (J Card Surg 1991 6:534)
H. Implant Techniques
1) Subcoronary
2) Inclusion
3) Root replacement
I. Immunologic responses
1) Cryopreservation maintains collagen but not cellular viability
2) Antibody production related to ABO type, HLA
3) Matching and immunosuppression

9. Pulmonary Autograft (Ross Procedure- 1967)

A. Advantages
1) Viable tissue, excellent hemodynamics
2) Near 0% thromboembolism, growth potential
3) Non-antigenic
4) Pulmonary valve equal in strength as aortic valve
B. Disadvantage
1) Creating 2-way valve pathology from single valve disease
C. Results
1) Freedom from re-operation 81% @ 8 years
2) 5-10% annular dilatation and regurgitation
3) Pulmonary homograft deterioration
D. Technique
1) Root replacement preferred
2) Tailoring of aortic/pulmonary size mismatch
3) Bolstering ring with Dacron strip
E. Long-term follow-up still accruing

10. Porcine Bioprosthesis

A. Introduced in 1972
B. Indications
1) Elderly, child-bearance, intolerance of anticoagulation, bleeding diatheses
C. Disadvantages
D. Structural deterioration
1) Less common in older patients
2) Faster in mitral vs aortic positions (55% vs 37% @15 years)
E. Calcification
1) Children, adolescents, renal failure, pregnancy?
F. Obstructive in smaller sizes
1) 19 mm: Porcine 0.8-1.2 cm2, Mechanical 1.6 cm2
2) Supra-annular: 2.1 cm2

11. Stentless Porcine Bioprosthesis

A. Stent is the major factor governing stress
B. Advantages
1) Better hemodynamics than stented prosthesis
2) Availability (full range of sizes)
C. Implant technique
1) Subcoronary/ inclusion/ root replacement
D. Long-term follow-up pending

12. Mechanical Prosthesis

A. Most commonly used prosthesis
B. Excellent durability
C. Higher incidence of anticoagulation related complications
D. Flow characteristics Flow Characteristics
1) ball/cage < tilting dic < bileaflet
E. Thrombogenic potential
1) ball/cage > tilting disc > bileaflet
2) Aortic < Mitral < both

13. Atrial Fibrillation and Valvular Disease

A. Anticoagulation substantially reduces stroke
B. Large immobile atrium with valve disease increases stroke risk
C. Anticoagulation should be maintained after valve replacement
D. No benefit to bioprosthesis

14. Antigcoagulation Management

A. TIA is most common event
B. Standardization of coagulation management (INR)
C. Narrow therapeutic range- balance between thrombolic and bleeding risk
D. ACCP recommendations: INR 2.5-3.5
1) Aortic: 2.5-3.0
2) Mitral: 3.0-3.5
3) Both: 3.5-4.0
E. Appropriate use of antiplatelet therapy

15. Moderate Aortic Stenosis with Coronary Artery Disease

A. Treatment plan
B. Life expectancy in the 7th decade
1) Male- 10 years
2) Female- 13 years
C. Valve area of 0.8
1) 1.5 cm2 - moderate stenosis
2) >1.5 cm2- mild stenosis
D. Gradient
1) <25 mmHG is mild stenosis

16. Natural History

A. Moderate aortic stenosis- 10 years- 30% need or AVR
B. (0.8-1.5 cm2)- 15 years- 50% need AVR
C. Aortic gradient increases by 7 mmHg/ year when base gradient is 10 mmHg or more
D. Valve area decreases by 11 cm2/ year
E. Progression of moderate to severe stenosis mean duration is 5-7 years

EXTENDED OUTLINE

1. 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
(1) common attachment with left coronary and 1/2 of the noncoronary cusps
b) posterior
2) Commissures'''
a) anterolateral
b) posteromedial
c) corresponding PM underneath
3) Annulus
a) insertion of atrial and ventricular muscle
b) attached to fibrous trigones
c) right trigone junctions between the MV, TV, AV & membranous septum
d) sphincter like function causing a 26% narrowing during systole
4) Chordae tendinae
a) insert into the distal part of the valve on the rough zone
b) anterior leaflet
c) main, paramedian, paracommissural
d) posterior leaflet
e) basal , rough zone , cleft
5) Papillary Muscles
a) anterolateral and posteromedial
6) Arterial Supply
a) leaflets
(1) anterior - Kugal's artery from the RCA or Circ.
b) PM
(1) anterolateral - LAD, Diagonal, Circ.
(2) 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:
(1) annular plication
(2) sliding plication
5) Repair of Anterior Leaflet
a) chordal rupture
(1) fix to secondary chordae
(2) chordal shortening
(3) chordal transposition (post. to ant.)
(4) chordal replacement
b) chordal shortening
6) Papillary Muscle
a) sliding plasty
b) cuneiform resection
c) concertina technique
7) Restricted Leaflet Motion
a) resection of secondary chordae
b) triangular resection of fused elements
C. Results
a) 72 % 5 year survival
b) 94 % freedom from embolic event
c) 97 % freedom from endocarditis
d) 87 % without reop @ 15 years
e) 2. 5 % with signs of MR

2. Tricuspid Valve

A. Anatomy
1) Leaflets
a) anterior, septal, posterior
2) Commissures
a) anteroseptal, anteroposterior
3) Annulus
a) 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
a) similar to the MV with the addition of free edge @ deep chordae
5) Papillary Muscles
a) anterior
b) largest
c) send chordae mainly to the anterior leaflet
d) posterior
e) may have more than one belly
f) chordae of the posterior and a few to the septal
g) 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
a) division of fused commissures
b) prolapse treated the same as MV
C. Results
1) .6 % reop rate with ring vs. DeVega

3. Aortic Valve

A. Anatomy
1) leaflets
a) tricuspid
(1) all insert into annulus
2) fibrous skeleton
a) does not change during the cardiac cycle
3) sinuses of valsalva
B. Repair
1) Annular dilatation
a) circular annuloplasty
b) commissural annuloplasty
2) Repair of leaflets
a) prolapse
(1) triangular resection
(2) leaflet resuspension
b) restricted
(1) commissurotomy
C. Results
1) 20 % reop rate