Twinning International Pediatric Cardiology Fellowship Programs: A Transformative Educational Experience for Trainees with Potential for Global Adoption.

Over the last decade, having endured the COVID-19 pandemic, education and training in pediatric cardiology have undergone a profound disruptive transformation. Trainees experience considerable stress achieving all the competencies required to become a competent pediatric cardiologist. Often the quality of the training experienced by trainees, the approach to patients, and potential institutional preference in management strategy is heavily influenced by the center in which they train. We developed an online live twin program of education between Texas Children's Hospital, Houston, Texas and Children's Health at Crumlin Dublin Ireland in 2019. We explored using grounded theory whether a regular scheduled shared teaching program improved fellow education and training between both centers. Trainees were surveyed to evaluate the benefits and disadvantages of such a twin program. The majority (93%) found the sessions helpful from an educational standpoint with many trainees reporting it to be a transformative experience. Three important learning themes emerged: practice variation between centers, managing uncertainty in clinical practice and cognitive overload. This pedagogical model could be replicated across multiple international pediatric cardiology units and facilitate "collaborative learning" among centers across the globe. Furthermore, this novel educational model could also be adopted by other medical specialties.

Cardiac Rhabdomyomas Presenting with Critical Cardiac Obstruction in Neonates and Infants: Treatment Strategies and Outcome, A Single-Center Experience.

Cardiac rhabdomyomas are the most common benign pediatric heart tumor in infancy, which are commonly associated with tuberous sclerosis complex (TSC). Most rhabdomyomas are asymptomatic and spontaneously regress over time. However, some cases especially in neonates or small infants can present with hemodynamic instability. Surgical resection of the tumor, which has been the gold standard in alleviating obstruction, is not always possible and may be associated with significant morbidity and mortality. Recently, mammalian target of rapamycin inhibitors (mTORi) have been shown to be safe and effective in the treatment of TSC. We present the outcomes of neonates and an infant who received treatment for symptomatic rhabdomyomas at a tertiary cardiology center. Medical records were reviewed to obtain clinical, demographic, and outcome data. Six patients received interventions for symptomatic rhabdomyomas, median age at presentation was 1 day old (range from 1 to 121 days old), and 67% of the patients had a pathogenic mutation in TSC gene. One patient underwent surgical resection of solitary tumor at right ventricular outflow tract (RVOT) successfully. In the four patients with left ventricular outflow tract (LVOT) obstruction, two patients received combined therapy of surgical debulking of LVOT tumor, Stage I palliation procedure, and mTORi and two patients received mTORi therapy. One patient with RVOT obstruction underwent ductal stenting and received synergistic mTORi. Four of the five patients had good response to mTORi demonstrated by the rapid regression of rhabdomyoma size. 83% of patients are still alive at their latest follow-up, at two to eight years of age. One patient died on day 17 post-LVOT tumor resection and Hybrid stage one due to failure of hemostasis, in the background of familial factor VII deficiency. Treatment of symptomatic rhabdomyoma requires individualized treatment strategy based on the underlying pathophysiology, with involvement of multidisciplinary teams. mTORi is effective and safe in inducing rapid regression of rhabdomyomas. A standardized mTORi prescription and monitoring guide will ensure medication safety in neonates and infants with symptomatic cardiac rhabdomyoma. Although the majority of tumors responded to mTORi, some prove to be resistant. Further studies are warranted, ideally involving multiple international centers with a larger number of patients.

Organizational Culture as a Determinant of Outcome in Teams: Implications for the Pediatric Cardiac Specialist.

Although enormous effort has focussed on how to build an effective culture in the business community, relatively little effort has addressed how to achieve this in the hospital environment, specifically related to the field of congenital heart disease teams. The examination of culture in pediatric cardiac care is particularly important for several key reasons: first, it represents high-stakes medicine, second, there are multiple stakeholders requiring collaboration between cardiologists, surgeons, anaesthesiologists, perfusionists, nursing staff, and allied health care professionals, and finally, both the patient and the family are intimately involved in the care pathway. This review article investigates some of the critical components to building an effective culture, drawing upon similarities in other disciplines, thereby fostering high performance multidisciplinary teams in congenital cardiology care. Strategies to change culture such as Kotter's model of change are also discussed. High performance teams share one common vital characteristic: psychological safety for team members to speak their minds, thereby fostering an open culture, in which creativity can flourish to facilitate major breakthroughs. Adoption of the "Flight Plan" review promotes patient centric care and champions a psychologically safe culture.

Multimodality imaging in delineation of complex sinus venosus defects and treatment outcomes over the last decade.

BACKGROUND: Diagnosis of sinus venosus defects, not infrequently associated with complex anomalous pulmonary venous drainage, may be delayed requiring multimodality imaging. METHODS: Retrospective review of all patients from February 2008 to January 2019. RESULTS: Thirty-seven children were diagnosed at a median age of 4.2 years (range 0.5-15.5 years). In 32 of 37 (86%) patients, diagnosis was achieved on transthoracic echocardiography, but five patients (14%) had complex variants (four had high insertion of anomalous vein into the superior caval vein and three had multiple anomalous veins draining to different sites, two of whom had drainage of one vein into the high superior caval vein). In these five patients, the final diagnosis was achieved by multimodality imaging and intra-operative findings. The median age at surgery was 5.2 years (range 1.6-15.8 years). Thirty-one patients underwent double patch repair, four patients a Warden repair, and two patients a single-patch repair. Of the four Warden repairs, two patients had a high insertion of right-sided anomalous pulmonary vein into the superior caval vein, one patient had bilateral superior caval veins, and one patient had right lower pulmonary vein insertion into the right atrium/superior caval vein junction. There was no post-operative mortality, reoperation, residual shunt or pulmonary venous obstruction. One patient developed superior caval vein obstruction and one patient developed atrial flutter. CONCLUSION: Complementary cardiac imaging modalities improve diagnosis of complex sinus venosus defects associated with a wide variation in the pattern of anomalous pulmonary venous connection. Nonetheless, surgical treatment is associated with excellent outcomes.

Transcarotid Approach to Ventricular Septal Defect Closure in Small Infants.

Perimembranous ventricular septal defect closure in small infants has traditionally been a surgically treated defect, although alternative hybrid strategies are emerging. We aim to describe a novel approach to retrograde device closure of clinically relevant perimembranous ventricular septal defects in small infants via carotid cutdown. A retrospective review of all patients managed with attempted carotid cutdown for device closure of a perimembranous ventricular septal defect was recorded at a single tertiary cardiac centre. We summarized data on successful device deployment, conversion to open repair, complications, and length of stay. Eighteen infants with median (IQR) age of 7 months (5-9 months) and weight of 7.1 kg (6.5-7.8 kg) with clinically relevant PMVSD underwent attempted retrograde closure via carotid cutdown. Median (IQR) defect size was 8 mm (7-9 mm). Successful device deployment without significant aortic or tricuspid valve interference occurred in 15 (83%) patients. Three patients were converted to open repair, one following damage to the tricuspid valve apparatus. Median (IQR) hospital stay was 1 day (1-3 days). There were no complications related to carotid cutdown. Retrograde device closure of hemodynamically significant PMVSD is feasible and effective in small infants. Decision to convert to surgical repair should be made early if suboptimal device placement occurs. Carotid evaluation should be performed to rule out any access-related complications.

Health-Related Quality of Life in Pediatric Cardiac Patients After Extracorporeal Life Support.

Extracorporeal Life Support (ECLS) is often considered successful if the child leaves intensive care alive. For the child and family, a major concern is quality of life. Aim of this study is to compare health-related quality of life scores of children following cardiac ECLS to a healthy control group. Cross-sectional prospective study using Pediatric Quality of Life Inventory 4.0 Generic Core Scale questionnaire. Population included consecutive children between two and sixteen years of age who underwent cardiac ECLS from 2005 to 2016 and their parents. Each age groups' mean and standard deviation was analyzed individually with minimal clinically important difference calculated. We then compared the scores to a healthy population group. Cronbach's alpha for reliability was calculated and linear regression assessed for relationships between demographics and quality of life scores. Forty-one (60%) families responded. The ECLS had significantly (statistically and clinically) lower health-related quality of life scores in every domain when compared to the healthy cohort. The lowest mean total score was school functioning for both children (59.79 vs 81.31, p < 0.01) and parents (59.01 vs 78.27, p < 0.01). Parents had excellent reliability (α = 0.93, 0.95 & 0.90) compared to children with reliability improving with increasing age in children. Improvements in the management of pediatric patients following ECLS are required to improve their health-related quality of life. Further research is warranted to explore the physical and psychological effects of cardiac ECLS on pediatric survivors to establish individual healthcare needs and optimize health-related quality of life.

Hybrid Subxiphoid Perventricular Approach as an Alternative Access in Neonates and Small Children Undergoing Complex Congenital Heart Interventions.

The hybrid subxiphoid perventricular approach provides direct access through the heart and may alleviate the technical limitations of complex percutaneous interventions particularly in infants with low body weight. We present the outcomes from a tertiary cardiology center using this approach. We performed a retrospective review of all patients less than 15 kg who underwent a hybrid perventricular approach via a small subxiphoid incision. Medical records were reviewed to obtain clinical, demographic and outcome data. Seventeen patients underwent 18 hybrid perventricular procedures using a subxiphoid approach. Median age at time of procedure was 4.6 months (IQR = 1.6 to 18 months) and median weight was 6.2 kgs (IQR = 3.4 to 8.6 kgs). Six patients underwent hybrid pulmonary valve replacement (PVR), 5 patients underwent pulmonary outflow stenting, and 5 infants underwent hybrid ventricular septal defect (VSD) device closure. One patient with a single ventricle who did not tolerate a percutaneous approach underwent left pulmonary artery (LPA) stenting for severe LPA coarctation with subsequent right ventricular outflow tract (RVOT) stenting. One further patient underwent implantation of a larger diameter stent for pulmonary artery bifurcation stenosis. Procedure success rate was 89% with two of the VSD cases reverted to open surgical repair. There were no intra-procedural complications; however, one patient died within 72 h. Minor adverse events occurred in 2 patients including a wound infection in one patient with an immunodeficiency syndrome. Hybrid subxiphoid perventricular approach provides an excellent alternative access to the heart especially in low birth weight infants to prevent hemodynamic instability or in small children requiring large delivery sheaths.

Procedural technique for hybrid pulmonary valve replacement in infants and small children.

OBJECTIVES: Hybrid approach to pulmonary valve replacement (PVR) in the paediatric population has been reported, although data in infants and small children are limited. Several strategies are now possible. The aim of this study is to review our hybrid PVR strategy in a complex patient cohort, outlining a variety of approaches employed in our centre. METHODS: We performed a retrospective review of infants and small children who underwent hybrid PVR between May 2017 and April 2019 in a single tertiary cardiology centre. Medical records were reviewed to ascertain demographic, clinical and outcome data. RESULTS: Ten patients with a median (interquartile range) age of 1.5 years (1.1-1.9) and weight of 8.8 kg (8-10.6) were managed with hybrid pulmonary valve insertion. Eight patients had perventricular approach (4 sternotomy and 4 subxiphoid) and 2 patients had surgically sutured valve. Six patients underwent cardiopulmonary bypass for associated lesions. Three had insertion of the valve into conduits and 7 were deployed into native right ventricular outflow tracts. The pulmonary valve was successfully inserted in all 10 patients with no mortality. Postprocedural complications included paravalvar leak in 2 patients, suspected endocarditis in 1 patient who developed early valve regurgitation and wound infection in 1 patient. CONCLUSIONS: Several approaches to hybrid PVR may be employed in small children with a high success rate. Follow-up studies are required to evaluate longer term durability of these approaches compared to standard surgical replacement.

An in-vitro evaluation of the flow haemodynamic performance of Gore-Tex extracardiac conduits for univentricular circulation.

OBJECTIVE(S): The Fontan procedure is a common palliative intervention for sufferers of single ventricle congenital heart defects that results in an anastomosis of the venous return to the pulmonary arteries called the total cavopulmonary connection (TCPC). In patients with palliated single ventricular heart defects, the Fontan circulation passively directs systemic venous return to the pulmonary circulation in the absence of a functional sub-pulmonary ventricle. Therefore, the Fontan circulation is highly dependent on favourable flow and energetics, and minimal energy loss is of great importance. The majority of in vitro studies, to date, employ a rigid TCPC model. Recently, few studies have incorporated flexible TCPC models, without the inclusion of commercially available conduits used in these surgical scenarios. METHOD: The methodology set out in this study successfully utilizes patient-specific phantoms along with the corresponding flowrate waveforms to characterise the flow haemodynamic performance of extracardiac Gore-Tex conduits. This was achieved by comparing a rigid and flexible TCPC models against a flexible model with an integrated Gore-Tex conduit. RESULTS: The flexible model with the integrated Gore-Tex graft exhibited greater levels of energy losses when compared to the rigid walled model. With this, the flow fields showed greater levels of turbulence in the complaint and Gore-Tex models compared to the rigid model under ultrasound analysis. CONCLUSION: This study shows that vessel compliance along with the incorporation of Gore-Tex extracardiac conduits have significant impact on the flow haemodynamics in a patient-specific surgical scenario.

Cardiac strangulation causing refractory cardiac arrest during elective pacemaker revision: a cautionary tale.

We describe a previously asymptomatic 7-year-old girl with a sudden cardiac arrest during elective pacemaker revision. Later imaging identified epicardial pacemaker lead strangulation of the left anterior descending and left circumflex coronary arteries. Anaesthetic induction led to a reduction in myocardial perfusion, precipitating the arrest. Extreme care should be taken during anaesthesia if cardiac strangulation is suspected.

Outcome of congenital tracheal stenosis in children over two decades in a national cardiothoracic surgical unit.

OBJECTIVE: To assess the outcomes of congenital tracheal stenosis among children. MATERIALS AND METHODS: A retrospective review of all children who underwent surgical repair of congenital tracheal stenosis reviewing charts, operative notes, echocardiograms, CT and MRI data from January 2002 to February 2019. RESULTS: Twenty-six children underwent surgical treatment for tracheal stenosis. The median age was 3 months (range 0.3-35 months) and the median weight was 4.7 kg (range 2.5-13 kg) at the time of surgical intervention. Stridor was the most common presenting symptom in 17 patients (65% of patients). Twenty-one patients (81%) had concurrent cardiac anomalies, with pulmonary arterial sling being the most common, present in nine patients (34%). Extracorporeal life support was utilised in seven patients (27%) pre-operatively. Laryngeal release was required in 16 patients. In 7 patients an end-to-end anastomosis was performed, in 18 patients slide tracheoplasty, and 1 patient had a double slide tracheoplasty. The median cardiopulmonary bypass time was 106 minutes (range 25-255 minutes). The median cross-clamp time was 30 minutes (range 5-67 minutes). The median post-operative duration of ventilation was 5 days (range 0.5-16 days). The median ICU length of stay was 12.5 days (range 2-60 days). There were three hospital mortalities with 88% survival. One patient only required reintervention with balloon dilation. Twenty-two patients (85%) remained symptom-free on median follow-up at 7.6 years (range 0.2-17 years). Two patients since 2017 had 3D printed tracheas produced from CT imaging to assist surgical planning. CONCLUSION: Congenital tracheal stenosis can be managed effectively with excellent outcomes and 3D printed models assist in planning the optimal surgical intervention.

Experience of stent implantation for recurrent aortic arch obstruction following Norwood or Damus-Kaye-Stansel operation over the last decade.

BACKGROUND: Recurrent aortic arch obstruction following the Norwood procedure is recognised as an important complication. Balloon arch angioplasty is associated with a high recoarctation rate. METHODS: We sought to evaluate the prevalence and outcome of stent implantation for recoarctation in children following Norwood or Damus-Kaye-Stansel procedure over the past decade at a single national cardiology centre. RESULTS: Of 114 children who underwent Norwood procedure or Damus-Kaye-Stansel procedure between January 2003 and June 2013, 80 patients survived. Of these 15 children underwent stent implantation for recoarctation. Six of these patients had previous balloon angioplasty. The median age at stent implantation was 4.4 months (range 2-82 months). The median peak aortic arch gradient at catheterisation decreased from 26mmHg (range 10-70mmHg) to 2mmHg (range 0-20mmHg). The median luminal diameter increased from 4.7 mm (range 3.2-7.9 mm) to 8.6 mm (range 6.2-10.9 mm). The median coarctation index increased by 0.49 (range = 0.24-0.64). A Valeo stent was employed in 11 children, a Palmaz Genesis stent in 2 patients, a MultiLink stent in 1 child, and a Jomed covered stent in 1 child. Two factors were associated with the need for stent placement: previous arch angioplasty (p valve < 0.001, χ-square 11.5) and borderline left ventricle (p = 0.04, χ-square = 4.1). Stent migration occurred in one child. There were two deaths related to poor right ventricular systolic function and severe tricuspid regurgitation. Six patients underwent redilation of the stent with no complications. CONCLUSIONS: The prevalence of recurrent aortic arch obstruction following Norwood/Damus-Kaye-Stansel procedure was 18%. Stent implantation is safe and reliably eliminates the aortic obstruction. Redilation can be successfully achieved to accommodate somatic growth or development of stent recoarctation.

Antimicrobial Susceptibility of Clinical and Environmental Mycobacterium chimaera Isolates.

Mycobacterium chimaera is a slow-growing nontuberculous Mycobacterium species belonging to the Mycobacterium avium complex (MAC). It has been identified globally as the cause of a large outbreak of cardiovascular infections following open heart surgery, but it can also cause respiratory infections in individuals with underlying structural pulmonary disease. Invasive M. chimaera infections are associated with poor clinical responses, and the optimal antibiotic treatment regimen for these infections is not known. In this study, the drug susceptibility profiles of clinical and environmental M. chimaera isolates for antimicrobial agents that are commonly considered for treatment of MAC infections were determined. All M. chimaera isolates were susceptible to clarithromycin, with a median MIC of 2 µg/ml, while 98% (85/87 isolates) were susceptible to amikacin. Twenty-five percent of isolates (22/87 isolates) had intermediate susceptibility and 52% (46/87 isolates) were resistant to moxifloxacin. Similarly, 39% of isolates (34/87 isolates) had intermediate susceptibility and 39% (34/87 isolates) were resistant to linezolid. MIC breakpoints derived from the literature were used to determine resistance to rifampin (16/87 isolates [18%]), ethambutol (10/87 isolates [11%]), rifabutin (2/87 isolates [2%]), and streptomycin (1/87 isolates [1%]). In conclusion, our results showed that clarithromycin, amikacin, rifabutin, and streptomycin had the best activity against M. chimaera isolates, while susceptibility rates were lower for rifampin and ethambutol. In contrast, there was a high prevalence of isolates that were not susceptible to moxifloxacin or linezolid. While factors in addition to antibiotic susceptibility may determine the outcomes of treatment of M. chimaera infections, our results should inform the selection of antimicrobials as part of the overall therapeutic strategy.

Retroaortic innominate vein in a patient with transposition of the great arteries: the surgical implications.

We describe the case of a newborn infant with transposition of the great vessels and a retroaortic innominate vein. This is a previously undescribed association. The decision was made to incorporate the retroaortic innominate vein into the Lecompte procedure at the time of surgery to avoid the risk of superior caval vein syndrome.

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.

High-risk Fontan completion patients achieve low perioperative risk and benefit from cavopulmonary connection 7 years out†.

OBJECTIVES: Our unit has pursued Fontan completion in all patients except those with immobility or combined poor ventricular function and high pulmonary artery pressures. We assessed retrospectively whether conventional high-risk criteria would predict patients with a poorer outcome. METHODS: One hundred and thirty-three consecutive children who underwent extracardiac Fontan completion (2004-2012) had their outcomes recorded (mean follow-up of 7 years). Three groups were analysed: those with 1 of 6 historical risk factors (outside 6 commandments), those with 1 of reduced systemic ventricular function or pulmonary artery pressure >15 mmHg (outside 2 commandments) versus those with no contraindications. The Fischer's exact test examined frequency differences, with the χ2 test to look for outcome associations. RESULTS: There were no differences in postoperative complication rates between the outside 6 commandments (n = 105) or outside 2 commandments (n = 49) versus the low-risk no-contraindication group (n = 28): arrhythmias [18% (P = 0.3) or 18% (P = 0.3) vs 25%], infection [22% (P = 0.6) or 33% (P = 0.2) vs 21%], cerebrovascular accident [6% (P = 0.5) or 10% (P = 0.3) vs 4%], length of stay [20 days (P = 0.4) or 23 days (P = 0.2) vs 21 days] and duration of chest drainage (P = 0.5). There was 1 predischarge mortality in each group. Long term, the majority of patients in each group had suitable haemodynamics for fenestration closure [95% (P = 0.7) or 95% (P = 0.7) vs 92%]. Long term, there was no difference in the rate of arrhythmias [11% (P = 0.5) or 12.5% (P = 0.3) vs 7%], protein-losing enteropathy [1% (P = 0.1) or 2% (P = 0.3) vs 7%] or moderate or more ventricular dysfunction on echocardiography [2% (P = 0.7) or 4% (P = 0.7) vs 4%]. Notably, there was a higher rate of catheter reinterventions in the high-risk groups [22% (P < 0.05) or 24% (P < 0.05) vs 7%]. CONCLUSIONS: The medium-term benefits of Fontan completion can be achieved for high-risk patients, suggesting that historical selection criteria should be re-examined.

Long-term outcomes following partial atrioventricular septal defect (AVSD) repair in Ireland.

BACKGROUND: We describe the long-term results of partial atrioventricular septal defect (AVSD) repair in a single centre encompassing a 22-year period. Described are rates of survival, reoperation and complications. METHODS: We performed a retrospective review of 556 patients undergoing AVSD repair to identify the 51 patients who underwent partial AVSD repair in Our Lady's Children's Hospital, Crumlin, Ireland, between 1993 and 2015 with long-term follow-up where available. RESULTS: A total of 29 (56.8%) of patients were male and mean age at operation was 3.32 years. Mean weight was 13.2 kg. Trisomy 21 was present in 29 (56.8%). Five patients (9.6%) had undergone prior surgery. Mean cardiopulmonary bypass time was 89 ± 36 min and mean aortic cross-clamp time was 57 ± 28 min. One patient underwent partial AVSD repair and concomitant tracheal resection and extracorporeal membrane oxygenation decannulation. One patient was managed with suture atrial septal defect (ASD) closure, the remainder with patch repair of ASD and mitral cleft closure. The length of hospital stay was 9 ± 5 days. Median follow-up was 6.06 years (IQR, 1.65-10.2 years). There were no early mortalities. One patient died 1 year following surgery (1.9%). One patient required reoperation at an interval of 2 years for severe mitral regurgitation (1.9%). CONCLUSIONS: Short- and long-term survival following partial AVSD repair in Ireland revealed excellent results compared with other published series. Reoperation incidence also compared excellently with other reports published in the literature.