Six-minute walk test distance at time of hospital discharge is strongly and independently associated with all-cause mortality following cardiac surgery.

We investigated the impact of distance covered in the six-minute walk test (6mWT) before being discharged from the hospital after cardiac surgery on the risk of all-cause mortality. Our study included 1127 patients who underwent cardiac surgery and then took part in a standardised physiotherapist-supervised inpatient rehabilitation programme during 2007-2017. The percentage of the predicted 6mWT distance, and the lower limit of normal distance was calculated based on individual patients' age, sex, and body mass index. We used Cox regression with adjustment for confounders to determine multivariable-adjusted hazard ratios (HRs) for mortality. Over a median follow-up period of 6.4 (IQR: 3.5-9.2) years, 15% (n = 169) patients died. We observed a strong and independent inverse association between 6mWT distance and mortality, with every 10 m increase in distance associated to a 4% reduction in mortality (HR: 0.96, 95% CI 0.94-0.98, P < 0.001). Those in the top tertile for predicted 6mWT performance had a 49% reduced risk of mortality (HR: 0.51, 95% CI 0.33-0.79) compared to those in the bottom tertile. Patients who met or exceeded the minimum normal 6mWT distance had 36% lower mortality risk (HR: 0.64, 95% CI 0.45-0.92) compared to those who did not meet this benchmark. Subgroup analysis showed that combined CABG and valve surgery patients walked less in the 6mWT compared to those undergoing isolated CABG or valve surgeries, with a significant association between 6mWT and mortality observed in the isolated procedure groups only. In conclusion, the longer the distance covered in the 6mWT before leaving the hospital, the lower the risk of mortality.

Technique of Coronary Button Transfer Has no Impact on Neoaortic Root Size in Simple Transposition.

We studied the effect of various coronary transfer techniques (CTT) on neo-aortic root size after an arterial switch operation (ASO) in simple transposition by excluding the impact of recognized predisposing factors. One hundred and seventy-eight patients with simple transposition were reviewed retrospectively (January 2004-December 2018) and grouped as Punch Hole (n = 83/178), Nonpunch Hole (n = 65/178; Trapdoor or Standard) and Mixed (n = 30/178). Factors predicting the neo-aortic root z-scores- annulus, mid-sinus, and sinotubular junction (STJ) were analyzed by uni/multivariable linear regression. Follow-up was 6 years, Interquartile range (IQR) 3.4,10.6. Preoperative aortic (7.4 mm, IQR 6.9,8) and pulmonary annulus (7.5 mm, IQR 6.8,8.1) sizes were identical (P = 0.831). The changes in preoperative, postoperative, and latest median z-scores for neo-aortic annulus (-0.2, IQR -1.2,0.9; 0.0, IQR -0.9,0.9; 0.9, IQR -0.4,2.6; P < 0.001), mid-sinus (1.1, IQR-0.1,2; 2.6, IQR 1.6,3.7; 2.9, IQR 1.8,4.3; P < 0.001) and STJ (-0.1, IQR -0.8,1.1; 2.1, IQR 0.7,3; 2.4, IQR 1,3.5; P < 0.001) were significant. On multivariate analysis, preoperative pulmonary annulus z-score predicted the latest neo-aortic annulus z-score [Beta estimate (BE) = 0.32, 95% confidence interval (CI) = 0.03,0.62; P = 0.03] and STJ z-score (BE= 0.45, 95% CI= 0.20,0.70; P < 0.0001). CTT did not predict any of the latest neo-aortic z-scores (all P > 0.05). Mild plus neo-aortic regurgitation (neoAR) was not significantly different across CTT groups [punch hole 20% (n = 15/74), mixed 37% (n = 11/30), nonpunch hole 21% (n = 13/62); Fisher-exact P = 0.186], one patient required valve replacement for severe neoAR. The neo-aortic root enlarges significantly over time at all 3 levels following an ASO in simple transposition, however, this is not significantly influenced by the CTT utilized.

Mid- and long-term outcomes after surgical correction of subaortic stenosis: a 27-year experience.

OBJECTIVES: We reviewed the mid- and long-term surgical outcomes of patients with subaortic stenosis (SAS). METHODS: Patients operated for SAS from April 1990 to August 2016 were reviewed retrospectively. Patients with major associations such as aortic arch obstruction were excluded. Time to reintervention and predictors of recurrence were assessed using Kaplan-Meier analysis, log-rank test and uni/multivariable Cox regression. RESULTS: 120 patients at a median age of 4.7 years (interquartile range 2.9, 8.1) underwent primary operation (median peak preoperative left ventricular outflow tract gradient 52.5 mmHg, interquartile range 40, 70) involving fibrous tissue excision (n = 120) with septal myectomy (93%; n = 112) as the procedure of choice.At median follow-up of 13 years (interquartile range 7, 18), freedom from reintervention at 1, 3, 5 and 10 years was 99% (95% confidence interval 94%, 99%), 94% (87%, 97%), 93% (86%, 96%) and 90% (82%, 94%), respectively. Recurrence occurred in 18% (n = 20) with 15 patients undergoing reinterventions, 13 of whom required radical reoperation. Multivariable analysis revealed higher preoperative peak left ventricular outflow tract gradient (hazard risk 1.06, confidence interval 1.03, 1.09, P < 0.001), and presence of bicuspid aortic valve (hazard risk 14.13, confidence interval 3.32, 60.1, P < 0.001) as predictors for reintervention. Mild/moderate aortic regurgitation occurred in 49% (n = 55) of patients at the most recent follow-up. CONCLUSIONS: Reintervention for recurrent SAS is common, predicted by higher preoperative peak left ventricular outflow tract gradient, and presence of bicuspid aortic valve, and frequently involves a radical procedure. Aortic regurgitation is a major consequence of SAS, but its severity usually remains low. CLINICAL REGISTRATION NUMBER: SCHN HREC reference number 2019/ETH02729, approved on 09 July 2019.

Longitudinal cohort study investigating neurodevelopmental and socioemotional outcomes in school-entry aged children after open heart surgery in Australia and New Zealand: the NITRIC follow-up study protocol.

INTRODUCTION: Despite growing awareness of neurodevelopmental impairments in children with congenital heart disease (CHD), there is a lack of large, longitudinal, population-based cohorts. Little is known about the contemporary neurodevelopmental profile and the emergence of specific impairments in children with CHD entering school. The performance of standardised screening tools to predict neurodevelopmental outcomes at school age in this high-risk population remains poorly understood. The NITric oxide during cardiopulmonary bypass to improve Recovery in Infants with Congenital heart defects (NITRIC) trial randomised 1371 children <2 years of age, investigating the effect of gaseous nitric oxide applied into the cardiopulmonary bypass oxygenator during heart surgery. The NITRIC follow-up study will follow this cohort annually until 5 years of age to assess outcomes related to cognition and socioemotional behaviour at school entry, identify risk factors for adverse outcomes and evaluate the performance of screening tools. METHODS AND ANALYSIS: Approximately 1150 children from the NITRIC trial across five sites in Australia and New Zealand will be eligible. Follow-up assessments will occur in two stages: (1) annual online screening of global neurodevelopment, socioemotional and executive functioning, health-related quality of life and parenting stress at ages 2-5 years; and (2) face-to-face assessment at age 5 years assessing intellectual ability, attention, memory and processing speed; fine motor skills; language and communication; and socioemotional outcomes. Cognitive and socioemotional outcomes and trajectories of neurodevelopment will be described and demographic, clinical, genetic and environmental predictors of these outcomes will be explored. ETHICS AND DISSEMINATION: Ethical approval has been obtained from the Children's Health Queensland (HREC/20/QCHQ/70626) and New Zealand Health and Disability (21/NTA/83) Research Ethics Committees. The findings will inform the development of clinical decision tools and improve preventative and intervention strategies in children with CHD. Dissemination of the outcomes of the study is expected via publications in peer-reviewed journals, presentation at conferences, via social media, podcast presentations and medical education resources, and through CHD family partners. TRIAL REGISTRATION NUMBER: The trial was prospectively registered with the Australian New Zealand Clinical Trials Registry as 'Gene Expression to Predict Long-Term Neurodevelopmental Outcome in Infants from the NITric oxide during cardiopulmonary bypass to improve Recovery in Infants with Congenital heart defects (NITRIC) Study - A Multicentre Prospective Trial'. TRIAL REGISTRATION: ACTRN12621000904875.

PI16 is expressed by a subset of human memory Treg with enhanced migration to CCL17 and CCL20.

The peptidase inhibitor PI16 was shown previously by microarray analysis to be over-expressed by CD4-positive/CD25-positive Treg compared with CD4-positive/CD25-negative Th cells. Using a monoclonal antibody to the human PI16 protein, we found that PI16-positive Treg have a memory (CD45RO-positive) phenotype and express higher levels of FOXP3 than PI16-negative Treg. PI16-positive Treg are functional in suppressor assays in vitro with potency similar to PI16-negative Treg. Further phenotyping of the PI16-positive Treg revealed that the chemokine receptors CCR4 and CCR6 are expressed by more of the PI16-positive/CD45RO-positive Treg compared with PI16-negative/CD45RO-positive Treg or Th cells. PI16-positive Treg showed enhanced in vitro migration towards the inflammatory chemokines CCL17 and CCL20, suggesting they can migrate to sites of inflammation. We conclude that PI16 identifies a novel distinct subset of functional memory Treg which can migrate to sites of inflammation and regulate the pro-inflammatory response at those sites.

Correlation of ventricular septal defect height and outcomes after complete atrioventricular septal defect repair.

OBJECTIVES: There are limited data available on the height of the ventricular component of the septal deficiency (VSD) in patients undergoing complete atrioventricular septal defect (CAVSD) repair. VSD height may influence optimal choice of repair strategy with potential consequences for long-term outcomes. We aimed to measure VSD height using 2-dimensional echocardiography and review its association with postoperative outcomes. METHODS: We retrospectively reviewed the preoperative echocardiograms of 45 consecutive patients who underwent CAVSD repair between May 2010 and December 2015 at a single centre. VSD height and left ventricular length on the four-chamber view were measured. Demographic details and early and late outcomes including reoperation and long-term survival were studied. RESULTS: Twenty patients underwent modified single-patch repair and 25 patients underwent double-patch repair of CAVSD. VSD height in the modified single-patch group ranged from 4.2 to 11.7 mm and in the double-patch group ranged from 5.1 to 14.9 mm. Nine patients had a deep 'scoop' with a VSD height of >10 mm, (7 double patch, 2 modified single patch). VSD height did not correlate with a specific Rastelli classification. There was no significant difference in the VSD height (P = 0.51) or the VSD height-to-left ventricular length ratio (P = 0.43) between the 2 repair groups. There was no 30-day mortality. Eight patients required reoperation; however, VSD height was not a significant predictor of reoperation (hazard ratio 0.95, 95% confidence interval 0.69-1.33; P = 0.08). CONCLUSIONS: There was no correlation between VSD height and risk of reoperation after CAVSD repair. A deep ventricular scoop is uncommon in CAVSD patients.

A Simplified Approach to Predicting Reintervention in the Arterial Switch Operation.

We investigated patients with transposition anatomy suitable for the arterial switch operation (ASO) to evaluate a simplified approach to prediction of reintervention. A retrospective review was performed of 180 consecutive patients who underwent ASO from 2009 to 2018. Patients were classified as Category I (n = 122) d-transposition of great arteries (dTGA) + intact ventricular septum, Category II (n = 28) dTGA + ventricular septal defect (VSD) and Category III (n = 30) dTGA + Aortic arch obstruction (AAO) +/- VSD or Taussig-Bing Anomaly (TBA) +/- AAO. Outcomes included reintervention-free survival (using Kaplan-Meier estimates) and predictors of reintervention. Median follow up was 3.3 (interquartile range 1.7-5.8) years with no difference between categories(P = 0.082). There were 3 mortalities- 2 early (one each in Category I and II) and one late (in Category I). Reintervention-free survival for the whole group at 1, 3, 5 and 8 years was 94%, 91%, 90% and 86% respectively. Conventional criteria predicting reintervention included the presence of TBA(P = 0.0054) and AAO(P = 0.027). Low birth weight did not predict reintervention(P = 0.2). When analyzed by category, multivariable analysis showed that patients in Category III carried a high risk of reintervention [Hazard risk (HR) = 7.43, 95% confidence interval (CI)=(2.39, 23.11), P < 0.001], but so did those in Category II [HR=6.90, 95% CI = (2.19, 21.75, P < 0.001] when compared to Category I. Conventional risk factors for technical difficulty may not be the best predictors of reintervention. A simplified approach highlights Category II patients (dTGA + VSD) as being at substantial risk of re-intervention, and not part of a low risk cohort.

Expression of Toll-like receptors by neonatal leukocytes.

The immune system of neonates is poorly developed; this increases the susceptibility of neonates to infection. For neonates to counter infection effectively, they first need to recognize the presence of pathogens. Toll-like receptors (TLR) are a family of pattern recognition receptors that alert the host to the presence of invading pathogens. To determine whether differences in TLR expression by leukocytes compensate for immunologic immaturity in neonates, TLR expression by monocytes and T lymphocytes from adults and neonates was compared. Expression of TLR1, TLR2, TLR3, TLR4, TLR8 and TLR9 by monocytes and T lymphocytes was detected with antibodies by flow cytometry. TLR1, TLR2, TLR3, TLR4, TLR8 and TLR9 expression by monocytes was detected in adults and neonates. TLR2, TLR3, TLR4, TLR8 and TLR9 expression by T lymphocytes was detected in adults and neonates. Monocytes and T lymphocytes from neonates are capable, like adults, of recognizing the presence of pathogens through TLR.

Anomalous systemic arterial supply to normal basal segment of the left lung.

BACKGROUND: Anomalous systemic arterial supply to normal segments of the lung is an unusual anomaly. It represents part of a spectrum of bronchovascular abnormalities which have various anatomical and clinical manifestations. METHODS: We retrospectively analysed cases from January 2007 to April 2010 from two institutions diagnosed with an anomalous systemic arterial supply to a normal lung segment. RESULTS: Three infants were found to have anomalous systemic arterial supply to normal segments of the lung. One patient was from The Children's Hospital at Westmead, Australia and two cases from Amrita Institute of Medical Sciences, Kochi, India. The mean age at diagnosis was 65 days (range 30-120 days) and mean weight was 3.05 kg (range 1.9-4.4 kg). All babies presented with tachypnoea. The diagnosis was suspected on echocardiography and confirmed by computerised tomography scan (CT scan) in one and by angiography in two cases. The preterm baby underwent ligation of the anomalous vessel by thoracotomy and other two infants had transcatheter occlusion of the collateral. There was no residual flow on echocardiography in any of the three cases and all have done well on follow up. CONCLUSION: Anomalous systemic arterial supply to normal lung segments is a very rare anomaly. A high index of suspicion is needed to expedite diagnosis. Transcatheter embolisation or surgical ligation of the collateral proved effective therapeutic approaches in young infants without a need for surgical lobectomy.

Five-year analysis of operative mortality and neonatal outcomes in congenital heart disease.

BACKGROUND: We sought to compare overall mortality with neonatal outcomes over a five year period to define risk factors for mortality and service development priorities. METHODS: A retrospective cohort study of surgical outcomes following repair or palliation of structural congenital heart defects January 2005-2010. We defined mortality according to contemporary international guidelines and classified surgical procedures using the Risk Adjustment in Congenital Heart Surgery (RACHS-1) score. The effect of age and weight at operation on mortality and annual variation in case-complexity and surgeon case-mix were assessed. Subgroup analysis was performed in patients who were ≤30 days at operation (neonates). RESULTS: Overall mortality within 30 days of operation or prior to hospital discharge was 1.3 and 1.9%, respectively. Mortality was higher in neonates (6.8%) and low birth weight infants (≤2.5kg) (12.1%). Mortality was similar in bypass versus non-bypass procedures (odds ratio 0.74, p=0.425). Annual mortality rates were consistent despite a marked increase in case-complexity. Neonates overall required longer periods of intensive care support and were more likely to suffer serious complications compared to older children. Age, weight and RACHS-1 score were independent risk factors for mortality on multivariate analysis. In neonates undergoing bypass procedures, only RACHS-1 score was a significant risk factor. CONCLUSIONS: This study provides an accurate and contemporary audit of mortality risk associated with congenital heart surgery. Outcomes compare favourably to international benchmarks but highlight the risks of morbidity and mortality associated with neonatal cardiac surgery.

Predictors of reoperation and mortality after complete atrioventricular septal defect repair.

OBJECTIVES: Previous studies investigating risk factors associated with reoperation or mortality after repair of complete atrioventricular septal defect (CAVSD) often have not included sizeable cohorts undergoing modified single-patch repair. Both double patch and modified single-patch techniques have been widely used in Australia since the 1990s. Using a large multi-institutional cohort, we aimed to identify risk factors associated with reoperation or mortality following CAVSD repair. METHODS: Between January 1990 and December 2015, a total of 829 patients underwent biventricular surgical repair of CAVSD in Australia at 4 centres. Patients with associated tetralogy of Fallot and other conotruncal abnormalities were excluded. Demographic details, postoperative outcomes including reoperation and survival, and associated risk factors were analysed. RESULTS: Fifty-six patients (6.8%) required early reoperation (≤30 days) for significant left atrioventricular valve regurgitation or residual septal defects. Freedom from reoperation at 10, 15 and 20 years was 82.7%, 81.1% and 77%, respectively. Patients without Down syndrome and moderate left atrioventricular valve regurgitation on postoperative echocardiogram were found to be independent risk factors for reoperation. Operative mortality was 3.3%. Overall survival at 10, 15 and 20 years was 91.7%, 90.7% and 88.7%, respectively. Prior pulmonary artery banding was a predictor for mortality, while later surgical era (2010-2015) was associated with a reduction in mortality risk. CONCLUSIONS: Improved survival in the contemporary era is in keeping with improvements in surgical management and higher rates of primary CAVSD repair over time. The presence of residual moderate left atrioventricular valve regurgitation on postoperative echocardiography is an important factor associated with reoperation and close surveillance is essential to allow timely reintervention. Primary CAVSD repair at age <3 months should be preferenced to palliation with pulmonary artery banding due to the association of pulmonary artery banding with mortality in the long-term.

Modified pulmonary artery banding: A novel strategy for balancing pulmonary blood flow with transposed great arteries.

OBJECTIVE: To study the outcomes of a novel modified pulmonary artery banding (mPAB) technique used for staged repair of a subset of patients with complex transposition physiology. METHODS: A total of 13 patients who underwent mPAB during their staged repair (biventricular repair [BVR], n = 6) or palliation (1-1/2 repair, n = 1; univentricular repair [UVR], n = 6) from 2004 to 2020 were studied retrospectively. A restrictive interposition graft was used to reconstruct the main PA between the pulmonary root and the distal pulmonary confluence, functioning as a mPAB. Twelve of the 13 patients (92.3%) underwent a concurrent arterial switch operation (ASO), of which 6 were palliative ASOs for 1-1/2 repair (n = 1) or UVR (n = 5). Patient weight and cardiac anatomy determined the size of interposition graft. RESULTS: The disease spectrum included dextro transposition of the great arteries (d-TGA) with multiple ventricular septal defects (VSDs) (n = 4), Taussig-Bing anomaly (n = 3), d-TGA with VSD and hypoplastic right ventricle (RV) (n = 3), double-inlet left ventricle with l-TGA (n = 2), and congenitally corrected TGA with double-outlet RV (n = 1). The Lecompte procedure was performed in 10 patients. Predischarge echocardiography revealed a band gradient of 61 mm Hg (interquartile range [IQR], 40-90 mm Hg) for BVR/1-1/2 ventricular repair (n = 7) and 49 mm Hg (IQR, 37-61 mm Hg) for UVR (n = 6). Survival was 100% at a median follow-up of 3.7 years (IQR, 2.6-4.0 years). CONCLUSIONS: The mPAB technique is effective and reproducible for staged BVR or UVR for patients with TGA. It effectively regulates pulmonary blood flow, may reduce neopulmonary root distortion, and eliminates complications associated with band migration in standard PAB.

Collection and processing of whole blood for transformation of peripheral blood mononuclear cells and extraction of DNA: the Type 1 Diabetes Genetics Consortium.

BACKGROUND: and PURPOSE: To yield large amounts of DNA for many genotype analyses and to provide a renewable source of DNA, the Type 1 Diabetes Genetics Consortium (T1DGC) harvested DNA and peripheral blood mononuclear cells (PBMCs) from individuals with type 1 diabetes and their family members in several regions of the world. METHODS: DNA repositories were established in Asia-Pacific, Europe, North America, and the United Kingdom. To address region-specific needs, different methods and sample processing techniques were used among the laboratories to extract and to quantify DNA and to establish Epstein-Barr virus transformed cell lines. RESULTS: More than 98% of the samples of PBMCs were successfully transformed. Approximately 20-25 microg of DNA were extracted per mL of whole blood. Extraction of DNA from the cell pack ranged from 92 to 165 microg per cell pack. In addition, the extracted DNA from whole blood or transformed cells was successfully utilized in each regional human leukocyte antigen genotyping laboratory and by several additional laboratories performing consortium-wide genotyping projects. LIMITATIONS: Although the isolation of PBMCs was consistent among sites, the measurement of DNA was difficult to harmonize. CONCLUSIONS: DNA repositories can be established in different regions of the world and produce similar amounts of high-quality DNA for a variety of high-throughput genotyping techniques. Furthermore, even with the distances and time necessary for transportation, highly efficient transformation of PBMCs is possible. For future studies/trials involving several laboratories in different locations, the T1DGC experience includes examples of protocols that may be applicable. In summary, T1DGC has developed protocols that would be of interest to any scientific organization attempting to overcome the logistical problems associated with studies/trials spanning multiple research facilities, located in different regions of the world.

Complete atrioventricular septal defect repair in Australia: Results over 25 years.

OBJECTIVES: To evaluate whether the long-term outcomes of modified-single-patch (MSP) repair of complete atrioventricular septal defect are equivalent to double-patch (DP) repair with respect to survival and risk of reoperation for left atrioventricular valve regurgitation or left ventricular outflow tract obstruction. METHODS: All patients who underwent biventricular repair of complete atrioventricular septal defect in Australia from 1990 to 2015 using either a MSP or DP technique were identified. Demographic characteristic details, operative data, and outcomes were analyzed. A propensity score analysis was performed to balance the 2 treatment groups according to several baseline covariates. Survival and freedom from reintervention between the 2 groups were compared using Kaplan-Meier curves and log-rank tests. RESULTS: A total of 819 patients underwent repair of complete atrioventricular septal defect (252 MSP and 567 DP) during the study period. There was no significant difference in unmatched survival (P = .85) and event-free survival (P = .49) between MSP and DP repair. Propensity score matching resulted in a total of 223 matched pairs. Matched analysis found no difference in overall survival (P = .59) or event-free survival (P = .90) between repair techniques, with an estimated event-free survival at 5, 10, and 15 years of 83%, 83%, and 74% for DP and 83%, 80%, and 77% for the MSP group, respectively. There was no significant difference between repair techniques in reoperation for left atrioventricular valve regurgitation or left ventricular outflow tract obstruction or need for permanent pacemaker. CONCLUSIONS: Overall and event free survival are similar following either MSP or DP repair of complete atrioventricular septal defect. There is no increased risk of reoperation for left ventricular outflow tract obstruction with the MSP technique.

Patient-Specific Approach to Mitral Valve Replacement in Infants Weighing 10 kilograms or less.

BACKGROUND: Mitral valve replacement (MVR) is the only option for infants with severe mitral valve disease that is not reparable; however, previously reported outcomes are not always favorable. Our institution has followed a tailored approach to sizing and positioning of mechanical valve prostheses in infants requiring MVR in order to obtain optimal outcomes. METHODS: Outcomes for 22 infants ≤10 kg who have undergone MVR in Sydney, Australia, from 1998 to 2016, were analyzed. Patients were at a mean age of 6.8 ± 4.1 months (range: 0.8-13.2 months) and a mean weight of 5.4 ± 1.8 kg at the time of MVR. Most patients (81.8%) had undergone at least one previous cardiac surgical procedure prior to MVR, and 36.4% had undergone two previous procedures. Several surgical techniques were used to implant mechanical bileaflet prostheses. RESULTS: All patients received bileaflet mechanical prostheses, with 12 receiving mitral prostheses and 10 receiving inverted aortic prostheses. Surgical technique varied between patients with valves implanted intra-annularly (n = 6), supra-annularly (n = 11), or supra-annularly with a tilt (n = 5). After a mean follow-up period of 6.2 ± 4.4 years, the survival rate was 100%. Six (27.3%) patients underwent redo MVR a mean of 102.2 ± 10.7 months after initial MVR. Four (18.2%) patients required surgical reintervention for development of left ventricular outflow tract obstruction and three (13.6%) patients required permanent pacemaker placement during long-term follow-up. CONCLUSIONS: The tailored surgical strategy utilized for MVR in infants at our institution has resulted in reliable valve function and excellent survival. Although redo is inevitable due to somatic growth, the bileaflet mechanical prostheses used displayed appropriate durability.

Impact of High-Risk Characteristics in Hypoplastic Left Heart Syndrome.

BACKGROUND: Management of hypoplastic left heart syndrome (HLHS) presents many challenges. We describe our institutional outcomes for management of patients with HLHS over the past 12 years and highlight our strategy for those with highly restrictive/intact interatrial septum (R/I-IAS). METHODS: Eighty-eight neonates with HLHS underwent surgical treatment, divided equally into Era-I (n = 44, April 2006 to February 2013) and Era-II (n = 44, March 2013 to June 2018). Up to 2013, all patients with R/I-IAS were delivered at an adjacent adult hospital and then moved to our hospital for intensive care and management. From 2014, these patients were delivered at a co-located theatre in our hospital with immediate atrial septectomy. The hybrid approach was occasionally used with preference for the Norwood procedure for suitable candidates. RESULTS: One-year survival after Norwood procedure was 62.5% and 80% for Era-I and Era-II (P = not significant (ns)), respectively, and 41% of patients were categorized as high risk using conventional criteria. Survival at 1 year differed significantly between high-risk and standard-risk patients (P = 0.01). For high-risk patients, survival increased from 42% to 65% between eras (P = ns). In the R/I-IAS subgroup (n = 15), 11 underwent Norwood procedure after emergency atrial septectomy. Of these, seven born at the adjacent adult hospital had 40% survival to stage II versus 60% for the four born at the colocated theatre. Delivery in a colocated theatre reduced the birth-to-cardiopulmonary bypass median time from 445 (150-660) to 62 (52-71) minutes. CONCLUSION: Reported surgical outcomes are comparable to multicenter reports and international databases. Proactive management for risk factors such as R/I-IAS may contribute to improved overall outcomes.

Evaluation of the extracardiac conduit modification of the Fontan operation for thrombus formation using magnetic resonance imaging.

BACKGROUND: The prevalence of thrombosis after the Fontan procedure depends upon the surgical technique used and the method of detection employed. Current investigations for thrombosis lack sensitivity and specificity or, in the paediatric population, require a general anaesthetic. We undertook a study to examine the feasibility of using magnetic resonance imaging (MRI) to detect thrombosis within the conduit, cardiac chambers and pulmonary arteries after the extracardiac conduit modification of the Fontan procedure. METHODS: Of the 50 children who had undergone this procedure at our institution between 1997 and 2002, 26 were eligible for, and 13 underwent, MRI study. The mean age was 10.2 years (range 8.2-16.8 years, median 9.5 years) and the average time from operation was 63 months (range 29-79 months, median 68 months). The mean age at Fontan operation was 4.9 years (range 2.1-10.5 years). Ten were on low dose aspirin, two were on warfarin and one was not anti-coagulated. In all cases, satisfactory imaging of the venous pathways and pulmonary arteries was obtained and there were no thrombi detected. CONCLUSIONS: We conclude that MRI is a potentially useful tool for the detection of thrombus in patients who have undergone the Fontan operation.

Congenitally corrected transposition: complex anatomic repair or Fontan pathway?

Background Successful anatomic repair of congenitally corrected transposition of the great arteries achieves excellent outcomes. Several centers report excellent long-term survival with the Fontan pathway as well. We have selectively applied both approaches depending on individual patient morphology, with anatomic repair preferred but utilizing the Fontan pathway when high technical complexity or operative risk is anticipated. Methods Hospital records over an 18-year period (1998-2016) were reviewed to identify patients with congenitally corrected transposition of the great arteries who underwent surgical management. Physiological repairs and hypoplastic ventricles were excluded. Patient- and procedure-related variables were reviewed. Results We identified 19 patients. Group 1 consisted of 12 anatomic repairs, of which 10 (83.3%) required prior interim staging procedures. Mean age at anatomic repair was 2.6 ± 1.3 years, mean follow-up was 8.7 ± 5.3 years. Nine (75%) patients experienced important complications and 4 (33.3%) required reintervention during follow-up. There were no deaths; one patient required heart transplantation. Group 2 (7 patients) underwent Fontan palliation. Mean age at Fontan completion was 7.2 ± 3.8 years, mean follow-up was 6.3 ± 4 years. There was no reintervention, death, or transplant. Conclusion Patients with congenitally corrected transposition of the great arteries and two adequate-sized ventricles do well with both anatomic repair and the Fontan pathway in the medium term. Excellent outcomes with reduced early complication and reintervention rates can be achieved for this cohort of patients when a strategy of avoiding complex anatomic repair in favor of the Fontan pathway is used.

Characterisation of the protein composition of peripheral blood mononuclear cell microsomes by SDS-PAGE and mass spectrometry.

Approximately 340 leucocyte plasma membrane proteins have been characterised by the eight Human Leucocyte Differentiation Antigen workshops held between 1982 and 2004, based primarily on their reactivity with monoclonal antibodies. The human genome is predicted to encode approximately 34,000 cDNA transcripts, of which between 15% and 20% are predicted to contain one or more transmembrane helices. We have used SDS-PAGE separation coupled with mass spectrometry-based peptide mass tag identification to identify novel plasma membrane proteins in microsome preparations prepared from mononuclear cells obtained from human peripheral blood. A total of 361 distinct proteins were identified in a single preparation, including 37 known leucocyte plasma membrane proteins, 27 potential novel plasma membrane proteins whose expression on PBMC is poorly characterised, and 51 other proteins for which the subcellular location could not be determined. Expression analysis using cDNA panels indicates that several of these novel plasma membrane proteins are differentially expressed in lymphocyte subsets. These results show that previously unidentified lymphocyte plasma membrane proteins can be identified using this approach.

Comparison of bipolar and unipolar radiofrequency ablation in an in vivo experimental model.

OBJECTIVE: Linear atrial radiofrequency lesions have been used effectively for the treatment of atrial fibrillation. In most cases an endocardial approach has been suggested. A method for epicardial placement of lesions would reduce the complexity of these procedures. We compared lesions created in ovine hearts in vivo using irrigated bipolar or unipolar handheld radiofrequency ablation devices. METHODS: Radiofrequency lesions were produced around a left pulmonary vein, around the left atrial appendage and in the free wall of the right ventricle in ovine hearts. All lesions were created in the beating heart. A bipolar clamping device (n = 7) or a handheld unipolar device (n = 6) was used. Measurements of local electrograms and pacing thresholds were performed before and after ablation at each site to assess the electrical integrity of lesions. Tetrazolium and digital image analysis were used to assess lesion geometry. RESULTS: In atrial tissue continuous transmural lesions were achieved more often with the bipolar than with the unipolar device (92.3 vs. 33.3%, P < 0.02). In atrial tissue the reduction in signal amplitude caused by the lesions was significantly larger with the bipolar than the unipolar device (87.6+/-9.4% vs. 60.6+/-23.7% reduction, P < 0.01). There was a significant relationship between loss of pacing capture and lesion transmurality (P < 0.05). The bipolar device created narrower lesions than the unipolar device (4.1+/-0.9 mm vs. 5.9+/-2.1 mm, P < 0.001). CONCLUSIONS: The bipolar clamping device produces narrower lesions which are more likely to be transmural and lead to electrical isolation of ablated tissue than those produced by the unipolar device. However, both devices failed to consistently produce transmural lesions using the epicardial beating heart technique studied, particularly in thicker tissues. High output pacing within the ablated tissue partially predicts lesion transmurality and be a guide to the need for further ablation. However, endocardial ablation or transmural bipolar ablation are likely to remain the techniques of choice for linear radiofrequency ablation in the atria until improved techniques are developed.