Nicholas Avdimiretz

All Publications

• Worldwide organ allocation systems for pediatric lung transplantation. Clinical transplantation Avdimiretz, N., Benden, C. 2023: e15018

  Abstract

  Pediatric lung transplantation (LTX) remains limited by the scarcity of small donor lungs, particularly in less populated parts of the world. Optimal organ allocation, including the prioritization and ranking of pediatric LTX candidates, and the appropriate matching of pediatric donors to recipients have been crucial elements in improving pediatric LTX outcomes. We aimed to elucidate the various pediatric lung allocation practices worldwide. A global survey of current pediatric solid organ transplantation deceased donation allocation practices was conducted by the International Pediatric Transplant Association (IPTA), and these policies were subsequently analyzed if publicly available, with focus on pediatric lung transplantation. Significant variation was found in lung allocation systems worldwide both in terms of prioritization and distribution for children. Definition of pediatrics varied from <12 years of age to <18 years of age. While several countries performing LTX for young children do not have a formal system to prioritize pediatric candidates, many countries that perform LTX at higher rates do offer prioritization methods for children: including the United States, United Kingdom, France, Italy, Australia, and countries serviced by Eurotransplant. Certain lung allocation practices for pediatrics are highlighted herein, including the newly instituted Composite Allocation Score (CAS) system in the United States, pediatric matching with Eurotransplant, and pediatric prioritization in Spain. The systems highlighted here explicitly aim to provide judicious and high quality LTX care for children.

  View details for DOI 10.1111/ctr.15018

  View details for PubMedID 37218644

• Monitoring practices of chronic lung allograft dysfunction in pediatric lung transplantation PEDIATRIC PULMONOLOGY Avdimiretz, N., Radtke, T., Benden, C. 2023; 58 (1): 213-221

  Abstract

  Chronic lung allograft dysfunction (CLAD) continues to negatively impact the survival of pediatric lung transplant (LTx) recipients. Current consensus guidelines are adult-focused. We sought to examine CLAD detection and monitoring practices at pediatric LTx programs.We conducted a survey among the International Pediatric Lung Transplant Collaborative. Questions consisted of practitioner's experience, LTx program demographics, and querying tests used for CLAD surveillance and detection. Investigations queried included: chest x-ray (CXR), chest computed tomography (CT), lung magnetic resonance imaging (MRI), ventilation/perfusion scanning, conventional pulmonary function testing (PFT), multiple breath washout (MBW), infant/preschool PFT, bronchoalveolar lavage, transbronchial biopsies (TBBx), or other tissue sampling techniques. Preferences for certain modalities over others were questioned based on a five-point Likert scale.Twenty-four of 25 programs responded. Chest CT and CXR are used generally for both CLAD surveillance and detection. No programs use lung MRI clinically, it may have some utility in the future. While all centers use conventional PFT, MBW, and infant/preschool PFT are used in one-fifth and one-third of centers, respectively. While the majority of programs use TBBx, only 41.7% would obtain a diagnosis based on tissue histopathology over noninvasive techniques if CLAD is suspected. Utilization of biomarkers is still limited.Our results indicate continued use of conventional PFT along with chest CT and less so CXR for CLAD detection and monitoring in the large majority of centers. Infant/preschool PFT and novel methods such as MBW are used in a few centers only. Respondents agreed there is a timely need for pediatric consensus guidelines on CLAD detection and monitoring.

  View details for DOI 10.1002/ppul.26187

  View details for Web of Science ID 000867799600001

  View details for PubMedID 36200536

• The changing landscape of pediatric lung transplantation CLINICAL TRANSPLANTATION Avdimiretz, N., Benden, C. 2022; 36 (4): e14634

  Abstract

  There has been a shift over decades in the diagnostic indications for lung transplantation in children; in particular, there has been a reduction in the proportion of pediatric cystic fibrosis (CF) patients undergoing lung transplantation early in life, and more transplants occurring in other diagnostic groups. Here, we examine trends in pediatric lung transplantation with regards to indications by analyzing data from the United Network of Organ Sharing, the International Society for Heart and Lung Transplantation Thoracic Transplant Registry, and other sources. Over the past two years, there has been a precipitous decline in both the number of transplants due to CF and the proportion of CF cases relative to the total number of transplants, likely not solely due to the COVID-19 pandemic. In 2020, primary pulmonary arterial hypertension for the first-time surpassed CF as main indication for pediatric lung transplantation in the United States, a finding that is also reflected in international data. We discuss the effect of novel CFTR modulator therapies as a major factor leading to this shifting landscape. Based on our trending, pulmonary hypertension-related diagnoses and pediatric interstitial lung diseases are rising indications, for which we suggest adjustments of consensus guidelines around candidate selection criteria.

  View details for DOI 10.1111/ctr.14634

  View details for Web of Science ID 000766946300001

  View details for PubMedID 35244236

• Alterations in the immune phenotype of thymectomized children and the development of atopic disorders after heart transplantation PEDIATRIC TRANSPLANTATION Kim, T. B., Ionescu, L., Avdimiretz, N., Murdoch, F., Larsen, I. M., Motyka, B., West, L. J., Urschel, S. 2022; 26 (4): e14252

  Abstract

  Atopic disorders are more common in children after heart transplant (HTx). We hypothesized that HTx at an early age and thymus excision (TE) affect development of T and B cells, especially regulatory T cells (Tregs), which help maintain tolerance.In this single-center study including 24 patients transplanted between 2013 and 2018, we investigated lymphocyte patterns in relation to these factors using flow cytometry. Clinical data were collected from standardized questionnaires and medical charts. Patients were stratified into TE and non-TE groups as well as patients with and without post-transplant atopy development/worsening.64% of TE patients experienced new or worsening asthma/eczema post-transplant compared to 20% of non-TE patients. TE patients had higher total Treg proportions (CD4+CD25+CD127lo) than non-TE patients (p = .043), but borderline significantly lower naïve Tregs (CD45RA+CD27-) (p = .057). Memory CD4+ T cells were higher in TE patients in trend (p = .084). Total Tregs did not differ between atopic/nonatopic groups, although naïve Tregs were significantly lower in atopic patients (p = .028). Memory CD4+ T cells were higher in atopic patients in trend (p = .082). IgM+IgD+ B cells were higher in nonatopic patients in trend (p = .064).New/worsening atopy is more common in thymectomized HTx children and is associated with alterations in T-cell profiles. Avoiding TE may prevent these alterations and reduce incidence of atopy post-HTx.

  View details for DOI 10.1111/petr.14252

  View details for Web of Science ID 000758153000001

  View details for PubMedID 35187796

• Novel Bridge to Recovery: Right Ventricular Assist Device for Primary Graft Dysfunction in Pediatric Lung Transplantation THE JOURNAL OF HEART AND LUNG TRANSPLANTATION Avdimiretz, N., Conway, J., Larson, C., Guerra, G. G., Jonker, D., Bates, A., Buccholz, H., Carroll, A. 2022; 41 (4)

  View details for DOI 10.1016/j.healun.2022.01.1310

• Bilateral leg swelling as the presenting symptom of Lofgren syndrome in a paediatric patient: a rare presentation of a rare paediatric disease BMJ CASE REPORTS Komishke, B., Foulds, J. L., McMillan, T., Avdimiretz, N. 2021; 14 (3)

  Abstract

  A 17-year-old previously healthy man presented with a 4-week history of progressive bilateral leg swelling with discomfort and erythema, but no signs of arthritis or erythema nodosum. An incidental finding of a query pulmonary nodule on chest X-ray prompted chest CT for further evaluation, revealing bilateral hilar and mediastinal lymphadenopathy. The patient then underwent endobronchial ultrasound and transbronchial needle aspiration biopsies of mediastinal lymph nodes. Biopsies and bronchoalveolar lavage samples were negative for microbiology, including mycobacterial culture. Pathology demonstrated non-caseating granulomas consistent with a diagnosis of sarcoidosis. Weeks later, he developed arthralgias of the left metacarpophalangeal joints and erythema nodosum and was diagnosed with Löfgren syndrome, a phenomenon rarely described in the paediatric population. This case highlights an approach to lower extremity swelling as well as hilar lymphadenopathy in the paediatric population. In addition, it emphasises the importance of multidisciplinary teamwork for accurate and timely diagnoses.

  View details for DOI 10.1136/bcr-2020-239434

  View details for Web of Science ID 000652594400041

  View details for PubMedID 33664030

  View details for PubMedCentralID PMC7934771

• Phase-Resolved Functional Lung (PREFUL) Magnetic Resonance Imaging (MRI) Ventilation Mapping in Children Born Prematurely with and Without Bronchopulmonary Dysplasia (BPD) American Thoracic Society International Conference Munidasa, S., Zanette, B., Abdeen, N., Katz, S. L., Jacobi, E., Avdimiretz, N., Moraes, T. J., Santyr, G. 2021

  View details for DOI 10.1164/ajrccm-conference.2021.203.1_meetingabstracts.a3307

• Passenger Lymphocyte Syndrome in a Pediatric Lung Transplant Recipient with Previous Bone Marrow Transplantation THE JOURNAL OF HEART AND LUNG TRANSPLANTATION Avdimiretz, N., Solomon, M. P. 2021; 40 (4)
• Rare broncho-pulmonary arterial fistula in a healthy 9-year-old girl BMJ CASE REPORTS Avdimiretz, N., Glicksman, A., Dell, S., John, P., Moraes, T. J. 2020; 13 (10)

  Abstract

  A 9-year-old previously well girl presented with multiple episodes of large volume haemoptysis and right sided consolidation. She continued to have haemoptysis despite intravenous antibiotics. CT chest suggested a right mainstem endobronchial lesion; this was not seen on bronchoscopy where an extensive blood clot was removed. Distal flexible bronchoscopy could not identify the source of bleeding. CT angiogram revealed a broncho-pulmonary arterial fistula, a rare cause of haemoptysis in children. Endovascular embolisation resulted in short-term symptom resolution; however, haemoptysis recurred months later, leading to re-embolisation. This case highlights a stepwise approach to the workup of large volume haemoptysis.

  View details for DOI 10.1136/bcr-2020-234865

  View details for Web of Science ID 000661541300014

  View details for PubMedID 33004353

  View details for PubMedCentralID PMC7534672

• Comparison of a handheld turbine spirometer to conventional spirometry in children with cystic fibrosis PEDIATRIC PULMONOLOGY Avdimiretz, N., Wilson, D., Grasemann, H. 2020; 55 (6): 1394-1399

  Abstract

  In pediatric cystic fibrosis (CF) ambulatory care, handheld spirometry in individual clinic rooms would improve patient flow and potentially reduce patient-to-patient contact. A validation study was conducted to examine the accuracy of an entirely handheld turbine spirometer vs a standard laboratory device in pediatric CF patients.Spirometric data were obtained from 76 CF patients aged less than 18 years in the ambulatory setting using the Micro Loop Spirometer (CareFusion) and compared to same-day data from conventional laboratory spirometry.Linear relationships were obtained between devices, demonstrating good correlation: r = .99, .99, .97, and .82 for forced expiratory volume in 1 second (FEV1) , forced vital capacity (FVC), FEF25%-75% , and peak expiratory flow, respectively (P < .001 for all). Biases (mean differences between devices) were -65 mL for FEV1 (P < .001) and -115 mL for FVC (P < .001) on the handheld. Bland-Altman plots demonstrated scatter in bias across all volumes. Limits of agreement (defined as mean ± 2 standard deviations [SD]) were large: +189 to -319 mL for FEV1 , equating to large limits of agreement for FEV1 percent predicted of +9.0% to -13.9%. For repeated measurements on the same device on different days, a larger percent SD was obtained with the handheld compared to the conventional spirometer (6.7% vs 5.1%, respectively). Importantly, a relatively large number (15%) demonstrated a decrease in FEV1 percent predicted of ≥10% on the handheld compared to conventional.This suggests that while both devices have passed the recommendations for spirometry testing per American Thoracic Society/European Respiratory Society, handheld turbine vs conventional spirometers may not be used interchangeably in the pediatric CF population.

  View details for DOI 10.1002/ppul.24743

  View details for Web of Science ID 000531318100018

  View details for PubMedID 32203645

• Comparison of Proton Based to Hyperpolarized Xenon Magnetic Resonance Imaging (MRI) Mapping of Ventilation in the Lungs of Children Born Prematurely American Thoracic Society International Conference Munidasa, S., Couch, M., Zanette, B., Grimm, R., Voskrebenzev, A., Seethamraju, R., Vogel-Claussen, J., Avdimiretz, N., Moraes, T. J., Santyr, G. 2020

  View details for DOI 10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a2320

• Infant Lung Transplantation in Suspected Case of Surfactant Protein Deficiency American Thoracic Society International Conference Wee, W. B., Avdimiretz, N., Moraes, T. J., McKinney, M. L., Grasemann, H., Solomon, M. 2019

  View details for DOI 10.1164/ajrccm-conference.2019.199.1_meetingabstracts.a5031

• Atopy in Pediatric Heart Transplantation ISHLT Monograph Series - Pediatric Heart Transplantation Avdimiretz, N., Urschel, S. UAB Printing. 2019; 13: 341-356

  View details for DOI https://ishlt.org/publications-resources/publications/monograph-series/monograph-volume-13

• Allergies and autoimmune disorders in children after heart transplantation CLINICAL TRANSPLANTATION Avdimiretz, N., Seitz, S., Kim, T., Murdoch, F., Urschel, S. 2018; 32 (10): e13400

  Abstract

  Pediatric heart transplantation requires lifelong immune suppression and may require thymectomy, both of which alter T-cell repertoires. We hypothesized that atopic and autoimmune diseases are more common in pediatric heart transplant patients than the general population, and that transplantation in early childhood increases the risk of development or worsening of atopic or autoimmune disease. A cross-sectional single-center study including 21 heart transplant patients aged ≤18 years was conducted. Data collected included age at transplant, induction, thymectomy, and development and severity of atopic or autoimmune disease. A majority (67%) reported having any atopic disease post-transplant, all of whom reported onset or worsening post-transplantation. Thymectomized patients were significantly more likely to have asthma (P = 0.018) and report asthma worsening post-transplant (P = 0.045). Patients with worsening of asthma post-transplant were transplanted at a significantly younger age (P = 0.040). ABO incompatible and ABO compatible recipients presented similarly. Anemia was common (38%) but not always clearly of autoimmune origin. Atopic diseases are common in children following heart transplantation: Compared to the general population, there is a higher prevalence of eczema (43% vs 11%) and asthma (33% vs 9%). Both thymectomy and younger age at transplant are associated with atopic disorders, possibly due to altered T-cell repertoires.

  View details for DOI 10.1111/ctr.13400

  View details for Web of Science ID 000447379000022

  View details for PubMedID 30176068

• Lymphocyte Proportions Post Thymectomy Are Associated with Allergic Disorders in Heart Transplanted Children Kim, T., Ionescu, L., Avdimiretz, N., Larsen, M., Murdoch, F., Motyka, B., Gilmour, S., West, L., Urschel, S. 2018
• Comparison of Handheld to Conventional Spirometry in Pediatric Cystic Fibrosis Avdimiretz, N., Wilson, D. 2018

  View details for DOI 10.1164/ajrccm-conference.2018.197.1_MeetingAbstracts.A3672

• Reduced Naive Regulatory T-Cells and B-10 Cells in Thymectomized Children Predispose for Allergic Disorders After Heart Transplantation THE JOURNAL OF HEART AND LUNG TRANSPLANTATION Kim, T. B., Avdimiretz, N., Ionescu, L., Larsen, I. M., Motyka, B., West, L. J., Urschel, S. 2017; 36 (4)

  View details for DOI 10.1016/j.healun.2017.01.263

• Allergies and Autoimmune Disorders in Children after Heart Transplantation Avdimiretz, N., Seitz, S., Cheveldayoff, M., Urschel, S. 2016

  View details for DOI 10.1016/j.healun.2016.01.1168

• Focus on pediatric intentional trauma Avdimiretz, N., Phillips, L., Bratu, I. LIPPINCOTT WILLIAMS & WILKINS. 2012: 1031-1034

  Abstract

  Based on our previous study, pediatric intentional trauma injuries with Injury Severity Scores (ISS) ≥ 12 were more commonly observed in the urban than the rural setting (15.2% vs. 5.5%) in Alberta from 1996 to 2006. We wish to understand differences between urban and rural pediatric intentional trauma to plan for prevention and supportive strategies.Data were extracted from the Alberta Trauma Registry on pediatric patients (0-17 years) with ISS ≥ 12, treated from 1996 to 2010 at the Stollery Children's Hospital. Statistical analysis was made comparing urban versus rural groups using t test and χ2 with p < 0.05 considered significant.There were 170 pediatric patients who suffered intentional injury (urban = 58.3%; rural = 41.8%; not significant), with a majority of males (72.4%). Two groups were predominant: the very young (<1 year) at 17.1% of all injuries and the teens (≥ 15 years) at 54.1%. The cause of intent injury was child abuse (31.2%), assault with blunt object (24.6%), assault with a sharp object (22.9%), and suicide (18.2%). The mean ISS was 22.9 ± 7.8 standard deviation. Tragically, 29 patients (17.1%) died. There were no differences between urban and rural pediatric trauma in terms of age, gender, cause of injury, ISS, survival, length of stay, pediatric intensive care unit length of stay, number of operations needed, or alcohol.An important pattern of intentional injuries can be seen where preventative efforts can be strengthened regardless of urban or rural area: the very young as shaken baby cases and the teens, who unfortunately, accounted for the majority of suicidal attempts.

  View details for DOI 10.1097/TA.0b013e3182452270

  View details for Web of Science ID 000302784600051

  View details for PubMedID 22491622

• Feedback/Feed-forward: Qualitative Analysis of Responsive Feedback Processes used to Enhance a Theatre-Based Elective in Undergraduate Medical Education Avdimiretz, N., Brett-MacLean, P., Brown, M., Du, Z., Olesen, J., Nagji, A. UNIV ALBERTA, INT INST QUALITATIVE METHODOLOGY. 2012: 841

  View details for Web of Science ID 000323937100220

• Stem cells in cardiac repair: A review of the changing landscape of cardiovascular medicine. UNIVERSITY OF ALBERTA HEALTH SCIENCES JOURNAL Avdimiretz, N. 2012; 7 (1)
• Functional analyses of Calu-3 human airway serous epithelial cells in response to different agonists: a model for cystic fibrosis JOURNAL OF UNDERGRADUATE MCGILL PHYSIOLOGY Avdimiretz, N., Hanrahan, J. 2009; 2