Cardiac Development and Factors Influencing the Development of Congenital Heart Defects (CHDs): Part I.

The traditional description of cardiac development involves progression from a cardiac crescent to a linear heart tube, which in the phase of transformation into a mature heart forms a cardiac loop and is divided with the septa into individual cavities. Cardiac morphogenesis involves numerous types of cells originating outside the initial cardiac crescent, including neural crest cells, cells of the second heart field origin, and epicardial progenitor cells. The development of the fetal heart and circulatory system is subject to regulatation by both genetic and environmental processes. The etiology for cases with congenital heart defects (CHDs) is largely unknown, but several genetic anomalies, some maternal illnesses, and prenatal exposures to specific therapeutic and non-therapeutic drugs are generally accepted as risk factors. New techniques for studying heart development have revealed many aspects of cardiac morphogenesis that are important in the development of CHDs, in particular transposition of the great arteries.

Successful Secondary Endovascular Intervention in Pediatric Patients with Venous Thromboembolic Events.

BACKGROUND: In the past, pediatric patients with venous thromboembolic events (VTE) were treated with low-molecular-weight heparin (LMWH) which was successful in around 70% of the cases. However, anticoagulation alone might not restore patency in all patients, and advanced therapeutic options to prevent postthrombotic syndrome are needed. During recent years, endovascular interventions have become a treatment option for pediatric patients with persistent thrombotic occlusion, not only in life- or limb-threatening VTE. METHODS: We evaluated 12 consecutive patients (11-17 years) with newly diagnosed VTE being treated at our department during the last 4 years (2017-2020). In case follow-up examination showed persistent venoocclusion under anticoagulation, patients received secondary interventional therapy like recanalization, percutaneous transluminal angioplasty with or without catheter-directed thrombolysis, and stenting. Patients with no clinical signs of venoocclusion or regredient thrombosis in imaging examination received anticoagulation alone. RESULTS: Six of 12 (50%) patients underwent catheter intervention. Median time from diagnosis to intervention was 4 months (0-12 months). Reintervention was necessary in one (8%) case and complete recanalization failed in one (8%) case. There were no major bleeding events or other major postinterventional complications, no acute or late local recurrence, and all patients reported clinical improvement after the procedure. CONCLUSION: If endovascular intervention is used in teenage patients with persistent symptomatic VTE, reduction of postthrombotic symptoms is possible, even if intervention is performed secondary to failure of anticoagulation. Multidisciplinary treatment decisions can be based on the clinical course and follow-up imaging.

A multi-center trial on efficacy and safety of the LifeTech CeraFlexTM ASD occluder for transcatheter closure in patients with secundum atrial septal defects.

Background: The last decades have brought remarkable improvements in treatment strategy and occluder modification of secundum atrial septal defect (ASD) closure. Approval, efficacy and safety of ASD closure devices have previously been demonstrated. This study investigated the clinical efficacy and safety of the LifeTech CeraFlexTM ASD occluder for interventional closure of secundum ASD with a 6-month follow-up (FU). Methods: Procedure specific data was collected on patients considered for ASD closure with the CeraFlexTM occluder between April 2016 and December 2019 in three German centers. Efficacy and safety were assessed after device closure, at discharge, and at 6-month FU. Results: The primary endpoint (successful ASD closure without severe complications) was reached by 102/103 patients (99%). Device embolization occurred in two patients (one early and one late embolization). After early snare-retrieval of an embolized device, this ASD was closed surgically and in the other patient with late device embolization the defect was closed with a larger CeraFlexTM occluder. The secondary endpoint (clincal efficacy after 6 months) was reached by 94/98 patients since new onset of arrhythmia occurred in four patients. Three patients had withdrawn their study-participation and one patient had moderate residual shunt, but not related to the occluder. Incomplete right bundle branch block (iRBBB) was seen in 31 patients. At last FU only 17 patients had remaining iRBBB documenting effective volume unloading of the right ventricle. Conclusions: Catheter interventional closure of secundum ASDs with the CeraFlexTM ASD occluder was feasible, safe and effective in this study.

Prospective multicenter study of the breakable babystent for treatment of aortic coarctation in newborns and infants.

To assess the efficacy and safety of a breakable BabyStent to treat complex aortic coarctation (CoA) in early childhood. Although recommended in several guidelines, there is no approved aortic stent for young infants, because of the dilemma between two mandatory requirements: expandable up to adult size on the one hand, and small enough to fit through a baby's femoral artery on the other. Prospective interventional, multi-center clinical trial with the breakable Osypka BabyStent® (OBS). The OBS is a low-profile, 15-mm long cobalt-chromium stent, pre-mounted on a 6 mm balloon and inserted via a 4 Fr sheath. After implantation, its diameter is adjustable from 6 to 12 mm by balloon dilation. Further dilation opens predefined joints enabling unrestricted growth. Nineteen patients (9 male), median age 112 days (range: 7-539), median body weight 5.6 kg (range: 2.4-8.4) were deemed high risk and underwent stent implantation. Of those, 74% suffered from re-CoA following surgery, 53% had additional cardiac and 21% noncardiac malformations. Our primary combined endpoint was fulfilled: All stents were implanted in the desired region, and a >50% intrastenotic diameter-extension was achieved in 15 patients (78.9%, 80% confidence interval [62.2; 90.5], 95% confidence interval [54.4; 93.9]). Secondary endpoint confirmed that the OBS fits the baby's femoral vessel diameter. All children survived the procedure and 12-month follow-up. This stent enables percutaneous stenting of complex aortic coarctation to treat high-risk newborns and infants.

Frequency of thyroid dysfunction in pediatric patients with congenital heart disease exposed to iodinated contrast media - a long-term observational study.

Background The thyroid gland of patients with congenital heart disease may be exposed to large doses of iodine from various sources. We assessed the thyroid response after iodine exposure during conventional angiography in cardiac catheterization and angiographic computer tomography in childhood. Methods Retrospective mid- to long-term follow-up of 104 individuals (24% neonates, 51% infants, 25% children) with a median age and body weight of 104 days [0-8 years] and 5.3 kg [1.6-20]. Serum levels of thyroid-stimulating hormone, free triiodthyronine and free thyroxine were evaluated at baseline and after excess iodine. We also assessed risk factors that may affect thyroid dysfunction. Results Baseline thyroidal levels were within normal range in all patients. The mean cumulative iodinate contrast load was 6.6 ± 1.6 mL/kg. In fact, 75% had experienced more than one event involving iodine exposure, whose median frequency was three times per patient [1-12]. During the median three years follow-up period [0.5-10], the incidence of thyroid dysfunction was 15.4% (n=16). Those patients developed acquired hypothyroidism (transient n=14, long-lasting n=2 [both died]) with 10 of them requiring temporary replacement therapy for transient thyroid dysfunction, while four patients recovered spontaneously. 88 individuals (84.6%) remained euthyroid. Repeated cardiac interventions, use of drugs that interfere with the thyroid and treatment in the intensive care unit at the index date were strong predictors for acquired thyroid dysfunction. Conclusions The incidence of acquired hypothyroidism after iodine excess was 15.4%. However, most patients developed only transient hypothyroidism. Systemic iodine exposure seems to be clinically and metabolically well tolerated during long-term follow-up.

Case Report: Hepatic Adenoma in a Child With a Congenital Extrahepatic Portosystemic Shunt.

Congenital extrahepatic portosystemic shunts (CEPS), previously also described as Abernethy malformations, are rare malformations in which the extrahepatic portal system directly communicates with the vena cava inferior, thereby bypassing the liver. A hypoplastic portal vein (PV) exists in most cases. CEPS have been associated with the development of liver nodules, ranging from mostly focal nodular hyperplasia (FNH) to hepatic adenoma (HA) and even hepatocellular carcinoma (HCC). Tumor development in CEPS may be due to changes in perfusion pressures, oxygen supply or endocrine imbalances. It is important to rule out CEPS in children with liver tumors, because resection could impede future shunt occlusion procedures, and benign masses may regress after shunt occlusion. Here, we review the case of a 9-years-old male with CEPS and hepatic nuclear Factor 1-alpha (HNF-1-alpha) inactivated HA to raise awareness of this condition and review histopathological changes in the liver of CEPS.

Catheter strategy to ease the procedure and reduce radiation exposure when requiring neck access.

OBJECTIVES: To assess the potential occupational radiation reduction and technical feasibility in patients rotated 180° (upside-down) when requiring neck access for transcervical or trans-subclavian catheterisation. METHODS: Upside-down positioning is defined as rotating patients in supine position by 180°, so that the feet come to rest where the head would otherwise be. We retrospectively evaluated all these procedures performed between March 2016 and May 2019. Furthermore, two different phantoms (paediatric and adult) were used prospectively to quantify the occupational dose between conventional or upside-down positioning. In this context, ambient dose equivalents were measured using real-time dosimeters. Three different projection angles were applied. RESULTS: 44 patients with median age and body weight of 1.0 year (range 0-56) and 9.5 kg (range 1.3-74.3) underwent 63 procedures positioned upside-down. This position proved advantageous for practical reasons, since the length of the examination table could be optimally used. Additionally, it resulted in a significantly lower overall ambient dose equivalent for the primary operator (PO) of 94.8% (mean: 2569±807 vs 135±23 nSv; p<0.01) in the adult, and of 65.5% (mean: 351±104 vs 121±56 nSv; p<0.01) in the paediatric phantom, respectively. CONCLUSION: Upside-down positioning facilitates handling in a straightforward manner when access from the neck is required. Moreover, it significantly reduces local radiation exposure for the PO in the paediatric and, most impressively, in the adult phantom.

Surgically placed radiopaque markers: Proof-of-concept of a novel technique to facilitate percutaneous interventions in neonates and infants.

OBJECTIVES: Aim of this study was to evaluate feasibility and benefit of self-designed, radiopaque markers as a novel technique in neonates and infants with shunt- or duct-dependent lesions. BACKGROUND: Surgically placed radiopaque markers have the potential to facilitate postoperative percutaneous interventions. METHODS: All consecutive children with surgically placed radiopaque markers involving systemic-to-pulmonary artery connections or arterial ducts in the context of hybrid palliation and subsequent cardiac catheterization between January 2013 and March 2019 were included in this analysis. Our primary endpoint was our concept's feasibility, which we defined as a combination of surgical feasibility and the percutaneous intervention's success. Secondary endpoint was the rate of complications resulting from the surgical procedure or during catheterization. RESULTS: Radiopaque markers that reveal the proximal entry of a surgical shunt or the arterial duct proved to be a feasible and beneficial approach in 25 postoperative catheterizations. The markers' high accuracy enabled easy probing and proper stent positioning in 13 neonates with a median age and weight of 121 days (range 9-356) and 4.7 kg (1.6-9.4) at the intervention. No procedural complications or unanticipated events associated with the radiopaque marker occurred. The markers were never lost, never migrated, and caused no local obstructive lesion. Surgical removal was straightforward in all patients. CONCLUSIONS: Radiopaque markers are a promising and refined technique to substantially facilitate target vessel access and enabling the accurate positioning of stents during postoperative percutaneous procedures.

Retrograde transcatheter aortic valve closure in an infant with failing Norwood stage I palliation: a case report.

BACKGROUND: Aortic valve regurgitation leading to coronary steal phenomenon can severely impair cardiac function in hypoplastic left heart syndrome, thus worsening long-term outcome. CASE PRESENTATION: A German infant with borderline aortic and mitral valve, hypoplastic left ventricle, ventricular septal defect, and hypoplastic aortic arch with critical coarctation initially underwent aortic arch reconstruction and aortic valve dilation with the aim of biventricular correction later on. Unfortunately, severe cardiac dysfunction necessitated a change in strategy entailing modified stage I Norwood palliation. Increasing aortic regurgitation with coronary steal was revealed postoperatively, which required redo surgery to oversew the valve. However, pronounced aortic regurgitation recurred, causing severe cardiac decompensation with repeated resuscitation. As a bailout strategy, we performed aortic valve closure via transfemoral retrograde implantation of an Amplatzer Duct Occluder II device. This led to the patient's rapid stabilization while circumventing highly risky renewed surgery in such a critically ill infant. CONCLUSIONS: Retrograde transcatheter aortic valve closure may be considered a feasible alternative in infants with a failing single ventricle due to aortic regurgitation, with critical device evaluation being crucial for successful device implantation in this young age group.

Left recurrent laryngeal nerve palsy following aortic arch stenting: A case report.

BACKGROUND: Aortic arch stenting is continuously emerging as a safe and effective option to alleviate aortic arch stenosis and arterial hypertension. CASE SUMMARY: We present a 15-year-old girl with aortic arch hypoplasia who had undergone implantation of an uncovered 22 mm Cheatham-Platinum stent due to severe (native) aortic arch stenosis. On follow-up seven months later, she presented a significant re-stenosis of the aortic arch. A second stent (LD Max 26 mm) was implanted and both stents were dilated up to 16 mm. After an initially unremarkable post-interventional course, the patient presented with hoarseness five days after the intervention. MRI and CT scans ruled out an intracranial pathology, as well as thoracic hematoma, arterial dissection, and aneurysm around the intervention site. Laryngoscopy confirmed left vocal fold paresis attributable to an injury to the left recurrent laryngeal nerve (LRLN) during aortic arch stenting, as the nerve loops around the aortic arch in close proximity to the area of the implanted stents. Following a non-invasive therapeutic approach entailing regular speech therapy, the patient recovered and demonstrated no residual clinical symptoms of LRLN palsy after six months. CONCLUSION: Left recurrent laryngeal nerve palsy is a rare complication of aortic arch stenting not previously reported.

Collateral closure in congenital heart defects with Amplatzer vascular plugs: single-center experience and a simplified delivery technique for exceptional cases.

The study describes our experience with Amplatzer Vascular Plugs (AVP2 and 4) and highlights a more refindes telescopic technique for AVP2 delivery. AVPs are well-established occlusion devices for vascular anomalies in congenital heart disease (CHD). The AVP2 is sometimes preferred to the AVP4 due to its shorter length, flat-profiled retention disks, and the availability of larger diameters, but its profile requires a larger inner lumen for safe delivery. The latter may actually hamper access to target lesions. This is a retrospective analysis of all CHD patients treated with the AVP2 and AVP4 between 12/2012 and 12/2015. Target vessels were characterized, measured, and the device-to-vessel diameter ratio calculated. A modified pigtail technique for AVP2 delivery was frequently used: a floppy wire was simply reinforced by the curved tip of a pigtail catheter (instead of the long sheath's dilator) to guide the required delivery sheath towards the desired landing zone. 59 patients with a median age and bodyweight of 3.0 years (range 0.1-75) and 13.8 kg (range 2.5-80) underwent the implantation of 106 plug-devices (30 AVP2, 76 AVP4) in 91 target vessels. Indications for their use were ductus arteriosus (19%), aortopulmonary (43%) as well as venovenous collaterals (34%) and other miscellaneous lesions (4%). The pigtail-supported AVP2 delivery in six patients proved very convenient. No complications occurred. AVPs are excellent devices for embolizing shunt vessels in CHD patients. Here, we describe a simplified telescoping technique for AVP2 delivery to enter curvy target lesions gently and efficiently.

Acquired von Willebrand syndrome in paediatric patients during mechanical circulatory support.

OBJECTIVES: Bleeding signs can become life-threatening complications in patients on mechanical circulatory support (MCS). Clinical phenotyping and comprehensive analyses of the cause of bleeding are, therefore, essential, especially when risk-stratifying patients during MCS workup. We conducted coagulation analyses and determined von Willebrand factor (VWF) parameters in a paediatric cohort on temporary extracorporeal life support, extracorporeal membrane oxygenation or long-term ventricular assist device support. METHODS: We carried out an observational single-centre study including 30 children with MCS (extracorporeal life support, n = 13; extracorporeal membrane oxygenation, n = 5; and ventricular assist device, n = 12). We also assessed the acquired von Willebrand parameters of each study participant: collagen binding capacity (VWF:CB), the ratio of collagen-binding capacity to VWF antigen (VWF:CB/VWF:Ag) and high-molecular-weight VWF multimers. We also documented bleeding events, transfusion requirement, haemolysis parameters and surgical interventions. RESULTS: All children developed AVWS (acquired von Willebrand syndrome) during MCS, usually during the early postoperative course. They presented no AVWS after device explantation. We detected a loss of high-molecular-weight VWF multimers, decreased VWF:CB/VWF:Ag ratios and reduced VWF:CB levels. Twenty of the 30 patients experienced bleeding complications; approximately 53% of them required surgical revision. There were no deaths due to bleeding during support. CONCLUSIONS: The AVWS prevalence in paediatric patients on MCS is 100% regardless of the types of devices tested in this study. The bleeding propensity of AVWS patients widely varies.

Intentional Fracture of Bioprosthetic Valve Frames in Patients Undergoing Valve-in-Valve Transcatheter Pulmonary Valve Replacement.

BACKGROUND: Percutaneous transcatheter pulmonary valve replacement (TPVR) has good clinical and hemodynamic outcomes in treating dysfunctional bioprosthetic valves (BPV) in the pulmonary position. Valve-in-valve therapy can further decrease the inner diameter (ID), potentially resulting in patient-prosthesis mismatch in patients with smaller BPVs. METHODS AND RESULTS: To evaluate feasibility and outcomes of intentional BPV fracture to enlarge the pulmonary valve orifice with TPVR, 37 patients from 13 centers who underwent TPVR with intended BPV fracture were evaluated. A control cohort (n=70) who underwent valve-in-valve TPVR without attempted fracture was evaluated. BPV was successfully fractured in 28 patients and stretched in 5 while fracture was unsuccessful in 4. A Melody valve was implanted in 25 patients with fractured/stretched frame and a Sapien (XT 3) valve in 8. Among patients whose BPV was fractured/stretched, the final ID was a median of 2 mm larger (0-6.5 mm) than the valve's true ID. The narrowest diameter after TPVR in controls was a median of 2 mm smaller ( P<0.001) than true ID. Right ventricular outflow tract gradient decreased from median 40 to 8 mm Hg in the fracture group. Cases with fracture/stretching were matched 1:1 (weight, true ID) to controls. Post-TPVR peak gradient was lower but not significant (8.3±5.2 versus 11.8±9.2 mm Hg; P=0.070). There were no fracture-related adverse events. CONCLUSIONS: Preliminary experience shows intentional fracture of BPV frame can be useful for achieving larger ID and better hemodynamics after valve-in-valve TPVR.

Implementing and Assessing a Standardized Protocol for Weaning Children Successfully From Extracorporeal Life Support.

Extracorporeal life support (ECLS) weaning is a complex interdisciplinary process with no clear guidelines. To assess ventricular and pulmonary function as well as hemodynamics including end-organ recovery during ECLS weaning, we developed a standardized weaning protocol. We reviewed our experience 2 years later to assess its feasibility and efficacy. In 2015 we established an inter-professional, standardized, stepwise protocol for weaning from ECLS. If the patient did not require further surgery, weaning was conducted bedside in the intensive care unit (ICU). Most of the weaning procedures are guided via echocardiography. Data acquisition began at baseline level, followed by four-step course (each step lasting 10 min), entailing flow-reduction and ending 30 min after decannulation. Moreover, data from the preprotocol era are presented. Between May 2015 and 2017, 26 consecutive patients (18 male), median age 177 days (2 days-20 years) required ECLS with median support of 4 (2-11) days. Excluding eight not weanable patients, 21 standardized weaning procedures were protocolled in the remaining 18 children. Our generally successful protocol-guided weaning rate (with at least 24-h survival) was 89%, with a discharge home rate of 58%. Practical application of the novel standard protocol seems to facilitate ECLS weaning and to improve its success rate. The protocol can be administered as part of standard bedside ICU assessment.

Management of a dissection of matrix P right ventricular-to-pulmonary artery conduit by implanting two pre-stents and a melody valve.

Reconstructing the right ventricular outflow tract and pulmonary valve via a bovine-derived valve conduit such as Matrix-P-Xenograft is a common surgical repair technique for pulmonary atresia and ventricular septal defect. After conduit degeneration due to calcification or aneurysmal dilatation, percutaneous transvenous stenting of the right ventricular outflow tract followed by pulmonary valve implantation has become the standard interventional treatment. Applied to stenotic conduits, the method is considered safe and effective. An important but seldom-reported problem is graft failure related to the formation of a Matrix membrane due to inflammation and fibrosis inside the xenograft, which can cause serious problems when dissection and rupture occur during transcatheter intervention. The torn pseudomembrane may cause the complete obstruction of both pulmonary arteries, resulting in a life-threatening situation requiring rapid intervention, as in this case presentation. © 2016 Wiley Periodicals, Inc.

Echocardiographic characteristics in Fontan patients before the onset of protein-losing enteropathy or plastic bronchitis.

BACKGROUND: It was this study's objective to evaluate the echocardiographic characteristics and flow patterns in abdominal arteries of Fontan patients before the onset of protein-losing enteropathy (PLE) or plastic bronchitis (PB). DESIGN: In this retrospective cohort investigation, we examined 170 Fontan patients from 32 different centers who had undergone echocardiographic and Doppler ultrasound examinations between June 2006 and May 2013. Follow-up questionnaires were completed by 105 patients a median of 5.3 (1.5-8.5) years later to evaluate whether one of the complications had occurred since the examinations. RESULTS: A total of 91 patients never developed PLE or PB ("non-PLE/PB"); they were compared to 14 affected patients. Eight of the 14 patients had already been diagnosed with "present PLE/PB" when examined. Six "future PLE/PB" patients developed those complications later on and were identified on follow-up. The "future PLE/PB" patients presented significantly slower diastolic flow velocities in the celiac artery (0.1 (0.1-0.5) m/s vs 0.3 (0.1-1.0) m/s (P = .04) and in the superior mesenteric artery (0.0 (0.0-0.2) m/s vs 0.2 (0.0-0.6) m/s, P = .02) than the "non-PLE/PB" group. Median resistance indices in the celiac artery were significantly higher (0.9 (0.8-0.9) m/s vs 0.8 (0.6-0.9) m/s, (P = .01)) even before the onset of PLE or PB. CONCLUSION: An elevated flow resistance in the celiac artery may prevail in Fontan patients before the clinical manifestation of PLE or PB.

Aneurysms of the azygos vein.

OBJECTIVE: Azygos vein aneurysms (AVAs) are uncommon and infrequently diagnosed. When confronted with a patient presenting with an AVA, physicians can rely on only a few case reports after an extensive literature search. To date, no guideline, no rule, and no review on the optimal treatment strategy for these patients exist. METHODS: A PubMed and MEDLINE database search for papers and case reports describing AVA was performed. Cases from our own institutions were also reviewed. RESULTS: The literature search identified 57 published case reports that were reviewed for inclusion. Of those published cases, etiologic factors can be classified into idiopathic, acquired, and traumatic causes. Most AVAs are limited to the azygos arch, a congenital anatomic weak point. Clinical symptoms generally remain nonspecific. Computed or magnetic resonance tomography scans are effective diagnostic tools, although the optimal therapeutic plan remains unclear. Complications include rupture, thromboembolism, mediastinal mass effects, and pulmonary artery hypertension. CONCLUSIONS: Conservative treatment along with oral anticoagulation may be reasonable for some AVAs, but to date, there is no clear guideline or evidence-based threshold for surgical or interventional therapy. In review of the existing data and from our clinical and scientific knowledge, interventional or surgical treatment should strongly be considered in cases with clinical symptoms, pulmonary embolism or pulmonary arterial hypertension, thrombus formation within the AVA in patients with oral anticoagulation or for patients with a contraindication to oral anticoagulants, considerable increase in diameter or compression of adjacent structures, saccular AVA, or an underlying connective tissue disease. The most common procedure is surgical ligation of the AVA, although endovascular occlusion of the aneurysms is becoming more frequent.