Aspirin Responsiveness in a Cohort of Pediatric Patients with Right Ventricle to Pulmonary Artery Conduits and Transcatheter Valve Replacement Systems.

The aim of this study was to determine the rate of aspirin responsiveness in a cohort of pediatric patients with in situ xenograft valved right ventricle to pulmonary artery (RV-PA) conduits and/or transcatheter valve replacements (TVR). Aspirin is routinely prescribed to these patients. Optimizing anti-platelet therapy could promote valve longevity and reduce the risk of infective endocarditis in this at-risk group. This was a prospective, observational study. Patients were recruited from both ward and outpatient settings. Patients were eligible if under 18 years and taking aspirin. Non-response to aspirin was defined as > 20% platelet aggregation using light transmission platelet aggregometry (LTA) and < 50% platelet inhibition by thromboelastography with platelet mapping (TEGPM). Participants were invited to provide a confirmatory sample in cases of aspirin resistance and dose adjustments were made. Thirty patients participated. Median age was 9 years (2 months to 18 years). The majority (93%) had complex right ventricular outflow tract pathology. 13 (43%) had an RV-PA conduit and 24 (80%) had a TVR, with valve situated in conduit in 7 (23%) cases. Rate of aspirin non-response on initial testing was 23% (n = 7/30) with median LTA 74.55% (60-76%) and TEG 13.25% (0-44%) in non-responders. Non-responders were more likely to be under 1 year. Two patients required dose increases and one patient non-adherence to dose was identified. Four patients on repeat testing were responsive to aspirin by laboratory tests. The rate of aspirin non-response on laboratory testing in this cohort of patients was 23% and resulted in therapeutic intervention in 10%.

Transfemoral Perimembranous Ventricular Septal Defect Device Closure in Infants Weighing ≤ 10 kg.

Transcatheter closure of Perimembranous VSDs (PMVSD) remains challenging particularly in infants. The aim of this study is to evaluate the efficacy and safety of transfemoral PMVSD device closure in infants weighing ≤ 10 kg in a single centre. Retrospective review of departmental databases and medical charts to define patient cohort and collect demographic, procedural and follow-up data. Between July 2014 and March 2021, 16 patients underwent attempted transfemoral PMVSD device closure (12 retrograde) at a median age of 11 months (interquartile range [IQR] 9-15.5) and a median weight of 8.3 kg (IQR 7.2-9.5). All patients were either symptomatic, had progressive left heart dilation or had VSD associated valve regurgitation. Median defect size on pre-procedural transoesophageal echocardiography was 6.8 mm (IQR 6-8.5). Median device waist size was 6 mm (IQR 4.5-8). Successful device placement was achieved in 14 patients (88%). One patient developed moderate aortic and tricuspid valve regurgitation upon retrograde and antegrade device deployment, respectively, and subsequently underwent surgical closure. The second patient developed progressive aortic regurgitation (AR) 2 days post procedure, and also underwent surgical removal with no residual AR. There was no cases of device embolization and no femoral arterial compromise. On median follow-up of 40.5 months (IQR 25-64), none of the patients developed complete heart block. Three patients (18.75%) had small residual shunts at latest follow-up which have not required any further intervention. Device closure of PMVSD's in children weighing ≤ 10 kg is feasible and safe with good procedural success rates. Use of both the antegrade and retrograde approaches may be necessary depending on anatomical variances.

An investigation into patient-specific 3D printed titanium stents and the use of etching to overcome Selective Laser Melting design constraints.

Due to limitations in available paediatric stents for treatment of aortic coarctation, adult stents are often used off-label resulting in less than optimal outcomes. The increasingly widespread use of CT and/or MR imaging for pre-surgical assessment, and the emergence of additive manufacturing processes such as 3D printing, could enable bespoke devices to be produced efficiently and cost-effectively. However, 3D printed metallic stents need to be self-supporting leading to limitations in their design. In this study, we investigate the use of etching to overcome these design constraints and improve stent surface finish. Furthermore, using a combination of experimental bench testing and finite element (FE) methods we investigate how etching influences stent performance. Then using an inverse finite element approach the material properties of the printed and etched stents were calibrated and compared. We show that without etching the titanium stents, the inverse FE approach underestimates the stiffness of the as-built stent (E = 33.89 GPa) when compared to an average of 76.84 GPa for the etched stent designs. Finally, using patient-specific finite element models the different stents' performance were tested to assess patient outcomes and lumen gain and vessel stresses were found to be strongly influenced by the stent design and postprocessing. Within this study, etching is confirmed as a means to create open-cell stent designs whilst still conforming to additive manufacturing 'rules' and concomitantly improving stent surface finish. Additionally, the feasibility of using an in-vivo imaging-to-product development pipeline is demonstrated that enables patient-specific stents to be produced for varying anatomies to achieve optimum device performance.

Atrioventricular septal defect and tetralogy of Fallot - A single tertiary center experience: A retrospective review.

BACKGROUND: Complete atrioventricular septal defect (CAVSD) in association with tetralogy of Fallot is a rare and complex disease that makes its repair more difficult than repair of either lesion alone. We reviewed retrospectively our experience in managing this lesion. PATIENTS AND METHODS: Between February 2006 and May 2017, 16 patients who underwent repair of CAVSD/tetralogy of Fallot (TOF) were reviewed retrospectively. Fifteen patients had trisomy 21. Five patients underwent primary repair while eleven patients went for staged repair in the form of right ventricular outflow tract (RVOT) stenting (n = 9) or systemic to pulmonary (S-P) surgical shunt (n = 2). RVOT stenting has replaced surgical shunt since 2012 in our center. Early presentation with cyanosis was the main determinant factor for staged versus primary repair. RESULTS: The median age at first palliation was 46 days (range 15-99 days). The median age at total repair for both groups was 6 months (range 3-18 months); the median age for the palliated patients was 6.5 months (range 5-18 months) while the median age for primary repaired patients was 5 months (range 3-11 months). The median weight at final repair was 6.9 kg (3.7-8.2 kg). The pulmonary valve was preserved in five patients (31%), four of them had no prior palliation. Chylothorax occurred in 50% of the patients. One late mortality occurred after final repair due to sepsis. CONCLUSION: CAVSD/TOF can be repaired with low mortality and morbidity. The use of RVOT stent has replaced the surgical (S-P) shunt with acceptable results in our center.

Going beyond the high-risk patient: the new boundaries for transcatheter device-focused therapy.

INTRODUCTION: Although congenital interventions continue to evolve to reach smaller and more complex patients, historically, adequate data collection and clinical trials have been lacking in comparison to adult coronary and structural interventions. This leads to difficulty in defining risk and providing meaningful data on risk-adjusted outcomes. AREAS COVERED: Risk-adjusted models have been recently developed for congenital interventions, and pre-procedural risk calculators are reaching everyday practice, providing an estimate of procedural risk to gauge the validity of a particular approach. These tools applied appropriately and consistently reviewed provide protection for physicians and patients alike and form the foundation of quality assessment and improvement. This review will outline many of the established and evolving interventions and surmise on how interventions in high-risk patients may be evaluated appropriately to encourage continued development of transcatheter therapies. Pre-assessment tools as well as risk-adjusted outcomes will be discussed, and the benefits and challenges of providing accurate data surrounding risk will be explored. EXPERT COMMENTARY: Risk assessment is part of the new frontier of congenital cardiac interventions. For the specialty to continue to meet expectations, appropriate engagement by institutions and physicians in evaluating risk must mirror the development of the technical aspects of procedures.

The 2017 Seventh World Congress of Pediatric Cardiology & Cardiac Surgery: week in review - interventional cardiology.

The interventional cardiology track at the 7th World Congress of Pediatric Cardiology and Cardiac Surgery reflects the pivotal position of transcatheter interventions in the future of our speciality. The highlights of the week are outlined in this review.

Current Status and Future Potential of Transcatheter Interventions in Congenital Heart Disease.

Percutaneous therapies for congenital heart disease have evolved rapidly in the past 3 decades. This has occurred despite limited investment from industry and support from regulatory bodies resulting in a lack of specific device development. Indeed, many devices remain off-label with a best-fit approach often required, spurning an innovative culture within the subspecialty, which had arguably laid the foundation for many of the current and evolving structural heart interventions. Challenges remain, not least encouraging device design focused on smaller infants and the inevitable consequences of somatic growth. Data collection tools are emerging but remain behind adult cardiology and cardiac surgery and leading to partial blindness as to the longer-term consequences of our interventions. Tail coating on the back of developments in other fields of adult intervention will soon fail to meet the expanding needs for more precise interventions and biological materials. Increasing collaboration with surgical colleagues will require development of dedicated equipment for hybrid interventions aimed at minimizing the longer-term consequences of scar to the heart. Therefore, great challenges remain to ensure that children and adults with congenital heart disease continue to benefit from an exponential growth in minimally invasive interventions and technology. This can only be achieved through a concerted collaborative approach from physicians, industry, academia, and regulatory bodies supporting great innovators to continue the philosophy of thinking beyond the limits that has been the foundation of our specialty for the past 50 years.

Surgical repair of left ventricular pseudoaneurysm following perventricular device closure of muscular ventricular septal defect.

Left ventricular pseudoaneurysm formation following perventricular device closure of a muscular ventricular septal defect is a rare complication. We describe a case of left ventricular pseudoaneurysm in an infant with Swiss-cheese ventricular septal defects who initially underwent closure with an Amplatzer device using a hybrid approach. The pseudoaneurysm was successfully resected surgically.

Transcatheter Tricuspid Valve-in-Valve Implantation for the Treatment of Dysfunctional Surgical Bioprosthetic Valves: An International, Multicenter Registry Study.

BACKGROUND: Off-label use of transcatheter aortic and pulmonary valve prostheses for tricuspid valve-in-valve implantation (TVIV) within dysfunctional surgical tricuspid valve (TV) bioprostheses has been described in small reports. METHODS AND RESULTS: An international, multicenter registry was developed to collect data on TVIV cases. Patient-related factors, procedural details and outcomes, and follow-up data were analyzed. Valve-in-ring or heterotopic TV implantation procedures were not included. Data were collected on 156 patients with bioprosthetic TV dysfunction who underwent catheterization with planned TVIV. The median age was 40 years, and 71% of patients were in New York Heart Association class III or IV. Among 152 patients in whom TVIV was attempted with a Melody (n=94) or Sapien (n=58) valve, implantation was successful in 150, with few serious complications. After TVIV, both the TV inflow gradient and tricuspid regurgitation grade improved significantly. During follow-up (median, 13.3 months), 22 patients died, 5 within 30 days; all 22 patients were in New York Heart Association class III or IV, and 9 were hospitalized before TVIV. There were 10 TV reinterventions, and 3 other patients had significant recurrent TV dysfunction. At follow-up, 77% of patients were in New York Heart Association class I or II (P<0.001 versus before TVIV). Outcomes did not differ according to surgical valve size or TVIV valve type. CONCLUSIONS: TVIV with commercially available transcatheter prostheses is technically and clinically successful in patients of various ages across a wide range of valve size. Although preimplantation clinical status was associated with outcome, many patients in New York Heart Association class III or IV at baseline improved. TVIV should be considered a viable option for treatment of failing TV bioprostheses.