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Abstract
Background
Cardiovascular repair in children often requires implant of conduits which do not have growth potential and will require reoperation. In the current study we sought to determine the feasibility of catheter-based interventions of anisotropic conduits inserted as interposition grafts in the main pulmonary artery (MPA) of growing lambs.
Methods
Lambs underwent interpositional implant of either an anisotropic expanded polytetrafluoroethylene (ePTFE) (Test) conduit or conventional PTFE (Control) conduit. In the postoperative period, lambs were anesthetized and underwent catheter-based interventions consisting of hemodynamic and angiographic data collection, balloon dilation and/or stenting of the conduit at 3, 6 or 9 month postoperative time point.
Results
At 3 months, control lambs showed significant increases in right ventricular pressures and trans-conduit gradients in comparison to test lambs. Test conduit diameters were significantly larger compared to controls due to spontaneous radial expansion of the anisotropic conduit. Balloon dilation of test conduits at 3 and 6 months showed a reduction in RV pressure and statistically significant improvement in the RV outflow tract gradient as well as significant increase in graft diameter, compared to both control and pre-dilation conditions. Furthermore, the test conduit diameter increased significantly compared to the pre-balloon and control conditions at each time point. Necropsy of test conduits showed no evidence of tears, perforations, or clot and smooth interiors with well-healed anastomoses.
Conclusions
Anisotropic conduits implanted as interposition grafts in the MPA show spontaneous expansion, and can safely and effectively undergo catheter-based interventions, with significant increases in graft diameter occurring after balloon dilation.
Acknowledgements
We thank Steff Yorek, Sally Brinkman, Peggy Norris, Gwen Kocher, Jennifer Orloske and the UMN Experimental Surgical Services Laboratory staff and students with their help in conducting the animal experiments; the UMN Research Animal Resources staff for their care and support of the research animals used in this study; Melanie Graham for her help with the editing process.
Disclosure statement
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article. The data that support the findings of this study are available from the corresponding author, JPC, upon reasonable request.