The ongoing debate: Longevity of biological valves in pulmonary position.

BACKGROUND: In patients with tetralogy of Fallot (ToF) or ToF-like anatomy, factors possibly impacting the longevity of biological valves in pulmonary position were investigated. METHOD: Between 1997 and 2017, 79 consecutive hospital survivors with a median age of 8.7 years (range 0.2-56.1 years; IQR 14.8 years) with ToF or ToF-like anatomy underwent surgical implantation of Contegra™ (n=34), Hancock™ (n=23), Perimount™ (n=9), pulmonary homograft (n=9), and miscellaneous (n=4) conduits. The median internal graft diameter was 19mm (range 11-29mm; IQR 8mm) which refers to a median z-score of 0.6SD (range -1.8-4.0SD; IQR 2.1SD). RESULTS: The median time of follow-up was 9.4 years (range 1.1-18.8 years; IQR 6.0 years). Thirty-nine patients (49%) underwent surgical (n=32) or interventional (n=7) pulmonary valve re-replacement. Univariate cox regression revealed patient age (p=0.018), body surface area (p=0.004), internal valve diameter (p=0.005) and prosthesis z-score (p=0.018) to impact valve longevity. Multivariate cox regression analysis, however, did not show any significant effect (likely related to multicollinearity). Subgroup analysis showed that valve revised patients have a higher average z-score (p=0.003) and a younger average age (p=0.007). CONCLUSION: A decreased longevity of biological valves in pulmonary position is related to younger age, lower valve diameter, and higher z-score. Because valve size (diameter and z-score) can be predicted by age, patient age is the crucial parameter influencing graft longevity.

Thymic Atrophy and Immune Dysregulation in Infants with Complex Congenital Heart Disease.

Congenital heart disease (CHD) is the most common birth defect, and up to 50% of infants with CHD require cardiovascular surgery early in life. Current clinical practice often involves thymus resection during cardiac surgery, detrimentally affecting T-cell immunity. However, epidemiological data indicate that CHD patients face an elevated risk for infections and immune-mediated diseases, independent of thymectomy. Hence, we examined whether the cardiac defect impacts thymus function in individuals with CHD. We investigated thymocyte development in 58 infants categorized by CHD complexity. To assess the relationship between CHD complexity and thymic function, we analyzed T-cell development, thymic output, and biomarkers linked to cardiac defects, stress, or inflammation. Patients with highly complex CHD exhibit thymic atrophy, resulting in low frequencies of recent thymic emigrants in peripheral blood, even prior to thymectomy. Elevated plasma cortisol levels were detected in all CHD patients, while high NT-proBNP and IL-6 levels were associated with thymic atrophy. Our findings reveal an association between complex CHD and thymic atrophy, resulting in reduced thymic output. Consequently, thymus preservation during cardiovascular surgery could significantly enhance immune function and the long-term health of CHD patients.

Anatomical Compliance of Cavopulmonary Assist Device Designs: A Virtual Fitting Study in Fontan Patients.

Several device designs for cavopulmonary mechanical circulatory support (MCS) are under investigation, however, challenged by the Fontan population's heterogeneity in size, cardiovascular and thoracic anatomy. This study aimed to preclinically assess the anatomical compliance of proposed device designs in silico. Representative double- and single-outlet cavopulmonary assist device (CPAD) designs were virtually implanted into CT imaging data of 10 patients previously palliated with total cavopulmonary connection (TCPC) for functionally univentricular hearts. Anatomical device compatibility was characterized concerning pump proximity to cardiovascular, respiratory and thoracic structures, as well as pump in- and outflow graft configuration. In 10 Fontan patients with a median age of 10.4 years (interquartile range [IQR] 5.0-15.3 years) and a median body surface area of 1.09 m2 (IQR 0.76-1.28 m2), implantation of a double-outlet CPAD was feasible in 1 patient (10%). In all other, adverse device intersection with the trachea and (neo-)aorta, or posterior pulmonary artery outflow graft kinking were observed. A single-outlet design permitted enhanced device mobilization adapting to individual anatomical conditions, resulting in device fit in nine of 10 patients (90%). Despite vast anatomical variations among single ventricle patients, a single-outlet device design may provide intracorporeal cavopulmonary MCS to a broad spectrum of failing Fontan patients.

Siblings with Gorlin-Goltz syndrome associated with cardiac tumors: a case report and review of literature.

Primary cardiac tumors in children are very rare and may be associated with severe arrhythmias and sudden infant death syndrome. These cardiac arrhythmias vary depending on the location and size of the tumor. Sixty-four percent of children with cardiac fibroma, the second most common benign cardiac tumor in children, have ventricular arrhythmias, affecting therapeutic management and risk profile of these children. We report on two siblings with cardiac fibromas whose clinical presentations differed depending on their locations and size of the tumors. The first child, a three-year-old girl, was diagnosed with a cardiac fibroma in the left ventricle at the age of 8 months after surviving resuscitation due to ventricular fibrillation. Secondary prophylactic implantation of an ICD was performed. On propranolol, no further malignant arrhythmias have occurred to date. The seven-month-old brother was diagnosed postnatally with a cardiac tumor adjacent to the right ventricle. A few weeks after birth, the boy had refractory supraventricular tachycardia and ventricular arrhythmia that only resolved with amiodarone. In genetic testing, Gorlin-Goltz syndrome was diagnosed in both children. Conservative pharmacological therapy is a therapeutic strategy for asymptomatic patients with cardiac fibromas. The anti-arrhythmic medication depends on the location of the tumor. Implantation of an ICD should be performed in cases of malignant arrhythmias. In rare cases, there is an association between cardiac tumors and genetic syndromes, such as Gorlin-Goltz syndrome. These should always be considered when such a tumor is diagnosed.

Outcomes of extracorporeal membrane oxygenation and cardiopulmonary bypass in children after drowning-related resuscitation.

Drowning is one of the leading causes of accidental deaths in children worldwide. However, the use of long-term extracorporeal life support (ECLS) in this setting is not widely established, and rewarming is often achieved by short-term cardiopulmonary bypass (CPB) treatment. Thus, we sought to add our experience with this means of support as a bridge-to-recovery or to-decision. This retrospective single-center study analyzes the outcome of 11 children (median 23 months, minimum-maximum 3 months-6.5 years) who experienced drowning and subsequent cardiopulmonary resuscitation (CPR) between 2005 and 2016 and who were supported by veno-arterial extracorporeal membrane oxygenation (ECMO), CPB, or first CPB then ECMO. All but one incident took place in sweet water. Submersion time ranged between 10 and 50 minutes (median 23 minutes), water temperature between 2°C and 28°C (median 14°C), and body core temperature upon arrival in the emergency department between 20°C and 34°C (median 25°C). Nine patients underwent ongoing CPR from the scene until ECMO or CPB initiation in the operating room. The duration of ECMO or CPB before successful weaning/therapy withdrawal ranged between 2 and 322 hours (median 19 hours). A total of four patients (36%) survived neurologically mildly or not affected after 4 years of follow-up. The data indicate that survival is likely related to a shorter submersion time and lower water temperature. Resuscitation of pediatric patients after drowning has a poor outcome. However, ECMO or CPB might promote recovery in selected cases or serve as a bridge-to-decision tool.

A potential future Fontan modification: preliminary in vitro data of a pressure-generating tube from engineered heart tissue.

OBJECTIVES: Univentricular malformations are severe cardiac lesions with limited therapeutic options and a poor long-term outcome. The staged surgical palliation (Fontan principle) results in a circulation in which venous return is conducted to the pulmonary arteries via passive laminar flow. We aimed to generate a contractile subpulmonary neo-ventricle from engineered heart tissue (EHT) to drive pulmonary flow actively. METHODS: A three-dimensional tubular EHT (1.8-cm length, 6-mm inner diameter, ca. 1-mm wall thickness) was created by casting human-induced pluripotent stem cell-derived cardiomyocytes (0.9 ml, 18 mio/ml) embedded in a fibrin-based hydrogel around a silicone tube. EHTs were cultured under continuous, pulsatile flow through the silicone tube for 23 days. RESULTS: The constructs started to beat macroscopically at days 8-14 and remained stable in size and shape over the whole culture period. Tubular EHTs showed a coherent beating pattern after 23 days in culture, and isovolumetric pressure measurements demonstrated a coherent pulsatile wave formation with an average frequency of 77 ± 5 beats/min and an average pressure of 0.2 mmHg. Histological analysis revealed cardiomyocytes mainly localized along the inner and outer curvature of the tubular wall with mainly longitudinal alignment. Cell density in the center of the tubular wall was lower. CONCLUSIONS: A simple tube-shaped contractile EHT was generated from human-induced pluripotent stem cells and developed a synchronous beating pattern. Further steps need to focus on optimizing support materials, flow rates and geometry to obtain a construct that creates sufficient pressures to support a directed and pulsatile blood flow.

Outcomes of Tricuspid Valve Detachment for Isolated Ventricular Septal Defect Closure.

Partial detachment of the septal and anterior leaflets of the tricuspid valve (TV) is a technique to visualize a perimembranous ventricular septal defect (VSD) for surgical closure in cases where the VSD is obscured by TV tissue. However, TV incision bears the risk of causing relevant postoperative TV regurgitation and higher degree atrioventricular (AV) block. A total of 40 patients were identified retrospectively in our institution who underwent isolated VSD closure between January 2013 and August 2015. Visualization of the VSD was achieved in 20 patients without and in 20 patients with additional partial detachment of the TV. The mean age of patients with partial tricuspid valve detachment (TVD) was 0.7 ± 0.1 years compared with 1 ± 0.3 years (p = 0.22) of patients without TVD. There was no difference in cardiopulmonary bypass time between patients of both groups (123 ± 11 vs. 103 ± 5 minutes, p = 0.1). Cross-clamp time was longer if the TV was detached (69 ± 5 vs. 54 ± 4 minutes, p = 0.023). There was no perioperative mortality. Echocardiography at discharge and after 2.5 years (2 months-6 years) of follow-up showed neither a postoperative increase of tricuspid regurgitation nor any relevant residual shunt. Postoperative electrocardiograms were normal without any sign of higher degree AV block. TVD offers enhanced exposure and safe treatment of VSDs. It did not result in higher rates of TV regurgitation or relevant AV block compared with the control group.

Right aortic arch forming a true vascular ring: a clinical review.

OBJECTIVES: This review aims at presenting and summarizing the current state of literature on the presentation and surgical management of a right-sided aortic arch with a left-sided ligamentum forming a complete vascular ring around the oesophagus and trachea. METHODS: A systematic database search for appropriate literature was conducted on PubMed/MEDLINE. Articles were considered relevant when providing details on the presentation, diagnosis and surgical treatment of this specific congenital arch anomaly in human beings. RESULTS: Affected patients present with respiratory and/or oesophageal difficulties due to tracheoesophageal compression. Conservative treatment might be reasonable in asymptomatic or mildly symptomatic cases; however, once moderate-to-severe symptoms develop, surgical intervention is definitely indicated. Surgery is commonly performed through a left thoracotomy or median sternotomy and includes the division of the left ductal ligamentum; if a Kommerell's diverticulum is present that is >1.5 times the diameter of the subclavian artery, then concomitant resection of the large diverticulum and translocation of the aberrant left subclavian artery is also conducted. Postoperative morbidity and mortality are low and are rather related to concomitant intracardiac and extracardiac anomalies than to the procedure itself. In a majority of patients, full resolution of symptoms is seen within months to years from the surgery. Nevertheless, there is also a subset of patients who remain with some tracheobronchial narrowing, sometimes even requiring reintervention during follow-up due to persisting or recurring symptoms. CONCLUSIONS: Overall, the surgical management of a right aortic arch forming a true vascular ring in infancy, childhood and adulthood seems relatively safe and effective in providing symptomatic relief despite some persistent tracheobronchial and/or oesophageal narrowing in some cases.

OMIP 073: Analysis of human thymocyte development with a 14-color flow cytometry panel.

This panel was designed for the identification and detailed characterization of the different developmental steps of human thymocytes. We optimized the panel for fresh tissue in order to provide an unbiased analysis of T cell development. Accurate selection of antibodies and precise gating allow us to phenotype 14 major stages of human thymocyte development and illustrate the trajectories of T cell development from early thymic progenitors (ETP) to mature T cells that are ready to populate the periphery. The panel identifies ETPs, T-lineage-committed cells (TC), CD34-positive immature single-positive CD4 cells (ISP4 CD34+), CD34-negative immature single-positive CD4 cells (ISP4 CD34-), CD45-low early double-positive cells (EDP CD45low), CD45-high early double-positive cells (EDP CD45high), late double-positive cells (LDP), single-positive CD4 cells (SP4), single-positive CD8 cells (SP8), ready-to-egress single-positive CD4 cells (rSP4), ready-to-egress single-positive CD8 cells (rSP8), T γδ cells (Tγδ), T regulatory cells (Treg), and ready-to-egress T regulatory cells (rTreg). To highlight important checkpoints during T cell development, we added antibodies relevant for specific developmental steps to the panel. These include CD1a to define TCs, CD28 as a marker for ß-selection and CD69 in combination with CD45RA to determine the maturation stage of thymocytes shortly before they become ready to egress the thymus and colonize the periphery. Moreover, Annexin V, as a marker for apoptosis, provides valuable extra information concerning the apoptotic death of thymocytes. Currently, we use this panel to identify aberrations in T cell development in health and disease.

Narrative review of Ebstein's anomaly beyond childhood: Imaging, surgery, and future perspectives.

Ebstein's anomaly is a rare congenital heart disease with malformation of the tricuspid valve and myopathy of the right ventricle. The septal and inferior leaflets adhere to the endocardium due to failure of delamination. This leads to apical displacement of their hinge points with a shift of the functional tricuspid valve annulus towards the right ventricular outflow tract with a possibly restrictive orifice. Frequently, a coaptation gap yields tricuspid valve regurgitation and over time the "atrialized" portion of the right ventricle may dilate. The highly variable anatomy determines the clinical presentation ranging from asymptomatic to very severe with need for early operation. Echocardiography and magnetic resonance imaging are the most important diagnostic modalities to assess the tricuspid valve as well as ventricular morphology and function. While medical management of asymptomatic patients can be effective for many years, surgical intervention is indicated before development of significant right ventricular dilatation or dysfunction. Onset of symptoms and arrhythmias are further indications for surgery. Modified cone reconstruction of the tricuspid valve is the state-of-the-art approach yielding the best results for most patients. Alternative procedures for select cases include tricuspid valve replacement and bidirectional cavopulmonary shunt depending on patient age and other individual characteristics. Long-term survival after surgery is favorable but rehospitalization and reoperation remain significant issues. Further studies are warranted to identify the optimal surgical strategy and timing before adverse right ventricular remodeling occurs. It is this article's objective to provide a comprehensive review of current literature and an overview on the management of Ebstein's Anomaly. It focuses on imaging, cardiac surgery, and outcome. Additionally, a brief insight into arrhythmias and their management is given. The "future perspectives" summarize open questions and fields of future research.

Autologous Tissue Technique to Repair Unilateral Isolated Absence of a Pulmonary Artery.

Isolated unilateral absence of a pulmonary artery (UAPA) is a rare congenital anomaly in which one branch pulmonary artery has no connection to the main pulmonary trunk (most often there is ductal origin). Without treatment, it may lead to ipsilateral pulmonary hypoplasia and contralateral pulmonary artery hypertension. To avoid these complications, early surgical repair of UAPA is necessary. Surgical strategies include direct anastomosis between the "isolated" branch pulmonary artery (PA) and the main pulmonary trunk or creation of an interposition graft using prosthetic material or flap techniques. We describe a surgical technique using a totally autologous interposition tube graft.

Aortic valve repair in adult congenital heart disease.

Aortic valve repair in adult congenital heart disease (ACHD) went through a major development during the last two decades to become an increasingly established treatment option in experienced heart valve repair centers. This mini-review addresses valve-sparing treatment strategies in the two most common clinical entities of patients with adult congenital aortic valve disease, namely those presenting with bicuspid (BAV) and unicuspid (UAV) aortic valve disease. Both diseases are integral components of the continuum of congenital aortic valve diseases and represent one of the most common reasons of cardiovascular morbidity in young and otherwise healthy adult patients. The review will highlight the most important advantages of aortic valve sparing procedures as compared to the conventional valve replacement strategy. New treatment aspects will be reviewed including minimally-invasive surgical approaches for aortic valve repair as well as modern protocols of enhanced perioperative recovery which will potentially improve the perioperative recovery and quality of life of the patients undergoing valve-sparing surgical procedures in the future.

Towards a Tissue-Engineered Contractile Fontan-Conduit: The Fate of Cardiac Myocytes in the Subpulmonary Circulation.

The long-term outcome of patients with single ventricles improved over time, but remains poor compared to other congenital heart lesions with biventricular circulation. Main cause for this unfavourable outcome is the unphysiological hemodynamic of the Fontan circulation, such as subnormal systemic cardiac output and increased systemic-venous pressure. To overcome this limitation, we are developing the concept of a contractile extracardiac Fontan-tunnel. In this study, we evaluated the survival and structural development of a tissue-engineered conduit under in vivo conditions. Engineered heart tissue was generated from ventricular heart cells of neonatal Wistar rats, fibrinogen and thrombin. Engineered heart tissues started beating around day 8 in vitro and remained contractile in vivo throughout the experiment. After culture for 14 days constructs were implanted around the right superior vena cava of Wistar rats (n = 12). Animals were euthanized after 7, 14, 28 and 56 days postoperatively. Hematoxylin and eosin staining showed cardiomyocytes arranged in thick bundles within the engineered heart tissue-conduit. Immunostaining of sarcomeric actin, alpha-actin and connexin 43 revealed a well -developed cardiac myocyte structure. Magnetic resonance imaging (d14, n = 3) revealed no constriction or stenosis of the superior vena cava by the constructs. Engineered heart tissues survive and contract for extended periods after implantation around the superior vena cava of rats. Generation of larger constructs is warranted to evaluate functional benefits of a contractile Fontan-conduit.

A multicentre evaluation of the autograft procedure for young patients undergoing aortic valve replacement: update on the German Ross Registry†.

OBJECTIVES: Conventional aortic valve replacement (AVR) in young, active patients represents a suboptimal solution in terms of long-term survival, durability and quality of life. The aim of the present work is to present an update on the multicentre experience with the pulmonary autograft procedure in young, adult patients. METHODS: Between 1990-2013, 1779 adult patients (1339 males; 44.7 ± 11.6 years) underwent the pulmonary autograft procedure in 8 centres. All patients underwent prospective clinical and echocardiographic examinations annually. The mean follow-up was 8.3 ± 5.1 years (range 0-24.3 years) with a total cumulative follow-up of 14 288 years and 662 patients having a follow-up of at least 10 years. RESULTS: The early (30-day) mortality rate was 1.1% (n = 19). Late (>30 day) survival of the adult population was comparable with the age- and gender-matched general population (observed deaths: 101, expected deaths: 91; P = 0.29). Freedom from autograft reoperation at 5, 10 and 15 years was 96.8, 94.7 and 86.7%, respectively, whereas freedom from homograft reoperation was 97.6, 95.5 and 92.3%, respectively. The overall freedom from reoperation was 94.9, 91.1 and 82.7%, respectively. Longitudinal modelling of functional valve performance revealed a low (<5%) probability of a patient being in higher autograft regurgitation grades throughout the first decade. Similarly, excellent homograft function was observed throughout the first 15 years. CONCLUSION: The autograft principle results in postoperative long-term survival comparable with that of the age- and gender-matched general population and reoperation rates within the 1%/patient-year boundaries and should be considered in young, active patients who want to avoid the shortcomings of conventional prostheses.

Age-related reoperation rate after the Ross procedure: a report from the German Ross Registry.

BACKGROUND AND AIM OF THE STUDY: An increasing number of young adult patients are choosing bioprostheses for aortic valve replacement (AVR). In this context, the Ross operation deserves renewed consideration as an alternative biological substitute. After both the Ross procedure and bioprosthetic AVR, reoperation rates remain a concern and may be related to age at surgery. Herein are reported details of freedom from reoperation after the Ross procedure for different age groups. METHODS: The reoperation rates of 1,925 patients (1,444 males, 481 females; mean age 41.2 ± 15.3 years) from the German Ross registry with a mean follow up of 7.4 ± 4.7 years (range: 0.00-18.51 years; total 12,866.6 patient-years) were allocated to three age groups: group I < 40 years; group II 40-60 years; and group III > 60 years. RESULTS: At 10 years (respectively 15 years) of follow up, freedom from reoperation was 86% (76%) in group I, 93% (85%) in group II, and 89% (83%) in group III. CONCLUSION: There is some evidence that, at least during the first 10 and 15 years after AVR, the Ross procedure provides a significantly lower reoperation rate in young adult and middle-aged patients aged < 60 years. This information may be of interest to the patients' or physicians' decision-making for aortic valve surgery.

Polytetrafluoroethylene-coated pacemaker leads as surgical management of contact allergy to silicone.

We have previously reported an 18-year-old girl with a congenital heart defect who developed complete heart block after one of her corrective surgeries and who needed an epicardial pacemaker implantation. She developed contact sensitivity to silicone compounds. The problem was solved by implanting a silicone-free pacemaker system utilizing silicone-free transvenous leads. The patient was readmitted 2 years later due to lead failure. As no silicone-free epicardial leads were available, we decided to use standard silicone epicardial leads and enclose the whole system in Gore-Tex material (W.L. Gore & Associates, Flagstaff, AZ). Based on our experience we would discourage the use of silicone-free transvenous pacing leads for epicardial use.

Fibronectin coating of oxygenator membranes enhances endothelial cell attachment.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) can replace the lungs' gas exchange capacity in refractory lung failure. However, its limited hemocompatibility, the activation of the coagulation and complement system as well as plasma leakage and protein deposition hamper mid- to long-term use and have constrained the development of an implantable lung assist device. In a tissue engineering approach, lining the blood contact surfaces of the ECMO device with endothelial cells might overcome these limitations. As a first step towards this aim, we hypothesized that coating the oxygenator's gas exchange membrane with proteins might positively influence the attachment and proliferation of arterial endothelial cells. METHODS: Sheets of polypropylene (PP), polyoxymethylpentene (TPX) and polydimethylsiloxane (PDMS), typical material used for oxygenator gas exchange membranes, were coated with collagen, fibrinogen, gelatin or fibronectin. Tissue culture treated well plates served as controls. Endothelial cell attachment and proliferation were analyzed for a period of 4 days by microscopic examination and computer assisted cell counting. RESULTS: Endothelial cell seeding efficiency is within range of tissue culture treated controls for fibronectin treated surfaces only. Uncoated membranes as well as all other coatings lead to lower cell attachment. A confluent endothelial cell layer develops on fibronectin coated PDMS and the control surface only. CONCLUSIONS: Fibronectin increases endothelial cells' seeding efficiency on different oxygenator membrane material. PDMS coated with fibronectin shows sustained cell attachment for a period of four days in static culture conditions.

Tissue engineering: selecting the optimal fixative for immunohistochemistry.

BACKGROUND: In the immunohistochemical analysis of tissue-engineered structures, aggressive treatments for fixation and antigen retrieval can impair the quality of specimen staining and visualization. HYPOTHESIS: We hypothesized that the adequate choice of fixative and antigen-retrieval method might improve the quality of immunohistochemical staining. METHODS: Tissue-engineered vascular grafts were fixed using formalin, Carnoy's, or HOPE(®) fixative. Antigen retrieval was performed where necessary and samples from each group were stained using hematoxylin and eosin to assess overall tissue preservation. For a set of proteins relevant to cardiovascular tissue development, immunohistochemical staining was applied to formalin-, Carnoy's-, and HOPE-fixed specimens to allow a comparative analysis. RESULTS: In tissue-engineered constructs, antigen retrieval methods necessary after formalin fixation led to significant destruction of the overall tissue structure. Carnoy's fixation resulted in good overall tissue preservation and adequate results for immunohistochemical staining of alpha-smooth muscle actin (α-SMA), vimentin, type I collagen, elastin, and laminin. HOPE fixative led to a loosened tissue structure and a swollen appearance but showed adequate results for staining against type III collagen and elastin. Formalin fixation without antigen retrieval led to inadequate visualization of α-SMA, vimentin, type I- and type III collagen, and laminin. CONCLUSION: Based on the present study, we recommend that Carnoy's fixative is employed for the preservation of tissue-engineered constructs to allow immunohistochemical analysis of type I- and type III collagen, elastin, laminin, α-SMA, and vimentin. However, it is clear that the technique requires optimization based on the particular tissue engineering application.