Pathology of valved venous homografts used as right ventricle-to-pulmonary artery conduits in congenital heart disease surgery

Valved Sano conduit improves immediate outcomes following Norwood operation compared with nonvalved Sano conduit

OBJECTIVE

Use of a valved Sano during the Norwood procedure has been reported previously, but its impact on clinical outcomes needs to be further elucidated. We assessed the impact of the valved Sano compared with the nonvalved Sano after the Norwood procedure in patients with hypoplastic left heart syndrome.

METHODS

We retrospectively reviewed 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a valved Sano conduit using a femoral venous homograft and 25 consecutive neonates with hypoplastic left heart syndrome who underwent a Norwood procedure with a nonvalved Sano conduit between 2013 and 2022. Primary outcomes were end-organ function postoperatively and ventricular function over time. Secondary outcomes were cardiac events, all-cause mortality, and Sano and pulmonary artery reinterventions at discharge, interstage, and pre-Glenn time points.

RESULTS

Postoperatively, the valved Sano group had significantly lower peak and postoperative day 1 lactate levels (P = .033 and P = .025, respectively), shorter time to diuresis (P = .043), and shorter time to enteral feeds (P = .038). The valved Sano group had significantly fewer pulmonary artery reinterventions until the Glenn operation (n = 1 vs 8; P = .044). The valved Sano group showed significant improvement in ventricular function from the immediate postoperative period to discharge (P < .001). From preoperative to pre-Glenn time points, analysis of ventricular function showed sustained ventricular function within the valved Sano group, but a significant reduction of ventricular function in the nonvalved Sano group (P = .003). Pre-Glenn echocardiograms showed competent conduit valves in two-thirds of the valved Sano group (n = 16; 67%).

CONCLUSIONS

The valved Sano is associated with improved multi-organ recovery postoperatively, better ventricular function recovery, and fewer pulmonary artery reinterventions until the Glenn procedure.

Application of Homograft Valved Conduit in Cardiac Surgery

Valved conduits often correct the blood flow of congenital heart disease by connecting the right ventricle to the pulmonary artery (RV-PA). The homograft valved conduit was invented in the 1960s, but its wide application is limited due to the lack of effective sterilization and preservation methods. Modern cryopreservation prolongs the preservation time of homograft valved conduit, which makes it become the most important treatment at present, and is widely used in Ross and other operations. However, homograft valved conduit has limited biocompatibility and durability and lacks any additional growth capacity. Therefore, decellularized valved conduit has been proposed as an effective improved method, which can reduce immune response and calcification, and has potential growth ability. In addition, as a possible substitute, commercial xenograft valved conduit has certain advantages in clinical application, and tissue engineering artificial valved conduit needs to be further studied.

Conduits for Right Ventricular Outflow Tract Reconstruction in Infants and Young Children

Purpose of Review: Right ventricular outflow tract (RVOT) reconstruction remains a challenge due to the lack of an ideal conduit. Data and experience are accumulating with each passing day. Therefore, it is necessary to review this topic from time to time. This is a 2021 update review focused on the history, evolution, and current situation of small-sized conduits (≤ 16 mm) for RVOT reconstruction in infants and young children.

Recent Findings: Currently, the available small-sized (≤16 mm) conduits can meet most clinical needs. Homograft is still a reliable choice for infants and young children validated by a half-century clinical experience. As an alternative material, bovine jugular vein conduit (BJVC) has at least comparable durability with that of homograft. The performance of expanded polytetrafluoroethylene (ePTFE) is amazing in RVOT position according to limited published data. The past century has witnessed much progress in the materials for RVOT reconstruction. However, lack of growth potential is the dilemma for small-sized conduits. Tissue-engineering based on cell-free scaffolds is the most promising technology to obtain the ideal conduit.

Summary: No conduit has proved to have lifelong durability in RVOT position. We are far from the ideal, but we are not in a state of emergency. In-depth clinical research as well as innovation in material science are needed to help improve the durability of the conduits used in infants and young children.

Revisiting prosthesis choice in mitral valve replacement in children: Durable alternatives to traditional bioprostheses

OBJECTIVE

To determine risk factors for re-replacement and death or transplant following mitral valve replacement (MVR) in children METHODS: This is a retrospective 26-year review of patients younger than 20 years of age undergoing MVR between 1992 and 2018 at single institution. Outcomes included freedom from re-MVR and transplant-free survival. Cox proportional hazards regression models assessed association between outcomes and potential risk factors.

RESULTS

At median age 4.2 years, 190 children underwent 290 MVR: 180 mechanical, 63 porcine, 13 pericardial, and 34 stented bovine jugular vein valves. Re-MVR occurred in 100 valves. Freedom from re-MVR at 5 and 10 years was 76% and 44%. Times to re-MVR were associated with prosthesis type (P < .001), with porcine and pericardial valves at greatest risk. Other risk factors for prosthetic failure included smaller prosthesis size and left ventricular hypoplasia. There were 9 transplants and 44 deaths. Transplant-free survival at 5 and 10 years was 81% and 76%. Prosthesis type was significantly associated with time to death/transplant in univariate analysis only (P = .021), with porcine at greater risk than mechanical. Independent risk factors for death/transplant included larger indexed geometric orifice area and longer bypass time.

CONCLUSIONS

In pediatric patients undergoing MVR, mechanical and stented bovine jugular vein valves were associated with increased durability compared with fixed-diameter bioprosthetic alternatives.