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

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. 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. 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). 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.