Midterm performance of a novel restorative pulmonary valved conduit: preclinical results

Aims: The Xeltis bioabsorbable pulmonary valved conduit (XPV), designed to guide functional restoration of patients' own tissue, is potentially more durable than current pulmonary bioprosthetic valves/valved conduits. The aim of this study was to assess the haemodynamic performance of the novel XPV implanted in an ovine model. Methods and results: The XPV was surgically implanted in adult sheep under general anaesthesia and cardiopulmonary bypass (XPV group, n= 20). Sheep that received a Hancock bioprosthetic pulmonary valved conduit served as a control group (HPV group, n = 3). Transthoracic echocardiograms from VARC-2 recommended time points at 3, 6, 9, 12, 18 and 24 months (XPV group) and at 3 and 6 months (HPV group) after the procedure were analysed in an independent core laboratory. The primary endpoint was favourable valved conduit performance, defined as peak systolic pressure gradient < 40 mmHg, no severe pulmonary regurgitation (PR), and a maximum conduit patency index of -20%. In the latter, negative values denote luminal narrowing and vice versa. The valvular peak systolic pressure gradient (mmHg) was 25.6 +/- 9.7 (3 months), 19.6 +/- 7.1 (6 months), 10.0 +/- 9.2 (24 months) in the XPV group and 18.4 +/- 6.6 (3 months), 17.7 +/- 4.6 (6 months) in the HPV group. The patency index (%) of the conduit at the valvular level was + 30.3 +/- 13.6 (6 months) and + 64.1 +/- 1.4 (24 months) in the XPV group and + 2.0 +/- 15.9 (6 months) in the HPV group. PR was trace or mild at all visits, except in one animal with persistent moderate PR in the XPV group, up to 24 months. Conclusions: The XPV showed a favourable and durable haemodynamic performance (up to two years after implantation), without conduit narrowing/obstruction or severe regurgitation.