Aortic Arch Reobstruction after the Norwood Operation using Pulmonary Allografts and ADPAT Treated Bovine Pericardium

Objectives: Aortic arch reconstruction during the Norwood operation almost always requires patch material. Reasons for arch reobstruction are still a matter of international debate. So far, pulmonary allografts demonstrated superior results in Norwood type reconstructions compared with other patch material. Unfortunately, the shortage of allografts represents a major challenge. Therefore, a suitable alternative is sought for. So, we studied in a retrospective analysis the incidence of aortic arch reobstruction in patients with Norwood type operations using pulmonary allografts compared with ADAPT treated bovine pericardium (CardioCel Admedus).

Methods: From 01/2014 to 06/2017, eighty-seven consecutive patients undergoing the Norwood operation were studied. Pulmonary allografts (n = 62, group A) and CardioCel patches (n = 25, group B) were chosen at surgeon's preference. At follow up an invasive peak to peak gradient ≥ 20 mmHg defined significant reobstruction. Consecutively, a balloon angioplasty or stent implantation was performed. Reoperation was undertaken in cases with persisting gradient ≥ 20 mmHg. Specimens were sent for histology. Survival, freedom from catheter intervention or reoperation was analyzed using the Kaplan-Meier method.

Results: Mean follow up was 17 ± 13 months. There was no difference regarding age, weight and gender among groups. No patch related mortality and morbidity except aortic arch reobstruction occurred. Survival was similar in both groups at 6, 12 and 24 months (A: 86, 86 and 84%; B: 84, 84, and 84%; p = 0.97). Freedom from catheter intervention was also not significantly different at 6, 12 and 24 months (A: 76, 76 and 76%; B: 84, 80 and 80%, p = 0.65). However, freedom from reoperation was significantly higher in group A (97, 97 and 97%; p = 0.04) compared with 88, 88 and 84% in group B. Histology of four explanted CardioCel patches confirmed very dense neo-adventitial and pseudointimal proliferation with marked collagen fiber formation compared with one explanted pulmonary homograft segment showing only some pseudointima and calcification.

Conclusions: The CardioCel patch provides a reasonable alternative to pulmonary allografts in this challenging patient cohort. Most of the reobstructions occurred within the first 6 months after implantation. Diminished elasticity and marked intima proliferation of the remodeled CardioCel structure impedes successful catheter intervention and therefore requires reoperation more frequently.