Right ventricular outflow tract prestenting with AndraStent XXL before percutaneous pulmonary valve implantation

Standardized Bench Test Evaluation of Biomechanical Characteristics of Stents Used in Right Ventricular Outflow Tract Revalvulation

PURPOSE

Pre-stenting of the right ventricular outflow tract (RVOT) is commonly performed before percutaneous pulmonary valve implantation (PPVI), to relieve obstruction, prevent valved stent fractures, and provide a landing zone. This study aimed to evaluate the biomechanical characteristics of the stents currently used to perform pre-stenting of the RVOT.

METHODS

We assessed five commercially available stents: Cheatham-Platinum Stent ("CP Stent"), AndraStent XL, AndraStent XXL, Optimus XL, and Optimus XXL. Following stent deployment at nominal pressure, radial and longitudinal elastic recoils and radial resistance were measured. The bending stiffness of the stents crimped onto the balloons was also evaluated.

RESULTS

Three samples were tested for each stent. Our study showed no significant difference between the stent platforms in terms of radial elastic recoil, which was relatively low (< 10%). The longitudinal elastic recoil was also low for all the devices (< 5%). Significant differences were observed in radial resistance (P < 0.001). CP Stent and AndraStent XL exhibited the highest radial resistances. The bending stiffnesses of the stents crimped on their balloons were significantly different (P < 0.00001). Optimus XL and XXL were more flexible than the other stents.

CONCLUSION

This study highlights the significant differences between the stents currently used in RVOT pre-stenting. Stents with good radial resistance are preferred, especially for calcified vessels, and flexibility is crucial for tortuous vessels. We proposed an algorithm for selecting the most suitable stent according to the need for radial force and flexibility, which will help inform clinicians considering RVOT revalvulation.

Current status of transcatheter intervention for complex right ventricular outflow tract abnormalities

Various transcatheter interventions for the right ventricular outflow tract (RVOT) have been introduced and developed in recent decades. Transcatheter pulmonary valve perforation was first introduced in the 1990s. Radiofrequency wire perforation has been the approach of choice for membranous pulmonary atresia in newborns, with high success rates, although complication rates remain relatively common. Stenting of the RVOT is a novel palliative treatment that may improve hemodynamics in neonatal patients with reduced pulmonary blood flow and RVOT obstruction. Whether this option is superior to other surgical palliative strategies or early primary repair of tetralogy of Fallot remains unclear. Transcatheter pulmonary valve replacement has been one of the biggest innovations in the last two decades. With the success of the Melody and SAPIEN valves, this technique has evolved into the gold standard therapy for RVOT abnormalities with excellent procedural safety and efficacy. Challenges remain in managing the wide heterogeneity of postoperative lesions seen in RVOT, and various technical modifications, such as pre-stenting, valve ring modification, or development of self-expanding systems, have been made. Recent large studies have revealed outcomes comparable to those of surgery, with less morbidity. Further experience and multicenter studies and registries to compare the outcomes of various strategies are necessary, with the ultimate goal of a single-step, minimally invasive approach offering the best longer-term anatomical and physiological results.

A Modified Technique for Transcatheter Pulmonary Valve Implantation of SAPIEN 3 Valves in Large Right Ventricular Outflow Tract: A Matched Comparison Study

INTRODUCTION

Percutaneous pulmonary valve implantation (PPVI) with a SAPIEN 3 valve is effective for treating treat right ventricle outflow (RVOT) dysfunction. A modified technique was developed without prestenting using a protective valve delivery method. We aimed to compare the procedural results of the modified technique group (MTG) to those of patients in a conventional technique group (CTG).

METHODS

We designed a matched before-after study. All consecutive PPVI with SAPIEN 3 performed in the MTG over 9 months were matched, based on the RVOT type and size, to consecutive procedures performed previously with SAPIEN 3.

RESULTS

A total of 54 patients were included, equally distributed in the two groups. The sizes of the SAPIEN 3 valves were 23 mm (n = 9), 26 mm (n = 9), 29 mm (n = 36). The two groups were similar regarding demographic data, RVOT type, and pre-procedure hemodynamics. PPVI was performed in a single procedure in all patients of the MTG, whereas six (22.2%) patients of the CTG group underwent prestenting as a first step and valve implantation later (p = 0.02). The procedures were successful in all cases. Stent embolization was reported in two patients (7.4%) in the CTG, which were impacted in pulmonary arteries. In one case (3.7%), in the MTG, an unstable 29 mm SAPIEN 3 valve was stabilized with two stents and additional valve-in-valve implantation. The hemodynamics results were good in all cases, without significant differences between the two groups. The procedures' durations and fluoroscopy times were significantly reduced in the MTG (48.1 versus 82.6 min, p < 0.0001; 15.2 versus 29.8 min, p = 0.0002). During follow-up, neither stent fracture nor valve dysfunction was noticed in either group.

CONCLUSION

PPVI without prestenting and with a protective delivery method of the SAPIEN 3 valve significantly reduces the procedure's complexity, the duration, and the irradiation while maintaining excellent hemodynamics results in selected cases.

Balloon-Expandable Pulmonary Valves for Patched or Native Right Ventricular Outflow Tracts

The implantation of percutaneous balloon expandable valves in native or patched right ventricular outflow tracts (nRVOT) is a challenging technique due to the diversity of anatomies and shapes, the large sizes, and the distensibility of the nRVOT, for which specific techniques have been developed. We present a single center experience with balloon expandable percutaneous pulmonary valves in nRVOT, describing the techniques used, complications observed, and a short-mid term follow-up.. This is a single center descriptive study of patients who underwent a percutaneous pulmonary valve implantation in a nRVOT with a balloon expandable pulmonary valve in our center between September 2012 and June 2022.. We implanted successfully 45 valves in 46 patients (20 Sapien and 25 Melody). Tetralogy of Fallot or pulmonary atresia with VSD were the main congenital heart disease (n = 32). All were pre-stented, 18 in a one step procedure. We used a Dryseal sheath in 13/21 Sapien. In 6 patients we used the anchoring technique, 5 with a very large nRVOT and one pyramidal nRVOT. In the 3.5 year follow-up 7 patients developed endocarditis and 3 required a valve redilation, no fractures were observed. PPVI of native RVOT with balloon expandable valves is feasible in a number of selected anatomies, including large or pyramidal nRVOT, using specific techniques, (presenting, LPA anchoring).

Multicentre experience with Optimus balloon-expandable cobalt-chromium stents in congenital heart disease interventions

OBJECTIVES

To evaluate bare-metal Optimus and polytetrafluoroethylene (PTFE)-covered Optimus-CVS balloon-expandable, cobalt-chromium, hybrid cell-designed stents in congenital heart disease (CHD) interventions.

METHODS

Retrospective multicentre review of patients with CHD receiving Optimus stents. Stent mechanical behaviour, clinical indications and outcomes were assessed.

RESULTS

183 stents (49.2% XXL/15-ZIG, 33.3% XL/12-ZIG, 17.5% L/9-ZIG) were implanted (98.9% success rate, 2.3% serious procedural complication rate) in 170 patients (57.6% men, 64.1% adults), median age 23.6 years (IQR, 15.2-39.2) and weight 63.5 kg (IQR, 47-75.7). Indications were right ventricular outflow tract stand-alone stenting or before revalvulation (62.4%), aortic coarctation treatment (15.3%), Fontan-circuit fenestration closure (12.4%) and miscellaneous (10%). 86/170 (50.6%) patients had PTFE-covered stenting (50% prophylactic). In 86/170 (50.6%) patients with stenotic lesions, median percentage of achieved stent expansion was 93.4% (IQR, 85.5%-97.7%), median gradient decreased from 28 mm Hg (IQR, 19-41) to 5 mm Hg (IQR, 1-9) (p<0.001), median vessel diameters increased from 13 mm (IQR, 7.9-17) to 18.9 mm (IQR, 15.2-22) (p<0.001) and percentage of vessel expansion was 45.2% (IQR, 19.8%-91.3%). In 30/36 (83.3%) patients with graft, median dilation of 2 mm (IQR, 2-5) above nominal diameter was achieved. Median stent shortening was 10.9% (IQR, 6.1-15.1) and was associated only with expansion diameter (OR: 0.66, 95% CI: 0.38 to 0.93). No clinically relevant fracture, stent embolisation or dysfunction occurred on a median follow-up of 9 (IQR, 4-14) months.

CONCLUSIONS

Optimus stents are effective tools for transcatheter treatment of simple and complex CHD. Optimus stents' reliable mechanical behaviour and particular covering design can promote widespread use.

Long-term outcomes of transcatheter pulmonary valve implantation with melody and SAPIEN valves

BACKGROUND

Transcatheter pulmonary valve implantation (TPVI) is effective for treating right ventricle outflow tract (RVOT) dysfunction. Factors associated with long-term valve durability remain to be investigated.

METHODS

Consecutive patients successfully treated by TPVI with Melody valves (n = 32) and SAPIEN valves (n = 182) between 2008 and 2020 at a single tertiary centre were included prospectively and monitored.

RESULTS

The 214 patients had a median age of 28 years (range, 10-81). The RVOT was a patched native pulmonary artery in 96 (44.8%) patients. Median follow-up was 2.8 years (range, 3 months-11.4 years). Secondary pulmonary valve replacement (sPVR) was performed in 23 cases (10.7%), due to stenosis (n = 22, 95.7%) or severe regurgitation (n = 1, 4.3%), yielding an incidence of 7.6/100 patient-years with melody valves and 1.3/100 patient-years with SAPIEN valves (P = 0.06). The 5- and 10-year sPVR-freedom rates were 78.1% and 50.4% with Melody vs. 94.3% and 82.2% with SAPIEN, respectively (P = 0.06). The incidence of infective endocarditis (IE) was 5.5/100 patient-years with Melody and 0.2/100 patient-years with SAPIEN (P < 0.0001). Factors associated with sPVR by univariate analysis were RV obstruction before TPVI (P = 0.04), transpulmonary maximal velocity > 2.7 m/s after TPVI (p = 0.0005), valve diameter ≤ 22 mm (P < 0.003), IE (P < 0.0001), and age < 25 years at TPVI (P = 0.04). By multivariate analysis adjusted for IE occurrence, transpulmonary maximal velocity remained associated with sPVR.

CONCLUSIONS

TPVI is effective for treating RVOT dysfunction. Incidence of sPVR is higher in patients with residual RV obstruction or IE. IE add a substantial risk of TPVI graft failure and is mainly linked to the Melody valve.

SOCIAL MEDIA ABSTRACT

Transcatheter pulmonary valve implantation is effective for treating right ventricular outflow tract dysfunction in patients with congenital heart diseases. Incidence of secondary valve replacement is higher in patients with residual obstruction or infective endocarditis.

Piggyback mounting for stent and valve deployment during percutaneous pulmonary valve implantation

OBJECTIVES

We report our experience in simultaneously implanting multiple stents and valves mounted on a single balloon before and during transcatheter pulmonary valve placement.

BACKGROUND

Heterogeneity and complexity of the right ventricular outflow tract (RVOT) may complicate stent deployment when preparing a landing zone for transcatheter pulmonary valve implantation.

METHODS

Retrospective analysis of patients from Children's Hospital of Colorado, USA; and Oslo University Hospital, Norway, undergoing transcatheter pulmonary valve replacement that had at least two stents mounted on a single balloon, deployed in the RVOT.

RESULTS

Over a 42-month period, a total of 50 subjects from the two centers met inclusion criteria for the study. Subjects were predominantly male (58%), and the median age was 17 years (4-78 years). In six subjects (12%), there was need for prestenting with use of the double or triple stent piggyback technique. Forty subjects (80%) had a Melody ™ TPV implanted. In 45 cases (90%), one or more stents were mounted over the pulmonary valve using its delivery system, either the Ensemble for the Melody™ TPV or the Edwards Commander for the SAPIEN 3 THV. Thirty-seven subjects (74%) had one stent mounted and eight subjects (16%) had two stents mounted over the pulmonary valve for simultaneous deployment. No complications related to this technique were reported.

CONCLUSIONS

The piggyback technique aims to simplify and facilitate adequate conduit preparation and valve insertion by minimizing manipulation across the outflow tract and decreasing the risk of stent distortion, misalignment, and embolization.

Unique challenges posed by a dysfunctional native right ventricular outflow tract for percutaneous pulmonary valve implantation using SAPIEN-S3 valve

Dysfunctional right ventricular outflow tracts after a repair for tetralogy of Fallot using a transannular patch offer limited nonsurgical opportunities due to their large dimensions. A discrete subannular narrowing between a dilated right ventricle and the enlarged pulmonary trunk was a potential anatomical target for the creation of a landing zone using a prestent in a young male with severe pulmonary regurgitation and moderate stenosis. Asymmetric expansion of the prestent in the angulated outflow tract led to distal stent embolization that was stabilized by another telescoping stent before successful valve implantation. This manuscript details the unique challenges posed by a dilated regurgitant outflow tract for implanting a pulmonary valve.

A New Solution for Stenting Large Right Ventricular Outflow Tracts Before Transcatheter Pulmonary Valve Replacement

BACKGROUND

Prestenting right ventricular outflow tracts (RVOTs) before transcatheter pulmonary valve replacement (TPVR) is essential. Optimus-XXL (AndraTec GmbH, Koblenz, Germany) is a new extra-large, balloon-expandable cobalt-chrome stent with promising technologies.

METHODS

From June 2020 to November 2020, 15 patients with congenital heart disease, dysfunctional RVOTs and target TPVR diameter ≥ 23 mm received Optimus-XXL stents before proceeding to TPVR using the SAPIEN valve (Edwards Lifesciences, Irvine, CA). Standard safety and outcomes were prospectively assessed.

RESULTS

Patients' median age and weight were 25.8 years (range: 10.5-63.1 years) and 58 kg (range: 43.8-101 kg), respectively. Underlying diagnosis was tetralogy of Fallot (66.7%), and RVOTs were patched (80%). Fifteen bare-metal stents were implanted using femoral (n = 14) and jugular approaches (n = 1). One conduit rupture was immediately controlled with a covered Optimus-XXL. Median stent length was 43 mm (range: 33-57 mm), and median target expansion diameter was 28 mm (range: 23-30 mm). Two procedural incidents occurred during stent delivery and were percutaneously treated. Stent stability was documented during TPVRs immediately performed in 14 patients. Median stent shortening was 13.7%, and median percentage of intended stent expansion was 95.9%. There was no stent fracture on the short-term follow-up (median: 4.5 months).

CONCLUSIONS

We report the first implantations of Optimus-XXL stents in dysfunctional RVOTs with excellent preliminary results. Optimus-XXL should be considered as a valuable adjunct in the armamentarium for routine and complex TPVR procedures.