A spatial human thymus cell atlas mapped to a continuous tissue axis

T cells develop from circulating precursors, which enter the thymus and migrate throughout specialised sub-compartments to support maturation and selection. This process starts already in early fetal development and is highly active until the involution of the thymus in adolescence. To map the micro-anatomical underpinnings of this process in pre- vs. post-natal states, we undertook a spatially resolved analysis and established a new quantitative morphological framework for the thymus, the Cortico-Medullary Axis. Using this axis in conjunction with the curation of a multimodal single-cell, spatial transcriptomics and high-resolution multiplex imaging atlas, we show that canonical thymocyte trajectories and thymic epithelial cells are highly organised and fully established by post-conception week 12, pinpoint TEC progenitor states, find that TEC subsets and peripheral tissue genes are associated with Hassall's Corpuscles and uncover divergence in the pace and drivers of medullary entry between CD4 vs. CD8 T cell lineages. These findings are complemented with a holistic toolkit for spatial analysis and annotation, providing a basis for a detailed understanding of T lymphocyte development.

A novel approach to stenting a stenotic graft housing a Berlin Heart cannula by utilizing an adapted left ventricular assist device circuit

BACKGROUND

A 9-year-old boy with Berlin Heart biventricular assist device for diagnosis of dilated cardiomyopathy developed progressive reduction in left ventricular assist device(VAD) emptying and evidence of low cardiac output despite alterations to the device settings. Computed tomography revealed that the Dacron graft attaching the systemic cannula to the ascending aorta was stenosed.

METHOD & RESULT

A minimally invasive approach with novel circuit modification was used to achieve antegrade stenting of the stenosed graft.

CONCLUSION

This proposed technique provides a large port for minimally invasive access via an adapted VAD circuit allowing stent insertion to the aortic graft with an excellent outcome.

Gender differences in the assessment, decision making and outcomes for ventricular assist devices and heart transplantation: An analysis from a UK transplant centre

PURPOSE

There are marked gender differences in all aetiologies of advanced heart failure. We sought to determine whether there is evidence of gender-specific decision making for transplant assessments, and how gender effects outcomes.

METHODS

Retrospective analysis of adult heart transplant assessments at a single UK centre between April 2015 and March 2020.

RESULTS

Females were 32% of referrals (N = 137 females, 285 males), with marked differences between diagnoses - 11% ischaemics and 43% of adult congenital. Females were younger, shorter, weighed less, and had lower pulmonary pressures. Females were much less likely to receive a ventricular assist device (13%). Blood type 'O' females were relatively more likely compared to males to receive a transplant (45%). Comparing males and females who received a ventricular assist device, both had similar levels of high pulmonary pressures, indicating consistent decision making based on haemodynamics to implant a device. Overall survival was better for females (in non congenital patients), and this was due to female patients who were not accepted for transplant or a ventricular assist device being more often 'too well for transplant', rather than in males when they were more often 'unsuitable'.

CONCLUSIONS

Marked gender differences exist at all stages of the heart transplant assessment pathway. Appropriate decision making based on clinical grounds is shown with less transplants in male blood type 'O's and haemodynamic criteria for ventricular assist device implantation in both genders. Further studies are need to determine if there is a wider community bias in advanced heart failure treatments for females. This article is protected by copyright. All rights reserved.

Ventricular assist devices in transposition and failing systemic right ventricle: role of tricuspid valve replacement

OBJECTIVES

Ventricular assist device (VAD) for systemic right ventricular (RV) failure patients post-atrial switch, for transposition of the great arteries (TGA), and those with congenitally corrected TGA has proven useful to reduce transpulmonary gradient and bridge-to-transplantation. The purpose of this study is to describe our experience of VAD in systemic RV failure and our move towards concomitant tricuspid valve replacement (TVR).

METHODS

This is a single-centre retrospective study of consecutive adult patients receiving HeartWare VAD for systemic RV failure between 2010 and 2019. From 2017, concomitant TVR was performed routinely. Demographic, clinical variables and echocardiographic and haemodynamic measurements pre- and post-VAD implantation were recorded. Complications on support, heart transplantation and survival rates were described.

RESULTS

Eighteen patients underwent VAD implantation. Moderate or severe systemic tricuspid regurgitation was present in 83.3% of patients, and subpulmonic left ventricular impairment in 88.9%. One-year survival was 72.2%. VAD implantation was technically feasible and successful in all but one. Post-VAD, transpulmonary gradient fell from 16 (15-22) to 10 (7-13) mmHg (P = 0.01). Patients with TVR (n = 6) also demonstrated a reduction in mean pulmonary and wedge pressures. Furthermore, subpulmonic left ventricular end-diastolic dimension (44.3 vs 39.6 mm; P = 0.03) and function improved in this group. After 1 year of support, 72.2% of patients were suitable for transplantation.

CONCLUSIONS

VAD is an effective strategy as bridge-to-candidacy and bridge-to-transplantation in patients with end-stage systemic RV failure. Concomitant TVR at the time of implant is associated with better early haemodynamic and echocardiographic results post-VAD.

Contemporary Ross procedure outcomes: medium- to long-term results in 214 patients

OBJECTIVE

Our goal was to present 2 decades of our experience with the Ross procedure and its sequential modifications, adopted since 2010, to improve the reoperation rate.

METHODS

We performed a single-centre, retrospective review of database information and medical notes about the implantation technique: the freestanding root. We compared era 1 (1997-2009) and era 2 (2010-2019).

RESULTS

Between 1997 and 2019, a total of 214 Ross procedures were performed (71% men, median age 24 years) [interquartile range (IQR) 15-38]. Of these, 87% had various forms of congenital-dysplastic aortic valves. The median cross-clamping and bypass times were 173 (IQR 148-202) and 202 (IQR 182-244) min. The median postoperative stay was 6 days (2-77). Thirty-day mortality was 0.5%. The median follow-up time was 8.2 years (IQR 3.9-13.2). Survival at 10 and 20 years was 97% and 95%; freedom from greater than moderate aortic regurgitation or aortic valve intervention was 91% and 80%; and 93% of the patients were in New York Heart Association functional class I. Twenty (21%) patients operated on during era 1 and 6 (9%) during era 2 underwent autograft reoperations. The median follow-up time was 14.3 (IQR 11.5-17.4) and 4.8 (IQR 2.5-7) years. Freedom from autograft reoperation was 87% and 69% at 10 and 20 years, with no significant difference between eras. Freedom from homograft reoperation was 96% and 76% at 10 and 20 years. The presence of aortic regurgitation, infective endocarditis and era 1 were predictors of autograft reoperation. Male gender and era 1 were predictors of neoaortic root dilatation.

CONCLUSIONS

The contemporary modified Ross procedure continues to deliver excellent results and should remain part of the strategy to treat children and young adults requiring aortic valve replacement.

A cell atlas of human thymic development defines T cell repertoire formation

The thymus provides a nurturing environment for the differentiation and selection of T cells, a process orchestrated by their interaction with multiple thymic cell types. We used single-cell RNA sequencing to create a cell census of the human thymus across the life span and to reconstruct T cell differentiation trajectories and T cell receptor (TCR) recombination kinetics. Using this approach, we identified and located in situ CD8αα⁺ T cell populations, thymic fibroblast subtypes, and activated dendritic cell states. In addition, we reveal a bias in TCR recombination and selection, which is attributed to genomic position and the kinetics of lineage commitment. Taken together, our data provide a comprehensive atlas of the human thymus across the life span with new insights into human T cell development.

Pigs in a blanket: an unusual presentation of malignant ascites in prostatic adenocarcinoma

Malignant ascites in prostatic acinar adenocarcinoma is very rare. We present an 84-year-old man with a rare malignant ascites due to prostatic adenocarcinoma demonstrating hepatoid differentiation by immunohistochemistry. The patient was diagnosed with the malignant ascites due to metastatic prostatic adenocarcinoma. We identified the unique cytological feature of envelopment of tumour cell clusters by benign mesothelial monolayers.

Duct Stenting Versus Modified Blalock-Taussig Shunt in Neonates With Duct-Dependent Pulmonary Blood Flow

Background:

Infants born with cardiac abnormalities causing dependence on the arterial duct for pulmonary blood flow are often palliated with a shunt usually between the subclavian artery and either pulmonary artery. A so-called modified Blalock-Taussig shunt allows progress through early life to an age and weight at which repair or further more stable palliation can be safely achieved. Modified Blalock-Taussig shunts continue to present concern for postprocedural instability and early mortality such that other alternatives continue to be explored. Duct stenting (DS) is emerging as one such alternative with potential for greater early stability and improved survival.

Methods:

The purpose of this study was to compare postprocedural outcomes and survival to next-stage palliative or reparative surgery between patients undergoing a modified Blalock-Taussig shunt or a DS in infants with duct-dependent pulmonary blood flow. All patients undergoing cardiac surgery and congenital interventions in the United Kingdom are prospectively recruited to an externally validated national outcome audit. From this audit, participating UK centers identified infants <30 days of age undergoing either a Blalock-Taussig shunt or a DS for cardiac conditions with duct-dependent pulmonary blood flow between January 2012 and December 31, 2015. One hundred seventy-one patients underwent a modified Blalock-Taussig shunt, and in 83 patients, DS was attempted. Primary and secondary outcomes of survival and need for extracorporeal support were analyzed with multivariable logistic regression. Longer-term mortality before repair and reintervention were analyzed with Cox proportional hazards regression. All multivariable analyses accommodated a propensity score to balance patient characteristics between the groups.

Results:

There was an early (to discharge) survival advantage for infants before next-stage surgery in the DS group (odds ratio, 4.24; 95% confidence interval, 1.37–13.14; P =0.012). There was also a difference in the need for postprocedural extracorporeal support in favor of the DS group (odds ratio, 0.22; 95% confidence interval, 0.05–1.05; P =0.058). Longer-term survival outcomes showed a reduced risk of death before repair in the DS group (hazard ratio, 0.25; 95% confidence interval, 0.07–0.85; P =0.026) but a slightly increased risk of reintervention (hazard ratio, 1.50; 95% confidence interval, 0.85–2.64; P =0.165).

Conclusions:

DS is emerging as a preferred alternative to a surgical shunt for neonatal palliation with evidence for greater postprocedural stability and improved patient survival to destination surgical treatment.

Combined heart-liver transplantation for failing Fontan circulation in a late survivor with single-ventricle physiology

Management of adults with failing Fontan physiology poses many challenges, especially as transplantation offers the only realistic alternative to palliative care. We present the first combined heart and liver transplant performed in Europe, for a late survivor of single ventricle palliation with the Fontan circulation. In addition to the conventional medical and surgical challenges posed, we highlight the management of the associated multi-organ failure with focus on the liver and novel strategies for assessment and optimization.

Outcome after transcatheter occlusion of patent ductus arteriosus in infants less than 6 kg: A national study from United Kingdom and Ireland

OBJECTIVES

This study aimed to report our national experience with transcatheter patent ductus arteriosus (PDA) occlusion in infants weighing <6 kg.

BACKGROUND

The technique of transcatheter PDA closure has evolved in the past two decades and is increasingly used in smaller patients but data on safety and efficacy are limited.

METHODS

Patients weighing < 6 kg in whom transcatheter PDA occlusion was attempted in 13 tertiary paediatric cardiology units in the United Kingdom and Ireland were retrospectively analyzed to review the outcome and complications.

RESULTS

A total of 408 patients underwent attempted transcatheter PDA closure between January 2004 and December 2014. The mean weight at catheterization was 4.9 ± 1.0 kg and mean age was 5.7 ± 3.0 months. Successful device implantation was achieved in 374 (92%) patients without major complication and of these, complete occlusion was achieved in 356 (95%) patients at last available follow-up. Device embolization occurred in 20 cases (5%). The incidence of device related obstruction to the left pulmonary artery or aorta and access related peripheral vascular injury were low. There were no deaths related to the procedure.

CONCLUSIONS

Transcatheter closure of PDA can be accomplished in selected infants weighing <6 kg despite the manufacturer's recommended weight limit of 6 kg for most ductal occluders. The embolization rate is higher than previously reported in larger patients. Retrievability of the occluder and duct morphology needs careful consideration before deciding whether surgical ligation or transcatheter therapy is the better treatment option.

An Extended Role of Continuous Flow Device in Pediatric Mechanical Circulatory Support

BACKGROUND

Mechanical circulatory support in the pediatric population is currently limited to pulsatile ventricular assist devices (VAD). In recent years, the use of durable, newer generation, continuous flow devices have increased substantially among adults with end-stage heart failure. We examined the extended role of this device in the pediatric population (aged less than 18 years).

METHODS

Between 2010 and 2015, 12 patients (median age 7.1 years; range, 3.7 to 17.0; one third of patients were aged 5 years or less) received a HeartWare ventricular assist device (HVAD; HeartWare, Framingham, MA), 11 for cardiomyopathy and 1 for posttransplant rejection. Right VAD support (n = 5; 42%) was provided by a short-term device (Levitronix, Zurich, Switzerland).

RESULTS

Overall, 1 patient died (day 638), 8 patients (67%) underwent transplantation, 1 patient (8.3%) recovered, and 2 patients (17%) remain on HVAD. The mean length of support was 150 days (range, 16 to 638). Four patients (33.3%) were discharged home (all left VAD). In the left VAD group (n = 7), 3 patients subsequently received transplants (days 185, 201, and 234, respectively), 1 recovered (day 149), 1 died (day 638), 1 remained on HVAD (day 198), and 1 needed conversion to biventricular assist device (BIVAD [day 73]). In the BIVAD group (n = 5), right VAD was weaned in 3 (60%), all subsequently received transplants, and 2 remained on BIVAD support until transplant (days 16 and 17, respectively). One BIVAD patient required conversion to central cannulation for longer-term support. Four BIVAD patients (80%) were in Interagency Registry for Mechanically Assisted Circulatory Support level 1 before VAD compared with 2 (29%) in the left VAD group (p = not significant). The actuarial survival rate was 100% at 1 year with no neurologic events.

CONCLUSIONS

The third-generation, continuous flow device can provide durable support in the pediatric population. The selection strategy for patients who benefit most from the device continues to evolve. It is anticipated that a smaller design in the future will benefit an even wider pediatric population with heart failure.

Management of the failing Fontan

With and increasing number of early survivors after the palliation of the single ventricle physiology there is a burgeoning Fontan population worldwide that will pose unique challenges because of the inevitable sequelae related to the absence of the alleged "needless" sub-pulmonic ventricle. The increasing number and older-age single-ventricle patients highlights the results of successful contemporary surgical palliation in children, leading to the development of an adult single-ventricle population with unpredictable socio-economic and health service impacts. The wide variability in clinical status of patients with Fontan circulation reflects not only the broadened spectrum of morphological substrates involved, but also the evolving surgical techniques during the last four decades. This has come in the wake of a gradual understanding of an incredibly tricky physiology. The magnitude of the disease, the physio-pathological mechanisms, and the therapeutic options to optimize the "failing Fontan" status and to delay the irreversible deterioration of "Fontan failure" condition are discussed in this review.

Patent foramen ovale closure with the Gore septal occluder: initial UK experience

OBJECTIVES

To report procedural outcome and short-term follow-up data for the Gore septal occluder (GSO), a new device for closure of patent foramen ovale (PFO).

BACKGROUND

Transcatheter closure of PFO is an established treatment modality but no current device provides a perfect solution. The GSO has a number of design features, which make it potentially attractive for closure of defects in the atrial septum.

METHODS

Data from 9 centers in the United Kingdom implanting the GSO device, submitted to an electronic registry for evaluation.

RESULTS

Two hundred twenty-nine patients undergoing PFO closure from June 2011 to October 2012 were included. Indications for closure were secondary prevention of paradoxical cerebral emboli (83.4%), migraine (2.1%), platypnoea orthodeoxia (3.9%), and other (10.5%). Median PFO size was 8 mm and 34 and 39%, respectively, had long tunnel anatomy or atrial septal aneurysms. A GSO was successfully implanted in all cases. A single device was used in 98% but in 4 patients the initial device was removed and a second device required. Procedural complications occurred in 3% and later complications (e.g., atrial fibrillation, atrial ectopics, and device thrombus) in 5.7% of cases. All patients have undergone clinical and echocardiographic follow-up and all devices remain in position. Early bubble studies (median 0 months) with Valsalva maneuver in 67.2% were negative in 89%.

CONCLUSIONS

The GSO is an effective occlusion device for closure of PFO of all types. Longer-term follow-up particularly to document later closure rates are required.

Tetralogy of Fallot With Absent Pulmonary Valve Syndrome, Right Aortic Arch, and Disconnected Left Pulmonary Artery

We present a rare case of a two-week-old infant with tetralogy of Fallot , absent pulmonary valve syndrome , right aortic arch, and disconnected left pulmonary artery (LPA) whose origin was from ductal ligament adjacent to the left subclavian artery. One-stage surgical correction, including closure of ventricular septal defect (VSD), LPA reconstruction and reconnection to the pulmonary trunk, reduction in size of the right pulmonary artery (RPA), and right ventricular outflow tract reconstruction with valved conduit, was successfully performed with good clinical mid-term outcome.

A novel approach to paraneoplastic intestinal pseudo-obstruction

Paraneoplastic neurologic syndromes (PNS) are uncommon, affecting fewer than 1 in 10,000 patients with cancer. PNS, while rare, can cause significant morbidity and impose enormous socio-economic costs, besides severely affecting quality of life. PNS can involve any part of the nervous system and can present as limbic encephalitis, subacute cerebellar ataxias, opsoclonus-myoclonus, retinopathies, chronic intestinal pseudo-obstruction (CIPO), sensory neuronopathy, Lambert-Eaton myasthenic syndrome, stiff-person syndrome, and encephalomyelitis. The standard of care for CIPO includes the use of promotility and anti-secretory agents and the resection of the non-functioning gut segment; all of which can cause significant compromise in the quality of life. There is significant evidence that paraneoplastic neurologic syndromes are associated with antibodies directed against certain nerve antigens. We successfully treated a patient with CIPO in the setting of small cell lung cancer with a combination of rituximab and cyclophosphamide. The patient, who had failed to respond to prokinetic agents, anti-secretory therapy, and multiple resections, responded to the immunomodulatory therapy, with minimal residuals with PEG tube feeding and sustained ostomy output. The use of rituximab and cyclophosphamide should therefore be considered in patients with CIPO, especially if it can avoid complicated surgical procedures.