1. 3/98medslides.com1 Aortic Valve Homografts A Cinical Perspective Michael E. Staab, MD Rick A. Nishimura, MD Joseph A. Dearani, MD Thomas A. Orszulak, MD Mayo Clin Proc 1998; 73:231-238

2. 3/98medslides.com2 Valve Prosthesis Mechanical –types: caged-ball, tilting-disk, bi-leaflet –advantage: durability –limitation: thrombogenicity Bioprosthetic –types: heterografts, homografts –advantage: short term anticoagulation –limitation: structural failure

3. 3/98medslides.com3 Mechanical Valve Prosthesis Types –caged-ball (Starr-Edwards) –tilting-disk (Medtronic-Hall) –bileaflet (St Jude) Advantage: durability (1) Limitation: thrombogenicity 1. N Engl J Med 1996;335:407-416

4. 3/98medslides.com4 Bioprosthetic Heterografts advantage –long term anticoagulation unnecessary (1) limitation: structural failure –leaflet calcification & tissue degeneration leading to valvular regurgitation –stenosis is uncommon –rate of porcine valve degeneration 26% (aortic), 39% (mitral) in 10 yrs (2) 1. N Engl J Med 1993; 329:524-529 2. Ann Thorac Surg 1990; 49:370-383

5. 3/98medslides.com5 Bioprosthetic Homografts 1956 - first aortic valve homograft was used in the descending thoracic aorta for aortic regurgitation 1962 - first sub-coronary use high incidence of post-op failure * (years) 5101520 survival rate (%)85665338 re-operation (%)22628595 * Circulation 1991; 84(suppl 3):III81-III88

6. 3/98medslides.com6 Bioprosthetic Homografts early preservation techniques –formaldehyde, chlorhexidine, propiolactone, ethylene oxide,  -irridiation, freezing at -70 o C –grafts are nonviable –high incidence of cusp rupture

7. 3/98medslides.com7 Bioprosthetic Homografts advances Improving valve durability –newer preservation techniques: cryopreservation by liquid nitrogen with low-dose antibiotics –homovital grafts (fresh unpreserved) –reduced time for graft procurement –donor rather than autopsy specimens

8. 3/98medslides.com8 Bioprosthetic Homografts University of Alabama 1981-1991 cryopreserved aortic grafts in 178 pts survival rate –91% at 1 year –85% at 8 years freedom from re-operation –95% at 8 years J Thorac Cardiovasc Surg 1993; 106:154-165

9. 3/98medslides.com9 Bioprosthetic Homografts Prince Charles Hsopital 1975-1994 cryopreserved aortic grafts in 680 pts hospital mortality 2.8% survival rate –77% at 10 year; 45% at 20 years freedom from re-operation –69% at 15 years O’Brian. Ann Thorac Surg 1996;60:S65-S70

10. 3/98medslides.com10 Homovital homografts London grafts are harvested, stored in tissue culture medium, and used in 3 days 275 grafts implanted over 13 years: 147 subcoronary, 128 aortic root no transmission of disease reported cumulative survival –85% at 10 yrs (94% in the aortic root gp) freedom from re-op: 91% in 10 yrs J Thorac Cardiovasc Surg 1995;110:186-193

11. 3/98medslides.com11 Bioprosthetic Homografts implantation techniques Freehand scalloped technique –retention of minimal donor tissue –technically challenging, require exact sizing to prevent regurgitation Cylinder technique –retention of native aortic sinuses and sinotubular junction –requires coronary reimplantation Ann Thorac Surg 1996;62:1069-1075

12. 3/98medslides.com12 Bioprosthetic Homografts implantation techniques Mayo Clinic series 1985-1994 implantation scalloped cylinder numbers59 78 late mod-sev AR26% 12% 7 yr re-op rate24.2% 11.5% Ann Thorac Surg 1996;62:1069-1075

13. 3/98medslides.com13 Bioprosthetic Homografts cylinder techniques improved outcome –maintaining the natural valve geometry and structure –ensures better aortic cusp coaptation –reduces the risk of aortic regurgitation Ann Thorac Surg 1996;62:1069-1075

14. 3/98medslides.com14 The “Ross procedure” A double valve procedure –transfer the patient’s native pulmonary valve into the aortic position –insert a homograft into the resected pulmonary position long term follow-up of 131 pts –47% survival at 20 yrs (age 11 - 52) –35% re-op (15% aortic, 10% pulmonary) Circulation 1997;96:2206-2214

15. 3/98medslides.com15 Aortic Valve Homograft complications aortic regurgitation is the major mode of graft failure –early aortic regurgitation technical factors (sizing, distortion) –late aortic regurgitation commissural malalignment, cuspal distortion, cuspal prolapse from root enlargement –cuspal deterioration is less common

16. 3/98medslides.com16 Aortic Valve Homograft endocarditis Low incidence of endocarditis affecting homografts: 6% at 15 yrs (1) Treatment of choice for prosthetic valve endocarditis (PVE) –mortality for PVE has been 20-50% –hospital mortality reduced to 8.3% with homografts in the treatment of PVE (2) 1. Ann Thorac Surg 1995;60:S65-S70 2. Semin Thorac Cardiovasc Surg 1997;11:53-61

17. 3/98medslides.com17 Aortic Valve Homograft anticoagulation Mechanical valves –risk of thromboembolism, major bleeding, stroke is approx 3% (1) with INR of 2.5-4.9 Aortic homografts –anticoagulation is unnecessary 1. N Engl J Med 1995; 333:11-17

18. 3/98medslides.com18 Aortic Valve Homograft Conclusion Advantage of not needing anticoagulation Not yet a perfect valve –Aortic regurgitaiton still occurs with modern preservation techniques –structual failure also a limitation, particularly in the young patient

19. 3/98medslides.com19 Aortic Valve Homograft Conclusion In older patients (age >60), heterografts have a relatively low rate of structural failure, the advantage of homografts is minimal Surgical expertise required; may not be available at all institutions

20. 3/98medslides.com20 Aortic Valve Homograft indications active endocarditis, particularly those with concomitant root abscess complex aortic pathology (aneurysm or dissection) when the valve is not amenable to repair or resuspension young patients (age <60) when long- term anticoagualtion is not desired or is contraindicated