Survival analysis for pediatric heart transplant patients using a novel machine learning algorithm: A UNOS analysis

BACKGROUND

Impact of pretransplantation risk factors on mortality in the first year after heart transplantation remains largely unknown. Using machine learning algorithms, we selected clinically relevant identifiers that could predict 1-year mortality after pediatric heart transplantation.

METHODS

Data were obtained from the United Network for Organ Sharing Database for years 2010-2020 for patients 0-17 years receiving their first heart transplant (N = 4150). Features were selected using subject experts and literature review. Scikit-Learn, Scikit-Survival, and Tensorflow were used. A train:test split of 70:30 was used. N-repeated k-fold validation was performed (N = 5, k = 5). Seven models were tested, Hyperparameter tuning performed using Bayesian optimization and the concordance index (C-index) was used for model assessment.

RESULTS

A C-index above 0.6 for test data was considered acceptable for survival analysis models. C-indices obtained were 0.60 (Cox proportional hazards), 0.61 (Cox with elastic net), 0.64 (gradient boosting), 0.64 (support vector machine), 0.68 (random forest), 0.66 (component gradient boosting), and 0.54 (survival trees). Machine learning models show an improvement over the traditional Cox proportional hazards model, with random forest performing the best on the test set. Analysis of the feature importance for the gradient boosted model found that the top 5 features were the most recent serum total bilirubin, the travel distance from the transplant center, the patient body mass index, the deceased donor terminal Serum glutamic pyruvic transaminase/Alanine transaminase (SGPT/ALT), and the donor PCO2.

CONCLUSIONS

Combination of machine learning and expert-based methodology of selecting predictors of survival for pediatric heart transplantation provides a reasonable prediction of 1- and 3-year survival outcomes. SHapley Additive exPlanations can be an effective tool for modeling and visualizing nonlinear interactions.

Basiliximab therapy for immune-mediated bowel disease in a pediatric heart transplant patient

In pediatric patients who undergo heart transplantation, severe immune-mediated bowel disease has been reported. Management is complex, and there are little data discussing the use of basiliximab for immune-mediated bowel disease. This case report discusses a pediatric patient who developed immune-mediated bowel disease following heart transplantation and was successfully managed with basiliximab.

Relieving bronchial compression due to cardiomegaly: The role of aortopexy when left ventricular assist device support just is not enough

Enlarged cardiac structures, especially those on left side have the potential to cause airway compression in pediatric patients with chronic heart failure, owing to their proximity to and impact on the trachea-bronchial tree. Ventricular assist devices are effective in decompressing such hearts thereby alleviating airway problems. Aortopexy serves as an effective airway decompressive measure in cases with persistent airway compression despite effective cardiac decompression by ventricular assist devices. We report a case of 1-year-old male patient with dilated cardiomyopathy in whom airway compression persisted despite ventricular assist device implantation. Aortopexy was effective in relieving airway compression allowing for subsequent extubation and successful heart transplantation.

Low descending aorta flow is associated with adverse feeding outcomes in neonates with small left-sided structures

Feeding intolerance and necrotizing enterocolitis (NEC) cause significant morbidity in neonates with duct-dependent systemic circulations. Whether these complications are associated with low blood flow to the bowel is unproven. The aim of this study was to determine whether low descending aortic (DAO) flow is associated with adverse feeding outcomes in neonates with small left-sided structures, including borderline left ventricle and hypoplastic left heart syndrome (HLHS). The cardiac magnetic resonance (CMR) imaging studies and abdominal Doppler ultrasound profiles prior to any cardiac interventions in neonates with small left-sided structures were analyzed. Descending aortic flows, indexed to body surface area, were collected. Medical charts were reviewed for a composite outcome of feeding intolerance and/or NEC. Among the 51 enrolled study patients (mean age 4.6, SD 4.5 days), 13 experienced the composite outcome (feeding intolerance in 13, NEC in 2). The mean DAO flow in patients who experienced the composite outcome was 0.89 L/min/m² (SD 0.33 L/min/m²), compared to 1.23 L/min/m² (SD 0.41 L/min/m²) in those that did not (p = 0.007). A DAO flow of 0.91 L/min/m² identified patients who experienced feeding intolerance or NEC with a sensitivity of 61% and a specificity of 76%. Doppler ultrasound metrics of DAO flow did not correlate with DAO flow or predict adverse feeding outcomes. Low DAO flow is associated with adverse outcomes, including feeding intolerance and NEC, in neonates with small left-sided structures. Heightened clinical vigilance towards feeding complications in patients with low DAO flow is recommended.

Young-onset Alzheimer dementia: a comparison of Brazilian and Norwegian carers' experiences and needs for assistance

OBJECTIVES

Although dementia typically occurs in older people, it can also emerge in people aged younger than 65 years in the form of young-onset dementia, the most common type of which is Alzheimer's disease (AD). However, few studies have examined the needs of persons with young-onset AD (YO-AD) and their families, and cross-cultural research on the topic is even scarcer. In response, we investigated the situations, experiences and needs for assistance of carers of persons with YO-AD in Brazil and Norway.

METHODS

As part of our qualitative study, we formed a convenience sample of Brazilian (n = 9; 7 women) and Norwegian carers (n = 11; 6 women) in 2014 and 2015, respectively, and analysed data in light of a modified version of grounded theory.

RESULTS

Carers' narratives from both countries revealed five common themes in terms of how YO-AD affected carers' psychological and emotional well-being, physical well-being, professional and financial well-being, social lives and need for support services.

CONCLUSIONS

The infrequent differences between carers of persons with YO-AD in Brazil and Norway indicate that carers' problems are highly similar regardless of cultural differences and public services provided. Copyright © 2017 John Wiley & Sons, Ltd.

d-serine levels in Alzheimer's disease: implications for novel biomarker development

Alzheimer's disease (AD) is a severe neurodegenerative disorder still in search of effective methods of diagnosis. Altered levels of the NMDA receptor co-agonist, d-serine, have been associated with neurological disorders, including schizophrenia and epilepsy. However, whether d-serine levels are deregulated in AD remains elusive. Here, we first measured D-serine levels in post-mortem hippocampal and cortical samples from nondemented subjects (n=8) and AD patients (n=14). We next determined d-serine levels in experimental models of AD, including wild-type rats and mice that received intracerebroventricular injections of amyloid-β oligomers, and APP/PS1 transgenic mice. Finally, we assessed d-serine levels in the cerebrospinal fluid (CSF) of 21 patients with a diagnosis of probable AD, as compared with patients with normal pressure hydrocephalus (n=9), major depression (n=9) and healthy controls (n=10), and results were contrasted with CSF amyloid-β/tau AD biomarkers. d-serine levels were higher in the hippocampus and parietal cortex of AD patients than in control subjects. Levels of both d-serine and serine racemase, the enzyme responsible for d-serine production, were elevated in experimental models of AD. Significantly, d-serine levels were higher in the CSF of probable AD patients than in non-cognitively impaired subject groups. Combining d-serine levels to the amyloid/tau index remarkably increased the sensitivity and specificity of diagnosis of probable AD in our cohort. Our results show that increased brain and CSF d-serine levels are associated with AD. CSF d-serine levels discriminated between nondemented and AD patients in our cohort and might constitute a novel candidate biomarker for early AD diagnosis.

Reversal of adrenal suppression with ciclesonide

BACKGROUND

Adrenal suppression secondary to high-dose inhaled corticosteroid use has been reported in children.

METHODS

The authors report the use of ciclesonide to reverse adrenal suppression secondary to inhaled fluticasone use in four pediatric patients.

RESULTS

In these four children, hypothalamic-pituitary-adrenal axis function normalized after the patients were changed to ciclesonide, while good asthma control was maintained.

CONCLUSIONS

Ciclesonide should be considered for the reversal of adrenal suppression secondary to the use of fluticasone, and perhaps other older inhaled corticosteroids as well.

Anti-alpha-glucose-based glycan IgM antibodies predict relapse activity in multiple sclerosis after the first neurological event

Background

There is no specific serum-based biomarker for the diagnosis or prognosis of relapsing-remitting multiple sclerosis (RRMS).

Objective

We investigated whether levels of IgM antibodies to Glc(α1,4)Glc(α) (GAGA4) or to a panel of four glucose-based glycans could differentiate MS from other neurological diseases (OND) or predict risk of early relapse following first presentation (FP) of RRMS.

Methods

Retrospective analysis of 440 sera samples of three cohorts: A) FP-RRMS (n = 44), OND (n = 44); B) FP-RRMS (n = 167), OND (n = 85); and C) FP (n = 100). Anti-GAGA4 IgM levels were measured by enzyme immunoassay in cohort-A and cohort-B. Cohort-C IgM antibodies to glucosebased glycan panel were measured by immunofluorescence.

Results

FP-RRMS had higher levels of anti-GAGA4 IgM than OND patients (cohort-A, P = 0.01; cohort-B, P = 0.0001). Sensitivity and specificity were 27% and 97% for cohort-A; and 26% and 90% for cohort-B, respectively. In cohort-C, 58 patients experienced early relapse (<24 months), 31 had late relapse (≥24 months), and 11 did not experience second attack during follow-up. Kaplan– Meier curves demonstrated decrease in time to next relapse for patients positive for the antibody panel (P = 0.02, log rank).

Conclusions

Serum anti-GAGA4 IgM discerns FP-RRMS patients from OND patients. Higher levels of serum anti-α-glucose IgM in FP patients predict imminent early relapse.

[Alzheimer's disease and magnetic resonance spectroscopy of the hippocampus]

OBJECTIVE

Acquisition of data of magnetic resonance metabolite spectrum of the hippocampal formation (hippocampus-hc) in the elderly, normal and with Alzheimer's disease (AD).

METHOD

Subjects matched for age: a. normal sample (n=20), CDR=0, and b. AD sample (n=40), CDR 1 and 2.

TECHNIQUE

Signa Horizon LX-GE, 1.5T, 1H-MRS with automated software PROBE/SV, VOI: hc (right and left); single voxel (2x2x2cm); TR 1500ms/TE 50ms; PRESS; metabolites: N-acetylaspartate (Naa), choline (Cho), creatine (Cr), myo-inositol (mI).

RESULTS

The present data relate to the ratios of Naa, Cho and mI, with Cr taken as reference, and the mI/Naa ratio. The study showed reduction of Naa, increase of mI and of the mI/Naa ratio, and not consistent results for Cho. The results of the whole sample of AD patients compared to the pooled normal mean +/- sd were significant for Naa, mI and mI/Naa (p<0.01). Accuracy in relation to the individual values of both samples showed satisfactory levels of sensitivity, specificity and positive predictive value.

CONCLUSION

The present results can be used as a helpful tool to detect pathologic changes of the hippocampus in AD, and allowing greater accuracy and an earlier diagnosis of this disease.

Efficacy and safety of risperidone oral solution in agitation associated with dementia in the elderly

BACKGROUND

Behavioral and psychological symptoms in dementia (BPSD) contribute to caregiver burden and institutionalization of elderly. Neuroleptics are prescribed to control agitation. Side effects of typical neuroleptics are harmful, making atypical neuroleptics an indication.

OBJECTIVES

To evaluate efficacy and tolerability of risperidone oral solution (ROS) given once daily to demented elderly outpatients with BPSD (agitation).

METHOD

Patients (n=26), 76.35+/-8.63 years, Diagnostic and Statistical Manual of Mental Disorders 4th ed. (DSM-IV) criteria for dementia. RSO was given, starting dose of 0.25 mg and increments of 0.25 mg every week. Mini-Mental State Examination (MMSE) assessed cognitive status, Behavioral and Emotional Activities Manifested in Dementia (BEAM-D) and Clinical Global Impression (CGI) measured BPSD, Extrapiramidal Symptom Rating Scale (ESRS) evaluated extrapyramidal symptoms. Cardiovascular side effects were evaluated clinically.

RESULTS

There was a 26% reduction in agitation and no cardiovascular side effects in the range from 1.0 to 1.25 mg. Side effects were more prevalent above 2.5 mg.

CONCLUSION

Risperidone oral solution improved agitation with good tolerability from 0.5 to 1.25 mg. A single dose with increments of 0.25 mg may be more acceptable to patients and caregivers.

Acute hemodilution: its effect of hemodynamics and oxygen transport in anesthetized man

The effects of acute normovolemic hemodilution on hemodynamics, oxygen transport, tissue perfusion and blood volume were studied. The subjects were four patients undergoing total hip replacement with prebleeding and hemodilution under fluoroxene and nitrous oxide anesthesia. The hematocrit was reduced to 29% and 21% by bleeding in two steps with simultaneous infusion of plasmanate and lactated Ringer's solution. The major compensation was a rise in CO to 123% and 136%. Systemic oxygen transport (COX arterial O(2) content) was only slightly reduced and the arteriovenous oxygen difference decreased. Tissue perfusion remained excellent. Blood volume was slightly expanded. The procedure was well tolerated by this group of selected patients, and homologous blood utilization was markedly reduced.