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

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.

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.

The XPV showed a favourable and durable haemodynamic performance (up to two years after implantation), without conduit narrowing/obstruction or severe regurgitation.