Early results of right ventricular-pulmonary artery conduits in patients under 1 year of age

Objectives: Management strategies for the repair of many complex heart defe cts require the implantation of a valved conduit between the right ventricl e (RV) and the pulmonary artery (PA), often using aortic or pulmonary homog raft valves. Their limited availability, however, has led to the developmen t and use of new conduits. We retrospectively compared our experience with small homografts in patients of less than 1 rear of age with the TissueMed( TM) bioprosthetic valved conduit, Methods: From March 1994 to November 1997 29 patients in their first year of life underwent conduit implantation for complex heart defects. These were retrospectively reviewed in order to det ermine the incidence of death or conduit stenosis. Seventeen patients recei ved homografts and 12 TissueMed(TM) conduits. Results: Diagnoses and operat ive details including conduit size were similar in the two groups and in al l cases complete repair of the underlying defect was carried out. Early pos t-operative mortality was 4/17 (23.5%) in the homograft group and 3/12 (25% ) in the TissueMed(TM) group. Echo Doppler evaluation within 1 month of ope ration showed no right ventricular outflow tract (RVOT) obstruction in any of the survivors. In the TissueMed(TM) group 8/9 (77%) survivors have gone on to develop significant RVOT obstruction within 12 months of operation. T here have been three fate deaths in this group all related to severe RVOT o bstruction. Two patients died during an attempt at balloon dilatation and o ne patient died of progressive right heart failure. Five patients had succe ssful replacement of the TissueMed(TM) conduit. One child remains wen with no evidence of RVOT obstruction. At operation to replace conduit, or at aut opsy, the stenoses were related to the deposition of fibrous tissue at the anastomotic suture lines. In the homograft group none of the survivors deve loped RVOT obstruction during the first 12 months post-operatively. There w as one late death (non-cardiac in origin) and one child is awaiting conduit replacement 40 months after initial implantation for obstruction. Conclusi ons: The homograft is a satisfactory conduit for re-establishment of RV-PA continuity in infancy. Further work needs to be undertaken in order to eluc idate the mechanisms of early graft failure in bioprosthetic conduits if th ese are to be a suitable alternative for RV outflow reconstruction in infan ts. (C) 2001 Elsevier Science B.V. All rights reserved.