Valved bovine jugular venous conduits for right ventricular to pulmonary artery reconstruction.

Abstract

Various valved and nonvalved external right ventricle (RV) to pulmonary artery (PA) conduits have been used to palliate congenital heart anomalies. The ideal conduit has not been found. Reasons for conduit failures include stenosis, thrombosis, calcification of the valve or graft wall, and development of an obstructive peel. We evaluated valved and nonvalved conduits constructed from a glutaraldehyde preserved segment of bovine jugular vein. Bovine jugular conduits (n = 31), 10-13 mm in diameter, were implanted into weight-matched adult mongrel dogs using a standard closed heart technique. Valved conduits (VC, n = 17) were stented at the valve annulus with a Gore-Tex ring, whereas the nonvalved conduits (NC, n = 14) were stented at their midpoint. The proximal PA was tightly banded to 3 mm with a ligature. Cardiac output (CO) and hemodynamic gradients were measured at the time of insertion and 8 months postoperatively. Pulmonary artery angiograms were used to assess bovine jugular conduit regurgitation. All xenografts were evaluated by gross and histologic exam. Two dogs had conduits placed but died for reasons unrelated to the conduit before evaluation. Valved conduit leaflets showed thickening, insignificant thrombus deposition in the base of one or more cusps, and a mild degree of regurgitation as assessed by angiograms. Examination of the NC showed mild conduit thickening and a moderate-to-severe degree of regurgitation as assessed by angiograms. There was a significant difference observed in pulmonary outflow gradients between the VC (11 +/- 2 mm Hg) and NC (17 +/- 2 mm Hg) (p < 0.05), although neither group developed a hemodynamically significant gradient. On gross examination, VC ventricles displayed significantly less evidence of volume and pressure overload compared with the NC ventricle. Valved conduits demonstrated significantly less obstruction and regurgitation. The potential clinical advantages of bovine jugular conduits are their availability, potential durability evidenced by lack of early calcification, and the advantage of not requiring a proximal extension for the RV anastomosis. The presence of a durable and functional xenograft valve in valved conduits may prevent postoperative sequelae in some patients.