Rapid desensitization through immunoadsorption during cardiopulmonary bypass. A novel method to facilitate human leukocyte antigen incompatible heart transplantation

BACKGROUND

Anti-human leukocyte antigen (HLA)-antibody production represents a major barrier to heart transplantation, limiting recipient compatibility with potential donors and increasing the risk of complications with poor waiting-list outcomes. Currently there is no consensus to when desensitization should take place, and through what mechanism, meaning that sensitized patients must wait for a compatible donor for many months, if not years. We aimed to determine if intraoperative immunoadsorption could provide a potential desensitization methodology.

METHODS

Anti-HLA antibody-containing whole blood was added to a Cardiopulmonary bypass (CPB) circuit set up to mimic a 20 kg patient undergoing heart transplantation. Plasma was separated and diverted to a standalone, secondary immunoadsorption system, with antibody-depleted plasma returned to the CPB circuit. Samples for anti-HLA antibody definition were taken at baseline, when combined with the CPB prime (on bypass), and then every 20 min for the duration of treatment (total 180 min).

RESULTS

A reduction in individual allele median fluorescence intensity (MFI) to below clinically relevant levels (<1000 MFI), and in the majority of cases below the lower positive detection limit (<500 MFI), even in alleles with a baseline MFI >4000 was demonstrated. Reduction occurred in all cases within 120 min, demonstrating efficacy in a time period usual for heart transplantation. Flowcytometric crossmatching of suitable pseudo-donor lymphocytes demonstrated a change from T cell and B cell positive channel shifts to negative, demonstrating a reduction in binding capacity.

CONCLUSIONS

Intraoperative immunoadsorption in an ex vivo setting demonstrates clinically relevant reductions in anti-HLA antibodies within the normal timeframe for heart transplantation. This method represents a potential desensitization technique that could enable sensitized children to accept a donor organ earlier, even in the presence of donor-specific anti-HLA antibodies.

Tibiotalocalcaneal nail and primary closure for the management of open ankle fractures in the elderly patient; results from a major trauma centre

INTRODUCTION

Open ankle fractures in elderly patients are challenging injuries to manage. The aim of this study was to assess the outcome of elderly patients with open ankle fractures treated with a tibiotalocalcaneal nail and primary wound closure.

METHODS

We identified all open ankle fractures in patients over 65 referred to our major trauma centre managed with a tibiotalocalcaneal nail and primary wound closure over 10 years. We recorded patient demographics, comorbidities, injury mechanism, length of stay, operation, weightbearing status, re-operations, infections and mortality.

RESULTS

We included 34 patients with an average age of 87 (73-99). We found 56 % of patients' mobility status declined post-operatively and 21 % of patients were discharged directly home. Four patients required further unplanned surgery including two deep infections requiring amputation. We had a 6 % three month mortality rate.

CONCLUSION

Use of a tibiotalocalcaneal nail with primary wound closure offers a reasonable treatment option for open fractures of the ankle in the elderly patient.

Treatment choice for first permanent molars affected with molar-incisor hypomineralization, in patients 7-8 years of age: a questionnaire study among Swedish general dentists, orthodontists, and pediatric dentists

PURPOSE

The aim of this study was to investigate attitudes and preferred therapy choice for first permanent molars (FPM) with Molar-Incisor Hypomineralization (MIH).

METHODS

An online questionnaire was sent out to general dentists (n = 559) working in the Public Dental Service in Region Västra Götaland, orthodontists (n = 293), and pediatric dentists (n = 156) (members from each interest association), in Sweden. The questionnaire contained three parts: general questions regarding the respondents, patient cases, and general questions regarding extraction of FPMs with MIH. Statistics were carried out using Chi-squared tests, with a significance level of 5%.

RESULTS

A response rate of 36% was obtained. Orthodontists and pediatric dentists were more prone to extract FPMs with both moderate and severe MIH, compared to general dentists. When restoring FPMs with moderate MIH, resin composite was preferred. Compared to the general dentists, the pediatric dentists were more prone to choose glass-ionomer cement in the FPMs with severe MIH. The most common treatment choice for FPMs with mild MIH was fluoride varnish. "When root furcation is under development of the second permanent molar on radiographs" was chosen as the optimal time for extracting FPMs with severe MIH, and the general dentists based their treatment decisions on recommendations from a pediatric dentist.

CONCLUSION

Extraction of FPMs with moderate and severe MIH is considered a therapy of choice among general dentists and specialists, and the preferred time of extraction is before the eruption of the second permanent molar.

Oxygen delivery in pediatric cardiac surgery and its association with acute kidney injury using machine learning

OBJECTIVE

Acute kidney injury (AKI) after pediatric cardiac surgery with cardiopulmonary bypass (CPB) is a frequently reported complication. In this study we aimed to determine the oxygen delivery indexed to body surface area (Do2i) threshold associated with postoperative AKI in pediatric patients during CPB, and whether it remains clinically important in the context of other known independent risk factors.

METHODS

A single-institution, retrospective study, encompassing 396 pediatric patients, who underwent heart surgery between April 2019 and April 2021 was undertaken. Time spent below Do2i thresholds were compared to determine the critical value for all stages of AKI occurring within 48 hours of surgery. Do2i threshold was then included in a classification analysis with known risk factors including nephrotoxic drug usage, surgical complexity, intraoperative data, comorbidities and ventricular function data, and vasoactive inotrope requirement to determine Do2i predictive importance.

RESULTS

Logistic regression models showed cumulative time spent below a Do2i value of 350 mL/min/m2 was associated with AKI. Random forest models, incorporating established risk factors, showed Do2i threshold still maintained predictive importance. Patients who developed post-CPB AKI were younger, had longer CPB and ischemic times, and required higher inotrope support postsurgery.

CONCLUSIONS

The present data support previous findings that Do2i during CPB is an independent risk factor for AKI development in pediatric patients. Furthermore, the data support previous suggestions of a higher threshold value in children compared with that in adults and indicate that adjustments in Do2i management might reduce incidence of postoperative AKI in the pediatric cardiac surgery population.

Occupational asthma in teachers

BACKGROUND

Work-related asthma symptoms are common in teachers and teaching assistants, there are few studies evaluating their causes.

AIMS

To identify causes of occupational asthma in teachers and teaching assistants referred to the Birmingham Occupational Lung Disease clinic 2000-20 using evaluation of serial Peak Expiratory Flow (PEF) records.

METHODS

Teachers and teaching assistants with possible occupational asthma were asked to record PEF 2-hourly at home and work for 4 weeks. Their records were evaluated with the Oasys programme. Those with a positive score for any of the three scores (area between curves (ABC), timepoint and Oasys score from discriminant analysis) were included. Repeat records were made as indicated to help identify the cause and the effects of remedial actions.

RESULTS

Thirty-eight teachers or teaching assistants met the inclusion criteria with all three Oasys scores positive in 24, 2/3 scores in nine and 1/3 in five. The building was the likely cause in 17 (in new builds particularly acrylates from carpet adhesives and in old buildings mould and construction dust), bystander exposure to agents in the schools in 12 (cleaning agents, acrylates from photocopiers and chloramines from indoor pools) and materials used in the classroom in 9 (most commonly MDF in design and technology classes). We illustrate how the PEF records helped identify the cause.

CONCLUSIONS

Oasys analysis of PEF records is a useful method of evaluating occupational asthma in teachers and identified difficult to confirm causes where successful remediation or redeployment was achieved.

Delivery outcomes as a result of snoring as determined by standard sleep surveys

Background

Sleep-disordered breathing (SDB), is an umbrella term that encompasses obstructive sleep apnea (OSA), central sleep apnea (CSA) and hypoventilation. is common but studies in the pregnant population are limited. Data suggests relationships between OSA and preeclampsia, but the relationship between snoring and pregnancy outcomes is unknown.

Methods

A prospective study of 2224 singleton pregnancies was undertaken. Women were questioned using the Berlin Questionnaire (BQ- 2 or more categories where the score is positive.) and the Epworth Sleepiness Scale (ESS >10/24), the results compared with pregnancy outcomes with regard to hypertension in pregnancy.

Results

Women having symptoms raising the possibility of OSA defined by the BQ with a score >7 was 45.5%, and using ESS with a score >10, was 36%. The birth and neonatal outcomes for self-reported snoring and increased daytime sleepiness showed increased adverse outcomes notably increased caesarean section rates and low APGAR scores but not birth before 37 weeks of gestation.

Conclusion

Using questionnaires designed for the general population, the prevalence of possible undiagnosed OSA is high in the pregnant population. The increased adverse delivery and neonatal outcomes for self-reported snoring and increased daytime sleepiness with these tools indicated the need for further investigation of the links between snoring SDB and pregnancy outcomes.

Can molar incisor hypomineralization cause dental fear and anxiety or influence the oral health-related quality of life in children and adolescents?-a systematic review

PURPOSE

Molar Incisor Hypomineralization (MIH) are first molars with developmental enamel defects and are common findings in many child populations. The porous nature of MIH enamel and the presence of post-eruptive enamel breakdown leads to the presence of hypersensitivity and pain, which is often the patient's main complaint and can result in dental fear and affect the quality of life. The present review aims to summarise the evidence for the ability of MIH to cause problems, such as dental fear and anxiety (DFA) and to summarise the evidence for a possibly negative impact on the oral health-related quality of life (OHRQoL) of MIH affected children and adolescents, in a systematic review.

METHOD

Two searches, (1) MIH AND dental anxiety and (2) MIH AND Quality of life, were performed in MEDLINE/PubMed and Scopus. Selection demands were fulfilling the MIH diagnosis criteria using validated instruments and questionnaires for assessing DFA and OHRQoL, respectively.

RESULTS

After removing duplicates and articles not fulfilling the selection demands, 6 studies concerning MIH and DFA and 8 studies concerning MIH and OHRQoL remained.

CONCLUSION

Children and adolescents with diagnosed MIH did not seem to suffer from increased dental fear and anxiety, but indicated an impaired oral health-related quality of life.

Patient-reported outcome measures in individuals with amelogenesis imperfecta: a systematic review

PURPOSE

Amelogenesis imperfecta (AI) is a hereditary condition which affects the composition and structure of enamel in terms of hypoplasia and/or hypomineralization. The condition severely affects patients facing such difficulties as hypersensibility, loss of tooth substance and poor aesthetics. The objective is to perform a systematic review of patient-reported outcome measures (PROMs) in patients with amelogenesis imperfecta.

METHODS

Inclusion criteria were articles written in English, including PROMs from patients with amelogenesis imperfecta. The databases PubMed, Scopus and Web of Science were searched on April 27, 2022, and eligible articles were screened. Exclusion criteria were articles based on proxy reports and single case reports.

RESULTS

405 studies were screened in terms of title and abstract, with 31 articles eligible for full-text screening, resulting in a total of 11 articles eligible for inclusion, (articles including 4-82 patients). The content was analyzed, resulting in the outcome divided into seven domains: Oral Health-Related Quality of Life (OHRQoL), Dental fear, Esthetics, Psychosocial factors, Function, Dental hypersensitivity, and Treatment outcome.

CONCLUSION

The limited quantity of research on PROMS from patients with AI indicates a significant impact of OHRQoL and daily life. A large variety of approaches have been presented in the articles. Patients report concerns of esthetics, hypersensitivity, function, and a general impact on well-being and social interaction. This highlights the importance for the need of early dental treatment.

PROSPERO REGISTRATION NUMBER

256875.

Engineering CuO-HfO2 interface toward enhanced CO2 electroreduction to C2H4

We report significantly enhanced electrochemical CO2 reduction (ECR) to C2H4 by tuning the interface of a metal oxide composite (CuOx/HfO2), enabling a C2H4 faradaic efficiency as high as 62.6 +...

Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy

BACKGROUND AND PURPOSE

Task-based fMRI is a noninvasive method of determining language dominance; however, not all children can complete language tasks due to age, cognitive/intellectual, or language barriers. Task-free approaches such as resting-state fMRI offer an alternative method. This study evaluated resting-state fMRI for predicting language laterality in children with drug-resistant epilepsy.

MATERIALS AND METHODS

A retrospective review of 43 children with drug-resistant epilepsy who had undergone resting-state fMRI and task-based fMRI during presurgical evaluation was conducted. Independent component analysis of resting-state fMRI was used to identify language networks by comparing the independent components with a language network template. Concordance rates in language laterality between resting-state fMRI and each of the 4 task-based fMRI language paradigms (auditory description decision, auditory category, verbal fluency, and silent word generation tasks) were calculated.

RESULTS

Concordance ranged from 0.64 (95% CI, 0.48-0.65) to 0.73 (95% CI, 0.58-0.87), depending on the language paradigm, with the highest concordance found for the auditory description decision task. Most (78%-83%) patients identified as left-lateralized on task-based fMRI were correctly classified as left-lateralized on resting-state fMRI. No patients classified as right-lateralized or bilateral on task-based fMRI were correctly classified by resting-state fMRI.

CONCLUSIONS

While resting-state fMRI correctly classified most patients who had typical (left) language dominance, its ability to correctly classify patients with atypical (right or bilateral) language dominance was poor. Further study is required before resting-state fMRI can be used clinically for language mapping in the context of epilepsy surgery evaluation in children with drug-resistant epilepsy.

Intraoperative anti-A/B immunoadsorption is associated with significantly reduced blood product utilization with similar outcomes in pediatric ABO-incompatible heart transplantation

Background

Intraoperative anti-A/B immunoadsorption (ABO-IA) was recently introduced for ABO-incompatible heart transplantation. Here we report the first case series of patients transplanted with ABO-IA, and compare outcomes with those undergoing plasma exchange facilitated ABO-incompatible heart transplantation (ABO-PE).

Methods

Data were retrospectively analysed on all ABO-incompatible heart transplants undertaken at a single centre between January 1, 2000 and June 1, 2020. Data included all routine laboratory tests, demographics and pre-operative characteristics, intraoperative details and post-operative outcomes. Primary outcome measures were volume of blood product transfusions, maximum post-transplant isohaemagglutinin titres, occurrence of rejection and graft survival. Secondary outcome measures were length of intensive care and hospital stay. Demographic and survival data were also obtained for ABO-compatible transplants during the same time period for comparison.

Results

Thirty-seven patients underwent ABO-incompatible heart transplantation, with 27 (73%) using ABO-PE and 10 (27%) using ABO-IA. ABO-IA patients were significantly older than ABO-PE patients (p < 0.001) and the total volume of blood products transfused during the hospital admission was significantly lower (164 [126-212] ml/kg vs 323 [268-379] ml/kg, p < 0.001). No significant differences were noted between methods in either pre or post-transplant maximum isohaemagglutinin titres, incidence of rejection, length of intensive care or total hospital stay. Survival comparison showed no significant difference between antibody reduction methods, or indeed ABO-compatible transplants (p = 0.6).

Conclusions

This novel technique appears to allow a significantly older population than typical to undergo ABO-incompatible heart transplantation, as well as significantly reducing blood product utilization. Furthermore, intraoperative anti-A/B immunoadsorption does not demonstrate increased early post-transplant isohaemagglutinin accumulation or rates of rejection compared to ABO-PE. Early survival is equivalent between ABO-IA, ABO-PE and ABO-compatible heart transplantation.

A cardiopulmonary bypass strategy to support a patient with vein of Galen malformation

We present a dissection of the patent ductus arteriosus and pulmonary artery for surgical repair utilising cardiopulmonary bypass in the setting of vein of Galen malformation. Several strategies were employed to attenuate the cerebral shunt including pH-stat, high cardiac index, restrictive venous drainage, continuous ventilation and deep hypothermic circulatory arrest. The patient recovered from surgery with no apparent neurological sequelae.

The effect of the COVID-19 lockdown on the epidemiology of hip fractures in the elderly: a multicentre cohort study

INTRODUCTION

The COVID-19 pandemic presented extraordinary challenges to the UK healthcare system. This study aimed to assess the impact of the COVID-19 lockdown on the epidemiology, treatment pathways and 30-day mortality rates of hip fractures. Outcomes of COVID-19 positive patients were compared against those who tested negative.

METHODS

An observational, retrospective, multicentre study was conducted across six hospitals in the South East of England. Data were retrieved from the National Hip Fracture Database and electronic medical records. Data was collected for the strictest UK lockdown period (period B=23 March 2020-11 May 2020), and the corresponding period in 2019 (period A).

RESULTS

A total of 386 patients were admitted during period A, whereas 381 were admitted during period B. Despite the suspension of the 'Best Practice Tariff' during period B, time to surgery, time to orthogeriatric assessment, and 30-day mortality were similar between period A and B. The length of inpatient stay was significantly shorter during period B (11.5 days vs 17.0 days, p<0.001). Comparison of COVID-19 positive and negative patients during period B demonstrated that a positive test was associated with a significantly higher rate of 30-day mortality (53.6% vs 6.7%), surgical delay >36h (46.4% vs 30.8%, p=0.049), and increased length of inpatient stay (15.8 vs 11.7 days, p=0.015).

CONCLUSIONS

The COVID-19 lockdown did not alter the epidemiology of hip fractures. A substantially higher mortality rate was observed among patients with a COVID-19 positive test. These findings should be taken into consideration by the healthcare policymakers while formulating contingency plans for a potential 'second wave'.

Tar Spot: An Understudied Disease Threatening Corn Production in the Americas

Tar spot of corn has been a major foliar disease in several Latin American countries since 1904. In 2015, tar spot was first documented in the United States and has led to significant yield losses of approximately 4.5 million t. Tar spot is caused by an obligate pathogen, Phyllachora maydis, and thus requires a living host to grow and reproduce. Due to its obligate nature, biological and epidemiological studies are limited and impact of disease in corn production has been understudied. Here we present the current literature and gaps in knowledge of tar spot of corn in the Americas, its etiology, distribution, impact and known management strategies as a resource for understanding the pathosystem. This will in tern guide current and future research and aid in the development of effective management strategies for this disease.

Dry heat and microwave-generated steam protocols for the rapid decontamination of respiratory personal protective equipment in response to COVID-19-related shortages

BACKGROUND

In the wake of the SARS-CoV-2 pandemic and unprecedented global demand, clinicians are struggling to source adequate access to personal protective equipment. Respirators can be in short supply, though are necessary to protect workers from SARS-CoV-2 exposure. Rapid decontamination and reuse of respirators may provide relief for the strained procurement situation.

METHOD

In this study, we investigated the suitability of 70°C dry heat and microwave-generated steam (MGS) for reprocessing of FFP2/N95-type respirators, and Type-II surgical face masks. Staphylococcus aureus was used as a surrogate as it is less susceptible than enveloped viruses to chemical and physical processes.

RESULTS

We observed >4 log10 reductions in the viability of dry S. aureus treated by dry heat for 90 min at 70°C and >6 log10 reductions by MGS for 90 s. After 3 reprocessing cycles, neither process was found to negatively impact the bacterial or NaCl filtration efficiency of the respirators that were tested. However, MGS was incompatible with Type-II surgical masks tested, as we confirmed that bacterial filtration capacity was completely lost following reprocessing. MGS was observed to be incompatible with some respirator types due to arcing observed around some types of metal nose clips and by loss of adhesion of clips to the mask.

CONCLUSION

Considering the advantages and disadvantages of each approach, we propose a reprocessing personal protective equipment/face mask workflow for use in medical areas.

It's a trap! The development of a versatile drain biofilm model and its susceptibility to disinfection

BACKGROUND

Pathogens in drain biofilms pose a significant risk for hospital-acquired infection. However, the evidence of product effectiveness in controlling drain biofilm and pathogen dissemination are scarce. A novel in-vitro biofilm model was developed to address the need for a robust, reproduceable and simple testing methodology for disinfection efficacy against a complex drain biofilm.

METHODS

Identical complex drain biofilms were established simultaneously over 8 days, mimicking a sink trap. Reproducibility of their composition was confirmed by next-generation sequencing. The efficacy of sodium hypochlorite 1000 ppm (NaOCl), sodium dichloroisocyanurate 1000 ppm (NaDCC), non-ionic surfactant (NIS) and peracetic acid 4000 ppm (PAA) was explored, simulating normal sink usage conditions. Bacterial viability and recovery following a series of 15-min treatments were measured in three distinct parts of the drain.

RESULTS

The drain biofilm consisted of 119 mixed species of Gram-positive and -negative bacteria. NaOCl produced a >4 log₁₀ reduction in viability in the drain front section alone, while PAA achieved a >4 log₁₀ reduction in viability in all of the drain sections following three 15-min doses and prevented biofilm regrowth for >4 days. NIS and NaDCC failed to control the biofilm in any drain sections.

CONCLUSIONS

Drains are one source of microbial pathogens in healthcare settings. Microbial biofilms are notoriously difficult to eradicate with conventional chemical biocidal products. The development of this reproducible in-vitro drain biofilm model enabled understanding of the impact of biocidal products on biofilm spatial composition and viability in different parts of the drain.

The Great Ormond Street Hospital immunoadsorption method for ABO-incompatible heart transplantation: a practical technique

Traditionally, ABO-incompatible heart transplantation was accomplished using a plasma exchange technique to remove recipient plasma containing donor-incompatible anti-A/B isohaemagglutinins. However, this technique exposed patients to large volumes of allogeneic blood and blood products (up to three times the patient’s circulating volume). In 2018, we published the first reported case of an ABO-incompatible heart transplant using an intraoperative immunoadsorption technique which minimises the exposure to blood products by specifically targeting anti-A/B isohaemagglutinins. We have subsequently used this technique in all children undergoing ABO-incompatible heart transplantation and become convinced of its efficacy in this population while observing no adverse effects. This article outlines the practical details required to perform the technique in order to avoid hyperacute rejection.

Understanding the conversion mechanism and performance of monodisperse FeF2 nanocrystal cathodes

The application of transition metal fluorides as energy-dense cathode materials for lithium ion batteries has been hindered by inadequate understanding of their electrochemical capabilities and limitations. Here, we present an ideal system for mechanistic study through the colloidal synthesis of single-crystalline, monodisperse iron(II) fluoride nanorods. Near theoretical capacity (570 mA h g^-1) and extraordinary cycling stability (>90% capacity retention after 50 cycles at C/20) is achieved solely through the use of an ionic liquid electrolyte (1 m LiFSI/Pyr_1,3FSI), which forms a stable solid electrolyte interphase and prevents the fusing of particles. This stability extends over 200 cycles at much higher rates (C/2) and temperatures (50 °C). High-resolution analytical transmission electron microscopy reveals intricate morphological features, lattice orientation relationships and oxidation state changes that comprehensively describe the conversion mechanism. Phase evolution, diffusion kinetics and cell failure are critically influenced by surface-specific reactions. The reversibility of the conversion reaction is governed by topotactic cation diffusion through an invariant lattice of fluoride anions and the nucleation of metallic particles on semicoherent interfaces. This new understanding is used to showcase the inherently high discharge rate capability of FeF₂.

Early Assessment of Molecular Progression and Response by Whole-genome Circulating Tumor DNA in Advanced Solid Tumors

Treatment response assessment for patients with advanced solid tumors is complex and existing methods require greater precision. Current guidelines rely on imaging, which has known limitations, including the time required to show a deterministic change in target lesions. Serial changes in whole-genome (WG) circulating tumor DNA (ctDNA) were used to assess response or resistance to treatment early in the treatment course. Ninety-six patients with advanced cancer were prospectively enrolled (91 analyzed and 5 excluded), and blood was collected before and after initiation of a new, systemic treatment. Plasma cell-free DNA libraries were prepared for either WG or WG bisulfite sequencing. Longitudinal changes in the fraction of ctDNA were quantified to retrospectively identify molecular progression (MP) or major molecular response (MMR). Study endpoints were concordance with first follow-up imaging (FFUI) and stratification of progression-free survival (PFS) and overall survival (OS). Patients with MP (n = 13) had significantly shorter PFS (median 62 days vs. 310 days) and OS (255 days vs. not reached). Sensitivity for MP to identify clinical progression was 54% and specificity was 100%. MP calls were from samples taken a median of 28 days into treatment and 39 days before FFUI. Patients with MMR (n = 27) had significantly longer PFS and OS compared with those with neither call (n = 51). These results demonstrated that ctDNA changes early after treatment initiation inform response to treatment and correlate with long-term clinical outcomes. Once validated, molecular response assessment can enable early treatment change minimizing side effects and costs associated with additional cycles of ineffective treatment.

Abstract P5-01-13: Longitudinal changes in whole-genome (WG) cell-free DNA (cfDNA) and methylation as a blood-based biomarker to identify early disease progression in advanced breast cancer

Background: Liquid biopsies have potential clinical utility as dynamic biomarkers for treatment response in advanced breast cancer. We evaluated a plasma-only assay to track serial changes in WG cfDNA to identify disease progression prior to routine imaging.

Methods: We prospectively enrolled and serially collected blood from 25 patients with advanced breast cancer. Blood was drawn and collected in Streck tubes prior to start of a new treatment, after the first cycle (median 22 days), and/or second cycle (median 52 days). 4 mL of plasma was separated from peripheral blood, after which cfDNA was isolated from plasma and used to prepare libraries (11 with bisulfite conversion) for WG sequencing (median 20x depth). Based on a patient-specific profile of WG features, including copy-number alterations and cfDNA fragment length, the fraction of tumor-derived cfDNA (ctDNA) was quantified over the initial course of treatment. For a subset of the cohort (11 of 25 patients), we also quantified changes in genome-wide methylation levels from baseline to subsequent timepoints to classify patients as progressors or non-progressors. Imaging was performed per standard practice with treatment response determined by an independent radiologist according to RECIST 1.1 guidelines.

Results: Median age of patients in the cohort was 65 (range 30-83) and included all subtypes—HR+ (n=14), HR+ & HER2+ (n=6), and triple negative (n=5). 52% of patients were on their third line of therapy (range 1-5). On-study therapies were chemotherapy alone (8), targeted + hormone therapy (5), hormone therapy alone (4), targeted + chemotherapy (5), targeted therapy alone (1), or immune checkpoint + HDAC inhibitors (2). Patients with predicted progression by cfDNA (n=5), indicated by an increase in tumor fraction at either post-treatment blood collection, had worse progression-free survival (median 67 days) compared to patients who did not show an increase (n=20; median 207 days) (hazard ratio 7.9, [95% CI 2.2-28.5], log-rank p=3 × 10-4). For the patients who were predicted to progress, the ctDNA assay preceded clinical evaluation by a median of 53 days. All patients with predicted progression were later confirmed to progress at the first follow-up evaluation (5/5, 100% positive predictive value). For the remaining patients, 15 of 20 did not progress (75% negative predictive value). Therefore, sensitivity for the assay was 50% and specificity was 100%. Comparing molecular predictions for 11 of 25 patients based on genomic versus methylation features, 8 non-progressors were classified correctly by both types of features. For the 3 progressors, 2 were predicted correctly based solely on methylation, increasing the sensitivity to detect progression early in the treatment course.

Conclusions: Analyzing ctDNA early in the course of a new therapy holds promise to identify patients with early disease progression across multiple types of treatment. The assay accurately identified patients with no durable clinical benefit earlier, indicating potential clinical utility to change therapy and to limit unnecessary side effects and costs associated with ineffective treatments, if validated in a prospective clinical trial.​ Finally, integrating methylation-based changes with information about genomic alterations may increase performance of ctDNA-based response monitoring.

Citation Format: Andrew A Davis, David Chan, Michael S Oh, Robert W Lentz, Neil Peterman, Alex Robertson, Rohith Srivas, Abhik Shah, Nicole Lambert, Ayse Tezcan, Haluk Tezcan, Young Kwang Chae. Longitudinal changes in whole-genome (WG) cell-free DNA (cfDNA) and methylation as a blood-based biomarker to identify early disease progression in advanced breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-01-13.

1 Review of the Identification and Management of Contractures in Inpatients with Dementia In A District General Hospital

Background

Patients with dementia are at risk of contractures which are associated with pain, pressure sores, increased carer burden and reduced function (1). It has been estimated up to 55% of residents in nursing homes have a contracture (2). Locally, patients are identified and treated in care homes. We questioned why comparatively few hospital inpatients were seen.

Methods

We audited acute elderly inpatients at a large district general hospital on two days. Patients with a diagnosis of dementia were identified and then checked for contractures. Information was collected on a proforma. Patients audited on day one were excluded from day two.

Results

410 patients were audited. 100 patients were identified with dementia. 21 individual contractures were identified with the hands been the most common site (47.6%). Only three contractures had been highlighted in the medical notes. Patients with contractures were more likely to be at home with carers or in a care facility (93.7% verse 64.3%). None of the patients with contractures were independently mobile. Higher proportions (31.2% vs 8.3%) with contractures were bedbound compared to those without. Complications were identified, with two patients reporting pain and three patients having pressure sores. Only one patient was receiving treatment for their contractures. Patients with contractures were more likely to have a higher frailty score, had a previous stroke (37.5% verse 13.1%) and have a vascular type dementia (31.3% verse 14.2%).

Conclusions

Contractures were a significant problem in our inpatient population in patients with a diagnosis of dementia. A large proportion were not identified by the clerking team, not receiving treatment and beginning to have complications. Subsequently a presentation highlighting this issue was carried out to junior doctors on the elderly wards, a coding proforma for contractures was produced and a guide to management of this issue is being put together for use in the inpatient setting.

References

1. Souren L, Franssen, Reisberg E. Contractures and loss of function in patients with Alzheimer's disease, J. Am. Geriatr. Soc. 1995; 43(6): 650–655.

2. Offenbacher M, Sauer S, Riess J, Muller M, et al. Disabil Rehabil 2013; 36(7): 529–538.

X-ray microanalysis of dentine in primary teeth diagnosed Dentinogenesis Imperfecta type II

Aim

To analyse the elemental composition of dentine in primary teeth from children diagnosed with Dentinogenesis Imperfecta type II (DI) and from normal sound primary teeth using X-ray microanalysis.

Materials and methods

X-ray microanalysis of the elements C, O, Na, Mg, P, Cl, K and Ca were performed in the dentine of five normal primary teeth and in seven primary teeth diagnosed DI. The analysis was made in a low magnification in 10 points from the enamel-dentine junction/root surface toward the pulp. The data was also evaluated with an inductive analysis.

Results

Lower values for C were found in DI-dentine compared with normal dentine. Na had significantly higher values in DI-dentine while Mg had significantly lower values. The inductive analysis revealed that Na and Mg were the most important elements for discriminating DI-dentine from normal dentine.

Conclusions

Dentine in primary teeth from patients diagnosed with Dentinogenesis Imperfecta type II analysed with XRMA have lower values of C and Mg and higher values of O and Na compared with normal primary dentine.

Electronic supplementary material

The online version of this article (10.1007/s40368-018-0392-2) contains supplementary material, which is available to authorized users.

Predicting Ischemic Risk Using Blood Oxygen Level-Dependent MRI in Children with Moyamoya

BACKGROUND AND PURPOSE

Moyamoya is a progressive steno-occlusive arteriopathy. MR imaging assessment of cerebrovascular reactivity can be performed by measuring the blood oxygen level-dependent cerebrovascular reactivity response to vasoactive stimuli. Our objective was to determine whether negative blood oxygen level-dependent cerebrovascular reactivity status is predictive of ischemic events in childhood moyamoya.

MATERIALS AND METHODS

We conducted a retrospective study of a consecutive cohort of children with moyamoya who underwent assessment of blood oxygen level-dependent cerebrovascular reactivity. The charts of patients with written informed consent were reviewed for the occurrence of arterial ischemic stroke, transient ischemic attack, or silent infarcts. We used logistic regression to calculate the OR and 95% CI for ischemic events based on steal status. Hazard ratios for ischemic events based on age at blood oxygen level-dependent cerebrovascular reactivity imaging, sex, and moyamoya etiology were calculated using Cox hazards models.

RESULTS

Thirty-seven children (21 female; median age, 10.7 years; interquartile range, 7.5-14.7 years) were followed for a median of 28.8 months (interquartile range, 13.7-84.1 months). Eleven (30%) had ischemic events, 82% of which were TIA without infarcts. Steal was present in 15 of 16 (93.8%) hemispheres in which ischemic events occurred versus 25 of 58 (43.1%) ischemic-free hemispheres (OR = 19.8; 95% CI, 2.5-160; P = .005). Children with idiopathic moyamoya were at significantly greater risk of ischemic events (hazard ratio, 3.71; 95% CI, 1.1-12.8; P = .037).

CONCLUSIONS

Our study demonstrates that idiopathic moyamoya and the presence of steal are independently associated with ischemic events. The use of blood oxygen level-dependent cerebrovascular reactivity could potentially assist in the selection of patients for revascularization surgery and the direction of therapy in children with moyamoya.

Postmagmatic Tectonic Evolution of the Outer Izu-Bonin Forearc Revealed by Sediment Basin Structure and Vein Microstructure Analysis: Implications for a 15 Ma Hiatus Between Pacific Plate Subduction Initiation and Forearc Extension

International Ocean Discovery Program Expedition 352 recovered sedimentary-volcaniclastic successions and extensional structures (faults and extensional veins) that allow the reconstruction of the Izu-Bonin forearc tectonic evolution using a combination of shipboard core data, seismic reflection images, and calcite vein microstructure analysis. The oldest recorded biostratigraphic ages within fault-bounded sedimentary basins (Late Eocene to Early Oligocene) imply a ~15 Ma hiatus between the formation of the igneous basement (52 to 50 Ma) and the onset of sedimentation. At the upslope sites (U1439 and U1442) extension led to the formation of asymmetric basins reflecting regional stretch of ~16-19% at strain rates of ~1.58 × 10-16 to 4.62 × 10-16 s-1. Downslope Site U1440 (closer to the trench) is characterized by a symmetric graben bounded by conjugate normal faults reflecting regional stretch of ~55% at strain rates of 4.40 × 10-16 to 1.43 × 10-15 s-1. Mean differential stresses are in the range of ~70-90 MPa. We infer that upper plate extension was triggered by incipient Pacific Plate rollback ~15 Ma after subduction initiation. Extension was accommodated by normal faulting with syntectonic sedimentation during Late Eocene to Early Oligocene times. Backarc extension was assisted by magmatism with related Shikoku and Parece-Vela Basin spreading at ~25 Ma, so that parts of the arc and rear arc, and the West Philippine backarc Basin were dismembered from the forearc. This was followed by slow-rift to postrift sedimentation during the transition from forearc to arc rifting to spreading within the Shikoku-Parece-Vela Basin system.

Exploring the association between ingestion of foods with higher potential salicylate content and symptom exacerbation in chronic rhinosinusitis. Data from the National Chronic Rhinosinusitis Epidemiology Study

INTRODUCTION

Pharmacological salicylates are known to trigger respiratory exacerbations in patients with Non-Steroidal Exacerbated Respiratory Disease (N-ERD), a specific phenotype of Chronic Rhinosinusitis (CRS) and asthma. The impact of dietary sources of salicylates across subgroups of CRS is not well understood. The hypothesis is that in patients with nasal polyps present, there is likely to be a higher incidence of symptom exacerbation due to dietary salicylates regardless of any known response to pharmacological salicylate.

METHODS

The Chronic Rhinosinusitis Epidemiology Study (CRES) was a questionnaire-based case-control study which sought to characterise the UK CRS population in terms of sociological, economic and medical factors. Using specific questions to examine participant responses relating to symptom exacerbation from food groups thought to be high in salicylate content, this analysis of the CRES database sought to compare an estimate of the prevalence of dietary sensitivity due to food with higher potential salicylate content across patients with CRS with (CRSwNPs) and without nasal polyposis (CRSsNPs) and with allergic fungal rhinosinusitis (AFRS).

RESULTS

The CRSwNPs group were significantly more likely than controls to report symptom exacerbation due to ingestion of food groups with higher potential dietary salicylate content. The same trend was observed amongst CRSsNPs participants to a lesser degree. Reported response to the individual specific food groups wine, nuts, spicy foods, fruit and vegetables demonstrated that a statistically significant proportion of CRSwNPs and AFRS participants reported sensitivity to wine.

CONCLUSIONS

This analysis suggests that there is an association between symptom exacerbation in response to food products with higher potential salicylate content, specifically wine, in CRS patients both with and without nasal polyposis when compared to controls, but especially in the CRSwNPs and AFRS phenotypes. Further studies are needed to detail if this relationship represents a causal relationship to dietary salicylate. The data present the possibility that a wider group of CRS patients may elicit salicylate sensitivity than those with known N-ERD.

Deep hypothermic extracorporeal membrane oxygenation cannula exchange in a child with necrotic pneumonia

Necrotizing pneumonia can lead to respiratory insufficiency in previously healthy children. Extracorporeal membrane oxygenation can be used for hemodynamic salvage and subsequent lung rest awaiting recovery. We present a case of a child initially placed on veno-arterial extracorporeal membrane oxygenation and converted to veno-venous extracorporeal membrane oxygenation. This was done under deep hypothermia in the operating theater.

Abstract 2279: Serial changes in tumor-derived whole-genome cfDNA fraction to identify early disease progression prior to imaging

Background:

Response to cancer treatment is usually determined by clinical exam and imaging assessment. Here, we analyzed changes in tumor-derived whole-genome cell-free DNA (cfDNA) at baseline and after treatment initiation to determine response to treatment prior to routine imaging.

Methods:

We prospectively enrolled and serially collected blood from 54 patients with metastatic malignancies (21 lung, 20 breast, 13 other tumor types). Baseline blood samples were drawn prior to initiation of a new treatment and at one or two additional time points, after the first cycle (median 21 days) and the second cycle (median 42 days). 4 mL of plasma was separated from peripheral blood collected in Streck Cell-Free DNA Blood Collection Tubes, and cfDNA was isolated from plasma aliquots using Qiagen QIAmp extraction kits. To prepare sequencing libraries, a method optimized for whole genome sequencing (WGS) was used based on the Kapa HyperPrep chemistry. WGS was performed at approximately 25X depth on the Illumina HiSeq X. Based on a patient-specific profile of whole genome features, changes in the fraction of tumor-derived cfDNA were quantified over the initial course of treatment. Imaging was performed per standard practice with treatment response determined by RECIST.

Results:

Median number of prior treatment lines was 1 [range 0-6]. Patients were treated with the following therapies: chemotherapy (27), immunotherapy (14), hormone therapy (7), or targeted therapy (6). For the entire cohort, patients with predicted progression by cfDNA (n=11), indicated by an increase in tumor fraction at either post-treatment blood collection, had worse event-free survival compared to patients that did not show an increase (n=43) (hazard ratio 8.0, [95% CI 3.4-19.2], log-rank p=4.5 x 10-8). For the patients who were predicted to progress, the cfDNA assay preceded clinical evaluation by a median of 39 days. Median progression-free survival was 62 days for patients with predicted progression versus 232 days for others. All patients with predicted progression were later confirmed to progress at the first follow-up evaluation (11/11, 100% positive predictive value). For the remaining patients, 32 of 43 did not progress (74% negative predictive value). Therefore, sensitivity for the assay was 50% and specificity was 100%.

Conclusions:

Analyzing tumor-derived cfDNA early in the course of a new therapy holds promise to identify patients with early disease progression across a variety of tumor histologies and types of treatment. Early identification of patients who are not benefitting from treatment will enable initiation of other potentially effective therapies, and reduce unnecessary side effects and cost associated with these treatments. Further studies are warranted to validate these findings in larger cohorts and to confirm the histology and treatment-independent nature of the approach.

Citation Format: Andrew A. Davis, Wade T. Iams, David Chan, Michael S. Oh, Robert W. Lentz, Neil Peterman, Alex Robertson, Abhik Shah, Rohith Srivas, Nicole Lambert, Tim Wilson, Peter George, Becky Wong, Ayse Tezcan, Ram Yalamanchili, Ken Nesmith, John C. Spinosa, Haluk Tezcan, Young Kwang Chae. Serial changes in tumor-derived whole-genome cfDNA fraction to identify early disease progression prior to imaging [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2279.

Whole-genome cell-free DNA (cfDNA) changes as a dynamic blood-based biomarker for early response assessment of advanced tumors

3041

Background: Liquid biopsies have potential clinical utility as dynamic biomarkers for treatment response. We analyzed serial changes in whole-genome (WG) cfDNA to identify patients with disease progression prior to routine imaging. Methods: We prospectively collected clinical data and blood from 69 advanced cancer patients (28 lung, 25 breast, 16 other). Blood was collected at baseline prior to initiation of a new treatment and at one or two additional timepoints (median 21 and 42 days). We isolated plasma cfDNA and prepared sequencing libraries for WG sequencing or WG bisulfite sequencing (median depth 20X). We quantified changes in the fraction of tumor-derived cfDNA over the initial course of treatment to predict progression vs. no progression. Treatment response at first post-treatment imaging was determined by RECIST 1.1 and clinical assessment. Study endpoints were agreement with first post-treatment imaging and progression-free survival (PFS) by cfDNA prediction. Results: Median age of patients was 70 and 59% were female. Patients were treated with the following therapies: chemotherapy (37), immunotherapy (17), endocrine (9), or targeted therapy (6). Patients with predicted progression by cfDNA (14), indicated by an increase in tumor fraction at either post-treatment blood collection, had shorter PFS (median 63 days) compared to patients without an increase (N = 55; median 255 days), with hazard ratio of 10.3 (95% confidence interval 4.6-23.4, log-rank P = 1x10-11). Positive predictive value was 100% for disease progression and negative predictive value was 78%. These findings were consistent in subset analyses of patients with lung (log-rank P = 2x10-5), breast (log-rank P = 3x10-4), and those treated with immunotherapy (log-rank P = 5x10-6). Conclusions: Our results show the ability to detect early disease progression with high fidelity using WG cfDNA prior to first imaging. These findings were consistent across multiple tumor types and treatments, including immunotherapy patients. Once validated, this dynamic, predictive, blood-based biomarker could aid in clinical decision making for early treatment change as a novel and cost-effective approach.

A prospective study tracking longitudinal changes in genome-wide cell-free DNA (cfDNA) methylation to identify early nonresponders to cancer treatment

3042

Background: Methylation is an epigenetic modification linked to cancer pathogenesis. The aim was to determine if changes in cfDNA methylation patterns before and after initiation of treatment could predict non-response to treatment prior to routine imaging and clinical follow-up. Methods: We prospectively collected clinical data and blood from 28 patients with metastatic malignancies (13 lung, 11 breast, 4 other). Blood was drawn prior to start of a new treatment, after first cycle (median 30 days), and/or second cycle (median 57 days). We performed whole-genome (WG) bisulfite sequencing (median depth 18X) on plasma cfDNA to determine methylation levels. By tracking how methylation levels deviate from unaffected individuals, from baseline to subsequent timepoints, we classified patients as either progressors (greater deviance) or non-progressors. Treatment response at first follow-up imaging (FUI) was determined by RECIST 1.1. Study endpoints were agreement with first FUI and progression-free survival (PFS) by cfDNA classification. Results: The cohort consisted of 68% females and the median age was 70. Main treatment regimens were chemo- (N = 12), immuno- (6), endocrine (5), or targeted-therapy (5). PFS was significantly shorter (log-rank p = 8 x 10-7) in patients classified as progressors by cfDNA (N = 8; median: 62 days) compared to non-progressors (N = 20, median: 263 days). For patients classified as progressors, the cfDNA assay preceded imaging and clinical evaluation by a median of 34 days. 7 out of 8 patients classified as cfDNA progressors were later confirmed to progress at first follow-up evaluation (88% positive predictive value). The one patient who was classified as progressor based on cfDNA was stable based on FUI (day 93 of treatment) but was later confirmed as progression on day 128 by FUI. For the remaining patients, 18 of 20 did not progress (90% negative predictive value). Thus, sensitivity for the assay for identifying progression was 78% and specificity was 95%. Conclusions: Our results show that WG cfDNA methylation change is a novel signature with potential to identify patients whose treatment regimen is ineffective prior to imaging.

Case report on surgical repair of unusual dissection of arterial duct involving main pulmonary artery in a child with vein of Galen malformation

Background

Dissection involving patent arterial duct (PDA) extending to main pulmonary artery (MPA) is an extremely rare condition.

Case summary

We report a case of complex dissection involving PDA extending to MPA, in a child with vein of Galen malformation. This was surgically corrected under deep hypothermic circulatory arrest, and we describe the pathophysiology and surgical rationale in this report.

Discussion

Management of intracardiac lesion in the presence of intracranial arterio-venous malformations such as vein of Galen is very difficult, and employing deep hypothermic circulatory arrest allows one to manage cerebral protection while offering the visualization of intracardiac anatomy more effectively.

Local Hemodynamic Conditions Associated with Focal Changes in the Intracranial Aneurysm Wall

BACKGROUND AND PURPOSE

Aneurysm hemodynamics has been associated with wall histology and inflammation. We investigated associations between local hemodynamics and focal wall changes visible intraoperatively.

MATERIALS AND METHODS

Computational fluid dynamics models were constructed from 3D images of 65 aneurysms treated surgically. Aneurysm regions with different visual appearances were identified in intraoperative videos: 1) "atherosclerotic" (yellow), 2) "hyperplastic" (white), 3) "thin" (red), 4) rupture site, and 5) "normal" (similar to parent artery), They were marked on 3D reconstructions. Regional hemodynamics was characterized by the following: wall shear stress, oscillatory shear index, relative residence time, wall shear stress gradient and divergence, gradient oscillatory number, and dynamic pressure; these were compared using the Mann-Whitney test.

RESULTS

Hyperplastic regions had lower average wall shear stress (P = .005) and pressure (P = .009) than normal regions. Flow conditions in atherosclerotic and hyperplastic regions were similar but had higher average relative residence time (P = .03) and oscillatory shear index (P = .04) than thin regions. Hyperplastic regions also had a higher average gradient oscillatory number (P = .002) than thin regions. Thin regions had lower average relative residence time (P < .001), oscillatory shear index (P = .006), and gradient oscillatory number (P < .001) than normal regions, and higher average wall shear stress (P = .006) and pressure (P = .009) than hyperplastic regions. Thin regions tended to be aligned with the flow stream, while atherosclerotic and hyperplastic regions tended to be aligned with recirculation zones.

CONCLUSIONS

Local hemodynamics is associated with visible focal wall changes. Slow swirling flow with low and oscillatory wall shear stress was associated with atherosclerotic and hyperplastic changes. High flow conditions prevalent in regions near the flow impingement site characterized by higher and less oscillatory wall shear stress were associated with local "thinning" of the wall.

Impact of test protocols and material binding on the efficacy of antimicrobial wipes

BACKGROUND

The use of effective cleaning/disinfectant products is important to control pathogens on healthcare surfaces. With the increasing number of wipe products available, there is a concern that combination of a formulation with the wrong material will decrease the efficacy of the product. This study aimed to use a range of efficacy test protocols to determine the efficacy of four formulations before and after binding to three commonly used wiping materials.

METHODS

Two quaternary ammonium (QAC)-based products, one hydrogen-peroxide-based product and one neutral cleaner were combined with microfibre, cotton or non-woven materials and tested for efficacy against Pseudomonas aeruginosa and Staphylococcus aureus with two surface tests (ASTM E2197-17 and EN13697-15) and two 'product' tests (ASTM E2967-15 and EN16615-15).

FINDINGS

Overall, the impact of using different materials on formulation efficacy was limited, except for an alkyl(C_12-16)dimethylbenzylammonium chloride-based product used at 0.5% v/v. The hydrogen peroxide product was the most efficacious regardless of the material used. The results from wipe test ASTM E2967-15 were consistent with those from the surface tests, but not with EN16615-15 which was far less stringent.

CONCLUSIONS

The use of different wiping cloth materials may not impact severely on the efficacy of potent disinfectants, despite the absorption of different volumes of formulation by the materials. QAC-based formulations may be at higher risk when a low concentration is used. There were large differences in efficacy depending on the standard test performed, highlighting the need for more stringency in choosing the test to make a product claim on label.

Procedural pain in routine dental care for children: a part of the Swedish BITA study

AIM

To investigate the frequency and reported intensity levels of dental treatment pain and discomfort in children, in conjunction with regular dental visits.

METHODS

The study included 2363 children in four different age cohorts. Data was collected from structured interviews by dental personnel regarding pain experiences or discomfort after treatments, including analgesia, extractions, operative treatments and radiographic examinations.

RESULTS

One-third of all treatment occasions were experienced as painful and/or causing discomfort. Treatment sessions including analgesia were assessed as painful in 49.7% of occasions, with injection being the most common given reason for pain. Extraction was painful in 62.4% of occasions, with injection as the main reason for pain. Operative treatments were assessed as painful in 38.8% of occasions, with drilling as the most common reason for pain and discomfort. Pain was reported in approximately 19% of all radiographic examinations.

CONCLUSIONS

Injection was the major reason for pain during treatment, including injection and extraction, while drilling was the most common cause of pain during restorative treatment. Dentists should try to minimise the experience of pain and discomfort by using all available measures to perform pain-free and effective dental injections.

Breath-Hold Blood Oxygen Level-Dependent MRI: A Tool for the Assessment of Cerebrovascular Reserve in Children with Moyamoya Disease

BACKGROUND AND PURPOSE

There is a critical need for a reliable and clinically feasible imaging technique that can enable prognostication and selection for revascularization surgery in children with Moyamoya disease. Blood oxygen level-dependent MR imaging assessment of cerebrovascular reactivity, using voluntary breath-hold hypercapnic challenge, is one such simple technique. However, its repeatability and reliability in children with Moyamoya disease are unknown. The current study sought to address this limitation.

MATERIALS AND METHODS

Children with Moyamoya disease underwent dual breath-hold hypercapnic challenge blood oxygen level-dependent MR imaging of cerebrovascular reactivity in the same MR imaging session. Within-day, within-subject repeatability of cerebrovascular reactivity estimates, derived from the blood oxygen level-dependent signal, was computed. Estimates were associated with demographics and intellectual function. Interrater reliability of a qualitative and clinically applicable scoring scheme was assessed.

RESULTS

Twenty children (11 males; 12.1 ± 3.3 years) with 30 MR imaging sessions (60 MR imaging scans) were included. Repeatability was "good" on the basis of the intraclass correlation coefficient (0.70 ± 0.19). Agreement of qualitative scores was "substantial" (κ = 0.711), and intrarater reliability of scores was "almost perfect" (κ = 0.83 and 1). Younger participants exhibited lower repeatability (P = .027). Repeatability was not associated with cognitive function (P > .05). However, abnormal cerebrovascular reactivity was associated with slower processing speed (P = .015).

CONCLUSIONS

Breath-hold hypercapnic challenge blood oxygen level-dependent MR imaging is a repeatable technique for the assessment of cerebrovascular reactivity in children with Moyamoya disease and is reliably interpretable for use in clinical practice. Standardization of such protocols will allow further research into its application for the assessment of ischemic risk in childhood cerebrovascular disease.