1. Types Selection Complications
Prosthetic valves
Types
Selection
Complications

2. Types Bioprosthetic valves Mechanical Heterograft (xenograft)
Bovine
porcine
Homograft (allograft)
Autograft
Pericardial
Pulmonary (Ross)
Mechanical
Caged ball valve
Tilting disc valve
Bileaflet valve

3. Heterografts(xenografts)
The Hancock M.O. II aortic bioprosthesis (porcine)
Stentless
Porcine
Toronto SPV valve, medtronic freestyle valve
Stented
- facilitate implant, maintain 3D relationship,more physiological flow
Hancock , carpenteir edward s, medtronic
Bovine
Stented bovine p prosthesis
Carpentier-Edwards Duralex mitral bioprosthesis

4. Tissue heterograft Advantages Disadvantages
- No need of anticoagulation after 1st 3 m
Little hemolysis
Disadvantages
Limited ,uncertain durability
Cuspal tear
Perforation
degeneration
Rapid deterioration esp children
Fibrin depostn
Ca++
10-30% need re op in 10 yr
30-60% need re op in 15 yr
Small size have poor hemodynamics

5. Bioprosthetic valve Preferred in Pregnancy Bleeding Diathesis
Age> 70 years
Poor compliance

6. Mechanical valves Caged ball valve Advantages Disadvantages
Oldest
durabilty upto 40 yr
Disadvantages
high profile
hemolysis
high thrombogenecity
Poor hemodynamics in small sizes
Unique features
Occluder travels completely out of the orifice, reduces thrombus & pannus growing from the sewing ring
Continuously changing points of contact of the ball reduces the wear & tear in any one area
Thrombogenic risk 4-6% / year

7. Starr Edwards Valve not suitable
- for the mitral position in patients with a small left ventricular cavity
- for the aortic position in those with a small aortic annulus
- those requiring a valve-aortic arch composite graft

8. Tilting disc valve- monoleaflet
- Medtronic Hall valve
- Omnicarbon (Medical CV)
- Monostrut (Alliance Medical Technologies)
- Bjork-Shiley valves
Adv
low profile
Good hemodynamics even in small sizes
Excellent durability
Permit central laminar flow
Medtronic hall valve
Titanium housing
teflon sewing ring
carbon coated disc
disadv –
Anticoagulation mandatory
higher risk of thrombosis than cage ball v
sudden catastrophic valve thrombosis

9. Bileaflet valve Adv – Anticoagulation mandatory risk of thrombosis
St. Jude Medical mechanical heart valve
Bileaflet valve
Adv –
Low bulk - flat profile
Less thrombogenicy
Central laminar flow
two semicircular discs that pivot between open and closed positions
No need for supporting struts
Good hemodynamics even in small sizes
2 lat ,1 central minor orifice , no chance of sudden catastro thrombosis
Disadv-
Anticoagulation mandatory
risk of thrombosis
Carbomedics
Titanium housing
Pyrolytic carbon

11. Model Thrombogenicity
Types of prosthetic valves and thrombogenicity
Type of valve
Model
Thrombogenicity
Mechanical
Caged ball
Starr-Edwards
++++
Single tilting disc
Bjork-Shiley,Medtronic Hall
+++
Bileaflet
St Jude Medical,Sorin Bicarbon,Carbomedics ++
Bioprosthetic
Heterografts
Carpentier-Edwards,Tissue Med (Aspire), Hancock II
+ to ++
Homografts +

12. TTK chitra tilting disc valve
- metallic housing (cobalt based wrought alloy)
- circular disc high molecular weight polyethylene
- A polyester suture ring
Hemodynamically comparable to other mechanical valves
valve related complications are similar

14. Characteristics of Various prosthetic valves

15. Flow Dynamics

16. Desired valves Mechanical valves - preferred in young patients
who have a life expectancy of more than 10 to 15 years who require long-term anticoagulant therapy for other reasons (e.g., atrial fibrillation)
Bioprosthetic valves
preferred in patients who are elderly
have a life expectancy of less than 10 to 15 years
who cannot take long-term anticoagulant therapy
A bileaflet-tilting-disk or homograft prosthesis is most suitable for a patient with a small valvular annulus in whom a prosthesis with the largest possible effective orifice area is desired.

17. algorithm for choice of prosthetic heart valve

19. Radiologic Identification
Starr-Edwards caged ball valve
Radiopaque base ring
Radiopaque cage
Three struts for the aortic valve; 4 struts for the mitral or tricuspid valve
Silastic ball impregnated with barium that is mildly radiopaque (but not in all models)

20. TTE – stenosis
Valve area calculations
Continuity equation
Area Ao prosthesis =
(diameter sewing ring)² x 0.785xLVOT VTI/ Ao prosthesis VTI
Area mitral prosthesis=
(diameter LVOT)²x 0.785xLVOT VTI/ VTI mitral prosthesis
Pressure Half time ( mitral valve prosthesis)
Dimensionless index-
LVOT velocity/ aortic prosthesis velocity
< 0.23 indicates prosthetic valve stenosis

21. Prosthetic Valve regugitation
Mitral – velocity2.5m/sec
- jet area 2cm²
Aortic aortic PHT≤ 250m/sec
-- flow reversal in aorta

22. Normal Doppler Values of Prosthetic Valves
Aortic Position
Mitral Position
Velocity Mean Gr Starr Edward 3.1±0.5 24±4 St Jude 3.0±0.8 11±6 Medtronic Hall 2.6±0.3 12±3 Aortic Homograft 0.8±0.4 7±3 Hancock 2.4±0.4 11±2 Carpentier’s 2.4±0.5 14±6
Velocity MeanGr
Starr Edward ± ±2
St Jude ± ±2
Medtronic Hall ± ±2
Aortic Homograft 1.5± ±2
Hancock ± ±2
Carpentier’s ± ±2

23. Importance of TEE higher-resolution image than TTE
size of vegetation defined more precisely
peri annular complications indicating a locally uncontrolled infection (abscesses, dehiscence, fistulas) detected earlier
limitation -inability to detect aortic prosthetic-valve obstruction or regurgitation, especially when a mitral prosthesis is present

24. Mitral Bileaflet

25. Cinefluoroscopy Structural integrity Motion of the disc or poppet
excessive tilt ("rocking") of the base ring - partial dehiscence of the valve
Aortic valve prosthesis - RAO caudal
- LAO cranial
Mitral -- RAO cranial

26. Fluoroscopy of a normally functioning CarboMedics bileaflet prosthesis in mitral position
A=opening angle B=closing angle

27. St. Jude medical bileaflet valve
Mildly radiopaque leaflets are best seen when viewed on end
Seen as radiopaque lines when the leaflets are fully open
Base ring is not visualized on most models

28. MRI Not useful in assessing prosthetic-valve structure
used only when prosthetic-valve regurgitation or para valvular leakage is suspected but not adequately visualized by echocardiography

29. Cardiac Catheterization
measure the transvalvular pressure gradient, from which the EOA can be calculated
can visualize and quantify valvular or paravalvular regurgitation

30. Valve dysfunction complication example Role of echo
Primary mechanical failure
Ball variance
Strut fracture
Visualize structure, assess gradient & regurgitation
Nonstructural dysfunction
Pt- prosthesis mismatch
pannus
Gradient, visualize tissue in & around the sewing ring
Bleeding event
Intracranial hge
Source of embolus, presence & mobility of masses
Endocarditis
Vegetation, abcess, dehiscence
Visualize area around the sewing ring, echo dense / lucent area, perivalvular regurgitation
Thrombosis
Thrombus impedes opening &closing of occluder mechanism
Localize mass, assess gradient, detect regurgitation
Embolism
stroke
Identify & characterize the source of emboli

31. patient-prosthesis mismatch
When the effective prosthetic valve area, after insertion into the patient less than that of a normal valve (Rahimtoola in 1978)
EOA indexed to BSA is less than 0.85 cm2/m2
EOA (echo) differs from geometric orifice area (measured directly)
EOA for each prostheses type & size obtained in literature from pts normally functioning prostheses
Average if > 1 value
-- mild ( cm² /m²
-- moderate ( cm2/m²
-- severe (iEOA < 0.6cm²/m² (Rahimtoola)

32. in-vitro area of the majority of valve prostheses ( int diameter <23 mm) < that of the normal human valve area
the in-vivo prosthetic area further reduced by IVS hypertrophy, progressive endothelialization and tissue ingrowth
(Aortic prosthetic devices may be functionally stenotic)

33. three-step algorithm Step 1: Calculation of the patient BSA.
Step 2: Reference to the specific table for identification of the adequate valvular EOA according to the patient BSA.
Step 3: Selection of the most appropriate type and size of valve prosthesis according to the target iEOA

35. Valve Thrombosis <0.2% per year for mech valves
Incidence of 0.1 to 5.7 % per patient-year
<0.2% per year for mech valves
<0.1% bioprosthetic valves
small thrombus, at the hinge portion of a bileaflet valve obstruct the mechanism
tilting disk -- a much larger thrombus to prevent function
Ball and cage valves – less susceptible  occluder has no
contact at all with the valve housing for a portion of every cycle
Clinical
Non obstructive- incidental/embolic phenomenon
Partial obstruction- dyspnea,systemic embolism , fever
Severe obstruction- overt heart failure

36. Fibrinolytic therapy - Rt sided thrombosis 80-100% success rate
Surgery for fibrinolysis failure/symptoms > 3 wk
Surgery – Lt sided thrombosis, large clot burden

37. FIBRINOLYTIC PROTOCOL heart 2007;93:137-142
2 types of protocol
-rescue fibrinolysis (short protocol for unstable pt)
- long protocol for stable pt
Short protocol
- r tPA 10 mg bolus + 90 mg in 90 min or
- SK 15lac in 60 min
Long protocol
-- SK- 5lac u in 20 min f/b 15lac u for 10 hr
-- rtPA mgbolus f/b 90mg/hr for 9 hrs
Urokinase
High dose: 4,500 IU/kg/h for 12 h without heparin
Low dose: 2,000 IU/kg/h with heparin for 24 h

40. Embolisation
cerebral embolization  CT normal/infarctwarf & heparin – 72 hrs APTT lower therapeutic level till the desired INR
anticoagulantion delayed for at least 7 to 14 days - ICH, extensive cerebral infarction  OAC

41. If embolic event occurs while the patient is on adequate antithrombotic therapy
If on warfarin with INR of 2.0 to 3.0: increase dose to achieve INR of 2.5 to 3.5
If on warfarin with INR of 2.5 to 3.5: add aspirin 50 to 100 mg/d
If on warfarin with INR of 2.5 to 3.5, plus aspirin 80 to 100 mg/d: aspirin dose may also need to be increased to 325 mg/d
If on aspirin 325 mg/d: switch to warfarin with goal INR of 2.0 to 3.0

42. Excessive Anticoagulation
vit K 2.5 mg daily until the INR is acceptable
fresh frozen plasma
Human recombinant factor VIIa, 15 to 19 g/kg (INR >10.0 with bleeding)

43. Structural Failure of Bioprosthetic Valves
About 30 % of heterograft bioprosthetic valves and 10 to 20 % of homograft valves require replacement within 10 to 15 years because of structural failure
severe regurgitation due to a tear or rupture of one or more of the valve cusps
calcified and rigid valves
Rarely severe valvular stenosis

44. Structural deterioration
Higher incidence patients <40 years & with mitral prostheses
gradual onset of dyspnea and other symptoms of heart failure
Bioprosthetic-valve regurgitation or stenosis can be detected by auscultation
valve dysfunction assessed by echocardiography or catheterization

45. Failure of Bio prosthetic Valves

46. Hemolysis Incidence - 6% Subclinical intravascular hemolysis
severe hemolytic anemia uncommon & suggests paravalvular leakage due to partial dehiscence of the valve or infection
Patients with a caged-ball valve / multiple prosthetic valves have an increased incidence & severity of hemolysis.

47. Hemolysis
Pts with hemolytic anemia treated with iron & folate supplements or blood transfusion
- decreased blood viscosity & increased COP a/w anemia increase the hemolysis
Paravalvular leakage & severe hemolysis – valve replacement or repair

48. Para valvular leak
improper implantation of a valve
A heavily calcified annulus is a risk factor for paravalvular leaks -- incomplete debridement of calcium compromises both suture placement and valve seating
Active endocarditis is also a risk factor
Late paravalvular leaks are suggestive of prosthetic valve endocarditis
generally result in hemolysis
In the absence of a paravalvular leak, a normally functioning modern valve should not result in hemolysis

49. Paravalvular Regurgitation
mild or moderate paravalvular leakage - asymptomatic , may have only a mild hemolytic anemia
- can be observed carefully with serial echo
severe paravalvular leakage - usually have symptoms of heart failure or severe anemia
- should be treated with surgical repair or replacement of the valve

50. PVE (2-6%) salient features
Endovascular, microbial infection occurring on parts of a valve prosthesis or on reconstructed native heart valves , with or without implantation of an annular ring
early PVE is 5% higher in surgery during active IE
Diagnostic approach, surgical indications same

51. PVE how diff from native? PVE NVE
Early- nosocomial
Late- comm acquired
Mech prosthesis -originate from the sewing cuff /from nearby located thrombi → periprosthetic leaks, ring abscesses, invasion of adjacent tissue
Bioprosthesis infections mostly restricted to the cusps → secondary bioprosthetic failure
Staphylococci, HACEK group, fungi occur more frequently in PVE
Strepto & enterococci found more frequently in native valve endocarditis

52. vegetations larger
irreversible adhesion production of a biofilm,  inhibit the host defence mechprotects against antimicrobial Tt
Duration of Tt longer
Smaller
No such biofilm

53. Pannus Valve obstruction occurs 5-10% of mechanical valves per year
Thrombus
Pannus
mobile, somewhat less echo-dense, associated with spontaneous contrast
Pannus formation -more common in aortic position
fibrous tissue ingrowth
highly echogenic
usually firmly fixed to the valve apparatus
Pre valve jet suggests pannus

56. MCQ

57. 1. Factors favouring bioprostheses include all except a
1.Factors favouring bioprostheses include all except a. Age > 70 yrs b. Bleeding diathesis c. Combined multivalvular placement d. Poor compliance

58. 2. Which of the following favours valve repair. a. RHD b
2. Which of the following favours valve repair? a. RHD b. Endocarditis c. Extensive leaflet destruction d. MVP

59. 3. Which is the most durable mechanical prosthesis. a
3. Which is the most durable mechanical prosthesis? a. St Jude medical b. Medtronic Hall c. Starr- Edwards d. Bjork Shiley

60. 4. Indication for long term anticoagulation in aortic bioprosthesis include all except a. Prior embolic events b. Atrial fibrillation c. Ventricular tachycardia d. LV dysfunction

61. 5. 55yr male, s/p AVR for BAV , SR, good LV function, Dental prophylaxis needed, anti thrombotic therapy would be the following
Stop warf 72 hrs before procedure, restart after control of bleeding
Stop warf 72 hrs before procedure, start heparin 48hrs before procedure
Stop warf 1wk before procedure
d. Continue warf

62. 6 . Heparin alone regimen in a pregnant lady on OAC, s/p MVR , thrombo embolic complications would be
25%
33%
43%
45%

63. 7. Ideal anti thrombotic therapy in a 45 yr female, s/p MVR for RHD, with h/o embolic stroke would be the following
Warfarin INR , aspirin mg
Warfarin INR , aspirin mg
Warfarin INR , aspirin mg
Warfarin INR , aspirin mg

64. 8. Prosthetic valve thrombosis would be catastrophic in the following
Bioprosthesis
Tilting disc valve
Bileaflet valve
Starr- Edwards valve

65. 9. Mitral prostheses best assessed by
RAO cranial
RAO caudal
LAO cranial
LAO caudal

66. 10. Clinical hemolysis is maximum with
Caged ball
Bioprosthesis
Tilting disc
Bileaflet