Methods: Since August 2000, TE grafts seeded with autologous BMCs have been implanted in thirty-five patients. The patients and/or their parents were fully informed and had given consent to the procedure. Five ml/kg of bone-marrow was aspirated under general anesthesia prior to the skin incision. The polymer tube serving as a scaffold for the cells was composed of a co-polymer of l-lactide and ε-caprolactone (PCL-PLA, 50:50). This co-polymer is degraded by hydrolysis. The matrix is > 80% porous and the diameter of each pore is 100-200 µM Polyglycolic acid (PGA) woven fabric with a thickness of 0.5 mm was used for reinforcement. Twenty-one TE conduits (TCPC grafts) and fourteen TE patches were used for the repair of congenital heart defects. The patients' ages ranged from 1 to 24 years (median, 5.5 years). All patients underwent a catheterization study and/or computed tomography (CT) scans for evaluation after operation. The patients received anticoagulation therapy for 3 to 6 months after surgery.

Results: Mean follow-up after surgery was 424 days (maximum, 38 months). There were no complications such as thrombosis, nor stenosis or obstruction of the tissue-engineered autografts. One late death at 3 months after TCPC was noted in HLHS patients, which was unrelated to the TE graft. There was no evidence of aneurys formation on cineangiography or CT. On examination in late period, all tube grafts were patent, and the diameter of the tube graft increased over time. (110 +/- % of the implanted size)

Conclusions: Biodegradable conduits or pulmonary vessel patches seeded with autologous BMCs showed normal function (good patency up to maximum follow-up of 38 months). As living tissues these vessels may have the potential for growth, repair and remodeling. The TE approach may provide an important alternative to the use of prosthetic materials in the field of pediatric cardiovascular surgery. Longer follow-up is necessary to confirm the feasibility of this approach.