Congenitally Corrected Transposition of the Great Arteries in Utero: Morphological Spectrum, Outcomes and Pitfalls in Fetal Diagnosis

Congenitally corrected transposition of the great arteries (ccTGA) is a rare malformation with diverse morphology. We assessed features of fetuses with ccTGA and evaluated neonatal and pediatric outcomes. This was a retrospective review of fetuses with ccTGA at Birmingham Women's and Children's Hospital born from 2005 to 2019. Of thirty-six fetuses identified, six had unavailable prenatal data, one was postnatally diagnosed with isomerism and 29 fetuses were evaluated. ccTGA without associated cardiac lesions was found in 28% (8/29), ccTGA with significant VSD in 31% (9/29), ccTGA with pulmonary obstruction in 24% (7/29) and ccTGA with complex anomalies in 17% (5/29). Tricuspid regurgitation (TR) was observed in 17% (5/29) and heart block (HB) in 10% (3/29) prenatally. Six, that is 21% underwent genetic testing of which one was abnormal. Five extra-cardiac anomalies were reported prenatally and postnatally. Pregnancy was discontinued in five, of which two had moderate TR. There were thirty-one liveborn. Coarctation of the aorta was found in five postnatally but not suspected prenatally. In one, pulmonary stenosis was underestimated; otherwise, prenatal morphology was confirmed. Cardiac interventions were performed in 77% (24/31) liveborn with 39% (12/31) undergoing neonatal intervention. Overall, 6/31 liveborn died including all three with prenatal heart block and one with TR. Estimated survival for all liveborn at 1, 5 and 10 years was 87% (95% CI 76-100%), 83% (95% CI 72-98%) and 80% (95% CI 66-96%) respectively. Accurate prenatal diagnosis of ccTGA is critical for counseling. Early outcomes are favorable with 77% of liveborn undergoing surgery. Fetuses with prenatal diagnosis of complex associated abnormalities, HB and TR appear to do less well.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Medium-term Outcome of Prenatally Diagnosed Hypoplastic Left-Heart Syndrome and Impact of a Restrictive Atrial Septum Diagnosed in-utero

OBJECTIVE

Surgical outcome data differs from overall outcomes of prenatally diagnosed fetuses with hypoplastic left heart syndrome (HLHS). Our aim was to describe outcome of prenatally diagnosed fetuses with this anomaly.

METHODS

Retrospective review of prenatally diagnosed classical HLHS at a tertiary hospital over a 13-year period, estimated due dates 01/08/2006 to 31/12/2019. HLHS-variants and ventricular disproportion were excluded.

RESULTS

203 fetuses were identified with outcome information available for 201. There were extra-cardiac abnormalities in 8% (16/203), with genetic variants in 14% of those tested (17/122). There were 55 (27%) terminations of pregnancy, 5 (2%) intrauterine deaths and 10 (5%) babies had prenatally planned compassionate care. There was intention to treat (ITT) in the remaining 131/201(65%). Of these, there were 8 neonatal deaths before intervention, two patients had surgery in other centers. Of the other 121 patients, Norwood procedure performed in 113 (93%), initial hybrid in 7 (6%), and 1 had palliative coarctation stenting. Survival for the ITT group from birth at 6-months, 1-year and 5-years was 70%, 65%, 62% respectively. Altogether of the initial 201 prenatally diagnosed fetuses, 80 patients (40%) are currently alive. A restrictive atrial septum (RAS) is an important sub-category associated with death, HR 2.61, 95%CI 1.34-5.05, p = 0.005, with only 5/29 patients still alive.

CONCLUSION

Medium-term outcomes of prenatally diagnosed HLHS have improved however it should be noted that almost 40% do not get to surgical palliation, which is vital to those doing fetal counselling. There remains significant mortality particularly in fetuses with in-utero diagnosed RAS.

Outcomes of the arterial switch for transposition during infancy using a standardised approach over 30 years

OBJECTIVES

To describe the early and late outcomes of the arterial switch for transposition.

METHODS

A single-centre retrospective cohort study was conducted to assess the early and late outcomes of arterial switch performed during infancy using a standardised institutional approach between 1988 and 2018, compared by morphological groups.

RESULTS

749 consecutive patients undergoing arterial switch during infancy were included, 464 (61.9%) with intact septum, 163 (21.8%) with isolated ventricular septal defect, and 122 (16.3%) with complex transposition with associated lesions, including 67 (8.9%) with Taussig-Bing anomaly. There were 34 early deaths (4.5%, 95% CI 3.1-6.1) with only 10 (2.6%) early deaths since 2000. Complex morphology (OR 11.44, CI 4.76-27.43) and intramural coronary artery (OR 5.17, CI 1.61-15.91) were identified as the most important risk factors for 90-day mortality. Overall survival was 92.7% (95% CI 90.8-94.6) at 5 years and 91.9% (95% CI 89.9-94.1) at 20 years; in hospital survivors, there were 15 (2.1%) late deaths during a median follow-up of 13.7 years. Cumulative incidence of surgical or catheter reintervention was 16.0% (95% CI 14.5-17.5) at 5 years and 22.7% (95% CI 21.0-24.0) at 20 years; early and late reinterventions were more common in the complex group, with no difference between the other groups.

CONCLUSIONS

Using a standardised approach, the arterial switch can be performed with low early mortality, moderate rates of reintervention, and excellent long-term survival. Concomitant lesions were the most important risk factor for early death and were associated with increased risk of late reintervention.

Non-invasive cardiac output monitoring with electrical velocimetry after cardiac surgery in infants

INTRODUCTION

Low cardiac output following cardiac surgery is a major determinant of outcome that may be improved by early detection, yet there are no widely accepted methods for its measurement in young children. We evaluated the feasibility of the routine use of electrical velocimetry, a non-invasive technique providing continuous measurement of cardiac output, in infants in the early postoperative period.

METHODS

With ethical approval and parental consent, infants undergoing cardiac surgery were recruited. The ICON electrical velocimetry monitor was attached on admission to the intensive care unit (ICU) and remained for up to 24h.

RESULTS

A total of 15 infants were recruited, median age 3 months (interquartile range (IQR) 0.5-7.5) and weight 4.8kg (IQR 3.9-7.1), undergoing various operations. Cardiac index had a weak correlation with arterial lactate (r=-0.24, p=0.02) and no correlation with blood pressure, central venous pressure or arteriovenous oxygen difference. Data were recorded for a median of 19h (range 5-24), with lead detachment or movement artefact the most common causes of data loss. There was marked minute-to-minute variability, with 25% of consecutive measurements having >5% variability.

CONCLUSION

Cardiac index measured by electrical velocimetry in infants in the early postoperative period is impaired by frequent data loss and marked intrapatient variability. Our feasibility study suggests that it is unsuitable for use as a routine monitoring tool in the setting of postsurgical ICU care.

Linkage of National Congenital Heart Disease Audit data to hospital, critical care and mortality national data sets to enable research focused on quality improvement

OBJECTIVES

To link five national data sets (three registries, two administrative) and create longitudinal healthcare trajectories for patients with congenital heart disease (CHD), describing the quality and the summary statistics of the linked data set.

DESIGN

Bespoke linkage of record-level patient identifiers across five national data sets. Generation of spells of care defined as periods of time-overlapping events across the data sets.

SETTING

National Congenital Heart Disease Audit (NCHDA) procedures in public (National Health Service; NHS) hospitals in England and Wales, paediatric and adult intensive care data sets (Paediatric Intensive Care Audit Network; PICANet and the Case Mix Programme from the Intensive Care National Audit & Research Centre; ICNARC-CMP), administrative hospital episodes (hospital episode statistics; HES inpatient, outpatient, accident and emergency; A&E) and mortality registry data.

PARTICIPANTS

Patients with any CHD procedure recorded in NCHDA between April 2000 and March 2017 from public hospitals.

PRIMARY AND SECONDARY OUTCOME MEASURES

Primary: number of linked records, number of unique patients and number of generated spells of care. Secondary: quality and completeness of linkage.

RESULTS

There were 143 862 records in NCHDA relating to 96 041 unique patients. We identified 65 797 linked PICANet patient admissions, 4664 linked ICNARC-CMP admissions and over 6 million linked HES episodes of care (1.1M inpatient, 4.7M outpatient). The linked data set had 4 908 153 spells of care after quality checks, with a median (IQR) of 3.4 (1.8-6.3) spells per patient-year. Where linkage was feasible (in terms of year and centre), 95.6% surgical procedure records were linked to a corresponding HES record, 93.9% paediatric (cardiac) surgery procedure records to a corresponding PICANet admission and 76.8% adult surgery procedure records to a corresponding ICNARC-CMP record.

CONCLUSIONS

We successfully linked four national data sets to the core data set of all CHD procedures performed between 2000 and 2017. This will enable a much richer analysis of longitudinal patient journeys and outcomes. We hope that our detailed description of the linkage process will be useful to others looking to link national data sets to address important research priorities.

Four right ventricle to pulmonary artery conduit types

OBJECTIVE

The most durable valved right ventricle to pulmonary artery conduit for the repair of congenital heart defects in patients of different ages, sizes, and anatomic substrate remains uncertain.

METHODS

We performed a retrospective analysis of 4 common right ventricle to pulmonary artery conduits used in a single institution over 30 years, using univariable and multivariable models of time-to-failure to analyse freedom from conduit dysfunction, reintervention, and replacement.

RESULTS

Between 1988 and 2018, 959 right ventricle to pulmonary artery conduits were implanted: 333 aortic homografts, 227 pulmonary homografts, 227 composite porcine valve conduits, and 172 bovine jugular vein conduits. Patients weighed 1.6 to 98.3 kg (median 15.3 kg), and median duration of follow-up was 11.4 years, with 505 (52.2%) conduits developing dysfunction, 165 (17.2%) requiring catheter intervention, and 415 (43.2%) being replaced. Greater patient weight, conduit z-score, type and position, as well as catheter intervention were predictors of freedom from replacement. Multivariable analysis demonstrated inferior durability for smaller composite porcine valve conduits, with excellent durability for larger diameter conduits of the same type. Bovine jugular vein conduit longevity was inferior to that of homografts in all but the smallest patients. Freedom from dysfunction at 8 years was 60.7% for aortic homografts, 72% for pulmonary homografts, 51.2% for composite porcine valve conduits, and 41.3% for bovine jugular vein conduits. Judicious oversizing of the conduit improved conduit durability in all patients, but to the greatest extent in patients weighing 5 to 20 kg.

CONCLUSIONS

Pulmonary and aortic homografts had greater durability than xenograft conduits, particularly in patients weighing 5 to 20 kg. Judicious oversizing was the most significant surgeon-modifiable factor affecting conduit longevity.

Unifocalization cannot rely exclusively on native pulmonary arteries: the importance of recruitment of major aortopulmonary collaterals in 249 cases†

OBJECTIVES

We sought to define the early and late outcomes of unifocalization based on a classification of the native pulmonary artery (nPA) system and major aortopulmonary collateral arteries (MAPCAs) with a policy of combined recruitment and rehabilitation and to analyse the role of unifocalization by leaving the ventricular septal defect (VSD) open with a limiting right ventricle-pulmonary artery (RV-PA) conduit in borderline cases.

METHODS

An analysis of 271 consecutive patients assessed for unifocalization at a single institution between 1988 and 2016 was performed. Patients were classified according to the pulmonary blood supply: group A, unifocalization based on nPA only; group B, based on nPA and MAPCAs; group C, MAPCAs only (absent nPAs).

RESULTS

Unifocalization was achieved in 249 (91.9%) cases with an early mortality of 2.8%. Group A included 72 (28.9%) patients, group B 119 (47.8%) patients and group C 58 (23.3%) patients with no difference in early survival between groups. Survival at 5, 10 and 15 years was 90.0% (85.9-94.3), 87.2% (83.5-91.2) and 82.3% (75.2-89.9), respectively. Late survival in groups A and B was similar but 10- and 15-year survival in group C decreased to 79.2% (68.2-92.1) and 74.3% (61.1-90.4) (P = 0.02), respectively. A mean of 1.9 (±0.6) MAPCAs were recruited per patient (range 0-6). The VSD was left open with a limiting RV-PA conduit in 97 (39.0%) cases, but subsequently closed in 48 patients, giving a total of 200 (80.3%) patients achieving VSD closure (full repair). Delaying VSD closure was not associated with increased risk for early or late survival. A central shunt to rehabilitate the nPAs was used in 56 (22.5%) cases. This was associated with a reduction in the number of MAPCAs recruited, but still required a mean of 1.8 (±0.5) MAPCAs recruited per patient to achieve unifocalization. In multivariate risk analysis, those suitable for single-stage full repair had the best long-term outcomes. Group C anatomy was associated with poor late survival compared to groups A and B (hazard ratio 2.7).

CONCLUSIONS

Survival is maximized by a combined approach of rehabilitation and recruitment. MAPCAs should always be recruited if they supply areas with absent nPA supply. A strategy of leaving the VSD open with a limiting RV-PA conduit is a safe and effective way of managing borderline cases.

Morphology of vascular ring arch anomalies influences prognosis and management

OBJECTIVE

This study aimed to explore the anatomical features of aortic arch anomalies associated with vascular rings, hoping to identify those which may increase the risk of symptomatic presentation and surgical intervention.

METHODS

This was a retrospective observational study at a single cardiac unit. Individuals diagnosed with an aortic arch anomaly, either isolated or non-isolated, between June 2014 and September 2018 were included. The morphology of the aortic arch was established via analysis of postnatal echocardiography, CT or MRI scans. CT and magnetic resonance studies were evaluated for the presence of a Kommerell diverticulum in those with aberrant vessels. Case notes were reviewed for relevant clinical data.

RESULTS

Of those with aberrant subclavian arteries, 24/79 (30.4%) were shown to have a Kommerell diverticulum. Additional forms of congenital heart disease were present in 133/227 (58.6%) individuals. Surgical division of the vascular ring was performed in 30/227 (13.2%), most commonly in the setting of a double aortic arch (70.8%). In those with aberrant subclavian arteries, no children without a Kommerell diverticulum were referred for surgery. In those with a Kommerell diverticulum confirmed on imaging, 11/24 underwent surgery.

CONCLUSION

Individuals with a double aortic arch, or an aberrant subclavian artery arising from a Kommerell diverticulum, have the highest requirement for surgical intervention, especially in isolated anomalies. These individuals should remain under monitoring. The subjective nature of symptoms remains problematic. Longitudinal research is required further to understand the natural history of vascular rings and how it links to morphology.

Bilateral Remote Ischaemic Conditioning in Children (BRICC) trial: protocol for a two-centre, double-blind, randomised controlled trial in young children undergoing cardiac surgery

INTRODUCTION

Myocardial protection against ischaemic-reperfusion injury is a key determinant of heart function and outcome following cardiac surgery in children. However, with current strategies, myocardial injury occurs routinely following aortic cross-clamping, as demonstrated by the ubiquitous rise in circulating troponin. Remote ischaemic preconditioning, the application of brief, non-lethal cycles of ischaemia and reperfusion to a distant organ or tissue, is a simple, low-risk and readily available technique which may improve myocardial protection. The Bilateral Remote Ischaemic Conditioning in Children (BRICC) trial will assess whether remote ischaemic preconditioning, applied to both lower limbs immediately prior to surgery, reduces myocardial injury in cyanotic and acyanotic young children.

METHODS AND ANALYSIS

The BRICC trial is a two-centre, double-blind, randomised controlled trial recruiting up to 120 young children (age 3 months to 3 years) undergoing primary repair of tetralogy of Fallot or surgical closure of an isolated ventricular septal defect. Participants will be randomised in a 1:1 ratio to either bilateral remote ischaemic preconditioning (3×5 min cycles) or sham immediately prior to surgery, with follow-up until discharge from hospital or 30 days, whichever is sooner. The primary outcome is reduction in area under the time-concentration curve for high-sensitivity (hs) troponin-T release in the first 24 hours after aortic cross-clamp release. Secondary outcome measures include peak hs-troponin-T, vasoactive inotrope score, arterial lactate and central venous oxygen saturations in the first 12 hours, and lengths of stay in the paediatric intensive care unit and the hospital.

ETHICS AND DISSEMINATION

The trial was approved by the West Midlands-Solihull National Health Service Research Ethics Committee (16/WM/0309) on 5 August 2016. Findings will be disseminated to the academic community through peer-reviewed publications and presentation at national and international meetings. Parents will be informed of the results through a newsletter in conjunction with a local charity.

TRIAL REGISTRATION NUMBER

ISRCTN12923441.

Tetralogy of Fallot: morphological variations and implications for surgical repair

OBJECTIVES

Tetralogy of Fallot is characterized by anterocephalad deviation of the outlet septum, along with abnormal septoparietal trabeculations, which lead to subpulmonary infundibular stenosis. Archives of retained hearts are an important resource for improving our understanding of congenital heart defects and their morphological variability. This study aims to define variations in aortic override, coronary arterial patterns and ventricular septal defects in tetralogy of Fallot as observed in a morphological archive, highlighting implications for surgical management.

METHODS

The Birmingham Children's Hospital archive contains 211 hearts with tetralogy of Fallot, of which 164 were analysed [69 (42.1%) unrepaired and 95 (57.9%) operated specimens]. A detailed morphological and geometric analysis was performed using a rigorous 5-layer review process.

RESULTS

Anomalies were observed in the orifices, origins and course of the coronary arteries: 20 hearts (13.0%) had more than 2 orifices and 3 hearts (1.9%) had a single orifice. In 7 hearts (4.3%), a coronary artery crossed the right ventricular outflow tract. The extent of aortic override ranged from 31.0% to 100% (median of 59.5%). The ventricular septal defect was most often perimembranous (139, 84.8%), but we also found muscular (14, 8.5%), atrioventricular (7, 4.3%) and doubly committed juxta-arterial (2, 1.2%) variants.

CONCLUSIONS

Anatomical variations are common and can impact surgical management. Anomalous coronary arteries may require a conduit rather than a transannular patch. Variability in aortic override determines the size of patch used to baffle blood to the aorta. The type of ventricular septal defect affects patch closure and the risk of postoperative conduction defects.

Borders as opposed to so-called geography: which should be used to classify isolated ventricular septal defects?

OBJECTIVES

Ventricular septal defects can be classified according to their borders or according to the fashion in which they open to the right ventricle, so-called geography. As yet, there is no consensus as to how they should be classified. In an attempt to achieve agreement, the International Society for Nomenclature of Congenital and Paediatric Heart Disease, in 2018, proposed a system incorporating both approaches. We have assessed the subjectivity of their suggested terms hoping to determine their suitability in the desired universal system for classification.

METHODS

We examined 212 specimens held in the archive of Birmingham Women's and Children's Hospital. Each defect was described by 3 independent examiners on the basis of borders and their relationship to the landmarks of the right ventricle. The interobserver agreement was then calculated using Fleiss' method.

RESULTS

Calculations to assess interobserver agreement showed that the examiners were more likely to agree on the borders of the defects than their so-called geography (κ = 0.804 vs κ = 0.518). The landmarks of the right ventricle proved to be highly variable such that the application of 'geographic' terms to hearts with perimembranous defects proved particularly challenging.

CONCLUSIONS

Interobserver agreement is lower when using terms based on 'geography' as opposed to borders. Whilst providing important morphological detail, the terms based on right ventricular landmarks are highly subjective. They should not be prioritized in a universal system of classification. Instead, the defects can be classified simply by using 'perimembranous', 'muscular', or 'doubly committed and juxta-arterial' as first-order terms.

Defining transposition: What have we learnt?

Understanding transposition is important for all who hope to effectively treat patients with the condition. The variants of the condition are frequently debated in the literature. We describe an unusual variant of transposition, in which despite the arterial roots being supported by morphologically inappropriate ventricles, the roots themselves were normally related, with the intrapericardial arterial trunks spiraling as they extended into the mediastinum. The specimen was identified following the re-categorization of our archive, and we subsequently conducted a detailed analysis of the underlying morphology. Using the principles of sequential segmental analysis, we compared the morphology with standard examples previously described. We show how it was the recognition of such hearts that promoted that concept that the combination of connections across the atrioventricular and ventriculo-arterial junctions was the essence of transposition. In the most common variant, the arrangements are concordant at the atrioventricular junctions, but discordant at the ventriculo-arterial junctions. We suggest that the overall arrangement of discordant ventriculo-arterial connections is best described simply as “transposition.” When the discordant ventriculo-arterial connections are combined with similarly discordant connections at the atrioventricular junctions, the transposition is congenitally corrected. We point out that the use of “d” and “l” as prefixes does not distinguish between transposition and its congenitally corrected variant. For those using segmental notations, the correct description for the rare variant found in the setting of a posteriorly located aortic root with the usual atrial arrangement is transposition (S, D, NR).

Anatomical Studies of Transposition - An Argument for a Unifying Morphological Classification

In the setting of transposition, recognition of the variability in the morphology of the outflow tracts and the arterial trunks is essential for surgical repair. Presence of a unifying system for classification would minimize the risk of misunderstanding. We examined an archive of 142 unrepaired hearts with transposition, defined as the combination of concordant atrioventricular and discordant ventriculoarterial connections, combined with the clinical records of 727 patients undergoing the arterial switch procedures. In the setting of usual atrial arrangement, we found the aortic root in leftward or posterior location in up to 5% of our cohorts, making the common term "d-transposition" ambiguous. Variability in the relationship of the trunks was commoner in the setting of deficient ventricular septation, especially when the trunks were side-by-side (14% vs 5.5% when the ventricular septum was intact). Bilateral infundibulums were present in 14% of cases, and bilaterally deficient infundibulums in 3.5%. Both of these findings were more common with deficient ventricular septation. Fibrous continuity between the tricuspid and pulmonary valves was not always seen with perimembranous defects, particularly when there were bilateral infundibulums. Fibrous continuity between the leaflets of the tricuspid and mitral valves, in contrast, proved a unifying characteristic of the perimembranous defect. The combination of concordant atrioventricular and discordant ventriculoarterial connections is best described simply as "transposition," with precision provided when details are given of atrial arrangement and the relationships of the arterial trunks.

Cardioplegia in paediatric cardiac surgery: a systematic review of randomized controlled trials

OBJECTIVES

Cardioplegia is the primary method for myocardial protection during cardiac surgery. We conducted a systematic review of randomized controlled trials of cardioplegia in children to evaluate the current evidence base.

METHODS

We searched MEDLINE, CENTRAL and LILACS and manually screened retrieved references and systematic reviews to identify all randomized controlled trials comparing cardioplegia solutions or additives in children undergoing cardiac surgery published in any language; secondary publications and those reporting inseparable adult data were excluded. Two or more reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases.

RESULTS

We identified 26 trials randomizing 1596 children undergoing surgery; all were single-centre, Phase II trials, recruiting few patients (median 48, interquartile range 30-99). The most frequent comparison was blood versus crystalloid in 10 (38.5%) trials, and the most common end points were biomarkers of myocardial injury (17, 65.4%), inotrope requirements (15, 57.7%) and length of stay in the intensive care unit (11, 42.3%). However, the heterogeneity of patients, interventions and reported outcome measures prohibited meta-analysis. Overall risk of bias was high in 3 (11.5%) trials, unclear in 23 (88.5%) and low in none.

CONCLUSIONS

The current literature on cardioplegia in children contains no late phase trials. The small size, inconsistent use of end points and low quality of reported trials provide a limited evidence base to inform practice. A core outcome set of clinically important, standardized, validated end points for assessing myocardial protection in children should be developed to facilitate the conduct of high-quality, multicentre trials.

PROSPERO registration

CRD42017080205.

Trends in surgical and catheter interventions for isolated congenital shunt lesions in the UK and Ireland

Objective

To evaluate time trends in the use of catheter and surgical procedures, and associated survival in isolated congenital shunt lesions.

Methods

Nationwide, retrospective observational study of the UK National Congenital Heart Disease Audit database from 2000 to 2016. Patients undergoing surgical or catheter procedures for atrial septal defect (including sinus venosus defect), patent foramen ovale, ventricular septal defect and patent arterial duct were included. Temporal changes in the frequency of procedures, and survival at 30 days and 1 year were determined.

Results

40 911 procedures were performed, 16 604 surgical operations and 24 307 catheter-based interventions. Transcatheter procedures increased over time, overtaking surgical repair in 2003–2004, while the number of operations remained stable. Trends in interventions differed according to defect type and patient age. Catheter closure of atrial septal defects is now more common in children and adults, although surgical interventions have also increased. Patent foramen ovale closure in adults peaked in 2009–2010 before falling significantly since. Surgery remains the mainstay for ventricular septal defect in infants and children. Duct ligation is most common in neonates and infants, while transcatheter intervention is predominant in older children. Excluding duct ligation, survival following surgery was 99.4% and ≈98.7%, and following catheter interventions was 99.7% and ≈99.2%, at 30 days and 1 year, respectively.

Conclusions

Trends in catheter and surgical techniques for isolated congenital shunt lesions plot the evolution of the specialty over the last 16 years, reflecting changes in clinical guidelines, technology, expertise and reimbursement, with distinct patterns according to lesion and patient age.

Randomized controlled trials in children's heart surgery in the 21st century: a systematic review

OBJECTIVES

Randomized controlled trials are the gold standard for evaluating health care interventions, yet are uncommon in children's heart surgery. We conducted a systematic review of clinical trials in paediatric cardiac surgery to evaluate the scope and quality of the current international literature.

METHODS

We searched MEDLINE, CENTRAL and LILACS, and manually screened retrieved references and systematic reviews to identify all randomized controlled trials reporting the effect of any intervention on the conduct or outcomes of heart surgery in children published in any language since January 2000; secondary publications and those reporting inseparable adult data were excluded. Two reviewers independently screened studies for eligibility and extracted data; the Cochrane Risk of Bias tool was used to assess for potential biases.

RESULTS

We identified 333 trials from 34 countries randomizing 23 902 children. Most were early phase (313, 94.0%), recruiting few patients (median 45, interquartile range 28-82), and only 11 (3.3%) directly evaluated a surgical intervention. One hundred and nine (32.7%) trials calculated a sample size, 52 (15.6%) reported a CONSORT diagram, 51 (15.3%) were publicly registered and 25 (7.5%) had a Data Monitoring Committee. The overall risk of bias was low in 22 (6.6%), high in 69 (20.7%) and unclear in 242 (72.7%).

CONCLUSIONS

The recent literature in children's heart surgery contains few late-phase clinical trials. Most trials did not conform to the accepted standards of reporting, and the overall risk of bias was low in few studies. There is a need for high-quality, multicentre clinical trials to provide a robust evidence base for contemporary paediatric cardiac surgical practice.

Right ventricular outflow tract stent versus BT shunt palliation in Tetralogy of Fallot

OBJECTIVE

This study sets out to compare morbidity, mortality and reintervention rates after stenting of the right ventricular outflow tract (RVOT) versus modified Blalock-Taussig shunt (mBTS) for palliation in patients with tetralogy of Fallot (ToF)-type lesions.

METHODS

Retrospective case review study evaluating 101 patients (64 males) with ToF lesions who underwent palliation with either mBTS (n=41) or RVOT stent (n=60) to augment pulmonary blood flow over a 10-year period. Procedure-related morbidity, mortality and reintervention rates were assessed and compared.

RESULTS

Admission rate to paediatric intensive care unit (PICU) was lower in the RVOT stent group (22% vs 100%; p<0.001). Thirty-day mortality in the RVOT stent group was (1/60 (1.7%)) compared with (2/41 (4.9%)) in the mBTS group (p=0.565). Mortality until surgical repair was comparable in both groups (5/60, 8.4%, including three non-cardiac death in the RVOT stent group vs 2/41, 4.9% (p=0.698)). Total hospital length of stay was shorter for the RVOT stent group (median 7 days vs 14 days; p<0.003). Time to surgical repair was shorter in the RVOT stent group (median 232 days, IQR 113-360) compared with the mBTS group (median 428 days, IQR 370-529; p<0.001) due to improved pulmonary arterial growth.

CONCLUSION

RVOT stenting in Fallot-type lesions can be accomplished safely, with lower PICU admission rate, a shorter hospital length of stay and shorter duration of palliation until complete repair compared with mBTS palliation.

Improving Risk Adjustment for Mortality After Pediatric Cardiac Surgery: The UK PRAiS2 Model

BACKGROUND

Partial Risk Adjustment in Surgery (PRAiS), a risk model for 30-day mortality after children's heart surgery, has been used by the UK National Congenital Heart Disease Audit to report expected risk-adjusted survival since 2013. This study aimed to improve the model by incorporating additional comorbidity and diagnostic information.

METHODS

The model development dataset was all procedures performed between 2009 and 2014 in all UK and Ireland congenital cardiac centers. The outcome measure was death within each 30-day surgical episode. Model development followed an iterative process of clinical discussion and development and assessment of models using logistic regression under 25 × 5 cross-validation. Performance was measured using Akaike information criterion, the area under the receiver-operating characteristic curve (AUC), and calibration. The final model was assessed in an external 2014 to 2015 validation dataset.

RESULTS

The development dataset comprised 21,838 30-day surgical episodes, with 539 deaths (mortality, 2.5%). The validation dataset comprised 4,207 episodes, with 97 deaths (mortality, 2.3%). The updated risk model included 15 procedural, 11 diagnostic, and 4 comorbidity groupings, and nonlinear functions of age and weight. Performance under cross-validation was: median AUC of 0.83 (range, 0.82 to 0.83), median calibration slope and intercept of 0.92 (range, 0.64 to 1.25) and -0.23 (range, -1.08 to 0.85) respectively. In the validation dataset, the AUC was 0.86 (95% confidence interval [CI], 0.82 to 0.89), and the calibration slope and intercept were 1.01 (95% CI, 0.83 to 1.18) and 0.11 (95% CI, -0.45 to 0.67), respectively, showing excellent performance.

CONCLUSIONS

A more sophisticated PRAiS2 risk model for UK use was developed with additional comorbidity and diagnostic information, alongside age and weight as nonlinear variables.

Improving risk adjustment in the PRAiS (Partial Risk Adjustment in Surgery) model for mortality after paediatric cardiac surgery and improving public understanding of its use in monitoring outcomes

Background

In 2011, we developed a risk model for 30-day mortality after children’s heart surgery. The PRAiS (Partial Risk Adjustment in Surgery) model uses data on the procedure performed, diagnosis, age, weight and comorbidity. Our treatment of comorbidity was simplistic because of data quality. Software that implements PRAiS is used by the National Congenital Heart Disease Audit (NCHDA) in its audit work. The use of PRAiS triggered the temporary suspension of surgery at one unit in 2013. The public anger that surrounded this illustrated the need for public resources around outcomes monitoring.

Objectives

(1) To improve the PRAiS risk model by incorporating more information about comorbidities. (2) To develop online resources for the public to help them to understand published mortality data.

Design

Objective 1 The outcome measure was death within 30 days of the start of each surgical episode of care. The analysts worked with an expert panel of clinical and data management representatives. Model development followed an iterative process of clinical discussion of risk factors, development of regression models and assessment of model performance under cross-validation. Performance was measured using the area under the receiving operator characteristic (AUROC) curve and calibration in the cross-validation test sets. The final model was further assessed in a 2014–15 validation data set.Objective 2 We developed draft website material that we iteratively tested through four sets of two workshops (one workshop for parents of children who had undergone heart surgery and one workshop for other interested users). Each workshop recruited new participants. The academic psychologists ran two sets of three experiments to explore further understanding of the web content.

Data

We used pseudonymised NCHDA data from April 2009 to April 2014. We later unexpectedly received a further year of data (2014–15), which became a prospective validation set.

Results

Objective 1The cleaned 2009–14 data comprised 21,838 30-day surgical episodes, with 539 deaths. The 2014–15 data contained 4207 episodes, with 97 deaths. The final regression model included four new comorbidity groupings. Under cross-validation, the model had a median AUROC curve of 0.83 (total range 0.82 to 0.83), a median calibration slope of 0.92 (total range 0.64 to 1.25) and a median intercept of –0.23 (range –1.08 to 0.85). In the validation set, the AUROC curve was 0.86 [95% confidence interval (CI) 0.83 to 0.89], and its calibration slope and intercept were 1.01 (95% CI 0.83 to 1.18) and 0.11 (95% CI –0.45 to 0.67), respectively. We recalibrated the final model on 2009–15 data and updated the PRAiS software.Objective 2We coproduced a website (http://childrensheartsurgery.info/) that provides interactive exploration of the data, two animations and background information. It was launched in June 2016 and was very well received.

Limitations

We needed to use discharge status as a proxy for 30-day life status for the 14% of overseas patients without a NHS number. We did not have sufficient time or resources to extensively test the usability and take-up of the website following its launch.

Conclusions

The project successfully achieved its stated aims. A key theme throughout has been the importance of collaboration and coproduction. In particular for aim 2, we generated a great deal of generalisable learning about how to communicate complex clinical and mathematical information.

Further work

Extending our codevelopment approach to cover many other aspects of quality measurement across congenital heart disease and other specialised NHS services.

Funding

The National Institute for Health Research Health Services and Delivery Research programme.

Does direct admission from an emergency department with on-site neurosurgical services facilitate time critical surgical intervention following a traumatic brain injury in children?

OBJECTIVES

To compare the proportion of trauma craniotomies performed within 4 hours of presentation to emergency departments (ED) with and without on-site neurosurgery.

DESIGN

A retrospective cohort analysis of data collected prospectively between January 2005 and April 2010 from patients with traumatic brain injury who were admitted to the paediatric intensive care unit (PICU) following traumatic brain injury.

METHODS

Times for admission to ED, PICU and theatre were obtained through analysis of prospectively collected data management systems. Emergency department admission to neurosurgical theatre lag time was calculated using Microsoft Excel. Statistical analysis was performed using R (version 2.11.0). Subjects. Fifty-seven cases were identified. Twenty patients were admitted directly from ED to an on-site neurosurgical unit. The remaining 37 were transferred from regional EDs.

RESULTS

Thirty-one craniotomies were performed. Thirteen in-patients admitted directly to hospital with neurosurgery on site. Eighteen in patients admitted at the local hospital and then transferred to the neurosurgical unit. Thirteen of Thirty-one (42%) craniotomies were performed within 4 hours. In the on-site group 10 of 13 (77%) craniotomies were performed within 4 hours compared to 3 of 18 (17%) in those transferred from regional ED (p = 0.001232) (Fisher exact test). Eleven patients were transferred directly from ED to neurosurgical theatre for emergency craniotomies. Within this subgroup, seven patients came from the cohort of admissions to a hospital with on-site neurosurgery. The remaining four patients were transferred from regional ED. There were eight extradural haematomas, one subdural haematoma and two intraparenchymal haemorrhages. The mean time from ED presentation to theatre was 1.68 hours and 5.46 hours for the on-site and regional transfer groups, respectively. There were no mortalities.

CONCLUSIONS

Forty-two per cent of trauma craniotomies are performed within 4 hours. However, presentation to an ED with on-site neurosurgical services significantly facilitates time critical surgery in children following a traumatic brain injury.

Calculating the need for intensive care beds

AIM

Prompted by high refused admission rates, we sought to model demand for our 20 bed paediatric intensive care unit.

METHODS

We analysed activity (admissions) and demand (admissions plus refused admissions). The recommended method for calculating the required number of intensive care beds assumes a Poisson distribution based upon the size of the local catchment population, the incidence of intensive care admission and the average length of stay. We compared it to the Monte Carlo method which would also include supra-regional referrals not otherwise accounted for but which, due to their complexity, tend to have a longer stay than average. For the new method we assigned data from randomly selected emergency admissions to the refused admissions. We then compared occupancy scenarios obtained by random sampling from the data with replacement.

RESULTS

There was an increase in demand for intensive care over time. Therefore, in order to provide an up-to-date model, we restricted the final analysis to data from the two most recent years (2327 admissions and 324 refused admissions). The conventional method suggested 27 beds covers 95% of the year. The Monte Carlo method showed 95% compliance with 34 beds, with seasonal variation quantified as 30 beds needed in the summer and 38 in the winter.

CONCLUSION

Both approaches suggest that the high refused admission rate is due to insufficient capacity. The Monte Carlo analysis is based upon the total workload (including supra-regional referrals) and predicts a greater bed requirement than the current recommended approach.

Early change in blood glucose concentration is an indicator of mortality in critically ill children

OBJECTIVE

Hyperglycaemia is associated with increased mortality in critically ill patients. A number of studies have highlighted an association between increased variability of blood glucose (BG) concentration and mortality, supporting a survival disadvantage if BG homeostasis is lost. By exploring the longitudinal BG profile of individual children over time, this study investigates the importance of intact homeostasis early after admission to the paediatric intensive care unit (PICU).

DESIGN, SETTING, AND PATIENTS

Retrospective single-centre observational study in a large multi-specialty PICU in the UK. Children admitted between August 2003 and February 2006 were included unless they met exclusion criteria. Data were merged from the PICU clinical database and blood gas analyser database by means of a unique PICU identifier. BG was measured frequently on a blood gas analyser (Bayer Rapidlink). Primary outcome was 100-day mortality. BG parameters were investigated for possible associations with mortality.

MEASUREMENTS AND MAIN RESULTS

A total of 1,763 patients were included (median age 1.1 years; IQR 0.1-5.8). Although admission BG was not associated with mortality, a survival advantage was found in children who showed a reduction in BG on day 1 relative to the admission BG value (p < 0.001). This remained statistically significant (p = 0.007) after adjusting for severity of illness.

CONCLUSIONS

This study supports an association between early BG profile and mortality in children admitted to PICU, with increased survival in those who demonstrate a fall in BG on day 1 relative to PICU admission. These findings are consistent with a survival advantage of intact BG homeostasis.

Repair of isolated aortic coarctation over two decades: impact of surgical approach and associated arch hypoplasia

OBJECTIVES

A variety of surgical approaches and techniques are used for isolated coarctation repair. We have retrospectively reviewed our results of isolated repair of coarctation over the last 20 years, to establish whether the approach affects clinical outcome and the need for re-intervention.

METHODS

Two hundred and eighty-eight patients who underwent isolated repair for coarctation of the aorta at Birmingham Children's Hospital between 1991 and 2010 were enrolled in this study. Chart review and the Departmental database were used to determine demographics, operative details and complications.

RESULTS

The majority of patients (n = 237, 82%) underwent surgical repair via thoracotomy techniques, whereas median sternotomy was used in patients where there was associated arch hypoplasia (n = 51, 18%). For all 288 patients, median age at operation was 24 days (range 0-14 years). Between 1991 and 2000, ten patients (6%) underwent repair through midline sternotomy, increasing to 41 patients (36%) between 2001 and 2010. Overall early mortality was 1% and late mortality was 3%. There was a statistically higher re-intervention rate (16%) in the decade 1991-2000, compared to 5% in the period 2001-10 (P = 0.02). In patients with hypoplastic arch, the midline approach has a lower re-intervention rate than thoracotomy (P < 0.001).

CONCLUSIONS

In our institution, there has been a trend in recent years towards increased use of median sternotomy to repair the aortic arch, which has been associated with a reduced rate of re-intervention. The midline sternotomy approach for coarctation with arch hypoplasia significantly reduces the risk of re-coarctation.

The effect of morphologic subtype on outcomes following the Sano-Norwood procedure

OBJECTIVES

Controversy exists concerning outcomes of patients with different morphologic subtypes of hypoplastic left heart syndrome undergoing the Norwood procedure, in particular, aortic atresia-mitral stenosis (AA-MS) patients receiving a systemic-pulmonary modified Blalock-Taussig (mBT) shunt. We sought to determine the influence of known risk factors and morphology on early survival in our cohort of Sano-Norwood patients with right ventricle-pulmonary artery (RV-PA) conduits as the source of pulmonary blood flow.

METHODS

We studied early survival in patients with Sano-modified Norwood procedures from 2002 to 2010 and included both typical and atypical (including unbalanced atrioventricular canal defect) morphologic variants. We included a comparison group composed of classical Norwood patients with mBT shunts.

RESULTS

Of 264 Sano-Norwood patients, 49 had AA-MS and 30 had atypical morphologies. Weight ≤ 2.5 kg was associated with a poorer 1-year survival (P = 0.0007), though ascending aorta (AscAo) size <2.0 mm was not. We did not observe a difference in 30-day or 1-year Kaplan-Meier (K-M) survival across typical morphologic variants for either a Sano or mBTS group. Atypical variants exhibited a trend towards lower 30-day and 1-year survival in both Sano and mBTS groups though this was not significant. Direct comparison of 30-day K-M survival for Sano versus mBTS in AA-MS patients showed similar outcomes (P = NS).

CONCLUSIONS

Use of the RV-PA conduit results in good early survival, even in those with a small AscAo size. Atypical morphologic variants seem to do worse irrespective of the Sano or mBTS group. Further studies will be required to determine conclusively whether the RV-PA shunt confers protective effects in the AA-MS subgroup compared with the mBTS.

Rapid ventricular pacing for catheter interventions in congenital aortic stenosis and coarctation: effectiveness, safety, and rate titration for optimal results

INTRODUCTION

Infants and children with congenital aortic stenosis and coarctation of the aorta can be treated by catheter intervention. There are several pharmacological and mechanical techniques described to overcome the balloon movement; none, however, have proved entirely satisfactory. An alternative method to achieve balloon stability is the use of rapid ventricular pacing. We describe our experience with titrating the pacing rate and the use of this technique.

METHODS

A retrospective review of database was performed, to identify patients who underwent transcatheter intervention with rapid ventricular pacing. Invasive systemic pressures were documented with a catheter in the aorta. Rapid ventricular pacing was initiated at the rate of 180 per minute and increased by increments of 20 per minute to a rate required to achieve a drop in systemic pressure by 50% and a drop in pulse pressure by 25%. The balloon was inflated only after the desired pacing rate was reached. Pacing was continued until the balloon was completely deflated.

RESULTS

Thirty patients were identified, 29 of whom had interventions with rapid ventricular pacing. Balloon valvuloplasty of aortic valve was performed on 25 patients while 4 patients had stenting for coarctation by this technique. The rate of ventricular pacing required ranged from 200 to 260 per minute with a median rate of 240. Balloon stability at the time of intervention was achieved in 27 patients.

CONCLUSION

Rapid ventricular pacing is a safe and effective method to provide transient decrease in cardiac output at the time of transcatheter interventions to achieve balloon stability.

The Norwood procedure using a right ventricle-pulmonary artery conduit: comparison of the right-sided versus left-sided conduit position

OBJECTIVE

We proposed that a right-sided right ventricle-pulmonary artery conduit during the stage I Norwood procedure would facilitate pulmonary artery reconstruction during the stage II procedure.

METHODS

Between 2002 and 2006, 153 patients underwent Norwood stage I reconstruction with a right ventricle-pulmonary artery conduit (125 in the right-sided group and 28 in the left-sided group). The previous 150 consecutive classic Norwood procedures (1997-2002) were used as a control group. Outcomes from stages I and II were analyzed, including ventricular function and pulmonary artery morphology.

RESULTS

The 30-day survival was 88% (110/125) in the right-sided group, 75% (21/28) in the left-sided group, and 70% (105/150) in the control group (P < .001, right-sided vs control groups). The conduit length was 35 +/- 9 mm in the right-sided group and 26 +/- 8 mm in the left-sided group (P = .001). Survival at 6 months demonstrated a significant survival benefit in the right-sided right ventricle-pulmonary artery conduit group over the control group (P = .009, log-rank test). There was no difference in ventricular function between the groups and no regional dyskinesia associated with the right ventricle-pulmonary artery conduit. Despite larger branch pulmonary artery size in the right ventricle-pulmonary artery conduit groups (compared with the control group), central pulmonary artery stenoses were common (62% in the right conduit and 80% in the left conduit). Bypass and ischemic times at stage II were 49 +/- 10 and 23 +/- 13 minutes in the right-sided group compared with 61.5 +/- 9.5 and 31 +/- 14 minutes in the left-sided group (P < .001 and P = .03, respectively). The 30-day mortality after the stage II procedure was 1.3% (1/76) in the right-sided group, 0% (0/18) in the left-sided group, and 3.3% (3/90) in the control group.

CONCLUSION

The right-sided conduit is a safe technique and has improved 30-day and overall post-stage II survival compared with that seen with the classic Norwood procedure. The right ventricle-pulmonary artery conduit is associated with central pulmonary artery stenosis but good development of the branch pulmonary arteries and preservation of ventricular function. The right-sided conduit significantly reduces cardiopulmonary bypass times at stage II.

Surgical management of hypoplastic left heart syndrome at the Birmingham Children's Hospital

Currently, a three-stage surgical palliation remains the treatment of choice at Birmingham Children's Hospital. After initial introduction of the classical Norwood with pulmonary blood flow provided by a modified Blalock-Taussig shunt, a right ventricular to right pulmonary artery conduit at stage 1 Norwood palliation is now used in most cases, a bi-directional 'Glenn' shunt at second stage and an extra-cardiac Fontan completion at third stage. Mortality and morbidity has improved after modification of the technique. Thirty-day mortality was 32.4% (79/244) for the 'classical' Norwood procedure, 25.0% (7/28) for the left-sided RV-PA conduit and 12.7% (22/173) for the right-sided RV-PA conduit. Interstage mortality was 8.6% (21/244) for the 'classical' Norwood procedure, 14.3% (4/28) for the left and 10.1% (15/148) for right-sided RV-PA conduit. After stage II, 30-day mortality was 3.0% (10/335) for all groups. Stage III 30-day mortality was 0.9% (1/115) for all groups.

Awareness of the risk of endocarditis associated with tattooing and body piercing among patients with congenital heart disease and paediatric cardiologists in the United Kingdom

Body art in the form of tattoos and piercing has become increasingly popular amongst children and teenagers, and is nowadays more socially acceptable despite media reports citing tissue destruction and death. Our study explored the awareness and experience of patients with congenital heart disease, and of cardiologists and professionals responsible for their care.

Creation of aorto-pulmonary window with pulmonary artery band is not good palliation for hypoplastic left heart syndrome

OBJECTIVE

A small sub-group of patients with hypoplastic left heart syndrome (HLHS) have normal-sized ascending aorta and arch. An alternative to the Norwood I procedure in these patients is the creation of an aorto-pulmonary (AP) window with a distal pulmonary artery band (PAB). We reviewed our experience with this technique and compared outcomes to the Norwood procedure for HLHS.

METHODS

All patients treated for HLHS in a single institution between 1992 and 2005 were analysed. This identified 13 patients treated with AP window and PAB compared to 333 patients undergoing stage I Norwood procedure. An unrestrictive AP window was created and the main PA was banded. Patient records and echocardiograms were analysed. Median follow-up was 10 (IQR 0-655) days and 100% complete.

RESULTS

There were seven early deaths (54%) in the AP window group and two conversions to Norwood circulation. This was a significantly worse outcome than for the Norwood procedure over the same period, which had an early mortality of 29% (p=0.03). Kaplan-Meier actuarial analysis demonstrated a continued survival benefit of the Norwood group at 6 months (p=0.0005). Deaths were due to either low cardiac output syndrome (n=4) or sudden unheralded arrest (n=3). This occurred despite aortic cross-clamp and circulatory arrest times being significantly lower in the AP window group compared to the Norwood group (35+/-27 vs 55+/-16 min, p<0.01 and 16+/-29 vs 55+/-20 min, p<0.01, respectively). No differences in arterial saturations or systolic blood pressure existed between the groups, but diastolic blood pressure was significantly lower in the AP window group at 27+/-10 mmHg compared to 42+/-8 mmHg in the Norwood group (p=0.01) with evidence of flow reversal in the descending aorta. Differences in diastolic blood pressure between groups were abolished after conversion to stage II.

CONCLUSIONS

Despite favourable anatomy and shorter ischaemic times, the AP window/PAB technique has a poor outcome compared to the Norwood procedure for HLHS. Low diastolic blood pressure with reversal of descending aortic flow in diastole was a feature of the AP window/PAB circulation. We recommend the Norwood procedure for these sub-types. This may have implications for newer 'hybrid' procedures for HLHS which create a similar palliative circulation.

Risk assessment and early outcome following the Norwood procedure for hypoplastic left heart syndrome

BACKGROUND

This study was undertaken to identify risk factors for early mortality following the Norwood procedure for hypoplastic left heart syndrome (HLHS) and develop a predictive risk model to monitor clinical performance.

METHODS AND RESULTS

Between December 1992 and June 2004, 333 patients with HLHS underwent a Norwood procedure at a single institution. The early mortality was 29% (n=95). Estimated early mortality improved progressively and was 10% at the end of the series. Multivariable analysis identified that body surface area at operation, size of the ascending aorta, preoperative right ventricular function and source of pulmonary blood flow established at operation were risk factors for early mortality (P<0.05). These variables were included in a preoperative risk model. The duration of cardiopulmonary support was an independent risk factor, which was included in a separate operative risk model. The performance of the risk models was evaluated by goodness-of-fit analyses, using the Hosmer-Lemeshow test and receiver operating characteristic (ROC) curve. Both models were well calibrated across all deciles (P=0.64, P=0.77) and discriminated moderately well. The area under the ROC curve was 0.71 for Model 1 and 0.75 for Model 2. Risk adjustment broadly accounted for the variation in early mortality observed during this series.

CONCLUSIONS

Patient-related and predetermined operative variables have a major influence on the early outcome following the Norwood procedure for HLHS. The identification of these risk factors allows the risk of early mortality to be calculated. This information could be applied as part of a risk-adjusted performance-monitoring system to enable early identification of meaningful changes in practice.

Right ventricular outflow tract reconstruction using Contegra® valved conduit: natural history and conduit performance under pressure

OBJECTIVE

To assess the performance of the bovine Contegra valved conduit used for right ventricular (RV) outflow tract reconstruction, particularly in relation to post-operative RV pressure.

METHODS

Follow-up study of 64 consecutive right ventricular to pulmonary artery-conduit implants in 62 patients between January 2000 and April 2003. The majority of cases were forms of pulmonary atresia/VSD (n=24, 39%) or Fallot's tetralogy (n=13, 21%). Thirteen cases (21%) had aortic atresia, truncus arteriosus or discordant connections with pulmonary atresia/VSD. Twelve cases (19%) were conduit replacements. Echocardiography was performed for a median follow-up of 14 months (range 0-38 months).

RESULTS

Median age at implantation was 13.8 months (range 0.1-244 months) and median weight was 8.9 kg (range 2.1-84.1 kg). Thirty-eight patients (59.4%) were <10 kg at the time of surgery. Early mortality was 6.4% (n=4). During follow-up there were four explantations (one for endocarditis and three for conduit dilatation) and 16 (28.6%) catheter interventions. Overall freedom from intervention at 1 and 3 years was 71+/-6% and 53+/-11%, respectively. Freedom from conduit-specific reintervention was 66+/-11% at the end of the study period. Reintervention was associated with small conduits (p=0.04), age <1 year (p=0.04) and with high RV/LV pressure ratio in the immediate post-operative period (p=0.0003). On multivariate analysis, the RV/LV pressure ratio was the strongest single factor predicting the overall reintervention (OR 5.45). Acquired distal conduit stenosis at suture line was the commonest indication for conduit-specific reintervention and was associated with the smaller conduits. The conduits explanted for dilatation showed neointimal proliferation, thrombosis, calcification and chronic inflammation.

CONCLUSIONS

The Contegra conduit is widely applicable to RVOT reconstruction with satisfactory mid-term results. However, there is a significant incidence of conduit-related complications, particularly with the smaller conduits. Adverse performance was strongly associated with high RV/LV pressure ratio at completion of surgery. We would recommend cautious use of the conduits in patients with predicted high RV/LV pressure ratios, where careful monitoring of conduit performance is crucial. There is some element of unpredictability, which adds to the importance of close follow-up. Further studies are needed to explore the issues of thrombogenicity, degeneration, possible 'rejection', and the potential role of anti-platelet and anti-inflammatory modulation.

Differential effects in cells exposed to ultra-short, high intensity electric fields: cell survival, DNA damage, and cell cycle analysis

High power, nanosecond pulsed electric field (nsPEF) effects have been focused on bacterial decontamination, but the impact on mammalian cells is now being revealed. During nsPEF applications, electrical pulses of 10, 60 or 300 ns durations were applied to cells using electric field amplitudes as high as 300 kV/cm. Because of the ultra-short pulse durations, the energy transferred to cells is negligible, and only non-thermal effects are observed. We investigated the genotoxicity of nsPEF on adherent and non-adherent cell lines including 10 human lines and one mouse cell line with different origin and growth characteristics. We present data examining the effects of nsPEF exposure on cell survival assessed by clonogenic formation or live cell count; DNA damage determined by the comet assay and chromosome aberrations; and cell cycle parameters by measuring the mitotic indices of exposed cells. Using each of these indicators, we observed differential effects among cell types with non-adherent cells being more sensitive to the genotoxic effects of nsPEF exposures than adherent cells. Non-adherent cultures showed a rapid decrease in cell viability (90%), induction of DNA damage, and a decrease in the number of cells reaching mitosis after one 60 ns pulse with an electric field intensity of 60 kV/cm. These effects were not observed in cells grown as adherent cultures, with the exception of the mouse 3T3 cell line, which showed survival characteristics similar to non-adherent cultures. These data suggest that nsPEF genotoxicity may be cell type specific, and therefore have potential applications in the selective removal of one cell type from another, for example, in diseased states.