Anisotropic Polytetrafluoroethylene Cardiovascular Conduits Spontaneously Expand in a Growing Lamb Model

Abstract

Background

Insertion of conduits from the right ventricle (RV) to the pulmonary artery (PA) is a commonly used technique for repair of congenital heart defects. The vast majority of infants and children will require reoperation and/or re-intervention to replace the conduit. Some children may require multiple reoperations, with the risk of death and morbidity increasing significantly with each subsequent operation. We evaluated the feasibility and performance of a relatively novel anisotropic conduit for cardiovascular repair in the growing lamb model.

Materials and Methods

Lambs were allocated into a control (n = 3) or test (n = 4, anisotropic) conduit group. Control conventional polytetrafluoroethylene (PTFE) conduits or test anisotropic expanded PTFE (ePTFE) based test conduits measuring 10–11 mm in diameter were sewn as interpositional grafts in the main pulmonary artery (MPA) and followed up to 6 months. Clinical and echocardiographic evaluations were performed monthly with hemodynamic and angiographic assessment at 3 and 6 months.

Results

Control conduits did not expand, all 3 animals developed one or more adverse events including tachypnea, ascites, inappetence, lethargy, and mortality due to severe right heart failure and significantly higher peak trans-conduit gradients (48.5 ± 5.1 p = 0.02). The test conduits spontaneously expanded up to 14.8 ± 0.8 mm in diameter, no adverse events were observed in any animals and trans-conduit gradients were significantly lower (27.0 ± 8.3, p = 0.02).

Conclusions

Anisotropic ePTFE conduits can be safely implanted in growing lambs with stable hemodynamics. This spontaneously expanding anisotropic conduit may represent a novel approach to congenital heart repairs that would avoid the need for reoperation or multiple operations.

Keywords:

• Growing lamb model
• conduits
• congenital heart defects
• cardiac surgery
• cardiovascular repair
• heart

Acknowledgment

We thank 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; Gurumurthy Hiremath for interventional cardiology expertise and helpful discussions.

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.

Additional information

Funding

This work was funded by the Fred C. & Katherine B. Andersen Foundation.