Treatment of Severe Pulmonary Regurgitation in Enlarged Native Right Ventricular Outflow Tracts: Transcatheter Pulmonary Valve Replacement with Three-Dimensional Printing Guidance

Figure 1. PT-Valve sizing. The PT-Valve is a symmetrical, dumbbell-shaped bioprosthesis with five different sizes utilized. Diameter 1 is the porcine valve size in the middle of the frame with 20, 23, and 26 mm, respectively. Diameter 2 represents the outflow and inflow diameters of the valve frame, which are equal and come in sizes of 28, 32, 36, 40, and 44 mm, respectively. There are three Mark points at the base of the valve leaflet to indicate the position of the leaflet intraoperatively. The length of the frame has five sizes: 38, 42, 46, 50, and 54 mm to fit the conduits. MPA—main pulmonary artery; RVOT—right ventricular outflow tract.

Figure 2. Preoperative three-dimensional (3D) reconstruction and enlarged right ventricular outflow tract 3D-printed models to help surgeons understand anatomical structures and make an accurate surgical plan. (a) The process of 3D reconstruction using Materialise Mimics version 21.0 (Materialise, Leuven, Belgium). (b) The 3D-printed models restore the enlarged native right ventricular outflow tracts and pyramidal right ventricle–pulmonary artery conduits of all eight patients; #1–#8, patient 1–8.

Figure 3. Simulation of transcatheter pulmonary valve replacement using a three-dimensional printed model for the bench test (e.g., data for patient #7). (A,B) The delivery system was inserted into the right ventricle–pulmonary artery conduit, and then the bioprosthesis was released for positing in the distal landing zone. (C,D) When the bioprosthesis is fully released, and the delivery system is withdrawn, the stability can be evaluated. (E,F) The stent effectively seals both ends of the conduit, ensuring there is no paravalvular leak.

Figure 4. The implantation of PT-Valve using 3D-printed models of all eight patients predicts the morphology and functionality of the bioprostheses without paravalvular leak and stent displacement. To minimize the risk of coronary compression, there is no contact between the conduit and the middle of the stent.

Figure 5. The implantation of a PT-Valve for the transcatheter pulmonary valve replacement procedure. (A) Fluoroscopy imaging revealed severe pulmonary regurgitation and an enlarged native right ventricular outflow tract. (B) The distal valve-containing capsule was transported to the predetermined position and confirmed under fluoroscopy imaging. (C) Outflow portions of the device were released. (D) The mid-segment of the device was released. (E) Inflow portions of the valve were finally released. (F) Fluoroscopy imaging showed that pulmonary regurgitation disappeared immediately.

Figure 6. Follow-up data after PT-Valve implantation. (A) pulmonary regurgitation and tricuspid regurgitation severity; (B) right ventricular ejection fraction volume index; (C) New York Heart Association class; (D) peak trans-pulmonary valve gradient; NYHA—New York Heart Association; PR—pulmonary regurgitation; RVEDVI—right ventricular ejection fraction volume index; TR—tricuspid regurgitation.