Early Results of Valved Bovine Jugular Vein Conduit for Right Ventricular Outflow Tract Reconstruction

Contegra®conduit: current outcomes and concerns

A variety of congenital cardiac anomalies with severe right ventricular outflow tract (RVOT) obstruction or RVOT interruption require surgical reconstruction from the infundibulum up to the pulmonary artery bifurcation or even into the branches of the pulmonary arteries. Ideally, the conduit or valve required for such reconstruction has to be formed of autologous tissue that grows, resists infection, lasts for the life span of the patient and is readily available in all sizes. Such conduits, however, are not available and although several alternatives have been used, none of which are without potential drawbacks. Contegra valved bovine internal jugular vein conduit (Medtronic Inc., MN, USA) has recently emerged as a promising option for pediatric RVOT reconstruction and has been advocated for its 'off-the-shelf' availability in sizes ranging from 12 to 22 mm, surgical pliability and encouraging short- and mid-term success in experimental animal, as well as clinical studies. This review focuses on the current outcomes of Contegra conduit and highlights some of the major concerns related to the use of this conduit and strategies to tackle these concerns.

Contegra conduit for reconstruction of the right ventricular outflow tract: a review of published early and mid-time results

Objective

The valved conduit Contegra (bovine jugular vein) has being implanted for more than 7 years in the right ventricular outflow tract and it is noted that the available reports have been mixed. The aim of this study is to review the reported evidence in the literature.

Methods

Search of the relevant literature for the primary endpoints of operative mortality and morbidity and secondary endpoints of follow-up haemodynamic performance including severe stenosis, regurgitation and need for reintervention are presented.

Results

We selected and analysed 17 series including 767 patients. Commonest indication was Fallot's tetralogy. Operative mortality was 2.6%. Operative morbidity was 13.9%. In follow-up, the incidence of intraconduit stenosis was 10.9% (incidence of stenosis for the 12 millimetre conduit was 83.3% in one series) and that of at least moderate regurgitation was 6.3%.

The aspirin users had a stenosis incidence of 10.5% compared to the non-users had a stenosis incidence of 9.6%.

Conclusion

A dissent on the performance of the Contegra is discussed, while results are satisfactory in the majority of studies apart for the smallest conduits (12 and 14 millimetre), suggesting an association to compromised run-off. The role of aspirin as antithrombotic modulator remains controversial.

Superior vena cava reconstruction using bovine jugular vein conduit

The glutaraldehyde-treated bovine jugular vein conduit (BJVC) is a xenograft conduit initially used for right ventricular outflow tract reconstruction and has never been used for reconstruction of superior vena cava (SVC). In September 2003, a patient with SVC obstruction underwent SVC reconstruction using BJVC. He has been alive for 42 months and free from signs and symptoms of SVC obstruction except that metastasis was found in the vertebrae. The radionuclide venography showed the graft tube was patent and only slight stenosis was found in the proximal anastomosis. The initial result supports BJVC as an acceptable alternative for SVC reconstruction.

Bovine Jugular Vein Conduit for Right Ventricular Outflow Tract Reconstruction: Evaluation of Risk Factors for Mid-Term Outcome

BACKGROUND

The bovine jugular vein conduit (Contegra [Medtronic, Inc, Minneapolis, MN]) is one option for right ventricular outflow tract reconstruction. We examined the effect of patient age, conduit size, hemodynamics, and cardiac malformation on early and mid-term outcome.

METHODS

Seventy-eight bovine jugular vein implantations were performed over 5 years. Follow-up averaged 31 +/- 17 months. Risk factor and adverse event analyses for graft dysfunction were performed by multivariate logistic regression and Kaplan-Meier analysis.

RESULTS

There was no early mortality. Two late deaths occurred after 9 and 15 months. Early postoperative echocardiography revealed bovine jugular vein regurgitation greater than 2+ in 10 patients, all of which had conduit dilatation, had received a 12-mm conduit, and had a right-ventricular-to-left ventricular pressure ratio greater than 0.6. Two additional patients had severe conduit incompetence develop at the 2-year follow-up. During follow-up, mean gradients increased from 15 to 23 mm Hg (p = 0.03) and stenosis at the distal anastomosis occurred in 25% of patients. Percutaneous interventions were performed in 19 patients (24.4%). Conduit exchange was required in 10 patients (12.8%) after a mean of 14.9 months for severe graft incompetence (8 patients) and progressive supravalvular stenosis (2 patients). Freedom from reoperation was 77.6% and 59.3% at 1 and 4 years for patients less than 1 year of age compared with 93.5% and 87.4% for patients older than 1 year of age (p < 0.001). Risk factors for reoperation were age less than 1 year, correction of truncus arteriosus, conduit size of 12 mm, and persistently elevated right-ventricular-to-left ventricular pressure ratio greater than 0.6 (p = 0.001 each).

CONCLUSIONS

Bovine jugular vein implantation is associated with low reoperation and acceptable reintervention rate in patients older than 1 year of age. In infants with persistently elevated right ventricular pressure, reoperation rate was high and had to be compared with other established surgical options.