Accelerated degeneration of allografts in the first two years of life. Discussion

Between January 1988 and May 1994, 53 of 159 patients have received cryopreserved aortic and pulmonary allografts for reconstruction of the pulmonary circuit in the first 2 years of life with body weight ranging from 2.2 to 18 kg (mean, 8.2 ± 3.4 kg). The implanted allografts ranged in internal diameter from 9 to 23 mm (mean, 16.3 ± 3.5 mm). Of the 38 survivors who regularly had postoperative echocardiographic examinations 15 (39.5%) underwent cardiac catheterization 1 to 31 months after operation. Allograft dysfunction (gradient ≥50 mm Hg with or without pulmonary insufficiency) was confirmed in 9 patients leading to reoperation in 5 and valvulo-angioplasty in 4. At 48 months actuarial survival was 64%. In the aortic and pulmonary allografts freedom from wall calcification at 20 months was 19% and 100%, respectively. Freedom from valve dysfunction in patients with aortic and pulmonary allografts was 53% and 88%, respectively ; it was 49% in allografts with an internal diameter of 17 mm or smaller. Freedom from reoperation in all patients was 78%. In conclusion, young age, antigenicity (ABO compatibility), and type of allograft seemed to be independent risk factors for early allograft conduit degeneration and late valve dysfunction. Pulmonary allografts seemed to be more resistant to early wall calcification and valve dysfunction than aortic allografts.