Can pulmonary conduit dysfunction and failure be reduced in infants and children less than age 2 years at initial implantation?

OBJECTIVES

We sought to examine risk factors for pulmonary conduit failure or dysfunction in infants less than age 2 years at initial implantation.

METHODS

From 2002 to 2005, 241 children at 17 institutions were discharged alive after initial pulmonary conduit insertion. Initial conduit type was pulmonary allograft in 37%, aortic allograft in 29%, bovine jugular venous valved conduit in 25%, porcine heterograft in 2%, and decellularized allograft in 7%. Parametric hazard analysis determined time-related prevalence and associated risk factors for pulmonary conduit intervention and explantation. Serial echocardiographic measurements after conduit implant were analyzed by mixed regression models.

RESULTS

There were 89 first conduit-related interventions after discharge and 37 initial conduit explants were performed. First conduit intervention occurred at a constant rate, with a prevalence of 58% at 3 years from initial implant. Pulmonary conduit explantation (30% at 3 years) was characterized by an early-rising risk, suggesting that catheter-based intervention effectively blunts this early initial risk. Common risk-factors for first conduit intervention and explantation were smaller conduit Z-score and younger age at initial conduit implant, and the presence of pulmonary arborization abnormalities or stenoses. Pulmonary conduit peak gradient and regurgitation progressed nonlinearly in all patients over time. Gradient progressed more rapidly in children with aortic allografts and when initial conduit Z-score was less than +1 or more than +3. Pulmonary conduit regurgitation also progressed more rapidly in children with initial conduit Z-score greater than +3 and in those without jugular venous valved conduits, especially aortic allografts.

CONCLUSIONS

Pulmonary conduit durability and hemodynamic function in patients undergoing initial conduit insertion at less than age 2 years can be improved by using pulmonary conduits with Z-scores between +1 and +3.