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Degeneration of aortic valve allografts in young recipients
D R Clarke1, D N Campbell, A R Hayward
1Childrens Hospital, Denver, Colo. 80218.
Insights
Cryopreserved aortic valve allografts show high rates of degeneration in young children (<3 years) undergoing left ventricular outflow tract reconstruction. This suggests exploring alternative strategies for this patient group.
Area of Science:
- Cardiovascular Surgery
- Pediatric Cardiology
- Transplantation Immunology
Background:
- Aortic allograft fibrocalcification and valvular insufficiency are concerns in young patients (<3 years) after left ventricular outflow tract reconstruction.
- Cryopreserved aortic valve allografts have been used for aortic root replacement in children.
Purpose of the Study:
- To evaluate the long-term outcomes of cryopreserved aortic valve allografts in pediatric patients undergoing aortic root replacement.
- To compare outcomes between younger (<3 years) and older (≥3 years) pediatric patient groups.
Main Methods:
- Retrospective analysis of 47 children undergoing aortic root replacement with cryopreserved aortic valve allografts (June 1985-May 1992).
- Patients divided into two groups: <3 years (n=14) and ≥3 years (n=33) at operation.
- Clinical follow-up assessed for mortality, reoperation, allograft degeneration, and calcification.
Main Results:
- In younger children (<3 years), hospital mortality was 21% (3/14), and 70% (7/10) of survivors experienced progressive allograft calcification or insufficiency, requiring reoperation in 6.
- In older children (≥3 years), hospital mortality was 9% (3/33), with 7% (2/29) requiring reoperation for reasons other than primary allograft degeneration.
- Possible immunologic causes for allograft failure in younger children are suggested.
Conclusions:
- Cryopreserved aortic valve allografts demonstrate a high prevalence of early degeneration in children <3 years old.
- Alternative strategies such as nonviable allografts, xenografts, pulmonary autografts, or minimal immunosuppression should be considered for this age group.
- Further research into the immunologic aspects of allograft failure is warranted.
Abstract:
Aortic allograft fibrocalcification and valvular insufficiency have been observed in patients less than 3 years of age at initial replacement of the left ventricular outflow tract. From June 1985 through May 1992, 47 children have undergone aortic root replacement with cryopreserved aortic valve allografts. Thirty-three children were 3 years of age or older and 14 were less than 3 years of age at operation. In the older patient group, there were three (9%) hospital deaths and one child underwent cardiac transplantation 30 hours after aortic root replacement because of left ventricular failure. Clinical follow-up of the 29 surviving older children is from 4 months to 6.6 years (mean 3.0 years). One patient was lost to follow-up. Two children (7%) have required reoperation, but primary allograft degeneration was not observed. In the younger patient group, there were three (21%) hospital deaths. Follow-up ranged from 2.5 months to 4.7 years (mean 2.3 years). Among 11 operative survivors, one late death resulted from a pulmonary embolus. Seven of 10 (70%) remaining allograft recipients had progressive allograft calcification or insufficiency. Six of them have required reoperation to explant the allograft, and one child is currently receiving cyclosporine therapy with the original valve allograft. The cause of allograft failure is possibly immunologic. The prevalence of early aortic valve allograft degeneration has prompted the consideration of nonviable allografts or xenografts, pulmonary autografts, or minimal immunosuppression as alternatives when left ventricular outflow tract reconstruction is necessary in children less than 3 years of age.