Mode of Failure of a Composite Stentless Conduit for RV-PA Connection in Infant Heart Surgery: Histomorphological and Surgical Considerations

Objectives: Bioprosthetic valved conduits for reconstruction of the right ventricular outflow tract (RVOT) are commonly used because of cryopreserved homograft shortage. The longevity of xenogenic right ventricle to pulmonary artery (RV-PA) conduits is limited due to multiple reasons. In this study, we evaluated short- and mid-term results of a composite stentless conduit for RVOT surgery in infant heart surgery.

Methods: Between 2014 and 2015, 19 patients (58% males; mean age 7 ± 7 years, range: 2 months–18 years) underwent reconstruction of the RVOT for different congenital heart pathologies by implantation of a composite stentless conduit (Labcor, Laboratorios Ltda, Belo Horizonte, Brazil). The median conduit size was 16 mm (range: 11–23 mm). Patients were prospectively followed up clinically and echocardiographically.

Results: Overall survival rates and follow-up of patients was 100%. Seven patients (37%) required reoperation due to degeneration of the RV-PA conduit at a mean follow-up of 12 months (range: 4–20 months). Echocardiographic examination before reoperation showed a mean systolic gradient in the main pulmonary artery of 68 ± 18 mm Hg. Histological examination demonstrated inflammatory infiltration (CD3⁺, CD8⁺, CD15⁺, CD34⁺, CD68⁺ cells) and fibrogenic pseudointimal reaction and concomitant stenosis formation. In explanted composite stentless conduits, a predominantly peripheral conduit narrowing without leaflet calcification was present.

Conclusions: Based on our short-term results, this composite stentless valve for reconstruction of the RVOT cannot be recommended as an ideal conduit in infant heart surgery, as the widespread use of these conduits may increase probability of frequent and early conduit failure.

No conflict of interest has been declared by the author(s).