Early and late failure of tissue-engineered pulmonary valve conduits used for right ventricular outflow tract reconstruction in patients with congenital heart disease.

Objectives: To identify factors associated with the surgical outcome in patients undergoing right ventricular outflow tract reconstruction (RVOTR) using decellularized tissue-engineered pulmonary valve conduits (TEPVc) and to study their safety and longevity.

Methods: From April 2006 to April 2010, 93 patients underwent either palliative or corrective RVOTR using Matrix P (37) and Matrix P Plus (56) xenogenic decellularized TEPVc (size range 11-27 mm). Median age and weight at operation were 20 (0.16-290) months and 10.15 (2.65-86) kg respectively. Primary and redo surgery occurred in 40 and 60% of cases, respectively. Eighty-eight patients (94.6%) received conduit implantation in the framework of corrective surgery, whereas in 5 (5.4%) a palliative procedure was undertaken. Follow-up was complete in 91% of patients, with a median duration of 12 months (range: 2 days-51 months). Data analysis included diagnosis, type of surgery (palliative vs. corrective) and age at surgery. Predetermined primary outcomes were represented by conduit failure or dysfunction.

Results: Two patients with Matrix P and two with Matrix P Plus died in the early post-operatively phase (4.3%). None of the deaths were conduit-related. One patient died at conduit replacement. Thirty-three patients (35.5%) experienced conduit failure whereas conduit dysfunction occurred in 27 patients (29%). Two-year freedom from conduit failure and dysfunction was 60.2% (95% CI: 50.1-69.6) and 77.4% (95% CI: 67.9-84.7), respectively. Reasons for failure were conduit stenosis in 20 cases (61%), pseudoaneurysm in 3 (9%), conduit dilatation (>50% of original diameter) in 2 (6%), stenosis of distal anastomosis involving pulmonary bifurcation in 6 (18%) and allograft dissection in 2 (6%). Histological examination showed inflammatory giant-type cells in the presence of a poor autologous cell seeding in all explanted specimens. Univariate and multivariate analyses showed an association between age at surgery ≤1 year and conduit dysfunction (adjusted HR: 2.29; 95% CI: 1.01-5.20, P = 0.04).

Conclusions: Compared with the other conduit for RVOTR Matrix conduits showed a high incidence of failure. Our results suggest that the use of Matrix conduits for RVOTR should be considered with caution.