Elevated sympathetic-mediated vasoconstriction at rest but intact functional sympatholysis during exercise in heart failure with reduced ejection fraction.

BACKGROUND: Patients with heart failure with reduced ejection fraction (HFrEF) have exaggerated sympathoexcitation and impaired peripheral vascular conductance. Evidence demonstrating consequent impaired functional sympatholysis is limited in HFrEF. This study aimed to determine the magnitude of reduced limb vascular conductance during sympathoexcitation and whether functional sympatholysis would abolish such reductions in HFrEF. METHODS: Twenty patients with HFrEF and 22 age-matched controls performed the cold pressor test (left foot 2-min in -0.5[1] °C water) alone (CPT) and with right handgrip exercise (EX+CPT). Right forearm vascular conductance (FVC), forearm blood flow (FBF), and mean arterial pressure (MAP) were measured. RESULTS: Patients with HFrEF had greater decreases in %ΔFVC and %ΔFBF during CPT (both P<0.0001) but not EX+CPT (P=0.449, P=0.199) compared to controls, respectively. %ΔFVC and %ΔFBF decreased from CPT to EX+CPT in patients with HFrEF (both P<0.0001) and controls (P=0.018, P=0.015), respectively. MAP increased during CPT and EX+CPT in both groups (all P<0.0001). MAP was greater in controls compared to patients with HFrEF during EX+CPT (P=0.025) but not CPT (P=0.209). CONCLUSIONS: Acute sympathoexcitation caused exaggerated peripheral vasoconstriction and reduced peripheral blood flow in patients with HFrEF. Handgrip exercise abolished sympathoexcitatory-mediated peripheral vasoconstriction and normalized peripheral blood flow in patients with HFrEF. These novel data reveal intact functional sympatholysis in the upper limb and suggest exercise-mediated, local control of blood flow is preserved when cardiac limitations that are cardinal to HFrEF are evaded with dynamic handgrip exercise.

An economic evaluation of chronic obstructive pulmonary disease clinical pathway in Saskatchewan, Canada: Data-driven techniques to identify cost-effectiveness among patient subgroups.

BACKGROUND: Saskatchewan has implemented care pathways for several common health conditions. To date, there has not been any cost-effectiveness evaluation of care pathways in the province. The objective of this study was to evaluate the real-world cost-effectiveness of a chronic obstructive pulmonary disease (COPD) care pathway program in Saskatchewan. METHODS: Using patient-level administrative health data, we identified adults (35+ years) with COPD diagnosis recruited into the care pathway program in Regina between April 1, 2018, and March 31, 2019 (N = 759). The control group comprised adults (35+ years) with COPD who lived in Saskatoon during the same period (N = 759). The control group was matched to the intervention group using propensity scores. Costs were calculated at the patient level. The outcome measure was the number of days patients remained without experiencing COPD exacerbation within 1-year follow-up. Both manual and data-driven policy learning approaches were used to assess heterogeneity in the cost-effectiveness by patient demographic and disease characteristics. Bootstrapping was used to quantify uncertainty in the results. RESULTS: In the overall sample, the estimates indicate that the COPD care pathway was not cost-effective using the willingness to pay (WTP) threshold values in the range of $1,000 and $5,000/exacerbation day averted. The manual subgroup analyses show the COPD care pathway was dominant among patients with comorbidities and among patients aged 65 years or younger at the WTP threshold of $2000/exacerbation day averted. Although similar profiles as those identified in the manual subgroup analyses were confirmed, the data-driven policy learning approach suggests more nuanced demographic and disease profiles that the care pathway would be most appropriate for. CONCLUSIONS: Both manual subgroup analysis and data-driven policy learning approach showed that the COPD care pathway consistently produced cost savings and better health outcomes among patients with comorbidities or among those relatively younger. The care pathway was not cost-effective in the entire sample.

Haemodynamic compensations for exercise tissue oxygenation in early stages of COPD: an integrated cardiorespiratory assessment study.

BACKGROUND: Cardiovascular comorbidities are increasingly being recognised in early stages of chronic obstructive pulmonary disease (COPD) yet complete cardiorespiratory functional assessments of individuals with mild COPD or presenting with COPD risk factors are lacking. This paper reports on the effectiveness of the cardiocirculatory-limb muscles oxygen delivery and utilisation axis in smokers exhibiting no, or mild to moderate degrees of airflow obstruction using standardised cardiopulmonary exercise testing (CPET). METHODS: Post-bronchodilator spirometry was used to classify participants as 'ever smokers without' (n=88), with 'mild' (n=63) or 'mild-moderate' COPD (n=56). All underwent CPET with continuous concurrent monitoring of oxygen uptake (V'O2) and of bioimpedance cardiac output (Qc) enabling computation of arteriovenous differences (a-vO2). Mean values of Qc and a-vO2 were mapped across set ranges of V'O2 and Qc isolines to allow for meaningful group comparisons, at same metabolic and circulatory requirements. RESULTS: Peak exercise capacity was significantly reduced in the 'mild-moderate COPD' as compared with the two other groups who showed similar pulmonary function and exercise capacity. Self-reported cardiovascular and skeletal muscle comorbidities were not different between groups, yet disease impact and exercise intolerance scores were three times higher in the 'mild-moderate COPD' compared with the other groups. Mapping of exercise Qc and a-vO2 also showed a leftward shift of values in this group, indicative of a deficit in peripheral O2 extraction even for submaximal exercise demands. Concurrent with lung hyperinflation, a distinctive blunting of exercise stroke volume expansion was also observed in this group. CONCLUSION: Contrary to the traditional view that cardiovascular complications were the hallmark of advanced disease, this study of early COPD spectrum showed a reduced exercise O2 delivery and utilisation in individuals meeting spirometry criteria for stage II COPD. These findings reinforce the preventive clinical management approach to preserve peripheral muscle circulatory and oxidative capacities.

Real-World Cost-Consequence Analysis of an Integrated Chronic Disease Management Program in Saskatchewan, Canada.

An integrated disease management program otherwise called a clinical pathway was recently implemented in Saskatchewan, Canada for patients living with chronic obstructive pulmonary disease (COPD). This study compared the real-world costs and consequences of the COPD clinical pathway program with 2 control treatment programs. The study comprised adult COPD patients in Regina (clinical pathway group, N = 759) matched on propensity scores to 2 independent control groups of similar adults in (1) Regina (historical controls, N = 759) and (2) Saskatoon (contemporaneous controls, N = 759). The study measures included patient-level healthcare costs and acute COPD exacerbation outcomes, both tracked in population-based administrative health data over a one-year follow-up period. Analyses included Cox proportional hazards models and differences in means between groups. The bias-corrected and accelerated bootstrap method was used to calculate 95% confidence intervals (CI). The COPD pathway patients had lower risks of moderate (hazard ratio [HR] =0.57, 95% CI [0.40-0.83]) and severe (HR = 0.43, 95% CI [0.28-0.66]) exacerbations compared to the historical control group, but similar risks compared with the contemporaneous control group. The COPD pathway patients experienced fewer episodes of exacerbations compared with the historical control group (mean difference = -0.30, 95% CI [-0.40, -0.20]) and the contemporaneous control group (mean difference = -0.12, 95% CI [-0.20, -0.03]). Average annual healthcare costs in Canadian dollars were marginally higher among patients in the COPD clinical pathway (mean = $10 549, standard deviation [SD] =$18 149) than those in the contemporaneous control group ($8841, SD = $17 120), but comparable to the historical control group ($10 677, SD = $21 201). The COPD pathway provides better outcomes at about the same costs when compared to the historical controls, but only slightly better outcomes and at a marginally higher cost when compared to the contemporaneous controls.

2023 Canadian Thoracic Society Guideline on Pharmacotherapy in Patients With Stable COPD.

Chronic obstructive pulmonary disease patient care must include confirming a diagnosis with postbronchodilator spirometry. Because of the clinical heterogeneity and the reality that airflow obstruction assessed by spirometry only partially reflects disease severity, a thorough clinical evaluation of the patient should include assessment of symptom burden and risk of exacerbations that permits the implementation of evidence-informed pharmacologic and nonpharmacologic interventions. This guideline provides recommendations from a comprehensive systematic review with a meta-analysis and expert-informed clinical remarks to optimize maintenance pharmacologic therapy for individuals with stable COPD, and a revised and practical treatment pathway based on new evidence since the 2019 update of the Canadian Thoracic Society (CTS) Guideline. The key clinical questions were developed using the Patients/Population (P), Intervention(s) (I), Comparison/Comparator (C), and Outcome (O) model for three questions that focuses on the outcomes of symptoms (dyspnea)/health status, acute exacerbations, and mortality. The evidence from this systematic review and meta-analysis leads to the recommendation that all symptomatic patients with spirometry-confirmed COPD should receive long-acting bronchodilator maintenance therapy. Those with moderate to severe dyspnea (modified Medical Research Council ≥ 2) and/or impaired health status (COPD Assessment Test ≥ 10) and a low risk of exacerbations should receive combination therapy with a long-acting muscarinic antagonist/long-acting ẞ2-agonist (LAMA/LABA). For those with a moderate/severe dyspnea and/or impaired health status and a high risk of exacerbations should be prescribed triple combination therapy (LAMA/LABA/inhaled corticosteroids) azithromycin, roflumilast or N-acetylcysteine is recommended for specific populations; a recommendation against the use of theophylline, maintenance systemic oral corticosteroids such as prednisone and inhaled corticosteroid monotherapy is made for all COPD patients.

Muscle metaboreflex control of left ventricular systolic function in heart failure with reduced ejection fraction.

Heart failure with reduced ejection fraction (HFrEF) exhibits exaggerated sympathoexcitation and altered cardiac and vascular responses to muscle metaboreflex activation (MMA). However, left ventricular (LV) responses to MMA are not well studied in patients with HFrEF. The purpose of this study was to examine LV function during MMA using cardiac magnetic resonance imaging (MRI) in patients with HFrEF. Thirteen patients with HFrEF and 18 healthy age-matched controls underwent cardiac MRI during rest and MMA. MMA protocol included 6 min of isometric handgrip exercise followed by 6-min of brachial postexercise circulatory occlusion. LV stroke volume index (SVi), end-systolic volume index (ESVi), end-diastolic volume index (EDVi), and global longitudinal strain (GLS) were measured by two- and four-chamber cine images. Volumes were indexed to body surface area. Heart rate (via ECG) and brachial mean arterial pressure (MAP) were recorded. Cardiac output and total peripheral resistance (TPR) were calculated. SVi decreased during MMA in HFrEF (P = 0.037) but not in controls (P = 0.392). ESVi (P = 0.007) and heart rate (P < 0.001) increased during MMA in HFrEF but not controls (P ≥ 0.170). TPR (P = 0.021) and MAP (P < 0.001) increased during MMA in both groups. Cardiac output (P = 0.946), EDVi (P = 0.177), and GLS (P = 0.619) were maintained from rest to MMA in both groups. Despite similarly maintained cardiac output, LV strain, and increased TPR in HFrEF and control groups, SVi decreased, and heart rate increased during MMA in patients with HFrEF. These findings suggest an impaired contractility reserve in response to increased TPR during MMA in HFrEF.NEW & NOTEWORTHY Stroke volume decreases and end-systolic volume increases during muscle metaboreflex activation in patients with heart failure with reduced ejection fraction (HFrEF), suggesting impaired contractile reserve during muscle metaboreflex activation in patients with HFrEF. Total peripheral resistance increases similarly during muscle metaboreflex activation in patients with HFrEF compared to controls, indicating normal levels of peripheral vasoconstriction during muscle metaboreflex activation in patients with HFrEF.

Impacts of Chronic Obstructive Pulmonary Disease Care Pathway on Healthcare Utilization and Costs: A Matched Multiple Control Cohort Study in Saskatchewan, Canada.

OBJECTIVES: This study aimed to evaluate the real-world impacts of a chronic obstructive pulmonary disease (COPD) care pathway program on healthcare utilization and costs in Saskatchewan, Canada. METHODS: A difference-in-differences evaluation of a real-life deployment of a COPD care pathway, using patient-level administrative health data in Saskatchewan, was conducted. The intervention group (n = 759) included adults (35+ years) with spirometry-confirmed COPD diagnosis recruited into the care pathway program in Regina between April 1, 2018 and March 31, 2019. The 2 control groups comprised adults (35+ years) with COPD who lived in Saskatoon during the same period (n = 759) or Regina between April 1, 2015 and March 31, 2016 (n = 759) who did not participate in the care pathway. RESULTS: Compared with the individuals in the Saskatoon control groups, individuals in the COPD care pathway group had shorter inpatient hospital length of stay (average treatment effect on the treated [ATT] -0.46, 95% CI -0.88 to -0.04) but a higher number of general practitioner visits (ATT 1.46, 95% CI 1.14 to 1.79) and specialist physician visits (ATT 0.84, 95% CI 0.61 to 1.07). Regarding healthcare costs, individuals in the care pathway group had higher COPD-related specialist visit costs (ATT $81.70, 95% CI $59.45 to $103.96) but lower COPD-related outpatient drug dispensation costs (ATT -$4.81, 95% CI -$9.34 to -$0.27). CONCLUSIONS: The care pathway reduced inpatient hospital length of stay, but increased general practitioner and specialist physician visits for COPD-related services within the first year of implementation.

Short-term air pollution exposure and exacerbation events in mild to moderate COPD: a case-crossover study within the CanCOLD cohort.

BACKGROUND: Infections are considered as leading causes of acute exacerbations of chronic obstructive pulmonary disease (COPD). Non-infectious risk factors such as short-term air pollution exposure may play a clinically important role. We sought to estimate the relationship between short-term air pollutant exposure and exacerbations in Canadian adults living with mild to moderate COPD. METHODS: In this case-crossover study, exacerbations ('symptom based': ≥48 hours of dyspnoea/sputum volume/purulence; 'event based': 'symptom based' plus requiring antibiotics/corticosteroids or healthcare use) were collected prospectively from 449 participants with spirometry-confirmed COPD within the Canadian Cohort Obstructive Lung Disease. Daily nitrogen dioxide (NO2), fine particulate matter (PM2.5), ground-level ozone (O3), composite of NO2 and O3 (Ox), mean temperature and relative humidity estimates were obtained from national databases. Time-stratified sampling of hazard and control periods on day '0' (day-of-event) and Lags ('-1' to '-6') were compared by fitting generalised estimating equation models. All data were dichotomised into 'warm' (May-October) and 'cool' (November-April) seasons. ORs and 95% CIs were estimated per IQR increase in pollutant concentrations. RESULTS: Increased warm season ambient concentration of NO2 was associated with symptom-based exacerbations on Lag-3 (1.14 (1.01 to 1.29), per IQR), and increased cool season ambient PM2.5 was associated with symptom-based exacerbations on Lag-1 (1.11 (1.03 to 1.20), per IQR). There was a negative association between warm season ambient O3 and symptom-based events on Lag-3 (0.73 (0.52 to 1.00), per IQR). CONCLUSIONS: Short-term ambient NO2 and PM2.5 exposure were associated with increased odds of exacerbations in Canadians with mild to moderate COPD, further heightening the awareness of non-infectious triggers of COPD exacerbations.

Factors Associated with Attrition in a Longitudinal Cohort of Older Adults in the Community.

Introduction: Retaining participants in longitudinal studies increases their power. We undertook this study in a population-based longitudinal cohort of adults with COPD to determine the factors associated with increased cohort attrition. Methods: In the longitudinal population-based Canadian Cohort of Obstructive Lung Disease (CanCOLD) study, 1561 adults > 40 years old were randomly recruited from 9 urban sites. Participants completed in-person visits at 18-month intervals and also were followed up every 3 months over the phone or by email. The cohort retention for the study and the reasons for attrition were analyzed. Hazard ratios and robust standard errors were calculated using Cox regression methods to explore the associations between participants who remained in the study and those who did not. Results: The median follow-up (years) of the study is 9.0 years. The overall mean retention was 77%. Reasons for attrition (23%) were: dropout by participant (39%), loss of contact (27%), investigator-initiated withdrawal (15%), deaths (9%), serious disease (9%), and relocation (2%). Factors independently associated with attrition were lower educational attainment, higher pack-year tobacco consumption, diagnosed cardiovascular disease, and a higher Hospital Anxiety and Depression Scale score: adjusted hazard ratios (95% confidence interval) were 1.43(1.11, 1.85); 1.01(1.00, 1.01); 1.44(1.13, 1.83); 1.06(1.02, 1.10) respectively. Conclusions: Identification and awareness of risk factors for attrition could direct targeted retention strategies in longitudinal studies. Moreover, the identification of patient characteristics associated with study dropout could address any potential bias introduced by differential dropouts.

Impaired Spirometry and COPD Increase the Risk of Cardiovascular Disease: A Canadian Cohort Study.

BACKGROUND: Individuals with COPD and preserved ratio impaired spirometry (PRISm) findings in clinical settings have an increased risk of cardiovascular disease (CVD). RESEARCH QUESTION: Do individuals with mild to moderate or worse COPD and PRISm findings in community settings have a higher prevalence and incidence of CVD compared with individuals with normal spirometry findings? Can CVD risk scores be improved when impaired spirometry is added? STUDY DESIGN AND METHODS: The analysis was embedded in the Canadian Cohort Obstructive Lung Disease (CanCOLD). Prevalence of CVD (ischemic heart disease [IHD] and heart failure [HF]) and their incidence over 6.3 years were compared between groups with impaired and normal spirometry findings using logistic regression and Cox models, respectively, adjusting for covariables. Discrimination of the pooled cohort equations (PCE) and Framingham risk score (FRS) in predicting CVD were assessed with and without impaired spirometry. RESULTS: Participants (n = 1,561) included 726 people with normal spirometry findings and 835 people with impaired spirometry findings (COPD Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 1 disease, n = 408; GOLD stage ≥ 2, n = 331; PRISm findings, n = 96). Rates of undiagnosed COPD were 84% in GOLD stage 1 and 58% in GOLD stage ≥ 2 groups. Prevalence of CVD (IHD or HF) was significantly higher among individuals with impaired spirometry findings and COPD compared with those with normal spirometry findings, with ORs of 1.66 (95% CI, 1.13-2.43; P = .01∗) (∗ indicates statistical significane with P < .05) and 1.55 (95% CI, 1.04-2.31; P = .033∗), respectively. Prevalence of CVD was significantly higher in participants having PRISm findings and COPD GOLD stage ≥ 2, but not GOLD stage 1. CVD incidence was significantly higher, with hazard ratios of 2.07 (95% CI, 1.10-3.91; P = .024∗) for the impaired spirometry group and 2.09 (95% CI, 1.10-3.98; P = .024∗) for the COPD group compared to individuals with normal spirometry findings. The difference was significantly higher among individuals with COPD GOLD stage ≥ 2, but not GOLD stage 1. The discrimination for predicting CVD was low and limited when impaired spirometry findings were added to either risk score. INTERPRETATION: Individuals with impaired spirometry findings, especially those with moderate or worse COPD and PRISm findings, have increased comorbid CVD compared with their peers with normal spirometry findings, and having COPD increases the risk of CVD developing.

Effect of Race and Ethnicity on Pulmonary Function Testing Interpretation: An American College of Chest Physicians (CHEST), American Association for Respiratory Care (AARC), American Thoracic Society (ATS), and Canadian Thoracic Society (CTS) Evidence Review and Research Statement.

BACKGROUND: Calls have been made to discontinue the routine use of race and ethnicity in medicine. Specific to respiratory medicine, the use of race- and ethnicity-specific reference equations for the interpretation of pulmonary function test (PFT) results has been questioned. RESEARCH QUESTIONS: Three key questions were addressed: (1) What is the current evidence supporting the use of race- and ethnicity-specific reference equations for the interpretation of PFTs? (2) What are the potential clinical implications of the use or nonuse of race and ethnicity in interpreting PFT results? and (3) What research gaps and questions must be addressed and answered to understand better the effect of race and ethnicity on PFT results interpretation and potential clinical and occupational health implications? STUDY DESIGN AND METHODS: A joint multisociety (American College of Chest Physicians, American Association for Respiratory Care, American Thoracic Society, and Canadian Thoracic Society) expert panel was formed to undertake a comprehensive evidence review and to develop a statement with recommendations to address the research questions. RESULTS: Several assumptions and gaps, both in the published literature and in our evolving understanding of lung health, were identified. It seems that many past perceptions and practices regarding the effect of race and ethnicity on PFT results interpretation are based on limited scientific evidence and measures that lack reliability. INTERPRETATION: A need exists for more and better research that will inform our field about these many uncertainties and will serve as a foundation for future recommendations in this area. The identified shortcomings should not be discounted or dismissed because they may enable flawed conclusions, unintended consequences, or both. Addressing the identified research gaps and needs would allow a better-a more informed-understanding of the effects of race and ethnicity on PFT results interpretation.

Physical Activity and Symptom Burden in COPD: The Canadian Obstructive Lung Disease Study.

Background: The relationship between symptom burden and physical activity (PA) in chronic obstructive pulmonary disease (COPD) remains poorly understood with limited data on undiagnosed individuals and those with mild to moderate disease. Objective: The primary objective was to evaluate the relationship between symptom burden and moderate-to-vigorous intensity PA (MVPA) in individuals from a random population-based sampling mirroring the population at large. Methods: Baseline participants of the Canadian Cohort Obstructive Lung Disease (n=1558) were selected for this cross-sectional sub-study. Participants with mild COPD (n=406) and moderate COPD (n=331), healthy individuals (n=347), and those at risk of developing COPD (n=474) were included. The Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire was used to estimate MVPA in terms of energy expenditure. High symptom burden was classified using the COPD Assessment Test ([CAT] ≥10). Results: Significant associations were demonstrated between high symptom burden and lower MVPA levels in the overall COPD sample (ß=-717.09; 95% confidence interval [CI]=-1079.78, -354.40; p<0.001) and in the moderate COPD subgroup (ß=-694.1; 95% CI=-1206.54, -181.66; p=0.006). A total of 72% of the participants with COPD were previously undiagnosed. The undiagnosed participants had significantly higher MVPA than those with physician diagnosed COPD (ß=-592.41 95% CI=-953.11, -231.71; p=0.001). Conclusion: MVPA was found to be inversely related to symptom burden in a large general population sample that included newly diagnosed individuals, most with mild to moderate COPD. Assessment of symptom burden may help identify patients with lower MVPA, especially for moderate COPD and for relatively inactive individuals with mild COPD.

Ambient Air Pollution and Dysanapsis: Associations with Lung Function and Chronic Obstructive Pulmonary Disease in the Canadian Cohort Obstructive Lung Disease Study.

Rationale: Outdoor air pollution is a potential risk factor for lower lung function and chronic obstructive pulmonary disease (COPD). Little is known about how airway abnormalities and lung growth might modify this relationship. Objectives: To evaluate the associations of ambient air pollution exposure with lung function and COPD and examine possible interactions with dysanapsis. Methods: We made use of cross-sectional postbronchodilator spirometry data from 1,452 individuals enrolled in the CanCOLD (Canadian Cohort Obstructive Lung Disease) study with linked ambient fine particulate matter (PM2.5) and nitrogen dioxide (NO2) air pollution estimates. Dysanapsis, or the ratio of the airway-to-lung volume calculated from thoracic computed tomography images, was used to examine possible interactions. Measurements and Main Results: In adjusted models, 101.7 ml (95% confidence interval [CI], -166.2 to -37.2) and 115.0 ml (95% CI, -196.5 to -33.4) lower FEV1 were demonstrated per increase of 2.4 ug/m3 PM2.5 and 9.2 ppb NO2, respectively. Interaction between air pollution and dysanapsis was not statistically significant when modeling the airway-to-lung ratio as a continuous variable. However, a 109.8 ml (95% CI, -209.0 to -10.5] lower FEV1 and an 87% (95% CI, 12% to 213%) higher odds of COPD were observed among individuals in the lowest, relative to highest, airway-to-lung ratio, per 2.4 µg/m3 increment of PM2.5. Conclusions: Ambient air pollution exposure was associated with lower lung function, even at relatively low concentrations. Individuals with dysanaptic lung growth might be particularly susceptible to inhaled ambient air pollutants, especially those at the extremes of dysanapsis.

Cerebral haemodynamics during arrhythmia in health, ischaemic heart disease and heart failure with reduced ejection fraction, and in a preclinical swine model.

Ventricular arrhythmias are associated with neurological impairment and could represent a source of cerebral hypoperfusion. In the present study, data from healthy individuals (n = 11), patients with ischaemic heart disease (IHD; ejection fraction >40%; n = 9) and patients with heart failure with reduced ejection fraction (HFrEF; EF = 31 (5)%, n = 11), as well as data from swine surgeries, where spontaneous ventricular arrhythmias were observed during cerebrovascular examination (transcranial Doppler ultrasound in humans and laser Doppler in swine) were analysed retrospectively to investigate the effect of arrhythmia on cerebral microvascular haemodynamics. A subset of participants also completed the Montreal Cognitive Assessment (MoCA). Middle cerebral artery mean blood velocity (MCAVmean ) decreased during premature ventricular contraction (PVC) in all groups, and data from swine indicate PVCs reduced cerebral microvascular perfusion. Overall MCAVmean was decreased in the HFrEF vs. control group. Further, %∆MCAVmean /%∆mean arterial pressure during the PVC was greater in the HFrEF vs. control group and was correlated with decreased MoCA scores. Subanalysis of HFrEF data revealed that during bigeminy MCAVmean decreased owing to reductions during irregular beats only. During non-sustained ventricular tachycardia, MCAVmean decreased but recovered above baseline upon return to sinus rhythm. Also, haemodynamic perturbations during and following the PVC were greater in the brachial artery vs. the MCA. Therefore, ventricular arrhythmias decreased indices of cerebral perfusion irrespective of IHD or HFrEF. The relative magnitude of arrhythmia-induced haemodynamic perturbations appears to be population specific and arrhythmia type and organ dependent. The cumulative burden of arrhythmia-induced deficits may exacerbate existing cerebral hypoperfusion in HFrEF and contribute to neurological abnormalities in this population. KEY POINTS: Irregular heartbeats are often considered benign in isolation, but individuals who experience them frequently have a higher prevalence of cerebrovascular and/or cognitive associated disorders. How irregular heartbeats affect blood pressure and cerebral haemodynamics in healthy and cardiovascular disease patients, those with and without reduced ejection fraction, remains unknown. Here it was found that in the absence of symptoms associated with irregular heartbeats, such as dizziness or hypotension, single, multiple non-sustained and sustained irregular heartbeats influence cerebral haemodynamics in a population-specific, arrhythmia-type and organ-dependent manner. Relative deficits in the index of cerebral blood flow normalized to relative deficits in blood pressure were greatest in patients with heart failure with reduced ejection and inversely related with cognitive performance. Chronic arrhythmias may exacerbate existing cerebral hypoperfusion in heart failure with reduced ejection fraction, thereby providing a mechanistic link between otherwise benign irregular heartbeats and cognitive dysfunction, independent of embolism.

Economic Burden of Chronic Obstructive Pulmonary Disease and Lung Cancer Between 2000 and 2015 in Saskatchewan: Study Protocol.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) and lung cancer are both detrimental diseases that present great burdens on society. Years of life lost (YLL), premature years of life lost (PYLL), working years lost (WYL), and productivity loss are all effective measures in identifying economic burden of disease. OBJECTIVE: We propose a population-based study to analyze comprehensive provincial cohorts of Saskatchewan residents with COPD, lung cancer, and combined COPD and lung cancer in order to identify the burden these diseases present. METHODS: Saskatchewan residents over the age of 35 years who had COPD, lung cancer, or both, between January 1, 2000, and December 31, 2015, will be identified and used in this study. Data for analysis including age, gender, and date of death, alongside Statistics Canada income estimates, will be used to estimate productivity loss and WYL. Statistics Canada life tables will be used to calculate YLL and PYLL by subtracting the patients' ages at death by their life expectancies, adjusted using sex and age at death. We will link the Saskatchewan cancer registry with Saskatchewan health administrative databases to create three cohorts: (1) COPD; (2) lung cancer; and (3) COPD and lung cancer. Individuals with lung cancer will be identified using ICDO-T (International Classification of Diseases for Oncology-Topography) codes, and those with COPD will be defined and identified as individuals who had at least 1 visit to a physician with a diagnosis of COPD or 1 hospital separation with a diagnosis of COPD. Those without a valid health care coverage for a consecutive 12 months prior to the first diagnostic code will be excluded from the study. Those with a combined diagnosis of COPD and lung cancer will be identified as individuals who were diagnosed with COPD in the 12 months following their lung cancer diagnosis or anytime preceding their lung cancer diagnosis. RESULTS: As of April 2021, we have had access to all relevant data for this study, have received funding (January 2020), and have begun the preliminary analysis of our data set. CONCLUSIONS: It is well documented that COPD and lung cancer are both destructive diseases in terms of YLL, PYLL, WYL, and productivity loss; however, no studies have been conducted to analyze a cohort with combined COPD and lung cancer. Understanding the economic burden associated with each of our 3 cohorts is necessary in understanding and thus reducing the societal impact of COPD and lung cancer. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR1-10.2196/31350.

Autonomic cardiovascular reflex control of hemodynamics during exercise in heart failure with reduced ejection fraction and the effects of exercise training.

Heart failure with reduced ejection fraction is associated with increased exercise intolerance, morbidity, and mortality. Importantly, exercise intolerance in heart failure with reduced ejection fraction is a key factor limiting patient quality of life and survival. Exercise intolerance in heart failure with reduced ejection fraction stems from a multi-organ failure to maintain homeostasis at rest and during exercise, including the heart, skeletal muscle, and autonomic nervous system, lending itself to a system constantly trying to "catch-up". Hemodynamic control during exercise is regulated primarily by the autonomic nervous system, whose operation, in turn, is partly regulated via reflexive information from exercise-stimulated receptors throughout the body (e.g., arterial baroreflex, central and peripheral chemoreceptors, and the muscle metabo- and mechanoreflexes). Persons with heart failure with reduced ejection fraction exhibit malfunctioning autonomic reflexes, which lead to exaggerated sympathoexcitation and attenuated parasympathetic tone. Chronic elevation of sympathetic activity is associated with increased morbidity and mortality. In this review, we provide an overview of how each main exercise-related autonomic reflex is changed in heart failure with reduced ejection fraction, and the role of exercise training in attenuating or reversing the counterproductive changes.