Assessment of untreated fresh autologous pericardium as material for construction of heart valve: Result at 5 years

Hemodynamic evaluation of biomaterial-based surgery for Tetralogy of Fallot using a biorobotic heart, in silico, and ovine models

Tetralogy of Fallot is a congenital heart disease affecting newborns and involves stenosis of the right ventricular outflow tract (RVOT). Surgical correction often widens the RVOT with a transannular enlargement patch, but this causes issues including pulmonary valve insufficiency and progressive right ventricle failure. A monocusp valve can prevent pulmonary regurgitation; however, valve failure resulting from factors including leaflet design, morphology, and immune response can occur, ultimately resulting in pulmonary insufficiency. A multimodal platform to quantitatively evaluate the effect of shape, size, and material on clinical outcomes could optimize monocusp design. This study introduces a benchtop soft biorobotic heart model, a computational fluid model of the RVOT, and a monocusp valve made from an entirely biological cell-assembled extracellular matrix (CAM) to tackle the multifaceted issue of monocusp failure. The hydrodynamic and mechanical performance of RVOT repair strategies was assessed in biorobotic and computational platforms. The monocusp valve design was validated in vivo in ovine models through echocardiography, cardiac magnetic resonance, and catheterization. These models supported assessment of surgical feasibility, handling, suturability, and hemodynamic and mechanical monocusp capabilities. The CAM-based monocusp offered a competent pulmonary valve with regurgitation of 4.6 ± 0.9% and a transvalvular pressure gradient of 4.3 ± 1.4 millimeters of mercury after 7 days of implantation in sheep. The biorobotic heart model, in silico analysis, and in vivo RVOT modeling allowed iteration in monocusp design not now feasible in a clinical environment and will support future surgical testing of biomaterials for complex congenital heart malformations.

Systematic Analysis of PTFE Monocusp Leaflet Design in a Patient-Based 3D in-Vitro Model of Tetralogy of Fallot

PURPOSE

Pulmonary valve (PV) monocusp reconstruction in transannular patch (TAP) right ventricular outflow tract (RVOT) repair for Tetralogy of Fallot has variable clinical outcomes across different surgical approaches. The study purpose was to systematically evaluate how monocusp leaflet design parameters affect valve function in-vitro.

METHODS

A 3D-printed, disease-specific RVOT model was tested under three infant physiological conditions. Monocusps were sewn into models with the native main pulmonary artery (MPA) forming backwalls that constituted 40% and 50% of the reconstructed circumference for z-score zero PV annulus and MPA diameters (native PV z-score - 3.52 and - 2.99 for BSA 0.32m2). Various leaflet free edge lengths (FEL) (relative to backwall), positions (relative to PV STJ), and scallop depths were investigated across both models. Pressure gradient, regurgitation, and coaptation were analyzed with descriptive statistics and regression models.

RESULTS

Increasing FEL beyond 100% of the MPA backwall decreased gradient but mildly increased regurgitation to a peak of 25%. Positioning the free edge 2 mm past the STJ mildly increased gradient for each FEL without significantly changing regurgitation compared to STJ placement. Scalloping leaflets trivially affected performance. Pre-folding leaflets improved mobility and slightly reduced gradient.

CONCLUSIONS

Balancing gradient, regurgitation, and oversizing for growth, a set of leaflet designs have been selected for pre-clinical evaluation. Designs with leaflet widths 140-160% in the 40% backwall model (110-120% in the 50% backwall), positioned at or 2 mm past the STJ, demonstrated the best results. The next stage of ex-vivo testing will additionally consider native RVOT distensibility, native leaflet interactions, and TAP characteristics.

Transannular patch repair of tetralogy of Fallot with or without monocusp valve reconstruction: a meta-analysis

Background

Tetralogy of Fallot (TOF) is one of the most common cyanotic congenital heart diseases. Pulmonary regurgitation is the most common and severe comorbidity after transannular patch (TAP) repair of TOF patients. It has not been confirmed whether a TAP repair with monocusp valve reconstruction would benefit TOF patients in perioperative period compared to those without monocusp valve reconstruction. The purpose of the study is to review and analyze all clinical studies that have compared perioperative outcomes of TOF patients undergoing TAP repair with or without monocusp valve reconstruction and conduct a preferable surgery.

Methods

Eligible studies were identified by searching the electronic databases. The year of publication of studies was restricted from 2000 till present. The primary outcome was perioperative mortality, and secondary outcomes included cardiopulmonary bypass time, aortic cross-clamp time, ventilation duration, ICU length of stay, hospital length of stay, perioperative right ventricular outflow tract (RVOT) pressure gradient, and moderate or severe pulmonary regurgitation (PR). The meta-analysis and forest plots were drawn using Review Manager 5.3. Statistically significant was considered when p-value ≤ 0.05.

Results

Eight studies were included which consisted of 8 retrospective cohort study and 2 randomized controlled trial. The 10 studies formed a pool of 526 TOF patients in total, in which are 300 undergoing TAP repair with monocusp valve reconstruction (monocusp group) compared to 226 undergoing TAP repair without monocusp valve reconstruction (non-monocusp group). It demonstrated no significant differences between two groups in perioperative mortality (OR = 0.69, 95% CI 0.20–2.41, p = 0.58). It demonstrated significant differences in perioperative cardiopulmonary bypass time (minute, 95% CI 17.93–28.42, p < 0.00001), mean length of ICU stay (day, 95% CI − 2.11–0.76, p < 0.0001), and the degree of perioperative PR (OR = 0.03, 95% CI 0.010.12, p < 0.00001). Significant differences were not found in other secondary outcomes.

Conclusion

Transannular patch repair with monocusp valve reconstruction have significant advantages on decreasing length of ICU stay and reducing degree of PR for TOF patients. Large, multicenter, randomized, prospective studies which focuse on perioperative outcomes and postoperative differences based on long-term follow-up between TAP repair with and without monocusp valve reconstruction are needed.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12893-022-01474-6.