Right Ventricular Outflow Tract Reconstruction Using Contegra (R) Valved Conduit: Natural History And Conduit Performance Under Pressure

Objective: To assess the performance of the bovine Contegra((R)) valved conduit used for right ventricular (RV) outflow tract reconstruction, particularly in relation to post-operative RV pressure. Methods: Follow-up study of 64 consecutive right ventricular to pulmonary artery-conduit implants in 62 patients between January 2000 and April 2003. The majority of cases were forms of pulmonary atresia/VSD (n = 24, 39%) or Fallot's tetralogy (n = 13, 21%). Thirteen cases (21 %) had aortic atresia, truncus arteriosus or discordant connections with pulmonary atresia/VSD. Twelve cases (19%) were conduit replacements. Echocardiography was performed for a median follow-up of 14 months (range 0-38 months). Results: Median age at implantation was 13.8 months (range 0.1-244 months) and median weight was 8.9 kg (range 2.1-84.1 kg). Thirty-eight patients (59.4%) were < 10 kg at the time of surgery. Early mortality was 6.4% (n = 4). During follow-up there were four explantations (one for endocarditis and three for conduit dilatation) and 16 (28.6%) catheter interventions. Overall freedom from intervention at 1 and 3 years was 71 +/- 6% and 53 +/- 11 %, respectively. Freedom from conduit-specific reintervention was 66 +/- 11% at the end of the study period. Reintervention was associated with small conduits (p = 0.04), age < 1 year (p = 0.04) and with high RV/LV pressure ratio in the immediate post-operative period (p = 0.0003). On multivariate analysis, the RV/LV pressure ratio was the strongest single factor predicting the overall reintervention (OR 5.45). Acquired distal conduit stenosis at suture tine was the commonest indication for conduit-specific reintervention and was associated with the smaller conduits. The conduits explanted for dilatation showed neointimal proliferation, thrombosis, calcification and chronic inflammation. Conclusions: The Contegra conduit is widely applicable to RVOT reconstruction with satisfactory mid-term results. However, there is a significant incidence of conduit-retated complications, particularly with the smaller conduits. Adverse performance was strongly associated with high RV/LV pressure ratio at completion of surgery. We would recommend cautious use of the conduits in patients with predicted high RV/LV pressure ratios, where careful monitoring of conduit performance is crucial. There is some element of unpredictabitity, which adds to the importance of close follow-up. Further studies are needed to explore the issues of thrombogenicity, degeneration, possible 'rejection', and the potential rote of anti-platelet and anti-inflammatory modulation. +/- 2006 Elsevier B.V. All rights reserved.