Results of the multicenter early feasibility study (EFS) of the Renata Minima stent as treatment for branch pulmonary artery stenosis and coarctation of aorta in infants.

BACKGROUND: Stent implantation has become standard of care in older children and adults for treatment of branch pulmonary artery stenosis (BPAS) and coarctation aorta (CoAo). There are no stents approved or available for infants that have the potential to be dilated to adult diameters. The Minima stent was designed to fulfill this unmet need. METHODS: Multicenter, prospective, nonrandomized early feasibility study evaluating safety and effectiveness of the Minima stent for treatment of BPAS and CoAo. Primary endpoints included: (1) successful deployment across lesion, (2) stenosis relief defined by an increase in angiographic diameter of >50% and (3) freedom from stent explant, embolization or migration at 30 days and 6 months. RESULTS: Between 2/2022 and 5/2022, 10 pts underwent Minima stent implantation with a median age and weight of 9 months (4-43 months) and 7.6 kg (5.1-16.9 kg). Procedural success and predefined stenosis relief was achieved in all cases (CoAo [n = 4], BPAS [n = 6]). Adverse events occurred in 3 pts: transient diminished lower extremity pulse (n = 2), distal stent on-balloon displacement successfully managed in the catheterization suite (n = 1). There were no deaths or major adverse events. All patients were free from stent explant and migration at 30 days and 6 months with no evidence for significant restenosis at latest follow-up. CONCLUSIONS: Implantation of the Renata Minima stent was safe and effective for the treatment of BPAS and CoAo in this small cohort of infants and young children during early follow-up. Based on these early results, an expanded study with longer follow-up is warranted.

Applying the Hybrid Concept as a Bridge to Transplantation in Infants Without Hypoplastic Left Heart Syndrome.

Therapies to support small infants in decompensated heart failure that are failing medical management are limited. We have used the hybrid approach, classically reserved for high-risk infants with single ventricle physiology, in patients with biventricular physiology with left ventricular failure. This approach secures systemic circulation, relieves left atrial hypertension, protects the pulmonary vasculature, and allows the right ventricle to support cardiac output. This approach can be used as a bridge to transplantation in select individuals. Infants without single ventricle congenital heart disease who were treated with the hybrid approach between 2008 and 2021 were included in analysis. Eight patients were identified. At the time of hybrid procedure, the median weight was 3.2 kg (range 2.4-3.6 kg) and the median age was 18 days (range 1-153 days). Seventy five percent were mechanically ventilated and 88% were on inotropic support. The median duration from hybrid procedure to transplant was 63 days (range 4-116 days). All patients experienced a good outcome (delisted for improvement or transplanted). The hybrid procedure is an appropriate therapeutic bridge to transplantation in a carefully selected subset of critically ill infants without single ventricle congenital heart disease in whom alternate therapies may confer increased risk for morbidity and mortality.

Right ventricular outflow tract obstruction associated with neointimal tissue accumulation and distortion of the Harmony TPV25 stent frame: Potential mechanisms and treatment.

BACKGROUND: The Harmony TPV25 transcatheter pulmonary valve (Medtronic Inc.) is constructed with a self-expanding stent frame comprising six zigged nitinol wires sewn together and covered with knitted polyester fabric, with flared inflow and outflow ends and a porcine pericardial valve sutured to the central portion of the device. It was approved for treatment of pulmonary regurgitation after prior right ventricular outflow tract repair in 2021. Early outcomes of this procedure have been excellent, but little is known about valve durability or ultimate mechanisms of dysfunction. METHODS: We collected data on patients who underwent reintervention for TPV25 dysfunction and described findings related to distortion of the stent frame and tissue accumulation. RESULTS: We describe six patients who underwent valve-in-valve implant for TPV25 obstruction (peak catheterization gradient peak 28-73 mmHg) 10-28 months after implant. In all cases, there was tissue accumulation within the inflow and valve-housing segments of the device and deformation of the self-expanding valve frame characterized by variable circumferential narrowing at the junction between the valve housing and the inflow and outflow portions of the device, with additional geometric changes in all segments. All six patients underwent valve-in-valve implant that results in a final peak gradient ≤10 mmHg and no regurgitation. DISCUSSION: The occurrence of short-term Harmony TPV25 dysfunction in multiple patients with a similar appearance of frame distortion and tissue accumulation within the inflow and valve housing portions of the device suggests that this may be an important failure mechanism for this valve. Potential causes of the observed findings are discussed. It is possible to treat this mechanism of TPV25 dysfunction with valve-in-valve implant using balloon expandable transcatheter valves.

Pulmonary vein stenosis in heart transplant patients.

BACKGROUND: Pulmonary vein stenosis (PVS) is a rare pediatric condition associated with significant mortality and morbidity. PVS in patients following heart transplant (HT) has not yet been described. METHODS: Patients who had clinically significant PVS following a heart transplant during the time period of April 1, 2013 to April 30, 2023, at Seattle Children's Hospital were identified. Clinically significant PVS was defined as an atretic vein or a vein with a gradient of ≥4 mmHg across at least one vein by echocardiogram or during cardiac catheterization. Patients who had a diagnosis of PVS prior to their transplant were excluded. A total of six patients were identified. We collected clinical data on these patients from their pre-transplant course to their most recent status. RESULTS: The median age at HT was 7.5 months (range 2-13 months). The median time from HT to diagnosis of PVS was 3.5 months (range 0.3-13 months). At the last follow-up, the patients had had two to five pulmonary vein interventions, and there were no mortalities. The donor-to-recipient weight and total cardiac volume (TCV) ratios were less than 2.0 in five of six of the patients. CONCLUSIONS: PVS is a rare complication that is associated with patients who undergo HT during infancy. PVS develops soon after HT and screening should occur accordingly. Interestingly, high donor-to-recipient weight and TCV ratios are not necessarily associated with the development of PVS. Further work will need to be performed in order to determine the significance of PVS in post-HT patients.

Use of the PK Papyrus covered coronary stent in the treatment of Kawasaki disease-associated giant coronary artery aneurysms.

Kawasaki disease (KD) is an acute vasculitis that can cause coronary artery inflammation and aneurysm formation leading to early obstructive disease. We describe the use of PK Papyrus covered stents (Biotronic, Inc.) in three pediatric patients to exclude coronary artery aneurysms (CAA) from the circulation and relieve aneurysm associated stenoses. Follow-up angiography at 11-17 months postprocedure demonstrated persistent exclusion of CAA and varying degrees of in-stent restenosis (ISR). Two patients required percutaneous coronary intervention with drug eluting stent (DES) implantation to relieve in-stent stenosis. Our findings suggest that CAA exclusion with the PK Papyrus stent is possible and may be a valuable tool in simultaneously treating stenotic and thrombogenic CAA in pediatric KD patients. ISR of these non-DES remains an issue and may require additional interventions within the short-term to maintain vessel patency.

Late Outcomes of Transcatheter Coarctation Intervention in Infants with Biventricular Anatomy.

Determine outcomes of catheter intervention for aortic coarctation in infants. Aortic coarctation in infants following surgical repair and in high surgical risk native cases remains a challenging problem. Catheter intervention is an alternative to surgical intervention. Single-center, chart review of infants with biventricular anatomy who underwent coarctation stent placement or balloon angioplasty between 04/2004 and 04/2020. Outcomes of interest included change in aortic lumen diameter, peak gradient, number of re-interventions, time to re-intervention, and adverse events. Thirty-four patients were included in analysis, of those 16 underwent stent placement. Patients' mean age was 4.0 ± 3.0 months and weight of 5.3 ± 1.9 kg. Follow-up interval was 5.4 ± 5.1 years (0.2-16.1 years). Twelve (35%) patients underwent procedure due to ventricular dysfunction; the rest were for high resting gradient. Coarctation diameter increased from 2.4 ± 1.0 to 4.5 ± 1.3 (p < 0.01) and gradient decreased from 32.0 ± 18.4 mmHg to 9.2 ± 8.8 mmHg (p < 0.01). Thirteen (81%) of the stented patients required at least one re-intervention, at an average of 1.7 ± 3.2 years from the index procedure. Five (28%) of those undergoing balloon angioplasty required repeat intervention. There was no mortality due to the procedure and one late mortality. One patient had a serious procedural adverse event. On follow-up, 12 (35%) were on anti-hypertensive medications. Catheter intervention, including stent placement, for aortic coarctation in infants is feasible with an acceptable adverse event profile. Repeat interventions are common.

Hot topics in interventional cardiology: Proceedings from the society for cardiovascular angiography and interventions (SCAI) 2021 think tank.

The Society for Cardiovascular Angiography and Interventions (SCAI) Think Tank is a collaborative venture that brings together interventional cardiologists, administrative partners, and select members of the cardiovascular industry community annually for high-level field-wide discussions. The 2021 Think Tank was organized into four parallel sessions reflective of the field of interventional cardiology: (a) coronary intervention, (b) endovascular medicine, (c) structural heart disease, and (d) congenital heart disease. Each session was moderated by a senior content expert and co-moderated by a member of SCAI's Emerging Leader Mentorship program. This document presents the proceedings to the wider cardiovascular community in order to enhance participation in this discussion, create additional dialog from a broader base, and thereby aid SCAI, the industry community and external stakeholders in developing specific action items to move these areas forward.

Consensus Guidelines for the Prevention and Management of Periprocedural Complications of Transcatheter Patent Ductus Arteriosus Closure with the Amplatzer Piccolo Occluder in Extremely Low Birth Weight Infants.

Transcatheter closure of patent ductus arteriosus (PDA) in premature infants is a feasible, safe, and an effective alternative to surgical ligation and may be performed with an implant success rate of 97%. Major procedural complications related to transcatheter PDA closure in extremely low birth weight (ELBW) infants are relatively infrequent (< 3%) ,but may be associated with a fatality if not optimally managed. Operators performing transcatheter PDA closures should be knowledgeable about these potential complications and management options. Prompt recognition and treatment are often necessary to avoid serious consequences. With strict guidelines on operator training, proctoring requirements, and technical refinements, transcatheter PDA closure in ELBW infants can be performed safely with low complication rates. This article summarizes the consensus guidelines put forward by a panel of physicians for the prevention and management of periprocedural complications of transcatheter PDA closure with the Amplatzer Piccolo Occluder in ELBW infants.

Percutaneous Impella RP use for refractory right heart failure in adolescents and young adults-A multicenter U.S. experience.

OBJECTIVE: To assess the outcomes of the use of the percutaneous Impella RP device (Abiomed, Danvers, MA) in adolescents and young adults. BACKGROUND: Results of the Impella RP device have been reported in adults, but a multicenter experience in adolescents and young adults has yet to be reported. METHODS: Patients ≤21 years of age who underwent implantation of an Impella RP device for refractory right heart failure from June, 2016 to April, 2018 at nine U.S. Centers were included. RESULTS: A total of 12 adolescents, median age of 18 (14-21) years and median weight 74.4 (49-112.4) kg underwent Impella RP implantation (INTERMACS Profile 1 in nine and Profile 2 in three patients. The central venous pressure decreased from 20 (16-35) to 12 (7-17) mmHg, (p = .001). One patient was concomitantly supported with an intra-aortic balloon pump (IABP) and the rest with a percutaneous/surgically placed left ventricular assist device. There was one adverse event related to the Impella RP device (thrombosis requiring explant). The support duration was 6.5 days (4.8 hr-18.4 days) and survival to hospital discharge was 83%. At a median follow-up of 11 months (5 days-2.5 years), 8 of 12 (67%) patients are alive. CONCLUSIONS: In this multicenter experience, the Impella RP device was found to be efficacious and safe when used in adolescents and young adults. Further studies are warranted to identify suitable young/pediatric candidates for Impella RP therapy for right heart failure.

Amplatzer Piccolo Occluder clinical trial for percutaneous closure of the patent ductus arteriosus in patients ≥700 grams.

OBJECTIVES: Characterize the safety and effectiveness of the Amplatzer Piccolo Occluder for patent ductus arteriosus (PDA) closure. BACKGROUND: The presence of a hemodynamically significant PDA has been associated with an increased risk of morbidity and mortality in children born premature. METHODS: This was a single arm, prospective, multicenter, non-randomized study to evaluate the Amplatzer Piccolo Occluder to treat PDA in patients ≥700 g. From June 2017 to February 2019, 200 patients were enrolled at nine centers, with 100 patients weighing ≤2 kg. Primary effectiveness endpoint was the rate of PDA closure at 6-month follow-up. Primary safety endpoint was the rate of major complications through 6 months. Secondary endpoint was rate of significant pulmonary or aortic obstruction through 6 months' follow-up. RESULTS: The implant success rate was 95.5% (191/200) overall and 99% in patients ≤2 kg (99/100). The primary effectiveness endpoint was achieved in 99.4% of implanted patients. Four patients experienced a primary safety endpoint event (2 transfusions, 1 hemolysis, and 1 aortic obstruction). There were no branch pulmonary artery obstructions. Five patients, all ≤2 kg, were noted to have worsening of tricuspid regurgitation (TR) after the procedure. None of the TR incidences manifested clinically. The Amplatzer Piccolo Occluder received FDA approval in January 2019 and became the first device approved for PDA closure in patients ≥700 g. CONCLUSIONS: This study supports the safety and effectiveness of the Amplatzer Piccolo Occluder, particularly in patients between 700 g and 2 kg where there is currently a significant unmet need in the United States. ClinicalTrials.gov identifier: NCT03055858.