First experience with andraStent XL implantation in children and adolescents with congenital heart diseases

Advances in the Treatment of Pulmonary Valve Stenosis

Pulmonary valve stenosis represents the most common congenital heart defect of dogs and appears to be increasing in prevalence due to the growing popularity of brachycephalic breeds. Current treatments include beta-blockade and balloon pulmonary valvuloplasty, though evidence-based approaches to this disease are lacking. Balloon pulmonary valvuloplasty is most effective for fused, doming valves leaving a large population of dogs with thick, dysplastic valves that fail to respond adequately to balloon dilation. Transpulmonary stent implantation is an emerging therapy to consider for dogs with valve dysplasia or who have failed balloon pulmonary valvuloplasty; current experience with transpulmonary stent implantation is provided.

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.

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

BACKGROUND

The indications for percutaneous pulmonary valve implantation (PPVI) have been extended to include large dysfunctional right ventricular outflow tracts (RVOTs). Prestenting of the RVOT is commonly performed before PPVI in order to ensure a stable landing zone. The AndraStent XXL (AndraMed GmbH, Reutlingen, Germany), a cobalt-chromium stent with semi-open cell design, has unique mechanical properties in this indication but is no longer available in France.

AIMS

To assess the efficiency of AndraStent XXL before PPVI.

METHODS

In this retrospective multicentre cohort study, 86 AndraStents XXL were implanted in 77 patients in 6 centres.

RESULTS

PPVI was indicated mainly for pulmonary regurgitation (75.3%) in native or patched RVOT (88.3%). The stents were manually mounted on balloon catheters and delivered through sheaths using a conventional femoral approach. PPVI was performed successfully in 97.4% of patients after successful prestenting, generally during the same procedure (77.9%). There were no deaths associated with stent implantation, and four patients experienced five complications, mainly stent embolization, including one requiring surgery. Neither stent fracture nor dysfunction were observed in any patient during a mean follow-up of 19.2±8.7months. Stent analysis showed an excellent maximal stent expansion (97.1%) regardless of balloon size. A 22.3%±3.4 stent shortening with a 30mm balloon was observed.

CONCLUSIONS

Implantation of large cobalt-chromium AndraStent XXL stents is efficient for prestenting before PPVI.

First in man study of a new semi-open cell design Zephyr cobalt-chromium stent in large vessels and conduits

OBJECTIVES

We present a first-in-man clinical use of a new hybrid design stent in stenosed large vessels. Its unique C and S polylinks prevent foreshortening without compromising its strength. Its thin profile permits use of smaller introducer sheaths.

BACKGROUND

Stent angioplasty is widely employed in large vessel and conduit stenosis. These procedures are associated with difficulties due to large stent profiles, stent fractures, foreshortening and recoil. Cobalt chromium stents have high tensile strengths compared to stainless steel stents.

METHODS

A retrospective analysis of feasibility and safety of a new Cobalt chromium stent in large vessels namely aorta, pulmonary arteries and outflow conduits was done from two institutions. Demographic patient details, procedural results, complications and medium term follow-up were analyzed. Stent recoil, foreshortening, fractures were assessed.

RESULTS

Twenty patients including three with aortic coarctations, seven with stenosed conduits and 10 with pulmonary artery stenosis underwent stent angioplasty using 23 stents. Three stents were deployed to expand further a previously implanted stent. Procedure was successful in all patients, lumen increased by 150-300%, gradients reduced in all patients. There was no stent recoil, foreshortening or fractures. There were no complications. At a follow up of 3-27 months, there were no stent related complications and the gradients remained stable.

CONCLUSIONS

The new Zephyr stent was useful in a wide variety of stenotic lesions involving large vessels including those that were previously stented. Lack of stent recoil and foreshortening seems to be an advantage for this new stent that needs validation in larger multicenter studies.

Computed tomography image quality of aortic stents in patients with aortic coarctation: a multicentre evaluation

BACKGROUND

Stents are commonly used to treat aortic coarctation. The objective of this study was to evaluate the post-implantation computed tomography (CT) image quality of different stent types used to treat aortic coarctation.

METHODS

Adult and paediatric patients with stent-treated aortic coarctation who underwent contrast-enhanced CT were retrospectively included from three tertiary care centres. CT scans were subjectively scored for image quality using a 4-point scale (1 = unacceptable; 2 = poor; 3 = good; 4 = excellent). Furthermore, the amount of stent-induced blooming artefacts was measured as the percentage of the difference between outer and inner stent diameters over the outer stent diameter.

RESULTS

A total of 35 children and 34 adults implanted with 71 stents of six different types were included. The most commonly used stent type was the Cheatham Platinum stent (52 stents, 73%). The subjective image quality of the Cheatham Platinum stents was moderate with a score of 2.0±0.8 (mean ± standard deviation) in children and 2.3±0.6 in adults. The image quality in patients with Formula stents was 2.3±1.2. The Cheatham Platinum stents induced 34-48% blooming, the Formula stents 44-55%. The image quality in patients with the less commonly used Atrium Advanta V12, IntraStent, AndraStent and Palmaz stents was scored 3 (good) to 4 (excellent) with less blooming. The electrocardiographic gating and tube voltage (kVp) did not affect image quality.

CONCLUSIONS

There is a substantial variation in CT image quality and blooming artefacts for different stent types used to treat aortic coarctation.

Use of the AndraStent XL and XXL for the treatment of coarctation of the aorta in children and adults: immediate and midterm results

AIMS

The aim of this study is to present our experience with a new type of extra-large stent, namely the AndraStent XL/XXL.

METHODS AND RESULTS

AndraStents were implanted in 46 patients, 38 with native coarctation of the aorta (CoA) and eight with recurrent coarctation of the aorta following previous surgery (ReCoA). All patients had arterial hypertension in the upper limbs, absent or weak femoral pulses, and continuous flow in the abdominal aorta on Doppler examination. The median age of patients was 25 years (range from nine to 65). The stents (cobalt-chromium with semi-open cell design) were manually mounted on balloon catheters and delivered through 10 to 14 Fr Mullins sheaths using a conventional femoral approach. All procedures were successful (no stent migration, proper expansion, no aorta dissection/rupture, major bleeding or major vessel injury). The systolic gradient across the aorta decreased from 40.6 mmHg before the procedure to 11.6 mmHg after the procedure (p<0.001). The mean fluoroscopy time was 5.7 minutes. Imaging examinations were scheduled and performed between six and 12 months after the initial procedure in 40 patients (angiography or angio CT or both). Procedural outcome remained favourable during a mean 2.4 years of follow-up. Neither stent fracture nor dislocation was observed in any patient at follow-up. In two patients, small aneurysm formation was observed six and eight months after the procedure -they were treated successfully with subsequent covered stent implantation. Re-dilatation of the implanted stent was performed between four and 26 months in 14 patients.

CONCLUSIONS

Implantation of new large cobalt-chromium stents is a good therapeutic option for the treatment of native and recurrent CoA.

"Intraoperative hybrid stenting of recurrent coarctation and arch hypoplasia with large stents in patients with univentricular hearts"

BACKGROUND

Obstruction of the reconstructed aortic arch, tubular hypoplasia and recurrent coarctation (RC) is an important risk factor in univentricular physiology. For the past two years we have adopted the concept of intraoperative hybrid stenting of RC and arch hypoplasia with large stents in patients with univentricular hearts as standard care procedure.

METHOD/RESULT

Retrospective analysis of the anatomy and procedural outcome of 14 patients was scheduled for intraoperative stenting of the aortic arch (12 during surgery for BCPS, 2 during Fontan completion). The median age was 5.3 months, weight 5.5 kg, height 62 cm. Five patients had tubular hypoplasia and 9 patients had distal stenosis of the aortic arch. Nine patients had a previous balloon dilatation. The mean diameter of the distal arch was 11.0mm, at the coarctation 5.1mm, at the level of the diaphragm 8.2mm (CoA-index 0.62). Intraoperative stenting was performed in 13/14 patients. Stents were implanted with a mean balloon diameter of 10.8mm (SD 3.4mm). The achieved final mean diameter was 9.8mm (mean, SD 2.8mm) with an oversized Coa-index of 1.2. There was no re-coarctation at a mean follow-up of 7.3 months (range 3 to 24), the maximum flow velocity of 2m/s across the stented lesion assessed by ECHO.

CONCLUSION

This hybrid approach is an easy and safe concept to manage recurrent aortic arch hypoplasia and stenosis. The use of large stents allows redilatation to adult size diameters later on.

Stents in paediatric and adult congenital interventional cardiac catheterization

A 'stent' is a tubular meshed endoprosthesis that has contributed to the development of interventional catheterization over the past 30 years. In congenital heart diseases, stents have offered new solutions to the treatment of congenital vessel stenosis or postsurgical lesions, to maintain or close shunt patency, and to allow transcatheter valve replacement. First, stents were made of bare metal. Then, stent frameworks evolved to achieve a better compromise between radial strength and flexibility. However, almost all stents used currently in children have not been approved for vascular lesions in children and are therefore used 'off-label'. Furthermore, the inability of stents to follow natural vessel growth still limits their use in low-weight children and infants. Recently, bioresorbable stents have been manufactured and may overcome this issue; they are made from materials that may dissolve or be absorbed in the body. In this review, we aim to describe the history of stent development, the technical characteristics of stents used currently, the clinical applications and results, and the latest technological developments and perspectives in paediatric and adult congenital cardiac catheterization.