Pulsta Valve, Unique Self-Expandable Transcatheter Pulmonary Valve

Author's summary

Pulsta valve is one of the large sized transcatheter pulmonary valve with a self-expandable nature for native right ventricular outflow tract (RVOT) diseases. Uniqueness of Pulsta valve is tissue engineered valve leaflets for longer durability and knitted woven nitinol wire stent frame with compact tubular design, which has proven extensive adaptability of Pulsta valve for varous RVOT lesions for over 750 cases worldwide by February 2025.

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.

RIGHT VENTRICULAR OUTFLOW TRACT DISEASE AND PULMONARY VALVE REPLACEMENT

Various congenital heart diseases (CHD) involving the right ventricular outflow tract (RVOT), such as tetralogy of Fallot (TOF), double outlet right ventricle, transposition of the great arteries with pulmonary stenosis (PS), congenital isolated PS, etc. inevitably need replacement of a new prosthetic valve because of clinically significant pulmonary regurgitation (PR) and/or PS and associated with right ventricular (RV) dysfunction overtime.¹⁾,²⁾ Pulmonary valve replacement (PVR) using various bioprosthetic valves in these patients group has shown significant improvement of RV function and quality of life and surgical PVR has been gold standard to treat RVOT disease for several decades.³⁾,⁴⁾ However, these surgical bioprosthetic valves are prone to be failed because of bioprosthetic valve tissue degeneration and/or calcification, which provoke significant PS and/or PR overtime (mostly in 20 years after PVR) and require redo PVR.⁵⁾ As a matter of course, repetitive open heart surgery and redo PVR increase risk of significant morbidity and mortality inevitably,⁶⁾ and patients who underwent surgical PVR after at least 3 previous open-heart surgeries had significantly higher mortality than those who underwent PVR less than 3.⁷⁾ Therefore, percutaneous pulmonary valve implantation (PPVI) has been developed as a less invasive treatment tool for various RVOT disease.

PERCUTANEOUS PULMONARY VALVE IMPLANTATION

Since the first PPVI using Melody valve for the previously surgically treated RVOT,⁸⁾ there has been huge progress for the treatment of RVOT disease for the last several decades and long-term data of valve durability has been well known to be good like surgical PVR. From Munich comparative study, there was no difference in the estimated survival free of surgery on the implanted valve at 10 years (Melody valve, 87%, versus surgical PVR, 87%; p=0.54) or in the survival with the originally implanted pulmonary valve (Melody valve, 80%; surgical PVR, 73%; p=0.46) between both groups.⁹⁾ Melody valve and Edwards SAPIEN valve, which are used as balloon-expandable PPVI procedure, have been successfully implanted over 18,000 cases at the surgically implanted bioprosthetic valve or homograft in the pulmonic position with excellent effectiveness and safety. However, because these balloon-expandable valves have inherent limitations for the native RVOT lesions with quite variable geometry¹⁰⁾ and associated significant PR, balloon-expandable valves could be used for about 20–25% of whole RVOT disease.¹¹⁾ Therefore, large sized valve of a self-expandable nature has been suggested as the next generation transcatheter pulmonary valve (TPV) to implant for various type of native RVOT lesions.¹²⁾ First-in-man successful implantation of a single self-expandable valve into a dilated pulmonary trunk was reported in 2010 by Schievano et al.,¹³⁾ and this Harmony valve¹⁴⁾ by Medtronic, Inc. was approved by U.S. Food and Drug Administration in March 2021. The other self-expandable valve for a dilated pulmonary trunk is the Venus-P valve,¹⁵⁾ which acquired CE approval with good clinical outcome in March 2022. Pulsta valve, which was developed in South Korea, is also another self-expandable valve for the native RVOT diseases.

ADVENT OF PULST VALVE

Pulsta valve development was initiated by the research team of the Xenotransplantation research center in the Seoul National University Hospital (principal investigator: professor Yong Jin Kim, congenital cardiac surgeon in the Seoul National University Hospital, Seoul National University College of Medicine) since May 2004. This project was funded by a grant from the Ministry for Health, Welfare, and Family Affairs, Republic of Korea. Research team initially focused on tissue engineering for longer valve durability by various tissue treatment of porcine and bovine pericardium to decrease immunogenicity and later calcification. These processes comprise of decellularization, alpha-galactosidase treatment, space filler, Glutaraldehyde fixation, and detoxification.¹⁶⁾,¹⁷⁾ During preparation of animal study for surgical and transcatheter prosthetic valve, TaeWoong Medical Co, (Gimpo, Korea) joined in this project and started pre-clinical animal study together using prototype of Pulsta valve (Figure 1A and B) since August 2011. For animal study using sheep, research team implanted prototype of Pulsta valve in 12 sheep through the femoral or jugular vein by using an 18 French delivery catheter system. Mean body weight of sheep was 43.9 kg, and the valve was implanted 24 mm diameter in 7 sheep, 26 mm diameter in 5 sheep. After 6 months of follow-up, survived 8 sheep were sacrificed. Histological findings of the sacrificed sheep showed well maintained collagen wave structure and no visible calcification in all explanted valve leaflets.¹⁸⁾

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.

PULSTA VALVE AND DELIVERY SYSTEM PROFILE

Pulsta valve is a tubular shaped self-expandable valve made by using double-strand nitinol wire with (0.0115-inch for 18–28 mm, 0.0125 inch for 30 and 32 mm Pulsta valve) thickness in knitted woven texture. Inside of stent wall is covered by treated porcine pericardium with 25 mm height. The outer diameter ranges from 18 to 32 mm with 2 mm increments. Both ends of the valve are flared 4 mm wider than the outer diameter. The total length of the Pulsta valve is 28, 31, 34 and 38 mm according to the outer diameter (Figure 1C, Table 1). Treated porcine pericardium was tightly hand sewn to the covered stent wall with 5–0 braided polyester to allow good valve coaptation as tricuspid leaflets.¹⁹⁾ Valve direction can be identified by covered status by treated porcine pericardium and distal part of Pulsta valve is less covered, which prevent branch PA flow obstruction. Woven texture valve stent is fracture resistant and stent frame underwent stent fatigue test for 400,000,000 times before clinical trial. Pulsta valve itself also underwent valve accelerated wear test for 200,000,000 times to be approved by the Korean Ministry of Food and Drug Safety before human clinical trial.

Table 1. Pulsta valve profile.

Model name	Outer diameter (mm)	Flare diameter (mm)	Total length (mm) ± tolerance (5%)
TPV1828	18	22	28±1.4
TPV2028	20	24	28±1.4
TPV2231	22	26	31±1.55
TPV2431	24	28	31±1.55
TPV2633	26	30	33±1.65
TPV2833	28	32	33±1.65
TPV1838	18	22	38±1.9
TPV2038	20	24	38±1.9
TPV2238	22	26	38±1.9
TPV2438	24	28	38±1.9
TPV2638	26	30	38±1.9
TPV2838	28	32	38±1.9
TPV3038	30	34	38±1.9
TPV3238	32	36	38±1.9

TPV = transcatheter pulmonary valve.

Delivery system for Pulsta valve is shown in Figure 2. Delivery system’s total usable length is 110 cm and comprises of head, shaft, and handle portion (Figure 2A). In the head portion, there is a conical shape nose cone with 17 mm in length for smooth transvenous introduction and 3 hooks for stable valve loading and controlled deployment (Figure 2B). 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 (Figure 2C). The outer sheath 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. The diameter of the shaft is 12 French (Figure 2D).¹⁹⁾

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.

PULSTA VALVE STANDARD PROCEDURE

Vessel preparation

For transcatheter introducer, one large venous sheath to accommodate sizing balloon for balloon interrogation test and one small venous sheath for serial angiography during valve deployment are needed. One additional small arterial sheath is necessary for aortic root angiography or coronary artery angiography to check coronary artery compression during valve implantation. Because a significant number of CHD patients have femoral or iliac vein occlusion or severe stenosis, be sure to check main venous route patency before inserting delivery system.

Right ventricular outflow tract angiography and balloon interrogation test

The purpose of RVOT angiography is to make best image to differentiate branch PA bifurcation site and check overall main PA shape. Standard fluoroscopy projection is right anterior oblique and cranial view for anteroposterior plane (Figure 3A) and full lateral or left anterior oblique and cranial view for lateral plane. Because of RVOT curvature to the right PA, be sure to consider that main PA looks shorter than the actual length from lateral plane fluoroscopy.

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.

Balloon interrogation test can be completed either by compliant sizing balloon (usually atrial septal defect sizing balloon 24 or 34 mm) or by semi-compliant static balloon (usually Tyshak balloon or Balloon-in-balloon catheter) for correct sizing of Pulsta valve and coronary artery compression test. By using atrial septal defect (ASD) sizing balloon, we can estimate main PA distensibility how big Pulsta valve can be implanted at the most stenotic area and estimate coronary artery could be compressed by Pulsta valve though there is a risk of over-sizing if balloon were inflated too much. Basically, radial force of Pulsta valve is stronger than ASD sizing balloon and Pulsta valve can be expanded more than narrowest area of ASD sizing balloon. By using semi-compliant static balloon, we can check feasibility of Pulsta valve for borderline sized main PA (Figure 3B) and evaluate that coronary artery could be compressed by static diameter of balloon diameter.

Pulsta valve size selection

Pulsta valve size selection depends on overall main PA morphology¹⁰⁾ including narrowest area diameter for stable valve landing. In general, Pulsta valve diameter could be selected 2–4 mm larger than narrowest diameter of main PA or 1–2 mm larger than overall main PA diameter. If there is concern about valve migration or embolization, selection of over-sized valve is permitted without hesitation. Especially, in case of pyramidal or reverse pyramidal shape, selection of over-sized valve is common in real practice. For example, in the patient with reverse pyramidal shape main PA like in Figure 3, we selected 32 mm Pulsta valve after checking minimal leakage from RV angiography during balloon interrogation test with Tyshak 25 mm balloon, which was at least 5–6 mm over-sized selection for stable procedure.

Guidewire selection during procedure

For stable and safe procedures, selection of supporting wire and wire selection to branch PA is very important. Because Pulsta valve and delivery system are relatively soft, there are several considering points during PPVI procedure. Any extra-stiff support wire can be used. However, Lunderquist extra-stiff wire (Cook Medical, Bloomington, IN, USA) is preferable for right PA wire selection to introduce delivery system easily into the main PA landing area if we decide wire selection into right PA. Amplatz super-stiff wire (Boston Scientific, Marlborough, MA, USA) is preferable for left PA selection to retrieve delivery system easily after valve deployment. In general wire selection into right PA is preferable because right PA wire selection provides very little valve geometry change during full deployment of Pulsta valve due to RVOT curvature to the right PA.

Delivery system introduction and Pulsta valve deployment

Before the introduction of the delivery system, the main transvenous route for Pulsta valve should be dilated using a provided dilator with a delivery system, which is 19 French dilator for 18 French delivery system and 21 French dilator for 20 French delivery system. Larger diameter guiding sheath is not necessary for Pulsta valve delivery system. For smooth delivery system introduction into the target Pulsta valve landing zone, keep the supporting wire position as far as deep distal part of branch PA. After checking the correct position of the loaded Pulsta valve by RVOT angiogram, prepare to start Pulsta valve deployment. During these processes, always keep tension of delivery system because delivery system easily slips down to RV due to stiff wire tension in the RVOT. If ready, rotate the knob clockwise to open distal valve strut (Figure 2C). In real practice, one third to a half of Pulsta valve tends to be opened by rotating the knob fully. After RV angiogram for proper positioning, start full deployment of Pulsta valve by pulling the slider slowly step-by-step checking full distal flaring of valve strut (Figure 2C).

Identification of hook detachment and safe retrieval of delivery system

Pulsta delivery system has 3 hooks at the head portion and checking hook detachment from valve strut after full deployment is important for safe delivery system retrieval. To check hook detachment properly, it is better to magnify fluoroscopy screen for clear identification. Because of stiff wire tone, natural hook detachment is difficult sometimes. 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 (Figure 4A and C). Depending on the wire position, hook can be caught in the right anterior side proximal strut (Figure 4B) or the left anterior side proximal strut (Figure 4D). In case of hooking in the right anterior side proximal strut, gentle pushing upward of the delivery system can be helpful to be released from hooking. In both situations, removing stiff wire to reduce wire tension at the RVOT anterior wall is a way to be free from hooks in most cases. After confirmation of hook detachment from the Pulsta valve strut, retrieve delivery system from the RVOT carefully and cover hooks using distal outer sheath by moving slider upward at the patient’s inferior vena cava.

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).

CLINICAL TRIAL OUTCOME

First in human experience of Pulsta valve was completed for 20-year-old female with post-operative TOF in February 2016, and Pulsta valve 28 mm diameter was implanted for her.²⁰⁾ Before Pulsta valve implantation, her indexed RV end-diastolic volume was 186.5 mL/m², however, indexed RV end-diastolic volume decreased continuously down to 139 mL/m² in 6 months follow-up, 119.9 mL/m² in 3 years follow-up. Follow-up echocardiography 9 years after Pulsta valve implantation still showed trivial PR and no significant PS (peak velocity: 1.58 m/sec). The Pulsta valve feasibility human trial was completed for 10 post-operative TOF patients with severe PR in 2016. All procedures were successful and there were no significant periprocedural complications. After 6 months follow-up, indexed RV end-diastolic volume was significantly decreased from 176.7±14.3 mL/m² to 126.3±20.3 mL/m². And the mean value of peak instantaneous pressure gradient between RV and PA also decreased from 6.8±3.5 mmHg to 5.7±6.7 mmHg.¹⁹⁾ After sponsor initiated clinical trial finished as a multi-center study for additional 15 patients in South Korea, mid-term results of 25 patients’ data including 10 patients of Pulsta feasibility study was published. All the patients were implanted with 26, 28, or 32 mm diameter of Pulsta valve successfully without serious device-related adverse event. At 6 months follow up, indexed RV end-diastolic volume was significantly decreased from 169.7±13.0 to 126.9±16.9 mL/m². At mean 33.1±14.3 months follow-up, the mean value of mean pressure gradient across the Pulsta valve was 6.5±3.0 mmHg without significant PR from echocardiography.²¹⁾ By these outcomes, Pulsta valve was approved for clinical use in October 2018 by the Ministry of the Food and Drug Safety in South Korea. CE approval study was performed at the 6 countries and 11 cardiac centers in Europe (Italy, Germany, Spain, Netherland, and Türkiye) and South Korea since December 2019 and finished enrollment in February 2022 for 58 patients with RVOT disease including 4 patients with valve-in-valve procedure. Now, Pulsta valve is being reviewed by the European Union Medical Device Regulation for approval in Europe since October 2023.

WORLDWIDE EXPERIENCE

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 5). Half of the cases were performed in South Korea and followed by Taiwan, Argentina, Vietnam, etc. Pulsta valve has been commercially approved in 8 countries until now (South Korea, Taiwan,²²⁾ Argentina, Vietnam, Thailand, Peru, Russia, and Belarus) and in the process for approval in several countries. Pulsta valve has been also implanted for patients as a compassionate use in Chile, Spain, Türkiye,²³⁾ Philippines, and Poland.²⁴⁾

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.

UNIQUENESS OF PULSTA VALVE AND ITS VARIOUS APPLICATIONS

Compared with other self-expandable TPVs with hour-glass appearance, Woven knitted texture stent design and relatively compact valve profile of Pulsta valve provide uniqueness and several advantages in the RVOT disease treatment. Firstly, Pulsta valve loading process is fast and relatively easy using a crimper on the table and delivery catheter system itself provides good trackability into the target landing zone without additional large guiding sheath. Secondly, woven knitted texture valve frame provides resistance to stent fracture at the dynamic RVOT area. In reality, there have been no report of stent fractures since 2016 over 750 cases worldwide. Stent fatigue test for 400,000,000 times before clinical trial provides experimental basis. Thirdly, compact design of Pulsta valve makes it possible for Pulsta valve to be implanted into various RVOT diseases including prosthetic valve. Park et al.²⁵⁾ revealed the adaptability of Pulsta valve from the investigation of implantation sites based on the native RVOT anatomy of 182 patients in 5 centers in South Korea and Taiwan. From this observation, Pulsta valve was implanted at the pyramidal (3.8%), straight (38.5%), reverse pyramidal (13.2%), convex (26.4%) and concave (18.1%) shape, respectively. In case of extremely large native RVOT anatomy which cannot accommodate Pulsta valve in the main PA, Pulsta valve can be implanted in both branch PA respectively.²⁶⁾ For example, in the 56-year-old post-operative TOF patient with extremely enlarged main PA (46.1 mm, Figure 6A), 30 mm diameter Pulsta valve in right PA and 28 mm diameter Pulsta valve in left PA were implanted respectively (Figure 6B). For the stenotic RVOT or failed bioprosthetic valve, Pulsta valve can also be implanted with or without pre-stenting. In case of surgically replaced bioprosthetic pulmonic valve, high pressure balloons such as Atlas balloons are needed to make a wide inner lumen to accommodate Pulsta valve. After ballooning, it is reasonable to check the inner lumen by ASD sizing balloon. If ASD sizing balloon could be expanded well in the bioprosthetic valve, Pulsta valve can be implanted without pre-stenting. Fourth, Pulsta valve is feasible to be recapturable if less than one third of valve were flared outside of sheath by rotating the knob counterclockwise. If there is worry of device embolization just before full release or unintended position from the planned landing zone, the whole delivery system retrieval with Pulsta valve is possible using hooking system mechanism with care though these maneuvers are not recommended to be used routinely.

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.

THREE-DIMENSIONAL SIMULATION SYSTEMS

Three-dimensional (3D) model printing of native RVOT and in vitro pre-procedural simulation of PPVI is promising for safe and precise implantation for complex and challenging RVOT anatomy to reduce complications. Odemis et al.²⁷⁾ from Türkiye and our research team are performing these 3D model printing and in vitro pre-procedural simulation test actively using Pulsta valve. From Odemis et al.’s²⁷⁾,²⁸⁾ data, they suggested that this approach allows for accurate valve sizing, minimization of oversized valve risks, preventing complications and valuable insights into hemodynamic behavior before implantation. Our research team is also making 3D printing model mimicking PA tissue properties which offer dynamic contraction and extension according to the forward flow at the mock circulation system (Figure 7, Supplementary Videos 1 and 2). This pre-procedural PPVI simulation was in accordance with real practice in a 20-year-old patient, who has reverse pyramidal shape main PA (Figure 7A), with pulmonary atresia and intact ventricular septum which was treated by balloon valvuloplasty just after birth (Supplementary Videos 3 and 4).

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.

LIMITATIONS OF PULSTA VALVE

Even though Pulsta valve has shown excellent safety and effectiveness for the treatment of various RVOT disease using its unique above-mentioned characteristics, there are several limitations to be solved for further progress. Firstly, rather compact and short total length of Pulsta valve (maximal total length ≤38 mm, only 4 mm proximal and distal flaring than valve outer diameter) could be a risk of device migration or embolization if height of the Pulsta valve anchoring point is narrow. Until now, there have been reported that 7 patients (0.9%) underwent additional operations because of Pulsta valve migration or embolization among 752 patients. Among them, 5 patients underwent Pulsta valve removal and surgical PVR and 2 patients underwent surgical fixation of Pulsta valve after open sternotomy. Secondly, the maximum diameter of Pulsta valve is 32 mm, however, we frequently meet patients with large main PA over 32 mm in real practice. Therefore, we need a larger Pulsta valve greater than 32 mm to expand the indication of Pulsta valve and TaeWoong medical company is trying to make bigger Pulsta valve for future candidate patients with large main PA which cannot accommodate 32 mm Pulsta valve. Thirdly, Korabiewska-Pluta et al.²⁴⁾ reported that 2 of 5 patients had abnormal motion of the leaflets with incomplete closure during early diastole and such a pattern presented once in a few cardiac cycles, which resulted in mild, short regurgitation. This observation would be quite unique finding after Pulsta valve implantation compared with other valves and which would be related with 2 unique features of Pulsta valve. The first feature is the woven knitted texture stent of Pulsta valve. The stent frame shape is not fixed during every cardiac cycle and is changed in shape according to each dynamic native RVOT contraction and distension. The second feature of Pulsta valve is the motion of leaflets. Three leaflets of Pulsta valve are basically prone to open, which means that there would be needed additional regurgitant volume to close 3 leaflets during diastolic phase. As the shape of the stent changes according to each cardiac cycle, it affects the closing of the cusp in either place, which may affect incomplete closing of one leaflet at early diastolic phase. Therefore, it is necessary to measure PR fraction during at least 10 cardiac cycles for correct measurement.

FUTURE PERSPECTIVE

Though the experience of Pulsta valve for various RVOT diseases is newly being 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. Pulsta valve has shown diverse applications in the various RVOT lesions including branch PAs and valve-in-valve procedures besides typical implantation at the native RVOT, it also could be implanted at the tricuspid valve position or inferior vena cava to control complications of tricuspid valve disease using its compact and flexible design. Because Pulsta valve itself provides an ideal landing zone for re-do PPVI, Pulsta valve-in-valve procedure could be possible when the previous Pulsta valve lost its function. We do not know how many times we can perform valve-in-valve procedure for Pulsta valve, however, we can estimate that it would be possible to perform at least 2–4 times of redo PPVI depends on the initial valve diameter according to the pathophysiology of Pulsta valve failure.

Because we have only 9 years of long-term follow up history about Pulsta valve since the first implantation,²⁰⁾ we should investigate long-term outcome result of Pulsta valve from diverse clinical observations from many centers where Pulsta valve has been implanted until now. For longer durability, Pulsta valve leaflets were treated as above-mentioned tissue engineering techniques to prevent leaflet calcification. However, ongoing hypo-attenuated leaflet thickening (HALT) and associated with hypoattenuation-affecting leaflet motion also could be a limitation factor for longer durability. Though every HALT lesion does not make valve dysfunction like our first Pulsta valve case 8 years after implantation (Figure 8), we should be careful to check the progression of HALT in the Pulsta valve and its association of valve failure. In most cases of Pulsta valve implantation, aspirin was prescribed for 6–12 months in our center. Because we still do not know the efficacy of life-long aspirin to prevent HALT in the Pulsta valve, we need to investigate the necessity of life-long antiplatelet or anti-coagulation prophylaxis after Pulsta valve implantation.

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.

SUPPLEMENTARY MATERIALS

Supplementary Video 1

The 3D model printing and in vitro simulation test, AP view.

Supplementary Video 2

The 3D model printing and in vitro simulation test, lateral view.

Supplementary Video 3

Main PA angiography after Pulsta valve implantation, RAO cranial view.

Supplementary Video 4

Main PA angiography after Pulsta valve implantation, lateral view.