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AVR Choice of Prosthesis

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					AVR: Choice of Prosthesis

       Tirone E. David
     University of Toronto
 AVR: Choice of Prosthesis



“The perfect heart valve substitute
    is yet to be discovered”
     AVR: Choice of Prosthesis


Mechanical valves are durable but require
life-long anticoagulation

Tissue valves do not require anticoagulation
but they are not as durable
AVR: Choice of Prosthesis

Mechanical Valves
Tissue Valves
    Bioprosthetic
          Porcine
          Pericardial
    Biological:
          Aortic homograft
          Pulmonary autograft
  AVR: Choice of Prosthesis



Does the type of heart valve prosthesis
affect patients’ survival?

Randomized clinical trials
           VA Randomized Trial
Outcomes 15 Years After Valve Replacement With a
Mechanical Versus a Bioprosthetic Valve: Final Report
of the Veterans Affairs Randomized Trial
Hammermeister K et al. - J Am Coll Cardiol 2000;36:115


Between 1977 and 1982, 394 men undergoing AVR were
randomized in the OR to receive either the Björk-Shiley
spherical disc mechanical prosthesis or a Hancock porcin
bioprosthetic valve
 VA Randomized Trial
Late Mortality After AVR

               79±3%


                   66±3%
        VA Randomized Trial
      Causes of Death After AVR

                     Björk-Shiley
 Hancock

Valve-related          37%
 41%
Cardiac-related        17%
 21%
Non-cardiac            36%
 26%
         Edinburgh Randomized Trial
Twenty year comparison of a Björk-Shiley mechanical
heart valve with porcine bioprosthesis

Oxenham H et al. – Heart 2003;89:715-21


Björk-Shiley mechanical vs. porcine bioprosthesis
        541 patients ~54±10 years of age
        211 – AVR
        261 – MVR
          61 – AVR+MVR
Edinburgh Randomized Trial
Patients’ Survival After AVR

           Survival at 20 years:
           Mechanical = 28±4%
           Bioprosthesis = 31±5%




                   All patients
        AVR: Choice of Prosthesis

• These two randomized trials used first
   generation bioprosthetic heart valves
• The mechanical valve used is no longer
  available
• Are the findings applicable to our practice
  today?
                                1st and 2nd Generation
                                Bioprosthetic Valves
                                        Hancock      Hancock II
                      100
% free from failure




                       80

                       60

                       40

                       20

                        0
                            2   4   6   8   10    12      14      16   18     20
                                             Years             Hancock - Stanford
                                                               Hancock II - Toronto
    AVR: Choice of Prosthesis



Does the type of heart valve prosthesis
 affect patients’ survival?

Retrospective clinical studies
        AVR: Choice of Prosthesis

Twenty-year comparison of tissue and mechanical
valve
replacement
Khan S et al - J Thorac Cardiovasc Surg
 AVR:
2001;122:257-69

666 patients with mechanical ~ 64 years of age
725 patients with bioprosthesis ~72 years of age
AVR: Mechanical vs Bioprosthesis
       Patients’ Survival




                 JTCVS 2001;122:257-69
       AVR: Choice of Prosthesis
Aortic valve replacement in patients aged 50 to 70
years: Improved outcome with mechanical versus
biologic prostheses
Brown ML, Schaff HV, et al – JTCVS
2008;135:878-84
  1990 to 2000:
  510 St. Jude +/- CABG and 257 CE +/-
  CABG

  Matched 1:1 - age, gender, CABG, valve
  size:
                 220 in each group
          AVR: Choice of Prosthesis

                              Mechanical   Porcine   p value
Operative mortality             1.8%        5.5%      0.04

10-year events:
Survival                         72%        50%      0.01
Freedom from redo AVR            97%        91%      0.1
Incidence of major bleeding      14%          6%     0.06

Follow-up 92% complete
Same proportion of cardiac deaths (heart + valve)
                                     JTCVS 2008;135:878-
                                     8
        AVR: Choice of Prosthesis
Risk-corrected impact of mechanical versus
bioprosthetic valves on long-term mortality after
aortic valve replacement
Ole Lund and Martin Bland – JTCVS
2006;132:20-6
                              Mechanical
Bioprosthetic
Number of articles              15                23
Number of patients            8,578             8,861
Mean age in years                58               69
CABG                             16%
34%
Endocarditis                       7%
2%
Overall death/year               3.99%
        AVR: Choice of Prosthesis
 Risk-corrected impact of mechanical versus
 bioprosthetic valves on long-term mortality after
 aortic valve replacement
 Ole Lund and Martin Bland – JTCVS
 2006;132:20-6
RESULTS:
• Patients’ mean age was directly related to death rates
  with no interaction with valve type.
• Death rate corrected for age, NYHA classes III and IV
  AI, and CABG and no interaction with valve
• No differences in rates of thromboembolism.
       AVR: Choice of Prosthesis

Conventional wisdom:

 Survival after AVR is not affected by the
 type of aortic valve prosthesis
       AVR: Choice of Prosthesis


• Are valve-related complications dependent
  on the type of heart valve prosthesis?
           VA Randomized Trial
        AVR: Morbid Events at 15 years
                                 Björk-Shiley    Hancock    p
value

Any valve-related complication   65±4%      66±5%          0.26
Systemic embolism                 18±4%     18±4%          0.66
Bleeding                           51±4%      30±4%
0.0001
Valve thrombosis                   2±1%         1±1%
0.33
Endocarditis                        7±2%        15±5%
0.45
Perivalvular regurgitation         8±2%         2±1%
0.09
Reoperation                        10±3%        29±5%
0.004
Primary valve failure              0±0%         23±5%
             AVR: Choice of Prosthesis
Performance of bioprostheses and mechanical prostheses
Assessed by composites of valve-related complications to
15 years after aortic valve replacement
V. Chan, WRE Jamieson et al. – J TCVS 2006;131:1267-73


              Study end-points:
              • Valve-related mortality
              • Valve-related morbidity
              • Valve-related reoperation
       Mechanical vs. Bioprosthesis
Freedom from valve-related reoperations 51-60 years




                                  JTCVS 2006;131:1267-73
       Mechanical vs. Bioprosthesis
Freedom from valve-related reoperations 61-70 years




                                 JTCVS 2006;131:1267-73
      Mechanical vs. Bioprosthesis
Freedom from valve-related reoperations >70 years




                                 JTCVS 2006;131:1267-73
Performance of bioprostheses and mechanical prostheses
Assessed by composites of valve-related complications to
15 years after aortic valve replacement
V. Chan, WRE Jamieson et al. – J TCVS 2006;131:1267-73


 Conclusion:

 No differences were observed in valve-related reoperation and
 mortality in patients >60 years. Comparative evaluation gives
 priority for bioprostheses in patients >60 years based on improved
 morbidity profile.
           AVR: Hancock II
      Freedom from Failure by Age
                                                 <65 yrs     >65 yrs
               100
                                                                            ±
                80
                               Age          10 yr      15yr
                60             <65y        94 ± 2     72 ± 5
Percent free
                40             >65y        99 ± 1     99 ± 1
                         Pts at risk
                20       306               250                 162                   61
                         704               442                 202                   25
                 0
                     0          2      4         6     8       10      12       14        16
                                                     Years
           Quality of Life
      Mechanical vs Bioprosthesis
“Quality of life in patients with biological and mechanical
prostheses. Evaluation of cohorts of patients aged 51 to 65
years at implantation” - Perchinsky et al. Circulation
1998;98:II-81-87.
Study design:
QOL in age and sex matched patients with
mechanical and biological valve and
general population
SF-12 form & Lamy Smiley Faces form
             Quality of Life
        Mechanical vs Bioprosthesis
• Patients with mechanical valves were troubled
  with noise, bleeding and blood tests (p<0.01)
• Patients with bioprosthesis were troubled with
  prospect of reoperation (p<0.01)
• No difference in fear of valve failure
• QOL similar in both groups and general
  population
• 97% would make the same choice of valve
                    Perchinsky et al. Circulation 1998
            Quality of Life
       Mechanical vs Bioprosthesis


Conclusions:
• Human beings are resilient and adaptable

• Most patients with prosthetic heart valves
  are well adjusted to their condition
      AVR: Choice of Prosthesis

• Patients’ age is probably the most important factor in
  recommending tissue or mechanical valve
• Bioprosthetic valves are ideally suitable for older
  patients (>70 years) or those who are not likely to
  outlive the valve (co-morbidities)
• Mechanical valves should be recommended to
  younger patients (<60 years)
• If anticoagulation is a perceivable problem, tissue
  valves can be used in younger patients but the
  probability of reoperation is high

				
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posted:5/6/2011
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