Molybdenum Disulphide Precipitation in Jet Reactors: Introduction of Kinetics Model for Computational Fluid Dynamics Calculations.

In our previous work, we used the population balance method to develop a molybdenum disulphide kinetics model consisting of a set of differential equations and constants formulated to express the kinetics of complex chemical reactions leading to molybdenum disulphide precipitation. The purpose of the study is to improved the model to describe the occurring phenomena more thoroughly and have introduced computational fluid dynamics (CFD) modelling to conduct calculations for various reactor geometries. CFD simulations supplemented with our nucleation and growth kinetics model can predict the impact of mixing conditions on particle size with good accuracy. This introduces another engineering tool for designing efficient chemical reactors.

Assessing a new coarctation repair simulator based on real patient's anatomy.

OBJECTIVES: To perform the preliminary tests of coarctation of aorta repair trainer, evaluate the surgical properties of the simulation and to assess and enhance residents' skills. METHODS: Single patient's angio-CT anatomy data were converted into magnified 3D-printed model of aortic coarctation with hypoplastic aortic arch, serving for creation of a mould used during wax copies casting. Wax cores were painted with six layers of elastic silicone and melted, yielding phantoms that were consecutively fixed in a mounting with and without a thoracic wall. Simulation included: proximal and distal aortic arch clamping, incision of its lesser curvature, extended end-to-end anastomosis with 7-0 suture. A head-mounted camera video recording enabled anastomosis time and mean one suture bite time evaluation. Leakage assessment was done by a water test. RESULTS: Two residents performed nine simulations each. Last four runs were performed with thoracic wall attached. All phantoms performed well, enabling tissue-like handling and cutting, excellent suture retention, and satisfactory elasticity. Median anastomosis times were 22'33″ and 24'47″ for phantoms without and with thoracic wall (p = not significant (NS)). Median times needed to pass suture through one side of anastomosis and regrasp needle were, respectively, 9″ and 13″ (p < 0.001). Median total number of leakages per phantom equalled 2 for both difficulty levels. There were no significant inter-resident differences in all assessed parameters. CONCLUSIONS: This medium-fidelity aortic coarctation repair trainer showed its feasibility in replication of major critical steps of the real operation. Objective surgical efficiency parameters could be obtained from each simulation and compared between trainees and at different adjustable difficulty levels.

Type of cardioplegic solution as a factor influencing the clinical outcome of open-heart congenital procedures.

INTRODUCTION: Cardioplegia is one of the most important modalities of myocardial protection during heart surgery. AIM: To assess the impact of blood cardioplegia on postoperative variables, in comparison with two types of crystalloid cardioplegic solutions during pediatric heart surgery. MATERIAL AND METHODS: One thousand one hundred and twenty-nine patients underwent surgical correction of congenital heart disease with cardioplegia administration between 2006 and 2012. Nonlinear regression models of postoperative low cardiac output syndrome (LCOS) incidence, catecholamine index and total complication count were developed using a genetic algorithm. The Akaike information criterion was applied for selection of the best model. The following explanatory variables were evaluated: cardioplegia type (ST - Saint Thomas, n = 440; FR - Fresenius, n = 432; BL - Calafiore, n = 257), congenital heart diseases (CHD) type, age, sex, genetic disorder presence, body surface area (BSA), cardiopulmonary bypass (CBP) time, aortic cross-clamp time, operation urgency, redo surgery, surgeon. RESULTS: Low cardiac output syndrome presence and higher than average catecholamine indexes were negatively influenced by use of crystalloid cardioplegia (ST or FR), presence of specific CHDs, redo surgery and prolonged CBP time. Increased complication count was related to: crystalloid cardioplegia, presence of specific CHDs, redo surgery, urgency of operation, operation time and CBP time. Higher BSA had a protective effect against higher catecholamine index and increased complication count. Older age was protective against LCOS. CONCLUSIONS: Cardioplegic solutions type influences postoperative variables in children after heart surgery by the negative impact of crystalloid cardioplegia. Blood cardioplegia presents potential advantages for patients - its application may reduce the incidence of low cardiac output syndrome and related complications.

Application of the CardioCel bovine pericardial patch - a preliminary report.

INTRODUCTION: Animal pericardial patches are widely used in adult and pediatric cardiac surgery. A search is ongoing for a new material with optimal surgical properties that will reduce intraoperative bleeding and the occurrence of restenosis, calcification, and pseudoaneurysms in long-term observation. One product of interest is the CardioCel bovine pericardial patch. AIM: Evaluation of the short-term results of CardioCel bovine pericardial patch implantation during pediatric cardiac surgery. MATERIAL AND METHODS: The study included 8 patients who underwent surgical correction of congenital cardiac defects between January 2015 and February 2016. Pericardial patches were used to repair supravalvular aortic stenosis and reconstruct the aortic arch and pulmonary arteries. The age of the patients ranged from 10 days to 14 years. RESULTS: There were no hospital deaths. The new material exhibited satisfactory durability and elasticity during surgery, facilitating optimal adaptation of the patch to the patient's tissues. No significant bleeding was reported from the suture site. The median duration of follow-up was 58 days. During the follow-up, there were no symptoms of pseudoaneurysm formation, patch thickening, or calcification in the areas where the pericardial patches were implanted. No clinical or laboratory symptoms of infection were observed in locations where the new material was applied. CONCLUSIONS: Satisfactory surgical properties of the patch were observed intraoperatively. Positive results using the new pericardial patch were obtained in short-term follow-up.

Late proximal pulmonary artery occlusion in a child with a single chamber after a right-sided Blalock-Taussig shunt.

The paper presents the management of a child born with pulmonary valve atresia, a single (double-inlet) ventricle, right ventricular hypoplasia, and perimembranous septal defect. The first stage of treatment consisted in a Blalock-Taussig shunt. Control angiography performed 1 year after surgery confirmed that the anastomosis was correct, and there was no narrowing at the connection. The first stage of treatment was complicated by the occlusion of the left pulmonary artery, as diagnosed during cardiac catheterization before the planned bidirectional Glenn anastomosis. A decision was made to perform surgery through a left thoracotomy without a cardiopulmonary bypass in order to restore the continuity of the left pulmonary artery.

Outcomes of Continuous Renal Replacement Therapy With Regional Citrate Anticoagulation in Small Children After Cardiac Surgery: Experience and Protocol From a Single Center.

Patients after a cardiac surgery in cardiopulmonary bypass often present an acute kidney failure. Continuous renal replacement therapy (CRRT) is often required. The aim of this study was to present effectiveness and safety of CRRT with regional citrate anticoagulation (RCA-CRRT) in small children after cardiac surgery. A retrospective analysis was conducted on 15 patients after cardiac surgery and who had RCA-CRRT performed in 2014. The established protocol was followed. Mean time on the RCA-CRRT was 192 h 40 min with the circuit mean lifetime of 43 h 33 min. Clotting was found to be a cause of shutdown in 29% of circuits. No severe electrolyte and metabolic disorders were observed. The RCA-CRRT is a safe procedure for critically ill children with contraindications to the CRRT with heparin anticoagulation. To avoid adverse effects related to metabolic disorders a proper procedure protocol has to be followed.

[Hybrid treatment of interrupted aortic arch in a newborn with contraindications for extracorporeal circulation: case report including 1.5 year follow-up]. / Leczenie hybrydowe noworodka z przerwanym lukiem aorty i przeciwwskazaniami do krazenia pozaustrojowego: opis przypadku z uwzglednieniem 1,5-rocznej obserwacji.

Despite marked improvement in the cardiosurgery, total repair of interrupted aortic arch with coexisting risk factors in neonatal or early infancy is associated with high mortality. We present a patient treated by an alternative hybrid procedure without exposing the critical ill neonate to the risk of cardiopulmonary bypass. At the 1.5 year of life a successful arch reconstruction, repair of associated anomalies and de-banding of pulmonary arteries with a stent cut out was done.

Evaluation of cardiac muscle microvessel density in children diagnosed with cyanotic heart defects.

Angiogenesis is largely an adaptive response to tissue hypoxia, which occurs in a wide variety of situations. Interestingly, the extent of hypoxia-induces angiogenesis in the cardiac muscle of children diagnosed with congenital cyanotic heart defects is not well established. Thus, the aim of this study was to 1) estimate the cardiac muscle microvessel density (MVD) in children diagnosed with cyanotic (study group) and non-cyanotic (control group) heart defects and to 2) evaluate the prognostic significance of MVD value in the development of ventricular dysfunction in the postoperative period. The study group included 42 children diagnosed with cyanotic heart defects. The control group comprised 33 patients with a diagnosis of non-cyanotic heart failure. The collected tissue included cardiac muscle sections from the right atrium and interventricular or interatrial wall during surgical correction of the defect. Immunocytochemistry with monoclonal mouse anti-human antibodies against CD31, CD34 and CD105 was employed to estimate the MVD value. The mean cardiac muscle MVD, defined by CD34 expression, was 596.7 ± 32.6 microvessels per 1 mm² in the study group, which was notsignificantly different from the mean MVD in the control group (461.2 ± 30.5). Interestingly, in non-cyanotic heart defects, an inner area of subendocardial meshwork was estimated to have 75.3 ± 7.0 microvessels per 1 mm², compared to 92.8 ± 10.9 microvessels per 1 mm² (p = 0.0082) in patients with cyanotic heart defects. No significant correlations between MVD value and ventricular dysfunction were found. Cyanotic heart defects resulting in chronic hypoxia might provoke angiogenesis in the subendocardial meshwork of the heart wall. The process seems to be independent of the type of cyanotic heart disease and most likely takes place during antenatal development. A ventricular dysfunction observed in some cases of cyanotic heart defects could not be predicted by the estimation of MVD.

A biodegradable ring enables growth of the native tricuspid annulus.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess the growth potential and function of the tricuspid valve (TV) annulus after annuloplasty with the intra-annular biodegradable ring. METHODS: Among 11 children (median age 4.5 years; age range: 0.2-10.9 years) who underwent surgery for severe congenital TV regurgitation, valve repair was completed using a biodegradable annuloplasty ring. The children were followed regularly using transthoracic echocardiography, whereby the TV annulus lateral diameter (TVALD) and valve function were monitored. Rates of valve growth were derived from the slope of the regression equations which related TVALD to the natural logarithm of the body surface area (lnBSA). RESULTS: The children's somatic growth was harmonious throughout the entire follow up period (mean 478 days; range: 171-1,477 days). The TVALD differed significantly at six months and at one and two years after surgery compared to the postoperative value at discharge, rising from 19 mm (range: 15.5-26.0 mm) to 24 mm (range: 19.0-30.0 mm) at the last control examination (p = 0.003), while the related Z-scores remained stable. A significant linear correlation between TVALD and lnBSA was found in 63.6% of patients. The median rate of growth for the whole cohort was 1.96-fold (range: 0.52-5.53-fold) higher than a norm, and correlated strongly and positively with age (r = 0.91; p <0.05). The median postoperative TV insufficiency fraction of 9.8% (range: 0-28.8%) remained constant during the follow up period. The postoperative TV maximal pressure gradient was 5.5 mmHg (range: 3.1-12.2 mmHg), and did not increase over time. CONCLUSION: The implantation of a biodegradable ring does not restrict growth of the native TV annulus; this enabled its stabilization in proportion to the somatic growth in the majority of the children. The TV annulus began to change its dimension at six months postoperatively, which may coincide with its biodegradation. The rate of growth of the TV annulus differed from that in the normal population, and was proportional to the patient age. The increase in TV annulus diameter over time did not have any negative influence on the function of the repaired valve.

Valve-sparing surgery for isolated cleft mitral valve complicated by endocarditis in a child.

A 12-year-old girl presented with an isolated cleft mitral valve complicated by infective endocarditis that was confined to the medial part of the cleft anterior leaflet. An innovative valve-sparing surgery was applied whereby the destroyed part of the leaflet was removed. The corresponding anterior annulus was plicated by approximation of the base of the cleft to the posteromedial commissure. The 'cleft' edge of AML was then sutured to the plicated annulus and to P3 at the level of the posteromedial commissure. The reconstructed valve was fully functional, and showed trivial regurgitation and an absence of stenosis for up to two years postoperatively.

[Staphylococcal sepsis due to ventricular septal defect patch infection 14 years after its closure]. / Posocznica gronkowcow w wyniku zakazenia laty na ubytku przegrody miedzykomorowej 14 lat po jego zamknieciu.

We report the case of a 17 year-old girl who developed sepsis due to Methicillin-Resistant Staphyloccocus Epidermidis (MRSE) infection of Dacron patch 14 years after ventricular septal defect (VSD) closure and 4 years after pacemaker implantation. Although MRSE grew in many cultures taken and proper antibiotic regimen was administered, no improvement in patient's clinical status was observed. Disseminated intravascular coagulation and multi-organ failure developed. An operation, at which perforated Dacron VSD-patch was replaced with a new Gore-Tex one, was performed by cardiac surgery team. The patient's clinical status improved immediately after the procedure. The girl remained well 12 months after discharge.

[Closure of major aorto-pulmonary collateral artery with the Amplatzer vascular plug in an infant with pulmonary atresia and ventricular septal defect - a difficult therapeutic problem]. / Zamkniecie nieprawidlowego polaczenia aortalno-plucnego zatyczka Amplatzer vascular plug u dziecka z zarosnieta zastawka plucna i ubytkiem miedzykomorowym - trudny problem terapeutyczny.

A case of a 2-day-old newborn with congenital heart disease, pulmonary atresia and ventricular septal defect is described. The Blalock-Taussig shunt was created 6 days after birth. After the procedure, the newborn developed symptoms of increased pulmonary blood flow and respiratory distress. We decided to close one of the major aortopulmonary collateral arteries with the Gianturco coil on the 41st day after birth, however the results were not satisfactory. On the 66th day of infant life (by that time the patient weighted 3 kg), another procedure with the Amplatzer vascular plug was performed. This procedure was successful. After a few days the infant was discharged from hospital.

Difficult to treat recurrent stenosis of the aorta.

The risk associated with repeated treatment of aortic stenosis is as high as 5% and increases to as much as 25% in complex heart diseases. Among the methods that are commonly accepted and used in the treatment of recurrent aortic stenosis are balloon dilatation and stent implantation. In this study we describe five patients with recurrent stenosis of the aorta treated with stent implantation. The short-term results of such treatment are promising. However, in some cases it is only palliative in character and does not completely resolve the problems arising from congenital heart disease. (Cardiol J 2007; 14: 186-192).

Is device closure for direct access valved stent implantation safe?

OBJECTIVE: Despite the progress made in the development of valved stents for trans-apical valve replacement, a reliable closure of the access orifice remains a major issue. The present study was designed to evaluate if device closure of the ventricular wall is safe. MATERIALS AND METHODS: Transventricular access for pulmonary valve replacement was simulated with a 26F sheath and the resulting orifice was closed with an Amplatzer Muscular VSD Occluder (AMuscVSDO) in chronic sheep experiments (body weight 45-48 kg). Mean procedure time, blood loss, and standard hemo-dynamics were recorded. The animals were sacrificed electively and the histopathological changes in and around AMuscVSDO in the right ventricular wall were systematically studied by semi-quantitative analysis of collagenisation, inflammatory response and 'resorptive' process. RESULTS: Mean procedure time was 31+/-10.7 min, blood loss was 22.5+/-8.7 ml, heart rate was 123+/-22.6 bits/min before and 128+/-28.7 bits/min after, mean arterial blood pressure was 88+/-16.7 mm Hg before and 82.6+/-18.3 mm Hg after the procedure. Mean survival was 5.3 weeks. The collagen and scar formation studies revealed three different periods: (1) initial fibrosis (0-3 weeks); (2) so-called 'capsulation' (3-9 weeks after the implantation of the Occluder); and (3) final remodelling and differentiation (9 weeks). The fabric inside the Occluder played the role of a collagenisation promoter, active from the 3rd week till it vanishes. Inflammation plays a role as a temporary reaction (0-3 weeks) during the healing process, with no signs of any active, focal or circumscribed, myocardial damage. CONCLUSIONS: (1) The closure of the free ventricular wall perforation with AMuscVSDO is safe due to the scar tissue resulting from the healing process around and in the device. (2) The myocardial healing around and inside an implanted AMuscVSDO represents two processes: extensive fibrosis ensues around metallic wires with the progression towards the inside of the myocardium, whereas inside AMuscVSDO the loose connective tissue fills the myocardial lesion. During cicatrisation, the fabric elements of AMuscVSDO act as the ground for collagen formation and fibroblast proliferation. (3) The cicatrisation processes after ventricular AMuscVSDO implantation show remodelling, with rearrangement of collagen fibres architecture and distribution.

Comparison of cardiac function in children after surgical and Amplatzer occluder closure of secundum atrial septal defects.

OBJECTIVE: The aim of the retrospective study was to examine the changes in the left and right ventricular size as well as the systolic and diastolic function of the left ventricle after surgical and transcatheter treatment of atrial septal defects with Amplatzer atrial septal defect occluder (ASDO). METHODS: Two groups of patients were examined using transthoracic cross-sectional echocardiography before and after the treatment of atrial septal defect: Group A--Amplatzer ASD occluder--38 children and Group S treated surgically--20 children. The following parameters were assessed: left and right ventricular end-diastolic diameter indexes, ejection fraction, mitral E wave to A wave velocity ratio, deceleration time (DCT), isovolumetric relaxation time (IVRT) and heart rate. RESULTS: There was a significant decrease in right ventricular and an increase in left ventricular size in both groups during the follow-up observation. The long-term ECHO examination revealed smaller right ventricle (RV) (Group A: RVEDI=1.00+/-0.20 vs Group S RVEDI: 1.18+/-0.20 (p=0.001)) and bigger left ventricle (Group A: LVEDI=1.04+/-0.08 vs Group S: LVEDI=0.99+/-0.07 (p=0.022)) in Group A in comparison to Group S. Children undergoing operation had significantly shorter IVRT (Group A: IVRT=50.00+/- 9.65 vs Group S: IVRT=42.5+/- 8.95 (p=0.02)) than patients after ASDO device application. CONCLUSIONS: (1) During the follow-up period, the diastolic function of the left ventricle is better in children with device closure of ASD compared with those patients treated surgically. (2) Postoperative changes of the left and right ventricular size indexes are more favourable in patients after the device closure of ASD compared with children undergoing the surgical procedure.

Closure of perimembranous ventricular septal defect using transcatheter technique versus surgical repair.

INTRODUCTION: Since the Membr VSD occluders have been introduced into clinical practice it is now possible to compare two treatment methods -- surgical and percutaneous. AIM: Assessment of the effectiveness and risk of complications in patients with perimembranous ventricular septal defect (VSD) treated with the Membr VSD occluder or surgery as well as comparison of postprocedural left and right ventricular systolic functions. METHODS: The study involved 11 children with perimembranous VSD treated with occluder implantation (Group A) and 12 children with surgical repair (Group C). Groups A and C differed slightly in terms of age of patients (p=0.026), but had similar mean weights (p=0.103), pulmonary to systemic flow ratios (Qp: Qs, p=0.929) and follow-up duration after the procedure. No significant differences were observed between the two groups in terms of left ventricular systolic function [left ventricular ejection fraction (EF, p=0.567)], diastolic function [mitral flow E/A ratio (p=0.975)], E deceleration time (DCT, p=0.346), isovolumetric relaxation time (IVRT, p=0.606), heart rate (HR, p=0.133) or left ventricular diameter (LV) on transthoracic echocardiography (TTE) before VSD closure. TEE was performed in all patients and the parameters listed above were measured within 3 to 16 months after the procedure, and then intra- and inter-group comparisons were carried out. Additionally, mitral (MV), tricuspid (TV) and aortic (Ao) valve regurgitations were evaluated. RESULTS: Tricuspid (TR, p=0.028) and mitral regurgitation (MR, p=0.043) decreased significantly after closure of VSD with the Membr VSDO. MR was significantly smaller in patients treated with the occluder than in those after surgery (p=0.026). Postprocedural TR (p=0.486) and aortic regurgitation (AR, 0.607) did not differ significantly between the two groups. Left ventricular EF was significantly (p=0.004) lower and HR higher (0.043) after surgery than in children treated with the occluder. No significant differences of the diastolic function were found - E/A (p=0.88), DCT (p=0.413), IVRT (p=0.09). CONCLUSIONS: 1. During the mid-term follow-up left ventricular EF was higher in patients after Membr VSDO occluder implantation than after surgical repair of VSD. 2. Higher EF and reduction of the left ventricular diameter after closure of perimembranous VSD with the occluder may result in a lower incidence and degree of MR in comparison to the subjects operated on.

Congenital heart defect with associated malformations in children.

BACKGROUND: Children with multisystem involvement including congenital heart defect (CHD) are a very salient problem. The purpose of this study was to evaluate the incidence of CHD associated with malformations of other systems and to assess the modalities of treatment and perioperative mortality among patients referred to the department of pediatric cardiac surgery. METHODS: The medical records of 1856 children were reviewed retrospectively from 1997 to 2002 to establish CHD and types of associated malformations. The connections between CHD and other lesions were investigated. Furthermore, the influence of patient and perioperative variables on mortality risk was scrutinized. Univariate and multivariate analyses were used. RESULTS: Eighty-four children (4.53%) had CHD and associated malformations. The malformations of digestive (35.7%), urinary (22.4%), and nervous (14.3%) systems were the most frequently observed associated defects. No relation was found between CHD and concomitant lesions. The results of multivariate logistic regression showed significant influence of patient age, primary cardiac procedure, and CHD type on mortality (ca 19%) in children with multiorgan lesions. CONCLUSIONS: The treatment of children with CHD and associated multiple lesions is connected with higher mortality risk. The following factors: younger age, urgency of surgical procedure, and primary surgical procedure had negative impact on patient's outcome. However, these risks in certain cases are inevitable. The cardiac procedure preceding the surgical operation may improve the overall effect of treatment because of circulatory stabilization, provided that the condition of the patient does not preclude any intervention at all.

Mid-term experience with valved bovine jugular vein conduits.

From June 1999 to January 2004, 43 children underwent implantation of a valved bovine jugular vein conduit and correction of complex congenital heart defects. Median age was 1.98 years (range, 11 days - 13.3 years). There were 7 early deaths (16.3%) unrelated to conduit failure or thrombosis. Median follow-up of 36 survivors was 24 months (range, 1-48 months, quartile range, 12-48 months), total follow-up was 78 patient-years. There were 3 late deaths (8.3%) due to infection, pulmonary thromboembolism, and sudden cardiac arrest after re-operation to repair a right ventricular outflow tract aneurysm. There were 2 conduit explantations due to dysfunction and suspected endocarditis. Three patients underwent balloon dilatation of distal stenoses. The mean peak gradient through the pulmonary anastomosis was 15 mm Hg (range, 3-42 mm Hg) among patients free from re-intervention. No severe valve regurgitation was observed. Freedom from re-intervention was 72% at 48 months. This conduit remains a good alternative to homografts. Causes of distal stenosis must be clarified, guidelines for prophylactic anticoagulation must be created, and the role of percutaneous balloon dilatation established.

[Ross operation using "contegra" conduit in a 5 year old girl with severe aortic valve insufficiency in Kawasaki disease coexisting with infective endocarditis--a case report]. / Ciezka niedomykalnosc aortalna w chorobie Kawasaki wspólistniejaca z bakteryjnym zapaleniem wsierdzia u 5-letniego dziecka. Operacja Ross'a z zastosowaniem Conduitu "Contegra".

A case of a 5-year-old girl with severe dysfunction of aortic valve in Kawasaki disease coexisting with endocarditis, is described. The role of Ross operation in the treatment of this condition is discussed. The 18-months follow-up showed good function of aortic valve and "Contegra" conduit (bovine jugular vein), but long-term follow-up of patients with "Contegra" conduit remains unknown. In conclusion, a Ross operation using "Contegra" conduit in pulmonary position could be effective method in the treatment of dysfunction of aortic valve in Kawasaki disease coexisting with endocarditis in children.

[Percutaneous procedures for the repair of iatrogenic occlusion or stenosis of peripheral vessels in children--report of 5 cases]. / Przezskórne zabiegi naprawcze zwezonych jatrogennie naczyn obwodowych. Opis pieciu przypadków.

Invasive percutaneous diagnostic or therapeutic procedures are associated with the risk of thrombosis and occlusion of peripheral vessels which are used for vascular access. Data on the transcatheter therapy of vascular complications in children are scarce. We described five children in four of whom percutaneous transluminal balloon angioplasty of occluded peripheral vessels was successfully performed. Technical aspects of this treatment and indications are discussed.