Downsized cryopreserved and standard-sized allografts for right ventricular outflow tract reconstruction in children

OBJECTIVES: The objective of this study was to determine long-Term results with bicuspidalized allografts compared to nonbicuspidalized allografts in children under 2 years undergoing primary correction of the right ventricular outflow tract.
METHODS: Thirty-five consecutive bicuspidalized allografts were compared to 45 consecutive non-bicuspidalized allografts implanted during the same period. Valve-related events were analysed with Kaplan'Meier and Cox-regression techniques. Mixed-effects modelling was used to analyse serial echocardiographic measurements of pulmonary gradient. In addition, a systematic review with meta-Analysis of the published literature concerning implantation of bicuspidalized allografts was performed.
RESULTS: Perioperative characteristics and in-hospital mortality [bicuspidalized 5 (14.3%), non-bicuspidalized 6 (13.3%)] were comparable (P = 0.902). Bicuspidalized allografts were smaller (14.7 vs 16.5 mm, P = 0.023) and always (100%) of pulmonary origin compared to 26 (57.8%) of the standard-sized allografts. There were no differences in late mortality between the bicuspidalized and non-bicuspidalized group (6.7% vs 7.7%, P = 0.798) or freedom from allograft replacement at 10 years (82 ± 10% and 71 ' 8%, for bicuspidalized and nonbicuspidalized allografts, respectively). Evolution of peak pulmonary gradient (P = 0.273) was comparable between bicuspidalized and non-bicuspidalized allografts. Meta-Analysis showed a pooled early and late mortality for bicuspidalized allograft patients of 10.72% [95% confidence interval (CI) 6.13'18.75] and 1.6% per year (95% CI 0.99'2.79), respectively. Pooled estimated late reintervention and replacement rates were 5.94% per year (95% CI 3.42'10.30) and 3.78% per year (95% CI 2.69'5.32), respectively.
CONCLUSIONS: Bicuspidalization seems to be a viable alternative to combat limited supply of small-sized allografts with acceptable survival and reintervention rates comparable to non-bicuspidalized allografts.