Understanding facilitators and barriers to oxygen therapy for patients with interstitial lung disease.

BACKGROUND: Interstitial lung disease (ILD) is comprised of a heterogeneous group of pulmonary diseases. Oxygen therapy is used in patients with advanced lung disease; however, there are challenges associated with initiation of oxygen therapy specific to individuals with ILD. The key objectives of this study were to create a common understanding of the facilitators and barriers to oxygen therapy for patients with ILD, and healthcare professionals (HCP) caring for patients with ILD. METHODS: This qualitative study included 1 hour semistructured focus groups/interviews. An iterative and concurrent process was used for data collection and analysis to allow for supplementary development of themes and concepts generated. Data analysis used a three-phase approach: coding, categorising and development of themes. RESULTS: A total of 20 patients and/or caregivers and 31 HCP took part in 34 focus groups/interviews held over 3 months (November 2022-January 2023). Facilitators to oxygen therapy were identified including support from HCP and support groups, the perseverance and self-advocacy of patients, a straightforward administrative process and vendors/private industry that expedite access to oxygen therapy. There were also several barriers to accessing oxygen therapy for patients with ILD. The themes identified include rural disparity, testing requirements and qualifying for funding and the need for ILD-specific evidence base for oxygen therapy. CONCLUSION: Further research is needed to facilitate development of specific exertional oxygen criteria for patients with ILD, to create supports for oxygen use and monitoring and to enable providers to tailor therapy to patients. Oxygen therapy education for ILD should address the benefits and risks of oxygen therapy.

Pulmonary rehabilitation with balance training for fall reduction in chronic obstructive pulmonary disease: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: Available evidence suggests that adults with chronic obstructive pulmonary disease (COPD) performed substantially worse than healthy controls on many balance measures and balance training can improve the balance measures in this population. We conducted this study to determine the effects of incorporating balance training into pulmonary rehabilitation (PR) on the incidence of falls at 12 months follow-up in high fall risk adults with COPD. METHODS: We conducted a prospective international multi-center randomized controlled trial. Eligible participants were adults with COPD at a high risk of future falls and were randomly assigned (1:1) to the intervention or control group. The intervention included personalized balance training for a targeted total of 90 min per week. Both the intervention and control groups received usual PR (2-3 times per week for 8-12 weeks). The primary outcome was the incidence of falls at 12-month follow-up using monthly fall diary calendars. Negative binomial regression or recurrent events models were used to examine the effects of the intervention on fall events. Multiple imputations were performed to deal with missing values. RESULTS: Of 258 participants who were enrolled in the trial, 178 provided falls information (intervention group = 91, control group = 87) and were included in the main analysis. Forty-one participants (45%) experienced at least one fall event in the intervention group and 33 (38%) in the control group (p = 0.34). The mean incidence of falls at 12 months was similar between the two groups (128 versus 128 per 100 person-years; mean difference: 0.30, 95% CI: -0.76 to 1.36 per 100 person-years). The results are robust after multiple imputations for missing data (n = 67). CONCLUSIONS: PR incorporating balance training compared to PR alone did not reduce the incidence of falls over the 12-month period in high fall risk adults with COPD. TRIAL REGISTRATION: The study was registered with ClinicalTrials.gov (NCT02995681) on 14/12/2016.

Reflections on the challenges of conducting an international multicentre randomized controlled trial of balance training in addition to pulmonary rehabilitation and its impact on fall incidence in people with COPD.

BACKGROUND: Pulmonary rehabilitation (PR) is accepted as standard care for individuals with COPD. We conducted an international, multi-centred randomized controlled trial (RCT) to determine if adding balance training to PR would reduce the incidence of falls in people with COPD. While there have been many trials investigating the effectiveness of PR, few have involved international collaboration. Successful execution of rehabilitation trials requires a significant investment of time, staffing, and resources. With the recent completion of the Balance Training for Fall Reduction in COPD RCT, we report on the design, implementation, and execution of our trial using project management phases. We also highlight our lessons learned for consideration in future multi-centre rehabilitation trials. METHODS: This was a retrospective review of the planning, preparation, timelines, and personnel training involved in the execution of this study using four of the five project management phases described by Farrell et al. in 2010: (1) initiation, (2) planning, (3) execution, and (4) monitoring and controlling. We report descriptive statistics as percentages and counts and summarize our lessons learned. RESULTS: Ten outpatient PR programs in three continents participated. Thirty-one personnel worked on the trial across all sites. Enrolment began in January 2017 and was suspended in March 2020 due to the COVID-19 pandemic. Approximately 1275 patients were screened, 455 (36%) were eligible, 258 (57%) consented, 243 (53%) participated, and 130 (61%) completed the 12-month follow-up assessment. Lessons learned through our experience included (1) ensuring awareness of funder policies and considering the impact on collaborating sites; (2) preparing for the possibility of human resource and program disruptions; (3) anticipating site dropout and having a contingency plan in place; (4) planning and monitoring process measure data before, during, and after trial initiation; (5) ensuring frequent and consistent communication with and between collaborating sites; (6) maximizing features of database platform to ensure data set completeness and controlled data access; and (7) identifying strategies for increasing patient engagement in a high-demand study. CONCLUSIONS: We identify seven lessons learned through our experience conducting an international, multicentre rehabilitation-based RCT. These lessons can provide guidance to other trialists conducting studies with similar logistics and may assist with future trial planning and implementation.

Translating the Interplay of Cognition and Physical Performance in COPD and Interstitial Lung Disease: Meeting Report and Literature Review.

TOPIC IMPORTANCE: Cognitive and physical limitations are common in individuals with chronic lung diseases, but their interactions with physical function and activities of daily living are not well characterized. Understanding these interactions and potential contributors may provide insights on disability and enable more tailored rehabilitation strategies. REVIEW FINDINGS: This review summarizes a 2-day meeting of patient partners, clinicians, researchers, and lung associations to discuss the interplay between cognitive and physical function in people with chronic lung diseases. This report covers four areas: (1) cognitive-physical limitations in patients with chronic lung diseases; (2) cognitive assessments; (3) strategies to optimize cognition and motor control; and (4) future research directions. Cognitive and physical impairments have multiple effects on quality of life and daily function. Meeting participants acknowledged the need for a standardized cognitive assessment to complement physical assessments in patients with chronic lung diseases. Dyspnea, fatigue, and age were recognized as important contributors to cognition that can affect motor control and daily physical function. Pulmonary rehabilitation was highlighted as a multidisciplinary strategy that may improve respiratory and limb motor control through neuroplasticity and has the potential to improve physical function and quality of life. SUMMARY: There was consensus that cognitive function and the cognitive interference of dyspnea in people with chronic lung diseases contribute to motor control impairments that can negatively affect daily function, which may be improved with pulmonary rehabilitation. The meeting generated several key research questions related to cognitive-physical interactions in individuals with chronic lung diseases.

Increasing exercise capacity and physical activity in the COPD patient.

Higher levels of exercise capacity and physical activity are desired outcomes in the comprehensive management of the COPD patient. In addition, improvements in exercise capacity and physical activity are instrumental to optimising other important therapeutic goals, such as improved health status, reduced healthcare utilisation and increased survival. Four general approaches towards increasing exercise capacity and physical activity in individuals with COPD will be discussed in this review: 1) pharmacological intervention, especially the administration of long-acting bronchodilators; 2) pulmonary rehabilitation, including exercise training and collaborative self-management; 3) behavioural interventions; and 4) web-based interventions. These are by no means the only approaches, nor are they mutually exclusive: indeed, combining them, as necessary, to meet the needs of the individual respiratory patient may promote optimal outcomes, although further research is necessary in this area.

Factors associated with phenotypes of dyspnea in post-COVID-19 condition: a cross-sectional study.

Post-COVID-19 condition (PCC) is defined as the persistence of symptoms, like fatigue and dyspnea, at least 3 months post-COVID infection. As dyspnea is a common symptom, we attempted to further clinically phenotype those with PCC-associated dyspnea. 1642 adults (average age of 49.6y with 63% female-predominance and BMI of 31.2 kg/m2) with physician confirmed diagnosis of PCC from June 2020-April 2023 in Alberta, Canada were included. Those with dyspnea were more likely to be female (56.5%, p = 0.005) and have higher BMI (31.3 kg/m2 vs. 29.5 kg/m2; p = 0.0008), history of asthma (21.1% vs. 12.3%; p < 0.001), more persistent PCC symptoms (p = 0.0001), more functional limitations, as well as lower quality of life (p < 0.0001). Multivariable-adjusted logistic regression analysis demonstrated dyspnea was independently associated with fatigue (OR = 4.20; CI = 2.71,6.59) and inversely associated with hospitalization for COVID-19 (OR = 0.53; CI = 0.32,0.91), age (OR = 0.98 per one year of age; CI = 0.96,0.99) and 6-min-walk-distance per 10 m difference (OR = 0.98, CI = 0.96,1.0). Fatigue was a predictor of dyspnea, and was associated with milder infection, higher BMI, and reduced 6-min-walk-distance despite normal pulmonary function. Reduced TLC or DLCO was associated with more severe infection and reduced 6-min-walk-distance. Thus, we speculate there are at least two dyspnea-associated phenotypes: phenotype with pronounced fatigue (normal PFT) and phenotype with pronounced pulmonary abnormalities (abnormal PFT). Improved understanding of the dyspnea-associated phenotypes may allow for better targeted rehabilitation.

Impact of COVID-19 Pandemic on Chronic Obstructive Pulmonary Disease Healthcare Use, Exacerbations, and Mortality: A Population Study.

Rationale: Existing work suggests that patients with chronic obstructive pulmonary disease (pwCOPD) presented less frequently to the emergency department and were less likely to be hospitalized during the coronavirus disease (COVID-19) pandemic, but it is unclear if this was due to improved health and disease management or to increased barriers and/or avoidance of health care. Objectives: The objective of this study was to determine the impact of the pandemic on inpatient and outpatient healthcare use, disease incidence, and mortality rates in pwCOPD. Methods: A retrospective population-based analysis using linked administrative datasets from Alberta, Canada 18 months before and after March 12, 2020 was conducted to measure hospitalization, emergency department and outpatient visits, and COPD outpatient exacerbations during these time periods. Mortality data were also analyzed before versus after the pandemic, taking confirmed COVID-19 infection within 30 days into account. Subgroup analysis based on COPD exacerbation risk stratification was undertaken to determine if healthcare use differed based on exacerbation risk. Finally, sex-based analysis of healthcare use during the pandemic was also completed. Results: Hospitalization or emergency department visits and outpatient treatment for acute exacerbations of COPD dropped, whereas total outpatient COPD visits, including both virtual and in person, increased during the pandemic for pwCOPD. The mortality rate increased even after adjusting for COVID-19-associated deaths. Sex-based subgroup analysis showed a greater drop in acute care use for females, but the rise in mortality was seen for both sexes, with men experiencing a greater rate of mortality than women. Conclusions: Overall, pwCOPD accessed acute care resources less during the pandemic, which may have contributed to a rise in non-COVID-19 all-cause mortality.

Balance measures for fall risk screening in community-dwelling older adults with COPD: A longitudinal analysis.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) increases fall risk, but consensus is lacking on suitable balance measures for fall risk screening in this group. We aimed to evaluate the reliability and validity of balance measures for fall risk screening in community-dwelling older adults with COPD. METHODS: In a secondary analysis of two studies, participants, aged ≥60 years with COPD and 12-month fall history or balance issues were tracked for 12-month prospective falls. Baseline balance measures - Brief Balance Evaluation Systems Test (Brief BESTest), single leg stance (SLS), Timed Up and Go (TUG), and TUG Dual-Task (TUG-DT) test - were assessed using intra-class correlation (ICC2,1) for reliability, Pearson/Spearman correlation with balance-related factors for convergent validity, t-tests/Wilcoxon rank-sum tests with fall-related and disease-related factors for known-groups validity, and area under the receiver operator characteristic curve (AUC) for predictive validity. RESULTS: Among 174 participants (73 ± 8 years; 86 females) with COPD, all balance measures showed excellent inter-rater and test-retest reliability (ICC2,1 = 0.88-0.97) and moderate convergent validity (r = 0.34-0.77) with related measures. Brief BESTest and SLS test had acceptable known-groups validity (p < 0.05) for 12-month fall history, self-reported balance problems, and gait aid use. TUG test and TUG-DT test discriminated between groups based on COPD severity, supplemental oxygen use, and gait aid use. All measures displayed insufficient predictive validity (AUC<0.70) for 12-month prospective falls. CONCLUSION: Though all four balance measures demonstrated excellent reliability, they lack accuracy in prospectively predicting falls in community-dwelling older adults with COPD. These measures are best utilized within multi-factorial fall risk assessments for this population.

Increased Virtual Visits to Physicians During the COVID-19 Pandemic and Estimated Impact on Physician Compensation: The Case of Lung and Colorectal Cancers, Chronic Obstructive Pulmonary Diseases, and Heart Failure in Alberta, Canada.

Introduction: The COVID-19 pandemic started in Alberta in March 2020 and significantly increased telehealth service use and provision reducing the risk of virus transmission. We examined the change in the number and proportion of virtual visits by physician specialty and condition (chronic obstructive pulmonary diseases [COPD], heart failure [HF], colorectal and lung cancers), as well as associated changes in physician compensation. Methods: A population-based design was used to analyze all processed physician claims comparing the number and proportion of virtual visits and associated physician billings relative to in-person between pre- (2019/2020) and intra-pandemic (2020/2021). Physician compensations were the claim amounts paid by the health insurance. Results: Pre-pandemic (intra-), there were 8,981 (8,897) lung cancer, 9,245 (9,029) colorectal, 37,558 (36,292) HF, and 68,270 (52,308) COPD patients. Each patient had totally 2.3-4.7 (of which 0.4-0.6% were virtual) general practitioner (GP) visits and 0.9-2.3 (0.2-0.7% were virtual) specialist visits per year pre-pandemic. The average number and proportion of per-patient virtual visits to GPs and specialists grew significantly pre- to intra-pandemic by 2,138-4,567%, and 2,201-7,104%, respectively. Given the lower fees of virtual compared with in-person visits, the reduction in physician compensation associated with the increased use of virtual care was estimated at $3.85 million, with $2.44 million attributed to specialist and $1.41 million to GP. Discussion: Utilization of telehealth increased significantly, while the physician billings per patient and physician compensation declined early in the pandemic in Alberta for the four chronic diseases considered. This study forms the basis for future study in understanding the impact of virtual care, now part of the fabric of health care delivery, on quality of care and patient safety, overall health service utilization (such as diagnostic imaging and other investigations), as well as economic impacts to patients, health care systems, and society.

Variations in COPD Health Care Access and Outcomes: A Rapid Review.

Background: Health inequities among individuals with chronic obstructive pulmonary disease (COPD) are often associated with differential access to health care and health outcomes. A greater understanding of the literature concerning such variation is necessary to determine where gaps or inequities exist along the continuum of COPD care. Methods: A rapid review of the published and grey literature reporting variations in health care access and/or health outcomes for individuals with COPD was completed. Variation was defined as differential patterns in access indicators or outcome measures within sociodemographic categories, including age, ethnicity, geography, race, sex, and socioeconomic status. Emergent themes were identified from the included literature and synthesized narratively. Results: Thirty-five articles were included for final review; the majority were retrospective cohort studies. Twenty-five studies assessed variation in access to health care. Key indicators included: access to spirometry testing, medication adherence, participation in pulmonary rehabilitation, and contact with general practitioners and/or respiratory specialists. Twenty-one studies assessed variation in health outcomes in COPD and key metrics included: hospital-based resource utilization (length of stay and admissions/readmissions), COPD exacerbations, and mortality. Patients who live in rural environments and those of lower socioeconomic status had both poorer access to care and outcomes at the system and patient level. Other sociodemographic variables, including ethnicity, race, age, and sex were associated with variation in health care access and outcomes, although these findings were less consistent. Conclusion: The results of this rapid review suggest that substantial variation in access and outcomes exists for individuals with COPD, highlighting opportunities for targeted interventions and policies.

The effect of inhaled nitric oxide on maximal oxygen consumption during exercise in acute hypoxia: a randomized double-blind crossover trial.

In moderate hypoxia [partial pressure of inspired oxygen ([Formula: see text]) = 85-111 mmHg], the reduction in maximal oxygen consumption (V̇o2max) has been attributed to arterial desaturation, whereas in severe hypoxia ([Formula: see text] < 85 mmHg), elevated pulmonary artery pressure (PAP) is thought to impair peak cardiac output ([Formula: see text]) and therefore V̇o2max. The purpose of this study was to examine whether reducing PAP with inhaled nitric oxide (iNO, a selective pulmonary vasodilator) would increase V̇o2max in moderate and severe acute hypoxia. Twelve young, healthy participants (mean V̇o2max = 45.3 ± 12.2 mL/kg/min), with normal lung function completed the randomized double-blind crossover study over six sessions. Experimental cardiopulmonary exercise tests (CPET) were completed on separate days with participants under the following conditions: 1) acute moderate hypoxia ([Formula: see text] = 89 mmHg), 2) acute severe hypoxia ([Formula: see text] = 79 mmHg), 3) acute moderate hypoxia with 40 ppm iNO, and 4) acute severe hypoxia with 40 ppm iNO (order randomized). On separate days, rest, and exercise (60 W), echocardiography was conducted to determine right ventricular systolic pressure (RVSP/PAP) under conditions 1-4. Resting RVSP was reduced by 2.5 ± 0.8 mmHg with iNO in moderate hypoxia (P = 0.01) and 1.8 ± 0.2 mmHg in severe hypoxia (P = 0.05); however, iNO had no effect on peak [Formula: see text] or V̇o2max in either hypoxic condition. Despite reducing RVSP with iNO in hypoxia, peak [Formula: see text] and V̇o2max were unaffected, suggesting that iNO may not improve exercise tolerance in healthy participants during hypoxic exercise.NEW & NOTEWORTHY The elevation of pulmonary artery pressure (PAP) with hypoxia may impair peak cardiac output ([Formula: see text]) and therefore V̇o2max. Our novel findings show that despite reducing resting RVSP in acute moderate ([Formula: see text] = 89 mmHg) and severe hypoxia ([Formula: see text] = 79 mmHg) with inspired nitric oxide, peak [Formula: see text], and V̇o2max were unaffected.

A fully automated pipeline for the extraction of pectoralis muscle area from chest computed tomography scans.

Background: Computed tomography (CT)-derived pectoralis muscle area (PMA) measurements are prognostic in people with or at-risk of COPD, but fully automated PMA extraction has yet to be developed. Our objective was to develop and validate a PMA extraction pipeline that can automatically: 1) identify the aortic arch slice; and 2) perform pectoralis segmentation at that slice. Methods: CT images from the Canadian Cohort of Obstructive Lung Disease (CanCOLD) study were used for pipeline development. Aorta atlases were used to automatically identify the slice containing the aortic arch by group-based registration. A deep learning model was trained to segment the PMA. The pipeline was evaluated in comparison to manual segmentation. An external dataset was used to evaluate generalisability. Model performance was assessed using the Dice-Sorensen coefficient (DSC) and PMA error. Results: In total 90 participants were used for training (age 67.0±9.9 years; forced expiratory volume in 1 s (FEV1) 93±21% predicted; FEV1/forced vital capacity (FVC) 0.69±0.10; 47 men), and 32 for external testing (age 68.6±7.4 years; FEV1 65±17% predicted; FEV1/FVC 0.50±0.09; 16 men). Compared with manual segmentation, the deep learning model achieved a DSC of 0.94±0.02, 0.94±0.01 and 0.90±0.04 on the true aortic arch slice in the train, validation and external test sets, respectively. Automated aortic arch slice detection obtained distance errors of 1.2±1.3 mm and 1.6±1.5 mm on the train and test data, respectively. Fully automated PMA measurements were not different from manual segmentation (p>0.05). PMA measurements were different between people with and without COPD (p=0.01) and correlated with FEV1 % predicted (p<0.05). Conclusion: A fully automated CT PMA extraction pipeline was developed and validated for use in research and clinical practice.

Normative Reference Equations for Breathlessness Intensity during Incremental Cardiopulmonary Cycle Exercise Testing.

Rationale: Cardiopulmonary exercise testing (CPET) is the gold standard to evaluate exertional breathlessness, a common and disabling symptom. However, the interpretation of breathlessness responses to CPET is limited by a scarcity of normative data. Objectives: We aimed to develop normative reference equations for breathlessness intensity (Borg 0-10 category ratio) response in men and women aged ⩾40 years during CPET, in relation to power output (watts), oxygen uptake, and minute ventilation. Methods: Analysis of ostensibly healthy people aged ⩾40 years undergoing symptom-limited incremental cycle CPET (10 W/min) in the CanCOLD (Canadian Cohort Obstructive Lung Disease) study. Participants had smoking histories <5 pack-years and normal lung function and exercise capacity. The probability of each Borg 0-10 category ratio breathlessness intensity rating by power output, oxygen uptake, and minute ventilation (as an absolute or a relative value [percentage of predicted maximum]) was predicted using ordinal multinomial logistic regression. Model performance was evaluated by fit, calibration, and discrimination (C statistic) and externally validated in an independent sample (n = 86) of healthy Canadian adults. Results: We included 156 participants (43% women) from CanCOLD; the mean age was 65 (range, 42-91) years, and the mean body mass index was 26.3 (standard deviation, 3.8) kg/m2. Reference equations were developed for women and men separately, accounting for age and/or body mass. Model performance was high across all equations, including in the validation sample (C statistic for men = 0.81-0.92, C statistic for women = 0.81-0.96). Conclusions: Normative reference equations are provided to compare exertional breathlessness intensity ratings among individuals or groups and to identify and quantify abnormal breathlessness responses (scores greater than the upper limit of normal) during CPET.

Reduced tidal volume-inflection point and elevated operating lung volumes during exercise in females with well-controlled asthma.

INTRODUCTION: Individuals with asthma breathe at higher operating lung volumes during exercise compared with healthy individuals, which contributes to increased exertional dyspnoea. In health, females are more likely to develop exertional dyspnoea than males at a given workload or ventilation, and therefore, it is possible that females with asthma may develop disproportional dyspnoea on exertion. The purpose of this study was to compare operating lung volume and dyspnoea responses during exercise in females with and without asthma. METHODS: Sixteen female controls and 16 females with asthma were recruited for the study along with 16 male controls and 16 males with asthma as a comparison group. Asthma was confirmed using American Thoracic Society criteria. Participants completed a cycle ergometry cardiopulmonary exercise test to volitional exhaustion. Inspiratory capacity manoeuvres were performed to estimate inspiratory reserve volume (IRV) and dyspnoea was evaluated using the Modified Borg Scale. RESULTS: Females with asthma exhibited elevated dyspnoea during submaximal exercise compared with female controls (p<0.05). Females with asthma obtained a similar IRV and dyspnoea at peak exercise compared with healthy females despite lower ventilatory demand, suggesting mechanical constraint to tidal volume (VT) expansion. VT-inflection point was observed at significantly lower ventilation and V̇O2 in females with asthma compared with female controls. Forced expired volume in 1 s was significantly associated with VT-inflection point in females with asthma (R2=0.401; p<0.01) but not female controls (R2=0.002; p=0.88). CONCLUSION: These results suggest that females with asthma are more prone to experience exertional dyspnoea, secondary to dynamic mechanical constraints during submaximal exercise when compared with females without asthma.

Evaluating a Telemedicine Video Game-Linked High-Intensity Interval Training Exercise Programme in Paediatric Heart Transplant Recipients.

Paediatric heart transplant recipients (HTRs) have reduced exercise capacity, physical activity (PA), health-related quality of life (HRQoL), and self-efficacy towards PA. Exercise interventions have demonstrated improvements in exercise capacity and functional status in adult HTRs, with a specific emerging interest in the role of high-intensity interval training (HIIT). Studies of exercise interventions in paediatric HTRs have been limited and nonrandomized to date. HIIT has not yet been evaluated in paediatric HTRs. We thus seek to evaluate the safety and feasibility of a randomized crossover trial of a 12-week, home-based, video game-linked HIIT intervention using a cycle ergometer with telemedicine and remote physiological monitoring capabilities (MedBIKE) in paediatric HTRs. The secondary objective is to evaluate the impact of the intervention on (1) exercise capacity, (2) PA, (3) HRQoL and self-efficacy towards PA, and (4) sustained changes in secondary outcomes at 6 and 12 months after intervention. After a baseline assessment of the secondary outcomes, participants will be randomized to receive the MedBIKE intervention (12 weeks, 36 sessions) or usual care. After the intervention and a repeated assessment, all participants will cross over. Follow-up assessments will be administered at 6 and 12 months after the MedBIKE intervention. We anticipate that the MedBIKE intervention will be feasible and safely yield sustained improvements in exercise capacity, PA, HRQoL, and self-efficacy towards PA in paediatric HTRs. This study will serve as the foundation for a larger, multicentre randomized crossover trial and will help inform exercise rehabilitation programmes for paediatric HTRs.

La tolérance à l'effort, le niveau d'activité physique (AP), le score de la qualité de vie liée à la santé (QVLS) ainsi que l'auto-efficacité à la pratique d'une AP se trouvent diminués chez les patients pédiatriques ayant reçu une transplantation cardiaque. Il a été montré que les exercices physiques permettent d'améliorer la tolérance à l'effort ainsi que le statut fonctionnel chez les patients adultes ayant reçu une transplantation cardiaque. D'ailleurs, le rôle de l'entraînement par intervalles de haute intensité (EIHI) suscite depuis peu un nouvel intérêt à cet égard. Les études réalisées à ce jour sur les programmes d'activité physique chez les patients pédiatriques ayant reçu une transplantation cardiaque sont toutefois peu nombreuses et ne reposent pas sur une répartition aléatoire. De plus, l'EIHI n'a pas encore été évalué chez ce groupe de patients. La présente étude a donc pour objectif d'évaluer la faisabilité et l'innocuité d'un essai clinique croisé à répartition aléatoire d'une durée de 12 semaines chez des patients pédiatriques ayant reçu une transplantation cardiaque. Le programme d'activité physique prendra la forme d'un EIHI à la maison au moyen d'un jeu vidéo et d'une bicyclette ergométrique permettant une assistance et une surveillance des données physiologiques à distance (MedBIKE). Les objectifs secondaires de l'étude consistent à évaluer les effets du programme sur : 1) la tolérance à l'effort; 2) le niveau d'AP; 3) la QVLS ainsi que l'auto-efficacité à la pratique d'une AP; et 4) le maintien des améliorations relatives aux critères d'évaluation se-condaires à 6 et 12 mois. Après une évaluation initiale des critères d'évaluation secondaires, les participants seront répartis aléatoirement dans le groupe suivant le programme à l'aide du vélo MedBIKE (36 séances réparties sur 12 semaines) ou dans le groupe recevant le traitement usuel. Tous les participants changeront ensuite de groupe, et une nouvelle évaluation des critères d'évaluation se-condaires sera effectuée. Les évaluations de suivi auront lieu 6 et 12 mois après la fin du programme. On s'attend à ce que ce dernier soit sûr, facile à suivre et accompagné d'améliorations soutenues de la tolérance à l'effort, du niveau d'AP, de la QVLS et de l'auto-efficacité à la pratique d'une AP chez les patients pédiatriques ayant reçu une transplantation cardiaque. Cette étude servira de modèle à un essai clinique croisé, multicentrique, à répartition aléatoire de plus grande envergure. Elle permettra aussi de générer des renseignements utiles pour les programmes de réadaptation destinés aux patients pédiatriques ayant reçu une transplantation cardiaque.

Association Between Arterial Stiffness and Measures of Autonomic Dysfunction in People With Chronic Kidney Disease.

Background: Autonomic nervous system (ANS) dysfunction and vascular stiffness increase cardiovascular risk in people with chronic kidney disease (CKD). Chronic elevations in sympathetic activity can lead to increased arterial stiffness; however, the relationship between these variables is unknown in CKD. Objective: To explore the association between measures of autonomic function and arterial stiffness in patients with moderate-to-severe CKD. Methods: This study was a prespecified secondary analysis of a randomized controlled trial. This included the following measures: 24-hour ambulatory blood pressure (BP), carotid-femoral and carotid-radial pulse wave velocity (PWV), and postexercise heart rate recovery (HRR). We used mixed effect linear regression models with Bayesian information criteria (BIC) to assess the contribution of ANS measurements. Results: Forty-four patients were included in the analysis. Mean carotid-femoral and carotid-radial PWV were 7.12 m/s (95% CI 6.13, 8.12) and 8.51 m/s (7.90, 9.11), respectively. Mean systolic dipping, calculated as percentage change in mean systolic readings from day to night, was 10.0% (95% CI 7.79, 12.18). Systolic dipping was independently associated with carotid-radial PWV, MD -0.09 m/s (95% CI -0.15, -0.02) and had the lowest BIC. Conclusions: Systolic dipping was associated with carotid-radial PWV in people with moderate-to-severe CKD; however, there was no association with carotid-femoral PWV. Systolic dipping may be a feasible surrogate of ANS function, as the association with carotid-radial PWV was consistent with the minimal clinically important difference (MCID). Future studies are needed to define the relationship between ANS function, arterial stiffness, and CV events over time in people with CKD.

Contexte: Le dysfonctionnement du système nerveux autonome (SNA) et la rigidité artérielle augmentent le risque d'événements cardiovasculaires chez les personnes atteintes d'insuffisance rénale chronique (IRC). Les élévations chroniques de l'activité sympathique peuvent accroître la rigidité artérielle, mais on ne connaît pas le lien entre ces variables en contexte d'IRC. Objectif: Explorer l'association entre les mesures de la fonction autonome et la rigidité artérielle chez les patients atteints d'IRC modérée ou grave. Méthodologie: Cette étude était l'analyze secondaire prédéfinie d'un essai contrôlé randomisé. Mesures incluses: le suivi de la pression artérielle (PA) ambulatoire sur 24 heures, la vitesse de l'onde de pouls (VOP) carotido-fémorale et carotido-radiale, et la récupération de la fréquence cardiaque (HRR­Heart Rate Recovery) après l'effort. Nous avons eu recours à des modèles de régression linéaire à effets mixtes avec critères d'information bayésiens (BIC ­ Bayesian Information Criteria) pour évaluer la contribution des mesures du SNA. Résultats: Quarante-quatre patients sont inclus dans l'analyze. La valeur moyenne des VOP carotido-fémorale et carotido-radiale était respectivement de 7,12 m/s (IC 95 %: 6,13 à 8,12) et de 8,51 m/s (IC 95 %: 7,90 à 9,11). La chute systolique moyenne, calculée en pourcentage de variation entre les valeurs systoliques moyennes du jour et de la nuit, était de 10,0 % (IC 95 %: 7,79 à 12,18). La chute systolique a été indépendamment associée à la VOP carotido-radiale, avec un écart moyen de -0,09 m/s (IC 95 %: -0,15 à -0,02) et a présenté les plus faibles BIC. Conclusion: La chute systolique a été associée à la VOP carotido-radiale chez les personnes atteintes d'IRC modérée ou grave, mais aucune association n'a été observée avec la VOP carotido-fémorale. La chute systolique pourrait être un substitut de la fonction du SNA, car l'association avec la VOP carotido-radiale était cohérente avec la différence minimale cliniquement importante (DMCI). D'autres études sont nécessaires pour mieux définir la relation entre la fonction du SNA, la rigidité artérielle et les événements cardiovasculaires au fil du temps chez les personnes atteintes d'IRC.

The Pulmonary Vasculature.

The pulmonary circulation is a low-pressure, low-resistance circuit whose primary function is to deliver deoxygenated blood to, and oxygenated blood from, the pulmonary capillary bed enabling gas exchange. The distribution of pulmonary blood flow is regulated by several factors including effects of vascular branching structure, large-scale forces related to gravity, and finer scale factors related to local control. Hypoxic pulmonary vasoconstriction is one such important regulatory mechanism. In the face of local hypoxia, vascular smooth muscle constriction of precapillary arterioles increases local resistance by up to 250%. This has the effect of diverting blood toward better oxygenated regions of the lung and optimizing ventilation-perfusion matching. However, in the face of global hypoxia, the net effect is an increase in pulmonary arterial pressure and vascular resistance. Pulmonary vascular resistance describes the flow-resistive properties of the pulmonary circulation and arises from both precapillary and postcapillary resistances. The pulmonary circulation is also distensible in response to an increase in transmural pressure and this distention, in addition to recruitment, moderates pulmonary arterial pressure and vascular resistance. This article reviews the physiology of the pulmonary vasculature and briefly discusses how this physiology is altered by common circumstances.