CONGENITAL – Original Submission
Initial Clinical Trial of a Novel Pulmonary Valved Conduit

https://doi.org/10.1053/j.semtcvs.2021.03.036Get rights and content

Valved allografts and xenografts for reconstruction of the right ventricular outflow tract (RVOT) lack durability and do not grow. We report the first clinical use of a completely bioabsorbable valved conduit (Xeltis pulmonary valve - XPV) in children. Twelve children (six male), median age five (two to twelve) years and median weight 17 (10 to 43) kg, underwent RVOT reconstruction with the XPV. Diagnoses were: pulmonary atresia with ventricular septal defect (VSD) (n = 4), tetralogy of Fallot (n = 4), common arterial trunk (n = 3), and transposition of the great arteries with VSD and pulmonary stenosis (n = 1). All had had previous surgery, including prior RVOT conduit implantation in six. Two diameters of conduit 16mm (n = 5) and 18mm (n = 7) were used. At 24 months none of the patients has required surgical re-intervention, 9 of the 12 are in NYHA functional class I and three patients in NYHA class II. None of the conduits has shown evidence of progressive stenosis, dilation or aneurysm formation. Residual peak gradient of >40 mm Hg was observed in three patients, caused by kinking of the conduit at implantation in 1 and distal stenosis in the peripheral pulmonary arteries in 2 patients. Five patients developed severe pulmonary valve insufficiency (PI); the most common mechanism was prolapse of at least one of the valve leaflets. The XPV conduit is a promising innovation for RVOT reconstruction. Progressive PI requires however an improved design (geometry, thickness) of the valve leaflets.

Section snippets

INTRODUCTION

The requirements for an ideal pulmonary valved conduit in children and infants are availability and durability, the ability to grow, low antigenicity and finally ease of implantation.1 None of the currently available allografts or xenografts meets all these requirements. We have previously reported favorable short-term outcome of a novel bioabsorbable restorative pulmonary valved conduit in a sheep model.2 In this study, which is part of an ongoing prospective, multicenter non-randomized,

The Valved Conduit

The valved conduit is fully synthetic, seamless, flexible, highly porous, and bioabsorbable (Xeltis Pulmonary Valved Conduit; XPV). The building blocks are based on supramolecular 2-ureido-4[1H]-pyrimidone (UPy). The conduit wall consists of poly-caprolactone-based UPy which gives a robust structure. The valve leaflets are made of poly-carbonate-based UPy, which provides flexibility for leaflet motion (Fig. 1). The XPV is designed to be absorbed and replaced by growing autologous tissue (Fig. 2

RESULTS

There were no early nor late deaths. There was no need for additional surgery in the immediate postoperative period and no conduit related acute adverse events were observed. All children were discharged within seven to 10 days after surgery. None of them has undergone reoperation. Compared to the preoperative functional class (five patients in NYHA class I, six patients in NYHA class II and one in NYHA class III), nine patients were in NYHA class I at 24 months, and three patients in NYHA

DISCUSSION

RVOT repair is a frequent procedure in children presenting with a congenital heart malformation. Types of repair include commissurotomy of the pulmonary valve, infra- and/or supravalvular patches or implantation of a RV-PA conduit using a homograft or xenograft. Pulmonary homografts would be the preferred material but they are not always available due to the scarce number of organ procurements in this age group. Xenografts are probably the most frequently used material but have also major

References (11)

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Funding: This study was funded by an unrestricted research grant from Xeltis B.V. the Netherlands.

Conflicts of interest: Cox, Schutte and Svanidze are employees of, or hold shares/ options in Xeltis. Dr.Carrel is a member of the Advisory Board of Xeltis (without clinical involvement). F.Asch directs an academic cardiovascular imaging core laboratory with institutional contracts to Xeltis (with no personal conflict of interest). All other authors have nothing to disclose.

ClinicalTrials.gov No: NCT02700100

Regulatory approvals: Hungary: Authority: Health Registration and Training Center, Division of Medical Devices

Date: 06 June 2016

Number: 035976-005/2016/OTIG

Poland: Authority: The Office for Registration of Medicinal Products, medical Devices and Biocidal Products

Date: 20 July 2016

Number: UR.D.WM.DNB.61.2016

Malaysia: Authority: Medical Device Authority, Ministry of Health Malaysia

Date: 20 Sept 2016

Number: MDA/IDE/2016/002

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