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

AVR: Choice of Prosthesis

Tirone E. David

University of Toronto


“The perfect heart valve substitute

is yet to be discovered”


Mechanical valves are durable but require life-long anticoagulation

Tissue valves do not require anticoagulation but they are not as durable


Mechanical Valves

Tissue Valves

Bioprosthetic Porcine

Pericardial

Biological:Aortic homograft

Pulmonary autograft


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 TrialHammermeister K et al. - J Am Coll Cardiol 2000;36:1152-8

Between 1977 and 1982, 394 men undergoing AVR wererandomized in the OR to receive either the Björk-Shiley spherical disc mechanical prosthesis or a Hancock porcinebioprosthetic valve

VA Randomized TrialLate Mortality After AVR

79±3%

66±3%

VA Randomized TrialCauses of Death After AVR

Björk-Shiley Hancock

Valve-related 37% 41% Cardiac-related 17% 21% Non-cardiac 36% 26% Undetermined 10% 12%

Edinburgh Randomized Trial

Twenty year comparison of a Björk-Shiley mechanicalheart 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 TrialPatients’ Survival After AVR

All patients

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


• 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

0

20

40

60

80

100

2 4 6 8 10 12 14 16 18 20

Years

% f

ree

from

fai

lure

Hancock Hancock II

Hancock - StanfordHancock II - Toronto


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

Retrospective clinical studies

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

666 patients with mechanical ~ 64 years of age725 patients with bioprosthesis ~72 years of age


AVR: Mechanical vs Bioprosthesis

Patients’ Survival

JTCVS 2001;122:257-69

Aortic valve replacement in patients aged 50 to 70 years: Improved outcome with mechanical versus biologic prosthesesBrown 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



Mechanical Porcine p valueOperative mortality 1.8% 5.5% 0.04

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

Follow-up 92% completeSame proportion of cardiac deaths (heart + valve)

JTCVS 2008;135:878-8

Risk-corrected impact of mechanical versus bioprosthetic valves on long-term mortality after aortic valve replacementOle Lund and Martin Bland – JTCVS 2006;132:20-6 Mechanical BioprostheticNumber of articles 15 23Number of patients 8,578 8,861Mean age in years 58 69 CABG 16% 34% Endocarditis 7% 2% Overall death/year 3.99% 6.33%


Risk-corrected impact of mechanical versus bioprosthetic valves on long-term mortality after aortic valve replacementOle 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.



Conventional wisdom:

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


• Are valve-related complications dependent on the type of heart valve prosthesis?

VA Randomized TrialAVR: 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% 0.0001Valve thrombosis 2±1% 1±1% 0.33 Endocarditis 7±2% 15±5% 0.45Perivalvular regurgitation 8±2% 2±1% 0.09 Reoperation 10±3% 29±5% 0.004 Primary valve failure 0±0% 23±5% 0.0001

Study end-points:• Valve-related mortality• Valve-related morbidity• Valve-related reoperation

Performance of bioprostheses and mechanical prosthesesAssessed by composites of valve-related complications to15 years after aortic valve replacementV. Chan, WRE Jamieson et al. – J TCVS 2006;131:1267-73


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. BioprosthesisFreedom from valve-related reoperations >70 years

JTCVS 2006;131:1267-73

Conclusion:

No differences were observed in valve-related reoperation and mortality in patients >60 years. Comparative evaluation givespriority for bioprostheses in patients >60 years based on improvedmorbidity profile.

Performance of bioprostheses and mechanical prosthesesAssessed by composites of valve-related complications to15 years after aortic valve replacementV. Chan, WRE Jamieson et al. – J TCVS 2006;131:1267-73

AVR: Hancock IIFreedom from Failure by Age

0

20

40

60

80

100

0 2 4 6 8 10 12 14 16

Years

Percent free

<65 yrs >65 yrs

Pts at risk306 250 162 61

704 442 202 25

±

Age 10 yr 15yr <65y 94 ± 2 72 ± 5 >65y 99 ± 1 99 ± 1

Quality of LifeMechanical 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


• 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


Conclusions:

• Human beings are resilient and adaptable

• Most patients with prosthetic heart valves are well adjusted to their condition


• 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

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

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