title: Early failure of xenogenous de-cellularised pulmonary valve conduits--a word of caution!
abstract: OBJECTIVE
  The longevity of valved right ventricle to pulmonary artery (RV-PA) conduits is limited due to calcification and degeneration of non-viable structures. Xenografts are commonly used because of the restricted availability of cryopreserved homografts. Tissue-engineered (de-cellularised) pulmonary valves (TEPVs) were thought to be a valuable alternative to cryopreserved pulmonary homografts due to postoperative seeding with viable autologous vascular endothelial cells.
  
  
  METHODS
  From July 2007 to December 2008, xenogenous TEPV (Matrix P plus) were implanted in 16 patients in the right ventricular outflow tract for different indications, related to congenital heart disease. Mean age at operation was 14+/-11 years, including three patients younger than 1 year. The median conduit size was 22 mm (range: 13-26 mm).
  
  
  RESULTS
  The early and late survival rates were 100%. At a median follow-up of 10 months (range: 2-17 months), six patients (38%) had to be re-operated upon due to obstructed grafts. Five of these patients were older than 13 years (range: 13-26 years); one patient was younger than 1 year. On echocardiography before re-operation, mean systolic gradient in the main PA was 66+/-18 mmHg. In explanted conduits, we found a predominantly peripheral conduit narrowing without leaflet calcification. Histological examination revealed stenosis formation, due to inflammatory infiltration and severely fibrogenic pseudo-intimal reaction.
  
  
  CONCLUSIONS
  On the basis of our short-term results, the Matrix P plus de-cellularised tissue-engineered pulmonary valve cannot be regarded as an ideal conduit for right ventricular outflow tract reconstruction, as the widespread use of these grafts may increase the possibility of frequent early conduit failures.
authors.affiliation: Department for Pediatric Cardiac Surgery, University Hospital Erlangen, Erlangen, Germany. andre.rueffer@uk-erlangen.de
authors.forename: André
authors.initials: A
authors.lastname: Rüffer
authors.forename: Ariawan
authors.initials: A
authors.lastname: Purbojo
authors.forename: Iwona
authors.initials: I
authors.lastname: Cicha
authors.forename: Martin
authors.initials: M
authors.lastname: Glöckler
authors.forename: Sergej
authors.initials: S
authors.lastname: Potapov
authors.forename: Sven
authors.initials: S
authors.lastname: Dittrich
authors.forename: Robert Anton
authors.initials: RA
authors.lastname: Cesnjevar
mesh_terms: D000293:Adolescent; D000328:Adult; D001705:Bioprosthesis; D002648:Child; D002675:Child, Preschool; D005260:Female; D005500:Follow-Up Studies; D006330:Heart Defects, Congenital / Q000601:surgery*; D006350:Heart Valve Prosthesis; D006352:Heart Ventricles / Q000601:surgery; D006801:Humans; D007223:Infant; D008297:Male; D011475:Prosthesis Failure; D011664:Pulmonary Valve / Q000473:pathology / Q000637:transplantation*; D012086:Reoperation; D016019:Survival Analysis; D023822:Tissue Engineering; D014183:Transplantation, Heterologous; D055815:Young Adult