Pulsta Valve, Unique Self-Expandable Transcatheter Pulmonary Valve

Abstract

Large sized valve of a self-expandable nature has been suggested as the next generation transcatheter pulmonary valve to implant for various type of native right ventricular outflow tract (RVOT) lesions. Tissue engineered Pulsta valve including decellularization, alpha-galactosidase treatment provide longer valve durability and knitted woven nitinol wire stent provide low risk of stent fracture at the dynamic RVOT. Compact tubular design of Pulsta valve also offer easy valve loading to delivery system and good trackability to valve landing area. From the worldwide experience over 750 cases by February 2025, adaptability of Pulsta valve for various RVOT has proven. Pulsta valve has been implanted for various type of main pulmonary artery (PA) including pyramidal, reverse pyramidal shape and for branch PA stenosis including stent in the branch PA. In case of extremely large native RVOT anatomy, Pulsta valve can be implanted in both branch PA respectively. For the stenotic RVOT or failed bioprosthetic valve, Pulsta valve can also be implanted with or without pre-stenting. Recapturability using delivery system itself if less than one third of valve were flared outside of sheath and capability of whole delivery system retrieval using hooking system are another merit for safe procedure. Though the experience of Pulsta valve for various RVOT diseases is newly accumulated in many centers every day, we still have to learn more about Pulsta valve applicability for various RVOT diseases and long-term outcomes after Pulsta valve implantation.

Keywords: Pulsta valve; Self-expandable valve; Transcatheter pulmonary valve.

Figure 1. Evolution of Pulsta valve. From animal study to human clinical trial, Pulsta valve design changed several times to increase radial force and not to be folded in longitudinal axis. Inside of stent wall is covered by treated porcine pericardium with 25 mm height. The outer diameter ranges from 18 to 32 mm. Both ends of the valve are flared 4 mm wider than the outer diameter. The maximum total length of the Pulsta valve is 28, 31, 34 and 38 mm according to the outer diameter.

Figure 2. Pulsta valve delivery system. In the head portion, there are 3 hooks for stable valve loading and controlled deployment. In the handle portion, there is a knob for initial distal flaring of the Pulsta valve by clockwise rotation and slider for full deployment by pulling down. The outer diameter of valve loading zone is 18 French for up to 28 mm Pulsta valve and 20 French for 30 and 32 mm Pulsta valve.

OD = outer diameter.

Figure 3. Main pulmonary artery angiography and balloon interrogation test. RV angiography during balloon interrogation test with Tyshak 25 mm balloon showed minimal leakage in the patient with reverse pyramidal shape main PA, which suggests feasibility to implant Pulsta valve 32 mm in the proximal landing zone.

PA = pulmonary artery; RV = right ventricle.

Figure 4. Hook attachment mechanism. If the hook and proximal strut of Pulsta valve are in the same plane from the fluoroscopy, one of the hooks still might be in caught with the valve proximal strut (A and C, black arrows). Depending on the wire position, hook can be caught in the right anterior side proximal strut (B, black arrow) or the left anterior side proximal strut (D, black arrow).

Figure 5. Worldwide experience of Pulsta valve. Since the first case in February 2016, Pulsta valve has been implanted for 752 patients from 45 centers in 16 countries by February 2025.

Figure 6. Bilateral Pulsta valve implantation. In the patient with extremely enlarged main PA (A), 30 mm Pulsta valve in right PA and 28 mm Pulsta valve in left PA were implanted respectively (B, black arrows).

PA = pulmonary artery.

Figure 7. The 3D model printing and in vitro simulation test. The 3D model mimicking pulmonary artery tissue properties for reverse pyramidal shape main PA (A). Pulsta valve was implanted in the proximal landing zone (B and C, black arrows) and 3D model are in the mock circulation system for simulation mimicking dynamic RVOT movement according to the forward flow.

PA = pulmonary artery; RV = right ventricle; RVOT = right ventricular outflow tract; 3D = three-dimensional.

Figure 8. Eight years of follow-up echocardiography and cardiac computed tomography. Though there were significant hypo-attenuated leaflet thickening inside of Pulsta valve (A and B, white arrows), Pulsta valve function was preserved with minimal PS and trivial PR 8 years after valve implantation (C and D).

PR = pulmonary regurgitation; PS = pulmonary stenosis.