New ideas - Congenital Off-bypass implantation of a self-expandable valved stent between inferior vena cava and right atrium q

A glutaraldehyde preserved valved bovine jugular xenograft mounted in a nitinol ‘Z’ stent, expandable from 7 to 28 mm of internal diameter, was evaluated in vitro (column of water developing a pressure of 45 mmHg and a mock loop including a pulsatile pump) and in vivo in five adult pigs with intra-vascular ultrasound to measure the inferior vena cava diameter via a retroperitoneal access. Through a stentgraft delivery system (24 French) the self expandable valved stent was implanted off-bypass in the inferior vena cava, between hepatic veins and cavo-atrial junction, with flow and pressure gradient recording. The mean length of the valved stent was 22.80 ^ 1.06 mm, the mean internal diameter 20.97 ^ 0.5 mm and the mean external diameter 26.67 ^ 0.9 mm. The valve leaking under pressure was 32.5 ^ 12.3 ml/min. The mean pressure gradient recorded across the self expandable valved stent implanted in the inferior vena cava was 1.0 ^ 0.5 mmHg (range 0 – 2 mmHg). Intra-vascular ultrasound showed partial opening and closing of the valve (mean area reduction from 148.5 to 81.5 mm 2 ), with almost complete occlusion only during deep breaths. The in vitro and in vivo experiments confirmed the feasibility of potential application of the self-expandable valved stent implanted off-bypass in the inferior vena cava for late conversion of failing total cavo-pulmonary connection; intra-vascular ultrasound allows for adequate implantation and evaluation. q 2003 Elsevier Science B.V. All rights reserved.