Longitudinal Evaluation of Congenital Cardiovascular Surgical Performance and Skills Retention Using Silicone-Molded Heart Models

Objective: Hands-on surgical training (HOST) for congenital heart surgery (CHS), utilizing silicone-molded models created from 3D-printing of patients' imaging data, was shown to improve surgical skills. However, the impact of repetition and frequency of repetition in retaining skills has not been previously investigated. We aimed to longitudinally evaluate the outcome for HOST on two example procedures of different technical difficulties with repeated attempts over a 15-week period. Methods: Five CHS trainees were prospectively recruited. Repair of coarctation of the aorta (CoA) and arterial switch operation (ASO) were selected as example procedures of relatively low and high technical difficulty. Procedural time and technical performance (using procedure-specific assessment tools by the participant, a peer-reviewer, and the proctor) were measured. Results: Coarctation repair performance scores improved after the first repetition but remained unchanged at the follow-up session. Likewise, CoA procedural time showed an early reduction but then remained stable (mean [standard deviation]: 29[14] vs 25[15] vs 23[9] min at 0, 1, and 4 weeks). Conversely, ASO performance scores improved during the first repetitions, but decreased after a longer time delay (>9 weeks). Arterial switch operation procedural time showed modest improvements across simulations but significantly reduced from the first to the last attempt: 119[20] versus 106[28] min at 0 and 15 weeks, P = .049. Conclusions: Complex procedures require multiple HOST repetitions, without excessive time delay to maintain long-term skills improvement. Conversely, a single session may be planned for simple procedures to achieve satisfactory medium-term results. Importantly, a consistent reduction in procedural times was recorded, supporting increased surgical efficiency.

Deviations From Best Practice: Findings From a Certified Patient Safety Organization Remote-Verification Observational Study of Intravenous Compounding of Chemotherapeutic and Ancillary Drugs

Background: Chemotherapeutic and immunomodulatory medications can pose a serious risk to patient and healthcare provider safety because of complex processes, cytotoxicity, and prevalent medication use. Objective: To evaluate chemotherapeutic and ancillary medication compounding in hospital pharmacies using a remote verification system, focusing on pharmaceutical deviations from best practice, compounding time, medication waste, and cost. Methods: This retrospective, blinded observational study used a remote intravenous (IV) workflow verification system to examine IV chemotherapeutic compounding errors in large hospital systems. A Patient Safety Organization securely obtained >5000 compounding records and photos from the IV workflow system. Blinded pharmacists evaluated IV chemotherapy preparations using picture slide viewers to assess any deviations from best practice. Time variables, medication waste, STAT vs non-STAT orders, and cost were also evaluated. Results: The most frequently reported deviations from best practice included medications exceeding the >10% additive volume guideline (35.9%) and inaccurate dose labels (28.3%). Time flow analyses demonstrated a substantial increase in total compounding time per vial for 1 vs 2 vials. Most medications in this analysis had an average waste ranging from 0-.36 vials. STAT orders, accounting for 38.4% of all orders, wasted more medication than non-STAT orders. Gemcitabine cost analyses showed an association for number of vials and compounding time with overall cost per dose. Conclusion: Substantial inconsistencies between workflow stations were observed-highlighting the lack of standardization across chemotherapeutics, volume of medication waste during preparation, and the need to establish improved quality controls to safeguard patient and health care provider safety.

Conventional oxygen therapy versus CPAP as a ceiling of care in ward-based patients with COVID-19: a multi-centre cohort evaluation

BACKGROUND

Continuous positive airway pressure (CPAP) therapy is commonly used for respiratory failure due to severe COVID-19 pneumonitis, including in patients deemed not likely to benefit from invasive mechanical ventilation (nIMV). Little evidence exists demonstrating superiority over conventional oxygen therapy, whilst ward-level delivery of CPAP presents practical challenges. We sought to compare clinical outcomes of oxygen therapy versus CPAP therapy in patients with COVID-19 who were nIMV.

METHODS

This retrospective multi-centre cohort evaluation included patients diagnosed with COVID-19 who were nIMV, had a treatment escalation plan of ward-level care and clinical frailty scale ≤ 6. Recruitment occurred during the first two waves of the UK COVID-19 pandemic in 2020; from 1^st March to May 31^st, and from 1^st September to 31^st December. Patients given CPAP were compared to patients receiving oxygen therapy that required FiO₂ ≥0_.4 for more than 12 hours at hospitals not providing ward-level CPAP. Logistic regression modelling was performed to compare 30-day mortality between treatment groups, accounting for important confounders and within-hospital clustering.

FINDINGS

Seven hospitals provided data for 479 patients during the UK COVID-19 pandemic in 2020. Overall 30-day mortality was 75.6% in the oxygen group (186/246 patients) and 77.7% in the CPAP group (181/233 patients). A lack of evidence for a treatment effect persisted in the adjusted model (adjusted odds ratio 0.84 95% CI 0.57-1.23, p=0.37). 49.8% of patients receiving CPAP-therapy (118/237) chose to discontinue it.

INTERPRETATION

No survival difference was found between using oxygen alone or CPAP to treat patients with severe COVID-19 who were nIMV. A high patient-initiated discontinuation rate for CPAP suggests a significant treatment burden. Further reflection is warranted on the current treatment guidance and widespread application of CPAP in this setting.

FUNDING

L Pearmain is supported by the MRC (MR/R00191X/1). TW Felton is supported by the NIHR Manchester Biomedical Research Centre.

3D Modeling and Printing in Congenital Heart Surgery: Entering the Stage of Maturation

3D printing allows the most realistic perception of the surgical anatomy of congenital heart diseases without the requirement of physical devices such as a computer screen or virtual headset. It is useful for surgical decision making and simulation, hands-on surgical training (HOST) and cardiovascular morphology teaching. 3D-printed models allow easy understanding of surgical morphology and preoperative surgical simulation. The most common indications for its clinical use include complex forms of double outlet right ventricle and transposition of the great arteries, anomalous systemic and pulmonary venous connections, and heterotaxy. Its utility in congenital heart surgery is indisputable, although it is hard to "scientifically" prove the impact of its use in surgery because of many confounding factors that contribute to the surgical outcome. 3D-printed models are valuable resources for morphology teaching. Educational models can be produced for almost all different variations of congenital heart diseases, and replicated in any number. HOST using 3D-printed models enables efficient education of surgeons in-training. Implementation of the HOST courses in congenital heart surgical training programs is not an option but an absolute necessity. In conclusion, 3D printing is entering the stage of maturation in its use for congenital heart surgery. It is now time for imagers and surgeons to find how to effectively utilize 3D printing and how to improve the quality of the products for improved patient outcomes and impact of education and training.

Human campylobacteriosis related to cross-contamination during handling of raw chicken meat: Application of quantitative risk assessment to guide intervention scenarios analysis in the Australian context

Quantitative Microbiological Risk Assessment (QMRA) is a methodology used to organize and analyze scientific information to both estimate the probability and severity of an adverse event as well as prioritize efforts to reduce the risk of foodborne pathogens. No QMRA efforts have been applied to Campylobacter in the Australian chicken meat sector. Hence, we present a QMRA model of human campylobacteriosis related to the occurrence of cross-contamination while handling raw chicken meat in Western Australia (WA). This work fills a gap in Campylobacter risk characterization in Australia and enables benchmarking against risk assessments undertaken in other countries. The model predicted the average probability of the occurrence of illness per serving of salad that became cross-contaminated from being handled following the handling of fresh chicken meat as 7.0 × 10^-4 (90% Confidence Interval [CI] ± 4.7 × 10^-5). The risk assessment model was utilized to estimate the likely impact of intervention scenarios on the predicted probability of illness (campylobacteriosis) per serving. Predicted relative risk reductions following changes in the retail prevalence of Campylobacter were proportional to the percentage desired in the reduction scenario; a target that is aiming to reduce the current baseline prevalence of Campylobacter in retail chicken by 30% is predicted to yield approximately 30% relative risk reduction. A simulated one-log reduction in the mean concentration of Campylobacter is anticipated to generate approximately 20% relative risk reductions. Relative risk reduction induced by a one-log decrease in the mean was equally achieved when the tail of the input distribution was affected-that is, by a change (one-log reduction) in the standard deviation of the baseline Campylobacter concentration. A scenario assuming a 5% point decrease in baseline probability of cross-contamination at the consumer phase would yield relative risk reductions of 14%, which is as effective as the impact of a strategic target of 10% reduction in the retail prevalence of Campylobacter. In conclusion, the present model simulates the probability of illness predicted for an average individual who consumes salad that has been cross-contaminated with Campylobacter from retail chicken meat in WA. Despite some uncertainties, this is the first attempt to utilize the QMRA approach as a scientific basis to guide risk managers toward implementing strategies to reduce the risk of human campylobacteriosis in an Australian context.

P6555A self-adaptive approach to antitachycardia pacing - a head to head comparison using advanced computational modeling

Background

Antitachycardia pacing (ATP) for monomorphic VT (MVT) reduces painful defibrillation shocks. Most ICD-treated ventricular arrhythmias are MVT, suggesting an opportunity for improved ATP to decrease shocks. We report on a new algorithm (Yee, Circ AE 2017) that uses electrophysiologic (EP) first-principles to design ATP sequences in real-time. Heart-rate history is used to design the first ATP sequence, and failed ATP post-pacing interval is used to design later sequences.

Purpose

The purpose of this modeling study was to understand how this new ATP algorithm would perform in a head-to-head comparison with traditional burst ATP. Modeling allows direct comparison of the two algorithms in identical, realistic, patient-derived cardiac arrythmias.

Methods

Patient-specific late gadolinium enhanced MRI and EP data were used to build an adjudicated cohort of realistic numerical heart models with varied EP, infarct, border zone. Publicly available EP modeling software CARPentry was used to calculate sustained reentrant VT initiated with the programmed electrical stimulation used to induce VT clinically. The VTs were physician-adjudicated to validate models. Burst ATP was 3 sequences of 8 pulses at 88% of VT cycle length, each decremented by 10ms. The new ATP was limited to 3 automatically designed sequences.

Results

Three hundred unique VT scenarios were generated from 6 human hearts with multiple VT circuits, 5 electrophysiologic states, and 10 pacing locations. Burst ATP terminated 168/300 VTs (56%) and accelerated 2.7%. The new ATP terminated 234/300 VTs (78%) with the same acceleration. The two dominant ATP failure mechanisms were identified as 1) insufficient prematurity to close the excitable gap, and 2) failure to reach the critical isthmus of the VT circuit. For these mechanisms, the new ATP algorithm reduce failures from 64 to 28 (44% reduction) without increasing acceleration.

Conclusion

The new automated ATP algorithm successfully adapted ATP sequences for VT episodes that burst ATP failed to terminate. The new ATP was successful even with complex scar geometries and electrophysiology heterogeneity as seen in the real world.

Examining the Association Between Electrodermal Activity and Problem Behavior in Severe Autism Spectrum Disorder: A Feasibility Study

Background: Many individuals with autism spectrum disorder (ASD) engage in problem behavior, presenting significant challenges for those providing care and services for this population. Psychophysiological measures of arousal, such as electrodermal activity (EDA), may provide an early indication of subsequent problem behavior. However, variability in EDA patterns associated with behaviors may limit this predictive ability. Methods: EDA data was sampled from eight individuals with severe ASD in a naturalistic setting, while participating in educational programming in a school setting at a residential facility for severely affected individuals with developmental disabilities, to examine variability in EDA patterns. Results: An anticipatory rise in EDA only occurred 60% of the time prior to the problem behavior. Additionally, EDA after a problem behavior returned to median baseline levels only 45% of the time. Conclusions: Heterogeneity of EDA responses in those with the most severe forms of ASD will be an important consideration in future studies utilizing psychophysiological tools such as EDA to anticipate problem behavior, including the need for monitoring of return to baseline after problem behaviors. Incorporation of this consideration may lead to greater reliability of these approaches to help anticipate and manage problem behaviors.

Cardiac regenerative capacity is age- and disease-dependent in childhood heart disease

Objective

We sought to define the intrinsic stem cell capacity in pediatric heart lesions, and the effects of diagnosis and of age, in order to inform evidence-based use of potential autologous stem cell sources for regenerative medicine therapy.

Methods

Ventricular explants derived from patients with hypoplastic left heart syndrome (HLHS), tetralogy of Fallot (TF), dilated cardiomyopathy (DCM) and ventricular septal defect (VSD) were analyzed following standard in vitro culture conditions, which yielded cardiospheres (C-spheres), indicative of endogenous stem cell capacity. C-sphere counts generated per 5 mm3 tissue explant and the presence of cardiac progenitor cells were correlated to patient age, diagnosis and echocardiographic function.

Results

Cardiac explants from patients less than one year of age with TF and DCM robustly generated c-kit- and/or vimentin-positive cardiac mesenchymal cells (CMCs), populating spontaneously forming C-spheres. Beyond one year of age, there was a marked reduction or absence of cardiac explant-derivable cardiac stem cell content in patients with TF, VSD and DCM. Stem cell content in HLHS and DCM strongly correlated to the echocardiographic function in the corresponding ventricular chamber, with better echocardiographic function correlating to a more robust regenerative cellular content.

Conclusions

We conclude that autologous cardiomyogenic potential in pediatric heart lesions is robust during the first year of life and uniformly declines thereafter. Depletion of stem cell content occurs at an earlier age in HLHS with the onset of ventricular failure in a chamber-specific pattern that correlates directly to ventricular dysfunction. These data suggest that regenerative therapies using autologous cellular sources should be implemented in the neonatal period before the potentially rapid onset of single ventricle failure in HLHS or the evolution of biventricular failure in DCM.

Survival to Stage II with Ventricular Dysfunction: Secondary Analysis of the Single Ventricle Reconstruction Trial

Ventricular dysfunction affects survival in patients with single right ventricle (RV), and remains one of the primary indications for heart transplantation. Since it is challenging to predict the capacity of patients with ventricular dysfunction to proceed to the stage II procedure, we sought to identify factors that would be associated with death or heart transplantation without achieving stage II for single RV patients with ventricular dysfunction after Norwood procedure. The Single Ventricle Reconstruction (SVR) trial public-use database was used. Patients with a RV ejection fraction less than 44% or a RV fractional area of change less than 35% on the post-Norwood echocardiogram were included. Parametric risk hazard analysis was used to identify risk factors for death or transplantation without achieving stage II. Of 365 patients with ventricular function measurements on the post-Norwood echocardiogram, 123 (34%) patients had RV dysfunction. The transplantation-free survival was significantly lower for those with ventricular dysfunction compared to those with normal function (log rank Chi-square = 4.23, p = 0.04). Furthermore, having a Blalock-Taussig (BT) shunt, a large RV, a post-Norwood infectious complication, and a surgeon who performs five or less Norwood per year were independent risk factors for death or transplantation without achieving stage II. The predicted 6-month transplantation-free survival for patients with all four identified risk factors was 1% (70% CI 0-13%). Early heart transplantation referral might be considered for post-Norwood patients with BT shunt and RV dysfunction, especially if other high-risk features are present.

Sutureless Versus Conventional Pulmonary Vein Repair: A Magnetic Resonance Pilot Study

BACKGROUND

Two different surgical techniques are used to repair anomalous pulmonary venous connection or pulmonary vein (PV) stenosis: the classic repair (CR) and the sutureless repair (SR). The purpose of this study was to compare the prevalence of PV stenosis between the two surgical approaches.

METHODS

Patients were prospectively recruited irrespective of symptoms or previous imaging findings. Cardiac magnetic resonance imaging and echocardiography were performed in a blinded fashion on the same day.

RESULTS

Twenty-five patients (13 male) after PV repair completed the study. Twelve patients had undergone CR and 13 SR (in 1 patient as a reoperation after CR). The median age at operation was 2 months (range: 1 day to 5 years) and was similar for both groups; the median age at the time of cardiac magnetic resonance was 9 years (range: 6 to 17 years) and 9 years (range: 6 to 14 years) for the CR and SR, respectively. Four patients had PV stenosis. All 4 patients had had total anomalous pulmonary venous connection, 1 patient had undergone repair with the CR and 2 with a primary SR; 1 patient had first undergone a CR, followed by a SR for stenosis. Echocardiography provided complete visualization of all PVs in only 11 patients (44%). Notable stenosis of at least one PV was missed by echocardiography in 2 patients.

CONCLUSIONS

This pilot study indicates that not only CR but also SR may be burdened by a risk of postoperative PV stenosis. Magnetic resonance imaging should be used routinely for the postoperative monitoring for the development of PV obstruction.

Fontan Failure and Death in Contemporary Fontan Circulation: Analysis From the Last Two Decades

BACKGROUND

We sought to evaluate the incidence of Fontan failure or complication and its relation to death in patients having contemporary Fontan strategies over 2 decades.

METHODS

Five hundred patients who underwent Fontan completion (extracardiac, n = 326; lateral tunnel, n = 174) from 1985 to 2012 were reviewed. Patient characteristics, modes of Fontan failure/complication and death, and predictors for Fontan failure/complication and death were analyzed.

RESULTS

There were 23 early deaths (4.6%) and 17 late deaths (3.4%), with no early death since 2000. Survival has improved over time (p < 0.001). Twenty-three of 40 patients who died were identified as Fontan failure before death, including ventricular dysfunction (n = 14), pulmonary vascular dysfunction (n = 4), thromboembolism (n = 2), and arrhythmia (n = 4). Mode of death was circulatory failure (n = 18), multiorgan failure (n = 6), pulmonary failure (n = 3), cerebral/renal (n = 5), and sudden death (n = 4). Modes of failure/complication were directly (65%) or conceivably (10%) related to death in 30 of 40 patients (75%). Forty-eight percent of survivors had late Fontan complication(s). Five-year freedom from late Fontan complication was lower among patients who died compared with patients who survived (29.4% versus 53.3%, p < 0.001). Ventricular dysfunction (p = 0.001) and higher pulmonary artery pressures (p < 0.001) after Fontan were predictors for death. Longer cardiopulmonary bypass time (p = 0.032) and reinterventions (p < 0.001) were predictors for late Fontan complication.

CONCLUSIONS

Early death in the early era has been overcome. Yet the incidence and causes of late death remain unchanged. There was a strong causative relationship between the mode of Fontan failure/complication and death, indicating the importance of early recognition and treatment of Fontan failure/complication.

Neuroinflammatory and morphological changes in late-life depression: the NIMROD study

We studied neuroinflammation in individuals with late-life depression, as a risk factor for dementia, using [¹¹C]PK11195 positron emission tomography (PET). Five older participants with major depression and 13 controls underwent PET and multimodal 3T magnetic resonance imaging (MRI), with blood taken to measure C-reactive protein (CRP). We found significantly higher CRP levels in those with late-life depression and raised [¹¹C]PK11195 binding compared with controls in brain regions associated with depression, including subgenual anterior cingulate cortex, and significant hippocampal subfield atrophy in cornu ammonis 1 and subiculum. Our findings suggest neuroinflammation requires further investigation in late-life depression, both as a possible aetiological factor and a potential therapeutic target.

Meeting the needs of people with learning disabilities: developing an interactive model of care

This paper describes the development and implementation of a model of care specifically designed to meet the complex needs of people with learning disabilities. This interactive model of nursing has been developed, implemented and evaluated in practice areas during the past 2 years. It is apparent from the data collected, that this model of nursing has moved carers' perceptions towards a more holistic understanding of their clients' needs. This has been achieved through a greater understanding of the inter-relationship between internal and external factors that, together, make us who we are. The necessity for carers to use their knowledge of health and the social sciences and their inter-relationship during the assessment process, demonstrates how accurate interpretation and synthesis of data creates an holistic profile of each individual. This enables carers to understand the clients' difficulties and how they may be overcome through appropriate care delivery. This model has been developed with the specific aim of enhancing quality of life through gains in health and total well-being.

Processing LHC data in the UK

The Large Hadron Collider (LHC) is one of the greatest scientific endeavours to date. The construction of the collider itself and the experiments that collect data from it represent a huge investment, both financially and in terms of human effort, in our hope to understand the way the Universe works at a deeper level. Yet the volumes of data produced are so large that they cannot be analysed at any single computing centre. Instead, the experiments have all adopted distributed computing models based on the LHC Computing Grid. Without the correct functioning of this grid infrastructure the experiments would not be able to understand the data that they have collected. Within the UK, the Grid infrastructure needed by the experiments is provided by the GridPP project. We report on the operations, performance and contributions made to the experiments by the GridPP project during the years of 2010 and 2011--the first two significant years of the running of the LHC.

Assessment of pulmonary veins after atrio-pericardial anastomosis by cardiovascular magnetic resonance

BACKGROUND

The atrio-pericardial anastomosis (APA) uses a pericardial pouch to create a large communication between the left atrium and the pulmonary venous contributaries in order to avoid direct suturing of the pulmonary veins during the repair of congenital cardiac malformations. Post-operative imaging is routinely performed by echocardiography but cardiovascular magnetic resonance (CMR) offers excellent anatomical imaging and quantitative information about pulmonary blood flow. We sought to compare the diagnostic value of echocardiography and CMR for assessing pulmonary vein anatomy after the APA.

METHODS

This retrospective study evaluated all consecutive patients between October 1998 and January 2010 after either a primary or secondary APA followed by post-repair CMR.

RESULTS

Of 103 patients who had an APA, 31 patients had an analyzable CMR study. The average time to CMR was 24.6 ± 32.5 months post-repair. Echocardiographic findings were confirmed by CMR in 12 patients. There was incomplete imaging by echocardiography in 7 patients and underestimation of pulmonary vein restenosis in 12, when compared to CMR. In total, 19/31 patients (61%) from our cohort had significant stenosis following the APA as assessed by CMR. Our data suggest that at least 18% (19/103) of all patients had significant obstruction post-repair.

CONCLUSIONS

Echocardiography incompletely imaged or underestimated the severity of obstruction in patients compared with CMR. Pulmonary vein stenosis remains a sizable complication after repair, even using the APA.

Blackawton bees

BACKGROUND

Real science has the potential to not only amaze, but also transform the way one thinks of the world and oneself. This is because the process of science is little different from the deeply resonant, natural processes of play. Play enables humans (and other mammals) to discover (and create) relationships and patterns. When one adds rules to play, a game is created.

THIS IS SCIENCE

the process of playing with rules that enables one to reveal previously unseen patterns of relationships that extend our collective understanding of nature and human nature. When thought of in this way, science education becomes a more enlightened and intuitive process of asking questions and devising games to address those questions. But, because the outcome of all game-playing is unpredictable, supporting this 'messyness', which is the engine of science, is critical to good science education (and indeed creative education generally). Indeed, we have learned that doing 'real' science in public spaces can stimulate tremendous interest in children and adults in understanding the processes by which we make sense of the world. The present study (on the vision of bumble-bees) goes even further, since it was not only performed outside my laboratory (in a Norman church in the southwest of England), but the 'games' were themselves devised in collaboration with 25 8- to 10-year-old children. They asked the questions, hypothesized the answers, designed the games (in other words, the experiments) to test these hypotheses and analysed the data. They also drew the figures (in coloured pencil) and wrote the paper. Their headteacher (Dave Strudwick) and I devised the educational programme (we call 'i,scientist'), and I trained the bees and transcribed the childrens' words into text (which was done with smaller groups of children at the school's local village pub). So what follows is a novel study (scientifically and conceptually) in 'kids speak' without references to past literature, which is a challenge. Although the historical context of any study is of course important, including references in this instance would be disingenuous for two reasons. First, given the way scientific data are naturally reported, the relevant information is simply inaccessible to the literate ability of 8- to 10-year-old children, and second, the true motivation for any scientific study (at least one of integrity) is one's own curiousity, which for the children was not inspired by the scientific literature, but their own observations of the world. This lack of historical, scientific context does not diminish the resulting data, scientific methodology or merit of the discovery for the scientific and 'non-scientific' audience. On the contrary, it reveals science in its truest (most naive) form, and in this way makes explicit the commonality between science, art and indeed all creative activities.

PRINCIPAL FINDING

'We discovered that bumble-bees can use a combination of colour and spatial relationships in deciding which colour of flower to forage from. We also discovered that science is cool and fun because you get to do stuff that no one has ever done before. (Children from Blackawton)'.

Temperature and manganese as determining factors in the presence of diatom or blue-green algal floras in streams

Diatoms are usually the major component of the algal flora in many streams, although green and blue-green algae may be present. These experiments were designed to determine if high temperature or a shift in the chemical composition of the water might bring about a dominance of blue-green algae and/or green algae rather than a dominance of diatoms in the algal flora.The results of these experiments indicate that an average temperature of 34 degrees to 38 degrees C results in a shift of dominance in the algal flora from diatoms to blue-green algae. Furthermore, a blue-green and green algal flora of species typically found in organically polluted water in favored if the manganese content is a few parts per billion. If the manganese content averaged 0.02-0.043 mg/liter in the natural stream to 0.04-0.28 mg/liter in the recycled water experiment, a diatom flora remained dominant.

Systemic arteriovenous fistulae for end-stage cyanosis after cavopulmonary connection: a useful bridge to transplantation

OBJECTIVE

Intractable cyanosis after partial or complete cavopulmonary connection may rarely be managed by creating a systemic arteriovenous fistula. We investigated the long-term performance of arteriovenous fistulae.

METHODS

All 21 patients who received an arteriovenous fistula at The Hospital for Sick Children since the 1950s were investigated using parametric competing risk techniques. Primary arteriovenous fistula indication was (1) suboptimal pulmonary blood flow (N = 15) or (2) pulmonary shunting via pulmonary arteriovenous malformations (N = 6). Arteriovenous fistula longevity was determined by time to "occlusion" (absence of arteriovenous fistula flow via surgical ligation or spontaneous occlusion).

RESULTS

All 21 patients had previously undergone second-stage palliation (Glenn shunt = 13; bidirectional shunt = 9). Five patients had undergone Fontan completion. Death in the presence of a functioning arteriovenous fistula occurred in 5 patients. Patients with bidirectional shunts had a significantly higher risk of death with a functioning arteriovenous fistula in situ (P = .04). High hemoglobin concentrations were associated with best outcome, and levels less than 170 g/L were associated with a high risk of death despite a functioning arteriovenous fistula (P < .01). Arteriovenous fistula occlusion occurred in 10 patients. Earlier occlusion was associated with previous Fontan completion (P = .02) and pulmonary arteriovenous malformations (P = .03). Surgical ligation during cardiac transplantation was the cause of occlusion in 7 patients. In these 7 patients, the arteriovenous fistula functioned for a median of 4.8 years. After transplantation, survival was 67% + or - 19% at 5 years. Overall survival was 73% + or - 10% 15 years after receiving an arteriovenous fistula (longest survival, 27.3 years).

CONCLUSION

In patients with adequate hematocrit, arteriovenous fistula offers an effective bridge to transplantation when a high-risk Fontan procedure is deferred. Performance is best after unidirectional cavopulmonary connection and worse in the presence of pulmonary arteriovenous malformations. Survival is 75% at 15 years, despite being considered end stage.

GridPP: the UK grid for particle physics

The start-up of the Large Hadron Collider (LHC) at CERN, Geneva, presents a huge challenge in processing and analysing the vast amounts of scientific data that will be produced. The architecture of the worldwide grid that will handle 15 PB of particle physics data annually from this machine is based on a hierarchical tiered structure. We describe the development of the UK component (GridPP) of this grid from a prototype system to a full exploitation grid for real data analysis. This includes the physical infrastructure, the deployment of middleware, operational experience and the initial exploitation by the major LHC experiments.

NKX2-5 regulates the expression of beta-catenin and GATA4 in ventricular myocytes

Background

The molecular pathway that controls cardiogenesis is temporally and spatially regulated by master transcriptional regulators such as NKX2-5, Isl1, MEF2C, GATA4, and β-catenin. The interplay between these factors and their downstream targets are not completely understood. Here, we studied regulation of β-catenin and GATA4 by NKX2-5 in human fetal cardiac myocytes.

Methodology/Principal Findings

Using antisense inhibition we disrupted the expression of NKX2-5 and studied changes in expression of cardiac-associated genes. Down-regulation of NKX2-5 resulted in increased β-catenin while GATA4 was decreased. We demonstrated that this regulation was conferred by binding of NKX2-5 to specific elements (NKEs) in the promoter region of the β-catenin and GATA4 genes. Using promoter-luciferase reporter assay combined with mutational analysis of the NKEs we demonstrated that the identified NKX2-5 binding sites were essential for the suppression of β-catenin, and upregulation of GATA4 by NKX2-5.

Conclusions

This study suggests that NKX2-5 modulates the β-catenin and GATA4 transcriptional activities in developing human cardiac myocytes.

The Impact of Patch Augmentation on Left Atrioventricular Valve Dynamics in Patients with Atrioventricular Septal Defects: Early and Midterm Follow-up

OBJECTIVE

Left atrioventricular valve pericardial patch may prevent valve replacement. We assessed patch annular dynamics compared with conventional repair and normal annuli.

METHODS

Transesophageal 3-dimensional echocardiography was acquired preoperatively and postoperatively in atrioventricular septal defects (n = 10, 5 patch, 5 conventional repair). Real-time 3-dimensional annular motion at midterm was compared with that of healthy children (n = 10). Parameters were: annular area, perimeter, segmental diameter, bending angle, stenosis, and regurgitation.

RESULTS

Regurgitant jet area ratio decreased in both patient groups. Conventional repair reduced annular area (P = .02). Patch repair showed an annular area larger than normal (P = .01). Control subjects had increased systolic area whereas operative groups showed a reduction. Patch repair had segmental diameters similar to normal whereas conventional repair was inhomogeneous. Annular bending angle was maintained after operation.

CONCLUSION

Patch repair in pediatrics shows durability without shrinkage or expansion. Improved stenosis and regurgitation does not change by midterm. Operation causes increased annular stiffness and diminished compliance. Neither technique establishes normal annular eccentricity.

Aneurysm of Right Atrium Diagnosed by 3-Dimensional Real-time Echocardiogram

We describe a case of giant aneurysm of right atrium in a child with a previous diagnosis of Ebstein's anomaly of tricuspid valve. Three-dimensional real-time echocardiography provided more precise anatomic detail of the tricuspid valve, right atrium, and right ventricle than did its 2-dimensional counterpart.

How is pulmonary arterial blood flow affected by pulmonary venous obstruction in children? A phase-contrast magnetic resonance study

BACKGROUND

Hemodynamic changes within a stenosed pulmonary vein might not reflect the severity of the obstruction if redistribution of pulmonary artery flow occurs.

OBJECTIVE

The purpose was to investigate flow changes in branch pulmonary arteries in the presence of pulmonary vein stenosis.

MATERIALS AND METHODS

Twelve children (age range 3-180 months) who had undergone MRI for pulmonary vein stenosis were identified. The severity of vein stenosis was assessed from percentage diameter reduction. Pulmonary artery flow distribution was correlated with the severity of pulmonary vein stenosis. Nine of the patients had unilateral stenosis; three had bilateral involvement.

RESULTS

Unilateral vein stenosis was associated with diastolic reversal in the ipsilateral branch pulmonary artery (mean flow reversal 12.3%, range 2.4-42%) and continuous diastolic forward flow in the contralateral pulmonary artery in seven of nine patients. Severe stenosis was associated with decreased systolic flow to the ipsilateral lung. The ratio of net forward flow through pulmonary arteries correlated well with the cross-sectional area ratio of pulmonary arteries (r=0.75, P=0.006).

CONCLUSIONS

Severe pulmonary vein obstruction results in redistribution of pulmonary arterial flow. When investigating pulmonary vein stenosis by MR, an evaluation of the pulmonary arterial system should be included to assess the functional importance of an obstruction.

Outcomes of mitral valve replacement in children: A competing-risks analysis

OBJECTIVE

We sought to define patient characteristics, outcomes, and associated factors after mitral valve replacement in children.

METHODS

We included 104 children undergoing at least one mitral valve replacement between 1980 and 2003 and reviewed clinical records. Competing-risks methodology was used to determine time-related prevalence and associated risk factors after initial mitral valve replacement for death and repeat replacement.

RESULTS

The underlying mitral valve disease was congenital in 83%, rheumatic in 13%, Marfan syndrome in 3%, and isolated endocarditis in 1%, with 64% having primarily regurgitation, 16% having stenosis, 20% having both, and 32% having undergone previous valvotomy, valvuloplasty, or repair. There were 137 valve replacements, with 26 patients having more than one. Valve prosthesis type was St Jude Medical in 37%, Bjork-Shiley in 25%, Carbomedics in 20%, Ionescu-Shiley in 10%, and other types in 8%. Both early and late complications were common. Median age at the initial replacement was 5.9 years (range, birth to 19 years). Competing-risks analysis predicted 19% to have died at 15 years after initial replacement, with risk factors including noncongenital valve morphology, lower weight, and longer duration of cardiopulmonary bypass. A repeat replacement was predicted for 71%, with risk factors including the presence of multiple left-heart obstructive lesions and Ionescu-Shiley valve prosthesis.

CONCLUSIONS

Mitral valve replacement might be necessary in children with extremely dysplastic valves and severe hemodynamic impairment or after failed repair. However, with the appropriate selection of the prosthetic valve and reduction of cardiopulmonary bypass time, surgeons might decrease mortality and increase prosthesis longevity.

Predictors of mortality and neurological morbidity in children undergoing extracorporeal life support for cardiac disease

OBJECTIVES

The objective of this study was to determine the incidence and risk factors for death and adverse neurological outcomes in children receiving extracorporeal life support (ECLS) for cardiac indications.

METHODS

A retrospective single centre consecutive cohort study was conducted in children who received ECLS for cardiac indications between January 1990 and June 2000. Health records and neuroimaging films were assessed, and long-term outcomes were obtained by standardized telephone follow-up or by assessments performed in outpatient clinic. Clinical, neuroimaging and surgical predictors of outcome were tested.

RESULTS

Of 90 children studied, short-term clinical neurological events (during hospitalization) occurred in 20 children (22%) during or following ECLS. Long-term neurological sequelae were present in 11 of 31 children discharged alive, after a mean follow-up interval of 4.5 years (range 4 months to 9 years). Death occurred in 59 children (66%) during hospitalisation, and in 3 following discharge. Of the 28 long-term survivors, only 15 children (17%) survived without neurological sequelae. Abnormal neuroimaging was associated with short-term neurological events (P = 0.03, OR 10.5), and the use of CPR prior to ECLS (P = 0.02, OR 2.9) was the only significant predictor of death. There were no significant predictors of long-term neurological sequelae.

CONCLUSIONS

More than two-thirds of the children receiving ECLS died, and 39% (11/28) of long-term survivors had neurological deficits. Although mortality is close to 100% without this type of support, there is still a significantly high morbidity and mortality with this type of support.

Pulmonary atresia with intact ventricular septum: management of, and outcomes for, a cohort of 210 consecutive patients

OBJECTIVES

We sought to determine trends, and outcomes, for a cohort of patients with pulmonary atresia with intact ventricular septum born between 1965 and 1998.

BACKGROUND

Pulmonary atresia with intact ventricular septum is a complex lesion that remains a therapeutic challenge, particularly regarding the suitability for biventricular repair.

METHODS

We identified 210 consecutive patients, and reviewed their medical records, initial angiograms, and echocardiograms, along with the relevant surgical and pathology reports.

RESULTS

The mean initial Z-score for the diameter of the tricuspid valve was -0.99 +/- 1.95, with Ebstein's malformation in 8%. A right ventricular dependent coronary arterial circulation was found in 23%. The proportion of patients who received treatment increased over time, although placement of an arterial shunt was the predominant initial procedure throughout the experience. At the last follow-up, 107 patients had not reached the planned final stage of their repair, and 79% of these had died. Of the 103 reaching the final stage of planned repair, 58 had undergone attempted biventricular repair, with 34% dying; 14 had undergone attempted one and a half ventricular repair, with 7% dying, and 31 had undergone attempted functionally univentricular repair, with 10% dying. Overall, survival was 57% at the age of 1 year, 48% at 5 years, and 43% at 10 years. Survival improved over time, with survival of 75% at 1 year, and 67% at 5 years, for patients born between 1992 and 1998. An earlier date of birth, the presence of Ebstein's malformation, and prematurity were all significant independent factors associated with decreased survival. A greater severity of coronary arterial abnormalities was significantly associated with a greater likelihood of left ventricular dysfunction during follow-up.

CONCLUSIONS

The outcomes for patients born with pulmonary atresia with intact ventricular septum have improved over time, albeit that careful initial management, and better selection, is still indicated for those planned to undergo biventricular repair.

Evolution of heart rate control after transplantation: conduction versus autonomic innervation

In cardiac transplantation, the donor organ is not initially innervated and demonstrates decreased heart rate variability (HRV). However, HRV may improve after several months. The mechanism for HRV improvement has not been elucidated; autonomic "reinnervation" of the donor heart has been proposed. The role of atrioatrial conduction from recipient to donor organ has not been evaluated. We prospectively evaluated cardiac transplant patients with a limited electrophysiology study at the time of their surveillance biopsies. Recordings were made of recipient and donor signals, observing conduction properties between recipient and donor atria. Holter recordings were analyzed and HRV was determined using spectral analysis techniques, recording mean RR interval, low-frequency power (LF), high-frequency power (HF), and the LF/HF ratio. These were compared to published norms. From November 1999 to May 2000, 21 patients (6 female) who underwent cardiac transplantation participated at a median age of 101 months (range, 4.1-217 months). Time posttransplant ranged from 26 days to 71 months. Holter data were available for 20 patients and demonstrated dissociated P waves in 13 (65%). The mean heart rate on Holter was 111 beats per minute (bpm) (range, 85-161 bpm). We were able to record distinct recipient atrial signals in 16 of 21 (76%) patients. The average recipient tissue heart rate was 55% that of the donor heart rate. We documented atrioatrial association in only 1 patient. HRV did not reach normal values for most patients and did not increase with time posttransplantation. The LF values were in the normal range for most patients, whereas 3 patients had normal HF values and 2 patients had values just below normal. Recipients of heart transplantation have a predominantly sympathetic influence of HRV. These preliminary data suggest that atrioatrial conduction does not play a role in reestablishing normal heart rate control following pediatric cardiac transplantation.

Glycoprotein biosynthesis in porcine aortic endothelial cells and changes in the apoptotic cell population

Porcine aortic endothelial cells (PAECs) produce glycoproteins with important biological functions, such as the control of cell adhesion, blood clotting, blood pressure, the immune system, and apoptosis. Cell surface glycoproteins play important roles in these biological activities. To understand the control of cell surface glycosylation, we elucidated biosynthetic pathways leading to N- and O-glycans in PAECs. Based on the enzyme activities, PAECs should be rich in complex biantennary N-glycans. In addition, the enzymes synthesizing complex O-glycans with core 1 and 2 structures are present in PAECs. The first enzyme of the O-glycosylation pathway, polypeptide GalNAc-transferase, was particularly active. Its specificity toward synthetic peptide substrates was found to be similar to that of purified bovine colostrum enzyme T1. A significant fraction of PAECs treated with tumour necrosis factor alpha or human serum detached from the culture plate, and most of these cells were apoptotic. The apoptotic cell population exhibited decreased core 2 beta 6-GlcNAc-transferase activity. In contrast, the activities of core 1 beta 3-Gal-transferase, which synthesizes O-glycan core 1, and of alpha 3-sialyltransferase (O), which sialylates core 1, were increased in apoptotic PAECs. Thus, apoptotic PAECs are predicted to have fewer complex O-glycans and a higher proportion of short, sialylated core 1 chains.

Extracardiac conduit versus lateral tunnel cavopulmonary connections at a single institution: impact on outcomes

OBJECTIVE

To compare outcomes of extracardiac conduit and lateral tunnel Fontan connections in a single institution over a concurrent time period.

METHODS

Between January 1994 and September 1998, 60 extracardiac conduit and 47 lateral tunnel total cavopulmonary connections were performed. Age, sex, and weight did not differ between the 2 groups. Compared with the lateral tunnel group (LT group), patients undergoing the extracardiac conduit procedure (EC group) had a trend to a higher incidence of morphologically right ventricle (EC group 48% vs LT group 32%; P <.09), a higher incidence of isomerism/heterotaxy syndrome (EC 22% vs LT 0%; P <.001), worse atrioventricular valve regurgitation (EC 11% moderate-plus vs LT 0%; P <.06), and lower McGoon indices (EC 1.8 +/- 0.5 vs LT 2.1 +/- 0.5; P <.03). Preoperative arrhythmias, transpulmonary gradients, room air oxygen saturations, ejection fractions, ventricular end-diastolic pressure, and pulmonary artery distortion did not differ between groups. Cardiopulmonary bypass times and fenestration usage were similar in both groups.

RESULTS

Overall operative mortality was 5.6% and did not differ between groups. The LT group had a significantly higher incidence of postoperative sinoatrial node dysfunction (45% vs EC group 15%; P <.007), supraventricular tachycardia (33% vs EC group 8%; P <.0009), and need for temporary postoperative pacing (32% vs 12%; P <.01). Median duration of intensive care unit stay (EC 2 days, range 1-10 days, vs LT 2.8 days, range 1-103 days; P <.07) and ventilatory support (EC 1 day, range 0.25-10 days, vs LT 1 day, range 0.25-99 days; P <.03) were all longer in the LT group. Median chest tube drainage (EC 8 days, LT 9 days) was similar in both groups. Follow-up averaged 2.5 +/- 1.4 years in the EC group and 2.8 +/- 1.9 years in the LT group. There were 2 late deaths. Overall survival is 94% at 1 month, 92% at 1 year, and 92% at 5 years. Late ejection fraction or atrioventricular valve function did not differ between groups. Intermediate follow-up Holter analysis showed a higher incidence of atrial arrhythmias in the LT group (23% vs 7%; P <.02). Multivariable analysis showed that (1) prolonged cardiopulmonary bypass time was the only independent predictor for perioperative mortality, prolonged ventilation and intensive care unit length of stay, and increased time to final removal of chest tube drains and (2) lateral tunnel Fontan connection is an independent predictor of early postoperative and intermediate atrial arrhythmias.

CONCLUSIONS

Although patients in the EC group were at higher preoperative risk, their outcomes were comparable with those of the LT group. Use of the extracardiac conduit technique for the modified Fontan operation reduces the risk of early and midterm atrial arrhythmia.

Outcomes of intraoperative device closure of muscular ventricular septal defects

BACKGROUND

The surgical management of muscular ventricular septal defects (mVSD) in the small infant is a challenge particularly when multiple and associated with complex cardiac lesions. Devices for percutaneous implantation have the advantage of ease of placement and for the double umbrella designs a wide area of coverage. We reviewed our experience and clinical outcomes of intraoperative mVSD device closure for such defects in small infants.

METHODS

Since October 1989, intraoperative VSD device closure was a component of the surgical strategy in 14 consecutive patient implants (median age, 5.5 months; range, 3 to 11 kg), whose defects were thought difficult to approach using conventional techniques. Nine patients had associated complex cardiac lesions, 10 multiple mVSDs, and 4 patients had a previous pulmonary artery banding.

RESULTS

There were 2 early deaths, 1 in a severely ill child who preoperatively had pulmonary hypertension and left ventricular failure and another in a patient with a hypoplastic left heart. Mean pulmonary to systemic flow ratio before device insertion was 3.5:1. Complete closure was achieved in 5 patients and clinically insignificant residual shunts persisted in 7. In 2 infants with significant residual lesions concomitant pulmonary artery banding was required. Postoperative mean pulmonary to systemic flow ratio was 1.7:1. In follow-up of the 12 surviving infants (mean, 41 months), 8 had complete closure and 3 persistent residual shunts. One patient with no residual shunting required heart transplantation for progressive ventricular failure 9 years after operation. All devices were well positioned on postoperative echocardiograms. There was 1 late death due to aspiration in a patient with a tiny residual shunt.

CONCLUSIONS

Infants requiring operative intervention with mVSDs are difficult to manage and have an increased mortality and morbidity. Intraoperative VSD device placement for closure of mVSDs is feasible, can avoid ventriculotomy, division of intracardiac muscle bands, and is ideally suited for the neonate or infant.

Mycophenolate mofetil in pediatric heart transplant recipients: a single-center experience

Mycophenolate mofetil (MMF) is emerging as an effective agent for the treatment of both established rejection and primary rejection prophylaxis in solid-organ transplantation (Tx). However, little data is available on the use of MMF in the pediatric population. We therefore report on our experience with MMF in 21 pediatric heart transplant recipients. Data were obtained by retrospective chart review. Median age at time of review was 12.3 yr (range 11 months to 16.9 yr). Median age at Tx was 10.7 yr (range 55 days to 16.7 yr). MMF was started at a median of 4.3 months after Tx (range 1 day to 4.5 yr). At the time of MMF institution, all patients were concurrently on prednisone and azathioprine; 20 of these patients were also undergoing treatment with tacrolimus (median dose 0.18 mg/kg, range 0.03-0.64 mg/kg) and one with cyclo-sporin A (10 mg/kg). Azathioprine was discontinued at the time of commencing MMF. The average MMF dose was 40 +/- 14 mg/kg. The rationale for switching to MMF included rejection (International Society for Heart and Lung Transplantation [ISHLT] 3A/B), 66%; inability to wean steroids, 14%; ABO blood group donor-recipient mismatch, 10%; coronary artery disease (CAD), 5%; and side-effects of immuno-suppression, 5%. Of the patients switched for rejection, 93% demonstrated resolved or improving rejection. Both ABO donor-recipient mismatch patients were started on tacrolimus/MMF as primary therapy and had no significant episodes of rejection. Two patients had rejection classified as unchanged (one with CAD, one treated with addition of sirolimus prior to improvement). Corticosteroids were successfully discontinued in 28% of patients, and 20% are currently on a reduced dose. Fourteen per cent developed significant rejection while attempting to reduce the steroid dose. Steroid reduction has not yet been attempted in 38% of patients. The following side-effects were reported in 38% of the patients: diarrhea, 10%; gastrointestinal discomfort, 20%; and leukopenia, 20%. Dose reduction or temporary discontinuation was required in 63% of the patients who experienced side-effects (24% of the total number of patients). Opportunistic infections developed in 10% (cryptococcus, cytomegalovirus). Hence, MMF appears to be effective for treatment of rejection in the pediatric heart transplant population and has an acceptable side-effect profile. In addition, it may have a role in primary rejection prophylaxis and may facilitate a reduced steroid dosage or a steroid-free immunosuppression regimen.

'Failure to rescue' as a measure of quality of hospital care: the limitations of secondary diagnosis coding in English hospital data

Although it is widely recognized that quality of care varies between hospitals, a robust and valid measure of outcome that can be used in comparisons has proven elusive. One measure that has recently been proposed by US researchers is the 'failure to rescue' (FTR) rate. This is based on the assumption that, whereas complications may reflect both patient severity and health care factors, the ability to save patients once complications arise is much more closely related to the quality of health care. We describe an evaluation of FTR in a national sample of English hospitals using hospital episode data. We found that the rate of secondary diagnosis recording in England is about one-tenth that in the United States. The FTR rate would be highly sensitive to variations in the completeness of coding of secondary diagnoses. Unless coding is of uniformly high quality, any attempt to compare severity adjusted outcomes will be potentially unreliable.

Local shielding of high dose rate brachytherapy in an operating theatre

A high-dose rate brachytherapy facility was installed into an established operating theatre by using local shielding in the form of mobile lead screens and by taking advantage of the ease with which staff movements can be controlled in an operating suite. This facility was inexpensive to develop, and has proved clinically efficient and entirely adequate from a radiation safety standpoint.

Public disclosure of health care performance reports: a response from the UK

In the UK, the experience with public disclosure of health care performance data related to provider organizations is limited to a small set of administrative data known as the 'Patient's Charter' which has concentrated mainly on aspects of efficiency and which is currently being reviewed, and, most recently, to a set of reference costs by case type (known as Healthcare Resource Groups). Clinically oriented performance data has been published in Scotland since 1994 and will be published in England and Wales early in 1999. Knowledge about the impact and effect of such publication is limited, even in the USA, but there is some evidence that consumers and purchasers become gradually familiar with them and confident in their use. However, even with this scant knowledge, it would appear that the publication of data across the public services will continue to be a policy of the current UK Government for the foreseeable future. It would seem likely that this policy will have the tacit approval of the general population who have been educated to be somewhat wary of professional self-regulation. The greater public accountability that public disclosure of information brings, needs to be evaluated against the overall costs of the exercise, particularly within a publicly financed system, and against the disadvantages in public confidence and impact on the patient-doctor relationship that might occur if not managed appropriately.

Complication of ventricular demand pacing after orthotopic heart transplantation: unusual case of pacemaker syndrome in an infant

BACKGROUND

Sinus node dysfunction is the most common indication for antibradycardiac permanent pacing after heart transplantation. Lack of atrioventricular synchrony during pacing can result in symptoms ranging from mild chest discomfort to severe manifestations such as dyspnea, hypotension, and cardiovascular collapse, all of which are ascribed to pacemaker syndrome. In infants pacemaker syndrome is often only recognized in the face of marked hemodynamic compromise.

RESULTS

This report details an unusual account of pacemaker syndrome in an infant after orthotopic heart transplantation.

CONCLUSIONS

Careful assessment of atrioventricular synchrony is important after infant transplantation.