The incremental prognostic importance of body fat adjusted peak oxygen consumption in chronic heart failure

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Comparison of Cardiorespiratory Fitness Prediction Equations and Generation of New Predictive Model for Patients with Obesity

PURPOSE

Cardiorespiratory fitness (CRF) is a critical marker of overall health and a key predictor of morbidity and mortality, but the existing prediction equations for CRF are primarily derived from general populations and may not be suitable for patients with obesity.

METHODS

Predicted CRF from different non-exercise prediction equations was compared with measured CRF of patients with obesity who underwent maximal cardiopulmonary exercise testing (CPET). Multiple linear regression was used to develop a population-specific nonexercise CRF prediction model for treadmill exercise including age, sex, weight, height, and physical activity level as determinants.

RESULTS

Six hundred sixty patients underwent CPET during the study period. Within the entire cohort, R2 values had a range of 0.24 to 0.46. Predicted CRF was statistically different from measured CRF for 19 of the 21 included equations. Only 50% of patients were correctly classified into the measured CRF categories according to predicted CRF. A multiple model for CRF prediction (mL·min -1 ) was generated ( R2 = 0.78) and validated using two cross-validation methods.

CONCLUSIONS

Most used equations provide inaccurate estimates of CRF in patients with obesity, particularly in cases of severe obesity and low CRF. Therefore, a new prediction equation was developed and validated specifically for patients with obesity, offering a more precise tool for clinical CPET interpretation and risk stratification in this population.

Quantifying assumptions underlying peak oxygen consumption equations across the body mass spectrum

The goal of this study is to quantify the assumptions associated with the Wasserman-Hansen (WH) and Fitness Registry and the Importance of Exercise: A National Database (FRIEND) predictive peak oxygen consumption (pVO2) equations across body mass index (BMI). Assumptions in pVO2 for both equations were first determined using a simulation and then evaluated using exercise data from the Stanford Exercise Testing registry. We calculated percent-predicted VO2 (ppVO2) values for both equations and compared them using the Bland-Altman method. Assumptions associated with pVO2 across BMI categories were quantified by comparing the slopes of age-adjusted VO2 ratios (pVO2/pre-exercise VO2) and ppVO2 values for different BMI categories. The simulation revealed lower predicted fitness among adults with obesity using the FRIEND equation compared to the WH equations. In the clinical cohort, we evaluated 2471 patients (56.9% male, 22% with BMI >30 kg/m2, pVO2 26.8 mlO2/kg/min). The Bland-Altman plot revealed an average relative difference of -1.7% (95% CI: -2.1 to -1.2%) between WH and FRIEND ppVO2 values with greater differences among those with obesity. Analysis of the VO2 ratio to ppVO2 slopes across the BMI spectrum confirmed the assumption of lower fitness in those with obesity, and this trend was more pronounced using the FRIEND equation. Peak VO2 estimations between the WH and FRIEND equations differed significantly among individuals with obesity. The FRIEND equation resulted in a greater attributable reduction in pVO2 associated with obesity relative to the WH equations. The outlined relationships between BMI and predicted VO2 may better inform the clinical interpretation of ppVO2 values during cardiopulmonary exercise test evaluations.

Evaluating current assessment techniques of cardiorespiratory fitness

INTRODUCTION

Considerable and convincing global data from cohorts across the health spectrum (i.e. apparently healthy to known disease) indicate that cardiorespiratory fitness (CRF) is a major predictor of overall and cardiovascular disease (CVD)-survival, seemingly with greater prognostic resolution compared to other traditional CVD risk factors. Therefore, the assessment of CRF in research and clinical settings is of major importance.

AREAS COVERED

In this manuscript, we review the technology of measuring CRF assessed by the 'gold standard,' cardiopulmonary exercise testing (CPET), as well as with various other methods (e.g. estimated metabolic equivalents, 6-minute walk tests, shuttle tests, and non-exercise equations that estimate CRF), all of which provide significant prognostic information for CVD- and all-cause survival. The literature through May 2024 has been cited.

EXPERT OPINION

The promotion of physical activity in efforts to improve levels of CRF is needed throughout the world to improve lifespan and, more importantly, healthspan. The routine assessment of CRF should be considered a vital sign that is routinely assessed in clinical practice.

Exercise, cancer, and the cardiovascular system: clinical effects and mechanistic insights

Cardiovascular diseases and cancer are the leading causes of death in the Western world and share common risk factors. Reduced cardiorespiratory fitness (CRF) is a major determinant of cardiovascular morbidity and cancer survival. In this review we discuss cancer- induced disturbances of parenchymal, cellular, and mitochondrial function, which limit CRF and may be antagonized and attenuated through exercise training. We show the impact of CRF on cancer survival and its attenuating effects on cardiotoxicity of cancer-related treatment. Tailored exercise programs are not yet available for each tumor entity as several trials were performed in heterogeneous populations without adequate cardiopulmonary exercise testing (CPET) prior to exercise prescription and with a wide variation of exercise modalities. There is emerging evidence that exercise may be a crucial pillar in cancer treatment and a tool to mitigate cardiotoxic treatment effects. We discuss modalities of aerobic exercise and resistance training and their potential to improve CRF in cancer patients and provide an example of a periodization model for exercise training in cancer.

Update on obesity, the obesity paradox, and obesity management in heart failure

Obesity is a major public health challenge worldwide. It is costly, predisposes to many cardiovascular (CV) diseases (CVD), is increasing at an alarming rate, and disproportionately affects people of low-socioeconomic status. It has a myriad of deleterious effects on the body, particularly on the CV system. Obesity is a major risk factor for heart failure (HF) and highly prevalent in this population, particularly in those with HF with preserved ejection fraction (HFpEF), to the extent that an obesity HFpEF phenotype has been proposed in the literature. However, once HF is developed, an obesity paradox exists where those with obesity have better short- and mid-term survival than normal or underweight individuals, despite a greater risk for hospitalizations. It may be argued that excess energy reserve, younger patient population, higher tolerability of HF therapy and better nutritional status may account for at least part of the obesity paradox on survival. Furthermore, body mass index (BMI) may not be an accurate measure of body composition, especially in HF, where there is an excess volume status. BMI also fails to delineate fat-free mass and its components, which is a better predictor of functional capacity and cardiorespiratory fitness (CRF), which particularly is increasingly being recognized as a risk modifier in both healthy individuals and in persons with comorbidities, particularly in HF. Notably, when CRF is accounted for, the obesity paradox disappears, suggesting that improving CRF might represent a therapeutic target with greater importance than changes in body weight in the setting of HF. In this narrative review, we discuss the current trends in obesity, the causal link between obesity and HF, an update on the obesity paradox, and a description of the major flaws of BMI in this population. We also present an overview of the latest in HF therapy, weight loss, CRF, and the application of these therapeutic approaches in patients with HF and concomitant obesity.

Observational and genetic associations between cardiorespiratory fitness and cancer: a UK Biobank and international consortia study

BACKGROUND

The association of fitness with cancer risk is not clear.

METHODS

We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of lung, colorectal, endometrial, breast, and prostate cancer in a subset of UK Biobank participants who completed a submaximal fitness test in 2009-12 (N = 72,572). We also investigated relationships using two-sample Mendelian randomisation (MR), odds ratios (ORs) were estimated using the inverse-variance weighted method.

RESULTS

After a median of 11 years of follow-up, 4290 cancers of interest were diagnosed. A 3.5 ml O2⋅min-1⋅kg-1 total-body mass increase in fitness (equivalent to 1 metabolic equivalent of task (MET), approximately 0.5 standard deviation (SD)) was associated with lower risks of endometrial (HR = 0.81, 95% CI: 0.73-0.89), colorectal (0.94, 0.90-0.99), and breast cancer (0.96, 0.92-0.99). In MR analyses, a 0.5 SD increase in genetically predicted O2⋅min-1⋅kg-1 fat-free mass was associated with a lower risk of breast cancer (OR = 0.92, 95% CI: 0.86-0.98). After adjusting for adiposity, both the observational and genetic associations were attenuated.

DISCUSSION

Higher fitness levels may reduce risks of endometrial, colorectal, and breast cancer, though relationships with adiposity are complex and may mediate these relationships. Increasing fitness, including via changes in body composition, may be an effective strategy for cancer prevention.

Distinct effects of type 2 diabetes and obesity on cardiopulmonary performance

AIM

Effort intolerance is frequent in patients with overweight/obesity and/or type 2 diabetes (T2D) free from cardiac and respiratory disease. We sought to quantify the independent effects of T2D and body mass index (BMI) on cardiopulmonary capacity and gain insights on the possible pathophysiology by case-control and regression analyses.

METHODS

Patients at high/moderate cardiovascular risk, with or without T2D, underwent spirometry and combined echocardiography-cardiopulmonary exercise test as part of their clinical workup. Subjects with evidence of cardiopulmonary disease were excluded. The effects of T2D and obesity were estimated by multivariable models accounting for known/potential confounders and the major pathophysiological determinants of oxygen uptake at peak exercise (VO2peak ) normalized for fat-free mass (FFM).

RESULTS

In total, 109 patients with T2D and 97 controls were included in the analysis. The two groups had similar demographic and anthropometric characteristics except for higher BMI in T2D (28.6 ± 4.6 vs. 26.3 ± 4.4 kg/m2 , p = .0003) but comparable FFM. Patients with T2D achieved lower VO2peak than controls (18.5 ± 4.4 vs. 21.7 ± 8.3 ml/min/kg, p = .0006). Subclinical cardiovascular dysfunctions were observed in T2D: concentric left ventricular remodelling, autonomic dysfunction, systolic dysfunction and reduced systolic reserve. After accounting for confounders and major determinants of VO2peakFFM , T2D still displayed reduced VO2peak by 1.0 (-1.7/-0.3) ml/min/kgFFM , p = .0089, while the effect of BMI [-0.2 (-0.3/0.1) ml/min/kgFFM , p = .06 per unit increase], was largely explained by a combination of chronotropic incompetence, reduced peripheral oxygen extraction, impaired systolic reserve and ventilatory (in)efficiency.

CONCLUSIONS

T2D is an independent negative determinant of VO2peak whose effect is additive to other pathophysiological determinants of oxygen uptake, including BMI.

Epicardial fat and Stage B heart failure among overweight/obese and normal weight individuals with diabetes mellitus

PURPOSE

Although up to 20% of people with type 2 diabetes (DM) have normal BMI (< 25 kg/m2), it remains unclear whether there is a difference in the development of cardiac dysfunction between those with normal and higher BMI. Furthermore, little is known about the relationship of visceral fat with BMI or fitness in asymptomatic patients with DM.

METHODS

We prospectively enrolled asymptomatic patients with DM and divided into two groups: BMI ≥ 25kg/m2 (overweight/obese group) versus < 25kg/m2(normal-weight group). Resting echocardiogram followed by exercise stress echocardiogram and exercise gas exchange analysis (in a subgroup) was performed. Cardiac function was evaluated using left ventricular longitudinal strain (LVLS), E/e', and relative wall thickness (RWT). In addition, epicardial fat thickness (EFT) was measured to estimate visceral fat.

RESULTS

Normal-weight patients with DM had more EFT compared with overweight/obese patients (0.66 ± 0.17 cm vs. 0.59 ± 0.22 cm, p < 0.05), despite the overlap between the groups. There was no significant difference in the prevalence of LV remodeling (p = 0.49), impaired LVLS (p = 0.22), or increased E/e' (p = 0.26), and these were consistently observed when matched for race. The majority of patients (63%) achieved ≥ 85% of percent peak-predicted VO2. At peak, there was no significant difference in peak VO2 normalized by eLBM (36.4 ± 7.7 vs. 37.8 ± 7.1 ml/kg eLBM/min, p = 0.43) while VO2 normalized by weight (23.6 ± 6.5 vs. 29.6 ± 6.7 ml/kg/min, p < 0.001) and VO2 ratio (5.7 ± 1.7 vs. 7.3 ± 2.4 METs, p = 0.001) were significantly lower in patients with obese/overweight group. There was no significant difference between patients with higher and lower EFT.

CONCLUSIONS

Patients with DM and normal BMI have excess epicardial fat compared to those with overweight/obese. Epicardial fat was not directly linked to prevalence of subclinical dysfunction.

Skeletal muscle quality, measured via phase angle, and cardiorespiratory fitness in patients with obesity and heart failure with preserved ejection fraction

OBJECTIVES

Cardiorespiratory fitness (CRF) is influenced by body composition quantity and quality in heart failure with preserved ejection fraction (HFpEF) and obesity. Bioelectrical impedance analysis (BIA) provides a noninvasive quantitative and qualitative body composition assessment. The aim of this study was to determine the role of phase angle (PhA), a BIA-measure of skeletal muscle quality and body cell mass, on CRF in patients with obesity and HFpEF.

METHODS

Fifty-nine consecutive outpatients with HFpEF underwent cardiopulmonary exercise testing to measure CRF. Single-frequency segmental BIA was used to measure PhA and body composition quantity. Resting Doppler echocardiography and biomarkers were measured to assess cardiac function and systemic inflammation.

RESULTS

Compared with patients with lower PhA, patients with higher PhA (above mean 5.8°) presented a greater absolute peak oxygen consumption (VO2; 1.83 [1.3-2.1] versus 1.39 [1.1-1.6] L/min, P = 0.003), VO2 peak adjusted for body weight (17.5 [12.3-18.1] versus 13.3 [12.7-15.2] mL/kg/min, P = 0.040), and a lower edema index (48.7 [2.9] versus 51.4% [2.7], P < 0.001) and N-terminal pro-B-type natriuretic peptide (NT-proBNP; 64 [50-121] versus 183 [68-343.5] pg/dL, P < 0.001). In the overall sample, PhA was correlated with absolute VO2 peak (r = 0.468, P < 0.001), VO2 peak adjusted for body weight (r = 0.368, P = 0.004), VO2 peak adjusted for fat-free mass (r = 0.315, P = 0.015), edema index (r = -0.508, P < 0.001), and NT-proBNP (r = -0.579, P < 0.001). PhA remained a significant predictor for CRF even after adjustment for potential confounders and HFpEF severity.

CONCLUSION

In patients with obesity and HFpEF, a greater PhA is an independent predictor for favorable CRF.

Cardiopulmonary Exercise Testing in Patients with Heart Failure: Impact of Gender in Predictive Value for Heart Transplantation Listing

BACKGROUND

Exercise testing is key in the risk stratification of patients with heart failure (HF). There are scarce data on its prognostic power in women. Our aim was to assess the predictive value of the heart transplantation (HTx) thresholds in HF in women and in men.

METHODS

Prospective evaluation of HF patients who underwent cardiopulmonary exercise testing (CPET) from 2009 to 2018 for the composite endpoint of cardiovascular mortality and urgent HTx.

RESULTS

A total of 458 patients underwent CPET, with a composite endpoint frequency of 10.5% in females vs. 16.0% in males in 36-month follow-up. Peak VO2 (pVO2), VE/VCO2 slope and percent of predicted pVO2 were independent discriminators of the composite endpoint, particularly in women. The International Society for Heart Lung Transplantation recommended values of pVO2 ≤ 12 mL/kg/min or ≤14 if the patient is intolerant to β-blockers, VE/VCO2 slope > 35, and percent of predicted pVO2 ≤ 50% showed a higher diagnostic effectiveness in women. Specific pVO2, VE/VCO2 slope and percent of predicted pVO2 cut-offs in each sex group presented a higher prognostic power than the recommended thresholds.

CONCLUSION

Individualized sex-specific thresholds may improve patient selection for HTx. More evidence is needed to address sex differences in HF risk stratification.

Cardiopulmonary Exercise Testing, Rehabilitation, and Exercise Training in Postpulmonary Embolism

Long-term exercise intolerance and functional limitations are common after an episode of acute pulmonary embolism (PE), despite 3 to 6 months of anticoagulation. These persistent symptoms are reported in more than half of the patients with acute PE and are referred as "post-PE syndrome." Although these functional limitations can occur from persistent pulmonary vascular occlusion or pulmonary vascular remodeling, significant deconditioning can be a major contributing factor. Herein, the authors review the role of exercise testing to elucidate the mechanisms of exercise limitations to guide next steps in management and exercise training for musculoskeletal deconditioning.

Heart failure classification based on resting ejection fraction does not display a unique exercise response pattern

BACKGROUND

Heart failure with preserved (HFpEF), mildly reduced (HFmrEF) and reduced (HFrEF) ejection fraction (EF) remains a controversial categorization. Whether these three categories reflect a distinct pattern of exercise limitation in cardiopulmonary exercise testing (CPET) needs to be investigated. We aimed to analyze whether CPET variables differ between all heart failure categories (HF).

METHODS

We analyzed CPET variables of stable HFpEF (n = 123), HFmrEF (n = 31), and HFrEF (n = 153; 74 patients with and 79 patients without left ventricular assist device, LVAD) patients. The association between HF and peak oxygen consumption (VO_2peak) was used as a primary outcome, while the association between HF, oxygen uptake efficiency slope (OUES), and increase of O₂ pulse (ΔO₂ pulse) were analyzed as secondary outcomes.

RESULTS

VO_2peak displayed a consistent decline across all HF categories (19.8 ml ± 6.2/kg/min vs. 17.5 ± 7.9 ml/kg/min vs. 13.7 ± 4.0 ml/kg/min, p < 0.001). OUES only showed differences between HFpEF and HFrEF (1.8 ± 0.6 vs. 1.4 ± 0.5, p < 0.001) as well as HFmrEF and HFrEF (1.9 ± 0.9 vs. 1.4 ± 0.5, p = 0.004). ΔO₂ pulse differed between HFpEF and HFrEF (7.7 ± 3.5 ml/beat/kg*100 vs. 5.5 ± 3.0 ml/beat/kg*100, p < 0.001) as well as HFpEF and HFmrEF (7.7 ± 3.5 ml/beat/kg*100 vs. 6.3 ± 4.1 ml/beat/kg*100, p = 0.049). Outcome variables did not differ between HFrEF with and without LVAD support (VO_2peak: p = 0.364, OUES: p = 0.129, ΔO₂ pulse: p = 0.564).

CONCLUSIONS

HF did not display a distinct CPET profile. Thus, EF-based categorization does not entirely reflect exercise limitations. CPET variables could contribute to better characterize HF phenotypes.

The effect of SGLT-2 inhibitors on cardiorespiratory fitness capacity: A systematic review and meta-analysis

Objective: The study aimed to evaluate the effect of sodium-glucose transporter 2 (SGLT-2) inhibitors on various parameters of exercise capacity and provide an evidence-based basis for type 2 diabetes mellitus (T2DM) combined with heart failure (HF) patients or HF patients without T2DM who use SGLT-2 inhibitors to improve cardiorespiratory fitness (CRF). Methods: According to the participant, intervention, comparison, and outcome (PICO) elements, the effects of SGLT-2 inhibitor administration on VO₂ or VO₂peak were researched in this study. Weighted mean difference (WMD) and 95% confidence intervals (CIs) were calculated (random-effects model). Heterogeneity was assessed by the I² test. Results: Six studies were included according to the eligibility criteria: four were RCTs, and two were non-RCTs. Compared with the control group, the merge results of RCTs showed that SGLT-2 inhibitors could significantly increase the VO₂peak (WMD, 2.02 ml kg^-1 min^-1, 95% CI: 0.68-3.37, and p = 0.03; I² = 0% and p = 0.40) and VAT (WMD, 1.57 ml kg^-1 min^-1, 95% CI: 0.06-3.07, and p = 0.04; I² = 0% and p = 0.52) of the obese population, patients with T2DM, and chronic HF patients with or without T2DM. Subgroup analysis showed that SGLT-2 inhibitors improved the VO₂peak in non-HF patients (WMD, 3.57 ml kg^-1 min^-1, 95% CI: 0.87-6.26, and p = 0.009; I² = 4% and p = 0.31) more than in HF patients (WMD, 1.46 ml kg^-1 min^-1, 95% CI: -0.13-3.04, and p = 0.07; I² = 0% and p = 0.81). Moreover, the merge of single-arm studies also indicated that empagliflozin could improve VO₂peak (MD, 1.11 ml kg^-1 min^-1, 95% CI: 0.93-1.30, and p = 0.827, Δ p = 0.000 and I² = 0%) of T2DM patients with chronic HF. Conclusion: Despite the limited number of studies and samples involved, the meta-analysis preliminarily demonstrated that SGLT-2 inhibitors could improve some parameters of exercise capacity (VO₂peak, VAT) in chronic HF patients with or without T2DM and obese individuals, which had a positive effect on promoting cardiopulmonary fitness to help these populations improve their prognosis. Systematic Review Registration: [https://www.crd.york.ac.uk/prospero/#recordDetails], identifier [CRD42020202788].

Predicted heart mass for size matching in obese heart transplant donors and recipients

INTRODUCTION

Predicted heart mass (PHM) was neither derived nor evaluated in an obese population. Our objective was to evaluate size mismatch using actual body weight or IBW-adjusted PHM on mortality and risk assessment.

METHODS

We conducted a retrospective cohort study of adult recipients with BMI ≥30 kg/m² or recipients of donors with BMI≥30 kg/m² from the ISHLT registry. We used multivariable Cox proportional hazard models to evaluate 30 day and 1-year mortality. The 2 models were compared using net reclassification index.

RESULTS

10,817 HT recipients, age 55 (IQR 46-62) years, 23% female, BMI 31 kg/m² (IQR 28-33) were included. Donors were age 34 (IQR 24-44) years, 31% female, and BMI 31 kg/m² (IQR 26-34). There was a significant non-linear association between mortality and actual PHM but not IBW-adjusted PHM. Undersizing using actual PHM was associated with higher 30-day and 1-year mortality (p<0.01), not seen with IBW-adjusted PHM. Actual PHM better risk classified 0.6% (95% CI 0.3-0.8%) patients compared to IBW-adjusted PHM.

CONCLUSION

Actual PHM can be used for size matching when assessing mortality risk in obese recipients or recipients of obese donors. There is no advantage to re-calculating PHM using IBW to define candidate risk at the time of organ allocation. This article is protected by copyright. All rights reserved.

Severe Obesity and Heart Failure

Obesity is associated with reduced mortality in some patients hospitalized for heart failure (HF). In this analysis, we determine if this nonlinear relation, referred to as the obesity paradox, extends to secondary outcomes in patients diagnosed with severe obesity. This is a retrospective cohort study using the 2017 and 2018 National Inpatient Sample that includes adults hospitalized for HF. Patients with diagnosis codes specifying severe obesity, nonsevere obesity, or without obesity are compared. The primary outcome is mortality. Secondary outcomes include the length of stay (LOS), total charges, and cardiogenic shock (CS). Multivariate regression is used to adjust for demographics and co-morbidities. A total of 2,439,845 hospitalizations are included. A decreased mortality is found in nonsevere obesity (odds ratio 0.74, 95% confidence interval 0.69 to 0.80, p = 0.000), affirming the obesity paradox. However, this decreased mortality is not found in severe obesity (odds ratio 1.01, 95% confidence interval 0.94 to 1.08, p = 0.766). Severe obesity and nonsevere obesity are also associated with less CS and increased LOS compared with non-obese patients. Severe obesity is associated with increased total charges. In conclusion, a nonlinear, U-shaped relation between obesity and mortality in patients hospitalized for HF is demonstrated, where those not obese and those severely obese experience greater mortality compared with the nonseverely obese. However, for secondary outcomes of CS, LOS, and total charges, the relation is linear and therefore not interpreted as paradoxical. More information is needed using the adiposity-based chronic disease model to characterize complex relations between obesity and mortality.

The Impact of Obesity in Heart Failure

Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Epidemiologic studies have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with leaner patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean mass as well as weight loss and improvements in quality of diet for the prevention and treatment of heart failure and concomitant obesity to improve cardiorespiratory fitness.

Obesity treatment: Weight loss versus increasing fitness and physical activity for reducing health risks

We propose a weight-neutral strategy for obesity treatment on the following grounds: (1) the mortality risk associated with obesity is largely attenuated or eliminated by moderate-to-high levels of cardiorespiratory fitness (CRF) or physical activity (PA), (2) most cardiometabolic risk markers associated with obesity can be improved with exercise training independent of weight loss and by a magnitude similar to that observed with weight-loss programs, (3) weight loss, even if intentional, is not consistently associated with lower mortality risk, (4) increases in CRF or PA are consistently associated with greater reductions in mortality risk than is intentional weight loss, and (5) weight cycling is associated with numerous adverse health outcomes including increased mortality. Adherence to PA may improve if health care professionals consider PA and CRF as essential vital signs and consistently emphasize to their patients the myriad benefits of PA and CRF in the absence of weight loss.

Listing Criteria for Heart Transplant: Role of Cardiopulmonary Exercise Test and of Prognostic Scores

Patients with advanced heart failure (AdHF) have a reduced quality of life and poor prognosis. A heart transplant (HT) is an effective treatment for such patients. Still, because of a shortage of donor organs, the final decision to place a patient without contraindications on the HT waiting list is based on detailed risk-benefit analysis. Cardiopulmonary exercise tests (CPETs) play a pivotal role in guiding selection in patients with AdHF considered for an HT. Furthermore, several validated multivariable predicting scores obtained through various techniques, including the CPETs, are available and part of the decision-making process for HT listing.

Assessing predicted heart mass size matching in obese heart transplant recipients

BACKGROUND

Predicted heart mass (PHM) is currently the most reliable metric for donor-recipient size matching in heart transplantation. Undersizing PHM donor-recipient match more than 20% independently predicts reduced survival. However, it is unclear if this is the case in obese recipients, in whom size matching can be challenging. We examined the use of PHM undersized hearts in obese recipients and assessed its impact on survival.

METHODS

The United Network for Organ Sharing database was queried for adult patients undergoing heart transplantation from 1995 to 2020. Obese recipients (BMI ≥ 30) were categorized based on donor-recipient PHM match ≤-20% (undersized) or >-20% (size-matched). Nearest-neighbor propensity score matching was performed to adjust for baseline differences between cohorts. Temporal outcomes were compared by Kaplan-Meier survival analysis.

RESULTS

A total of 13,668 obese recipients met inclusion criteria, with 9.6% receiving undersized and 90.4% receiving size-matched hearts. The proportion of undersized donor hearts in obese recipients significantly decreased over the study period (16.2% [1995] to 7.4% [2019], NP-trend < 0.001). Propensity-score matching resulted in 984 well-matched pairs of undersized and size-matched obese recipients. Recipients of undersized hearts saw similar 30-day mortality (5.5% vs 6.0%, p= 0.11) and re-transplantation rates (1.2% vs 1.2%, p = 1.00) as size-matched recipients. Survival at 1 year (88.4% vs 87.9%, p = 0.14), and 15 years (35.1% vs 31.0%, p = 0.12) was similar across cohorts.

CONCLUSIONS

A decreasing proportion of PHM undersized hearts are being utilized in obese recipients. However, utilizing PHM undersized hearts in obese recipients was not associated with a detriment in survival.

Sex-specific associations of obesity with exercise capacity and diastolic function in Koreans

BACKGROUND AND AIMS

Women with obesity are highly predominant among patients with heart failure with preserved ejection fraction (HFpEF). We aimed to elucidate sex-specific associations of obesity with exercise capacity and diastolic function.

METHODS AND RESULTS

Healthy individuals without known cardiovascular diseases undergoing cardiopulmonary exercise test and echocardiography (n = 736) were included and categorized into 4 groups according to their sex and obesity. Exercise capacity was lower in women than men. Obesity was associated with a lower exercise capacity in women (23.5 ± 7.3 vs. 21.3 ± 5.4 ml/kg/min, p < 0.05) but not in men (28.2 ± 7.8 vs. 28.0 ± 6.6 ml/kg/min, p > 0.10). Overall, women had a higher E/e' than men. Women without obesity had a similar E/e' to men with obesity (8.2 ± 1.8 vs. 8.4 ± 2.1, p > 0.10), and women with obesity had the highest E/e'. Among 5 risk factors (aging, obesity, elevated blood pressure, elevated heart rate, and elevated fasting glucose), obesity was a significant determinant of exercise intolerance in women but not men. Furthermore, obesity was associated with a greater risk of diastolic dysfunction in women than men (women, adjusted odds ratio 4.35 [95% confidence interval 2.44-7.74]; men, adjusted odds ratio 2.91 [95% confidence interval 1.42-5.95]).

CONCLUSION

Obesity had a more deleterious effect on exercise capacity and diastolic function in women than men, even in a healthy cohort. These subclinical changes might contribute to the development of a female predominance among HFpEF patients, particularly among individuals with obesity.

Shah K, Medina de Chazal H, Chiabrando JG, Vecchié A, Dell M, L. Mihalick V, Bogaev R, Hart L, Van Tassell BW, Arena R, Celi FS, Abbate A. The effects of canagliflozin compared to sitagliptin on cardiorespiratory fitness in type 2 diabetes mellitus and heart failure with reduced ejection fraction: The CANA-HF study

BACKGROUND

Canagliflozin reduces hospitalizations for heart failure (HF) in type 2 diabetes mellitus (T2DM). Its effect on cardiorespiratory fitness and cardiac function in patients with established HF with reduced ejection fraction (HFrEF) is unknown.

METHODS

We conducted a double-blind randomized controlled trial of canagliflozin 100 mg or sitagliptin 100 mg daily for 12 weeks in 88 patients, and measured peak oxygen consumption (VO₂ ) and minute ventilation/carbon dioxide production (VE/VCO₂ ) slope (co-primary endpoints for repeated measure ANOVA time_x_group interaction), lean peak VO₂ , ventilatory anaerobic threshold (VAT), cardiac function and quality of life (ie, Minnesota Living with Heart Failure Questionnaire [MLHFQ]), at baseline and 12-week follow-up.

RESULTS

The study was terminated early due to the new guidelines recommending canagliflozin over sitagliptin in HF: 17 patients were assigned to canagliflozin and 19 to sitagliptin, total of 36 patients. There were no significant changes in peak VO₂ and VE/VCO₂ slope between the two groups (P = .083 and P = .98, respectively). Canagliflozin improved lean peak VO₂ (+2.4 mL kg_LM^-1 min^-1 , P = .036), VAT (+1.5 mL kg^-1 min^-1 , P = .012) and VO₂ matched for respiratory exchange ratio (+2.4 mL Kg^-1 min^-1 , P = .002) compared to sitagliptin. Canagliflozin also reduced MLHFQ score (-12.1, P = .018).

CONCLUSIONS

In this small and short-term study of patients with T2DM and HFrEF, interrupted early after only 36 patients, canagliflozin did not improve the primary endpoints of peak VO₂ or VE/VCO₂ slope compared to sitagliptin, while showing favourable trends observed on several additional surrogate endpoints such as lean peak VO₂ , VAT and quality of life.

Visceral fat and cardiorespiratory fitness with prevalence of pre-diabetes/diabetes mellitus among middle-aged and elderly Japanese people: WASEDA'S Health Study

The relationships between cardiorespiratory fitness (CRF) measurements not confounded by adiposity and the prevalence of pre-diabetes mellitus (pre-DM) and diabetes mellitus (DM) are not well known. Thus, we aimed to investigate the associations of visceral fat (VF) and CRF with the prevalence of pre-DM/DM among Japanese adults. The study included 970 individuals (327 women and 643 men) who were 40-87 years old and had complete health examinations, abdominal fat area, and fitness data from WASEDA'S Health Study during 2015-2018. The VF area was measured using magnetic resonance imaging. CRF was measured using a cycle ergometer and was defined as VO2peak divided by fat free mass. The pre-DM/DM was identified based on the questionnaire and fasting blood tests. The odds ratios (ORs) and 95% confidence intervals (CIs) for prevalence of pre-DM/DM were calculated. Seventy-three participants had pre-DM and 48 participants had DM. Compared to the low VF group, the high VF group had a higher prevalence of pre-DM/DM (OR: 1.87, 95% CI: 1.18-2.96), although no significant relationship was observed between CRF and pre-DM/DM prevalence (P for trend = 0.239). The sub-group analyses also revealed no significant relationship between CRF and pre-DM/DM prevalence in the low VF group (P for trend = 0.979), although CRF values were inversely related to the prevalence of pre-DM/DM in the high VF group (P for trend = 0.024). Although CRF was not independently related to the prevalence of pre-DM/DM after adjusting for adiposity, higher VF values were related to a higher prevalence of pre-DM/DM. In addition, CRF levels were inversely associated with the prevalence of pre-DM/DM only among high VF individuals.

Android to gynoid fat ratio and its association with functional capacity in male patients with heart failure

AIMS

We studied the association between android (A) to gynoid (G) fat ratio and functional capacity (peak VO₂ ) in male patients with heart failure with reduced ejection fraction (HFrEF).

METHODS AND RESULTS

We enrolled 118 male patients with HFrEF with left ventricular ejection fraction (LVEF) <40%. Body composition (by using dual x-ray absorptiometry) and peak VO₂ (by cardiopulmonary exercise testing) were measured. Sarcopenic obesity was defined according to the Foundation for the National Institutes of Health criteria (FNIH). Blood sample for metabolic and hormonal parameters were measured. Fifteen patients (12.7%) showed sarcopenic obesity (body mass index > 25 kg/m² with FNIH index < 0.789). The median A/G ratio was 0.55. A/G ratio > 0.55 was detected in 60 patients. Relative peak VO₂ was lower in patients with A/G ratio > 0.55 than in patients with A/G ratio <0.55 (18.7 ± 5.3 vs. 22.5 ± 6.1 mL/kg/min, P < 0.001). Logistic regression analysis showed A/G ratio >0.55 to be independently associated with reduced peak VO₂ adjusted for age, body mass index, LVEF, presence of sarcopenia, anabolic hormones, and haemoglobin (odds ratio 3.895, 95% confidence interval 1.030-14.730, P = 0.045).

CONCLUSIONS

Body fat distribution, particularly android and gynoid fat composition, together with other cofactors, might have an important adverse role on functional capacity in male patients with HFrEF. Future studies are needed to address possible mechanisms involved in this relationship.

Exercise Intolerance in Patients With Heart Failure: JACC State-of-the-Art Review

Exercise intolerance is the cardinal symptom of heart failure (HF) and is of crucial relevance, because it is associated with a poor quality of life and increased mortality. While impaired cardiac reserve is considered to be central in HF, reduced exercise and functional capacity are the result of key patient characteristics and multisystem dysfunction, including aging, impaired pulmonary reserve, as well as peripheral and respiratory skeletal muscle dysfunction. We herein review the different modalities to quantify exercise intolerance, the pathophysiology of HF, and comorbid conditions as they lead to reductions in exercise and functional capacity, highlighting the fact that distinct causes may coexist and variably contribute to exercise intolerance in patients with HF.

The Impact of Obesity in Heart Failure

Obesity has reached worldwide epidemic proportions, adversely impacting health on a global scale. Overweight and obesity adversely impact cardiac structure and function, affecting systolic and diastolic ventricular function. Studies and meta-analyses have documented an obesity paradox in large heart failure cohorts, where overweight and obese individuals with established heart failure have a better short- and medium-term prognosis compared with lean patients; this relationship is strongly impacted by level of cardiorespiratory fitness. There are implications for therapies aimed at increasing lean and muscle mass, and weight loss, for the prevention and treatment of compared with in patients with concomitant obesity.

Spiroergometric assessment of cardiorespiratory fitness in subjects with severe obesity: A challenge of reference

BACKGROUND AND AIMS

Severe obesity is associated with poor physical performance but objective data are scarce.

METHODS AND RESULTS

Bicycle spiroergometry data with focus on peak oxygen uptake (V˙O_2,peak) and workload (W_peak) from 476 subjects with severe obesity (BMI ≥ 35.0 kg/m²; 70% women) were analysed. In a first step, V˙O_2,peak values were compared with reference values calculated upon different formulas (Wassermann; Riddle). Thereafter, multivariate regression analyses were performed to identify determinants of cardiorespiratory fitness. Cardiorespiratory fitness reference classes for V˙O_2,peak and W_peak were established by stratifying the sample upon identified determinants. Absolute V˙O_2,peak (1.87 ± 0.47 vs. 2.40 ± 0.59 l/min) and W_peak (131 ± 26 vs. 168 ± 44 W) were lower in women than men (both p<0.001). Same pattern was found for relative V˙O_2,peak and W_peak, respectively (both p < 0.05). In women, measured V˙O_2,peak was lower than predicted by Wasserman (p < 0.001) but not by Riddle (p = 0.961). In men, V˙O_2,peak was lower than calculated by both Wasserman and Riddle formulas (both p ≤ 0.003). Multivariate analyses revealed height and age to be the main determinants of cardiorespiratory fitness in both sexes. Subsequent statistical analyses of calculated reference fitness classes revealed that V˙O_2,peak and W_peak differed between the age- and height-defined groups in both sexes (all p < 0.001).

CONCLUSION

Data indicate that the evaluation of cardiorespiratory fitness in subjects with severe obesity is largely biased by selected references values for comparison. Our newly established reference fitness classes upon height and age might be helpful in the clinical context when dealing with obese patients.

Effects of Physical Activity, Exercise, and Fitness on Obesity-Related Morbidity and Mortality

Obesity is associated with increased prevalence of cardiovascular (CV) disease (CVD) risk factors, which may adversely impact CV structure and function and may increase the prevalence of most CVD, particularly heart failure (HF) and coronary heart disease (CHD). Physical activity (PA), exercise training (ET) and cardiorespiratory fitness (CRF) are all associated with marked reductions in most CVD, including HF and CHD. Additionally, PA/ET and, especially CRF, markedly alter the relationship between adiposity and subsequent major CVD outcomes and dramatically impact the "obesity paradox," which are all reviewed, including attention to the debate regarding "fitness versus fatness" for long-term prognosis, including in patients with established CVD.

Obesity, risk of diabetes and role of physical activity, exercise training and cardiorespiratory fitness

The epidemic of obesity contributes to the burden of type 2 diabetes mellitus (T2DM) in the United States and worldwide. Importantly, obesity is not only preventable but can be treated, particularly with lifestyle modifications to forestall T2DM in those with excess adiposity. The mechanisms linking obesity to T2DM are numerous and involve adipose tissue remodeling as a result of unhealthy behaviors, including unhealthy diet, reduced physical activity (PA) and exercise training (ET), and increased sedentary behaviors. Taken together, these factors markedly reduce cardiorespiratory fitness (CRF), one of the strongest predictors for cardiovascular outcomes and all-cause mortality in the general population, but also in those with T2DM. In this review we describe the mechanisms leading to adipose tissue remodeling resulting in obesity, as well as the mechanisms linking excess adiposity to insulin resistance and, in turn, T2DM. We then present the therapeutic strategies that can be implemented in obesity to prevent T2DM, with a brief discussion on weight loss, and greater emphasis on PA and ET. We finally present the evidence to support the beneficial effects of such strategies in patients with established T2DM and discuss the importance of achieving improvements in CRF in this population to potentially improve clinical outcomes.

Sex differences on peak oxygen uptake in heart failure

Women represent nearly half of the adult heart failure (HF) population and they remain underrepresented in HF studies. We aimed to evaluate the evidence about peak oxygen uptake (peak VO₂) for clinical stratification in women with HF. This narrative review summarizes (i) the evidence endorsing the value of cardiopulmonary exercise testing for clinical stratification and phenotyping HF population; (ii) the determinants of a person's functional aerobic capacity to understand predicted values for patients with chronic HF; and (iii) sex differences on peak VO₂ data in different forms of HF. Lastly, based on existing data in patients with HF, we provide a perspective on how to improve existing gaps about the utility of peak VO₂ in clinical stratification in women. Peak VO₂ provides prognosis information in patients with HF; however, its use has been limited for a reduced number of patients excluding women, elderly, and HF patients with preserved ejection fraction. Further studies will help to fill the wide gender gap about the utility of cardiopulmonary exercise testing in the risk assessment and management in women with HF.

Aerobic Fitness and Adherence to Guideline-Recommended Minimum Physical Activity Among Ambulatory Patients With Type 2 Diabetes Mellitus

OBJECTIVE

Lifestyle intervention remains the cornerstone of management of type 2 diabetes mellitus (T2DM). However, adherence to physical activity (PA) recommendations and the impact of that adherence on cardiorespiratory fitness in this population have been poorly described. We sought to investigate adherence to PA recommendations and its association with cardiorespiratory fitness in a population of patients with T2DM.

RESEARCH DESIGN AND METHODS

A cross-sectional analysis of baseline data from a randomized clinical trial (NCT00424762) was performed. A total of 150 individuals with medically treated T2DM and atherosclerotic cardiovascular disease (ASCVD) or risk factors for ASCVD were recruited from outpatient clinics at a single academic medical center. All individuals underwent a graded maximal exercise treadmill test to exhaustion with breath-by-breath gas exchange analysis to determine VO_2peak. PA was estimated using a structured 7-Day Physical Activity Recall interview.

RESULTS

Participants had a mean ± SD age of 54.9 ± 9.0 years; 41% were women, 40% were black, and 21% were Hispanic. The mean HbA_1c was 7.7 ± 1.8% and the mean BMI, 34.5 ± 7.2 kg/m². A total of 72% had hypertension, 73% had hyperlipidemia, and 35% had prevalent ASCVD. The mean ± SD reported daily PA was 34.3 ± 4 kcal/kg, only 7% above a sedentary state; 47% of the cohort failed to achieve the minimum recommended PA. Mean ± SD VO_2peak was 27.4 ± 6.5 mL/kg fat-free mass/min (18.8 ± 5.0 mL/kg/min).

CONCLUSIONS

On average, patients with T2DM who have or are at risk for ASCVD report low levels of PA and have low measured cardiopulmonary fitness. This underscores the importance of continued efforts to close this therapeutic gap.

Obesity paradox in cardiovascular disease: where do we stand?

Obesity is associated with an increased risk of developing cardiovascular disease (CVD), particularly heart failure (HF) and coronary heart disease (CHD). The mechanisms through which obesity increases CVD risk involve changes in body composition that can affect hemodynamics and alters heart structure. Pro-inflammatory cytokines produced by the adipose tissue itself which can induce cardiac dysfunction and can promote the formation of atherosclerotic plaques. When obesity and HF or CHD coexist, individuals with class I obesity present a more favorable prognosis compared to individuals who are normal or underweight. This phenomenon has been termed the “obesity paradox.” Obesity is defined as an excess fat mass (FM), but individuals with obesity typically also present with an increased amount of lean mass (LM). The increase in LM may explain part of the obesity paradox as it is associated with improved cardiorespiratory fitness (CRF), a major determinant of clinical outcomes in the general population, but particularly in those with CVD, including HF. While increased LM is a stronger prognosticator in HF compared to FM, in patients with CHD excess FM can exert protective effects particularly when not associated with increased systemic inflammation. In the present review, we discuss the mechanisms through which obesity may increase the risk for CVD, and how it may exert protective effects in the setting of established CVD, with a focus on body composition. We also highlight the importance of measuring or estimating CRF, including body composition-adjusted measures of CRF (ie, lean peak oxygen consumption) for an improved risk status stratification in patients with CVD and finally, we discuss the potential non-pharmacologic therapeutics, such as exercise training and dietary interventions, aimed at improving CRF and perhaps clinical outcomes.

Exercise Ventilatory Efficiency in Older and Younger Heart Failure Patients With Preserved Ejection Fraction

BACKGROUND

Patients with heart failure with preserved ejection fraction (HFpEF) exhibit pulmonary abnormalities, but the studies to date have reported wide variability in the ventilatory equivalent for carbon dioxide (V̇_E/V̇CO₂) slope. It is possible that aging may contribute to that variability. We sought to compare ventilatory efficiency and its components in older and younger HFpEF patients during exercise.

METHODS AND RESULTS

Eighteen older (O; 80 ± 4 y) and 19 younger (Y; 59 ± 7 y) HFpEF patients performed cardiopulmonary exercise testing to volitional fatigue. Measurements of arterial blood gases were used to derive V_D/V_T, dead space ventilation, and alveolar ventilation. V̇_E/V̇CO₂ slope was greater in older compared with younger HFpEF patients (O 36 ± 7vs Y 31 ± 7; P = .04). At peak exercise, older HFpEF exhibited greater V_D/V_T compared with younger HFpEF (O 0.37 ± 0.10vs Y 0.28 ± 0.10; P < .01), whereas PaCO₂ was not different between groups (P = .58). V̇_E and alveolar ventilation were similar (P > .23), but dead space ventilation was greater in older compared with younger HFpEF at peak exercise (P = .04).

CONCLUSIONS

Older HFpEF patients exhibit greater ventilatory inefficiency resulting from elevated physiologic dead space during peak exercise compared with younger HFpEF patients. These results suggest that aging can worsen the pathophysiologic mechanisms underlying ventilatory efficiency during exercise in HFpEF.

Body mass index and all-cause mortality in heart failure patients with normal and reduced ventricular ejection fraction: a dose-response meta-analysis

BACKGROUND

For patients with heart failure, there is an inverse relation between body mass index (BMI) and mortality, sometimes called the obesity-paradox. However, the relationship might be either U- or J-shaped and might differ between patients with reduced (HFrEF) or preserved left ventricular ejection fraction (HFpEF). We sought to investigate this further in a dose-response meta-analysis of published studies.

METHODS

PubMed and Embase from June 1980 to April 2017 were searched for prospective cohort studies evaluating associations between BMI and all-cause mortality in patients with HFrEF (LVEF < 40%) or HFpEF (LVEF ≥ 50%). Summary estimated effect sizes were obtained by using a random-effects model. Potential non-linear relationships were evaluated by using random-effects restricted cubic spline models.

RESULTS

Ten studies were identified that included 96,424 patients of whom 59,263 had HFpEF (mean age 68 years of whom 38% were women) and 37,161 had HFrEF (mean age 60 years of whom 17% were women). For patients with HFpEF, the summary hazard ratio (HR) for all-cause mortality was: 0.93 (95% CI 0.89-0.97) per 5 units increase in BMI (I² = 75.8%, p for heterogeneity = 0.01 and Begg's test, p = 1.0, Egger's test, p = 0.29) but the association was U-shaped (p for non-linearity < 0.01) with the nadir of risk at a BMI of 32-33 kg/m². For patients with HFrEF, the summary HR for all-cause mortality was: 0.96 (95% CI 0.92-0.99) (I² = 95%, p for heterogeneity < 0.001 and Begg's test, p = 0.45, Egger's test, p = 0.01). The relationship was also U-shaped (p < 0.01), although 'flatter' than for HFpEF, with the nadir at a BMI of 33 kg/m².

CONCLUSIONS

For patients with heart failure, the relation between BMI and mortality is U-shaped with a similar nadir of risk for HFpEF and HFrEF at a BMI of 32-33 kg/m². Whether interventions that alter weight in either direction can alter risk is unknown.

Cardiopulmonary Exercise Testing in Patients with Heart Failure with Specific Comorbidities

Exercise capacity is one of the most powerful predicting factors of life expectancy, both in patients with and those without cardiac disease. Cardiopulmonary exercise testing provides a global assessment of the integrative exercise responses involving the pulmonary, cardiovascular, hematopoietic, neuropsychological, and skeletal muscle systems, which are not adequately reflected through the measurement of individual organ system function. This relatively noninvasive, dynamic, physiologic overview allows the evaluation of both submaximal and peak exercise responses, providing the physician with relevant information for clinical decision-making. Chronic heart failure is a significant cause of worldwide mortality and morbidity, whose clinical picture is characterized by exercise intolerance and impaired quality of life. The purpose of this review is to provide an update of the role of cardiopulmonary exercise testing in patients with heart failure with specific comorbidities. Patients with heart failure frequently present concomitant clinical conditions, such as obesity, anemia, lung or kidney disease, diabetes mellitus, cancer, depression, and psychogenic disorders, which could affect length and quality of life, including everyday activities and exercise performance. Poor effort and malingering may be suspected when early discontinuation of the exercise test with irregular breathing occurs.

The Obesity Factor: How Cardiorespiratory Fitness is Estimated More Accurately in People with Obesity

OBJECTIVE

Cardiopulmonary exercise testing is clinically used to estimate cardiorespiratory fitness (CRF). The relation to total body mass (TBM) leads to an underestimation of CRF in people with obesity and to inappropriate prognostic and therapeutic decisions. This study aimed to determine body composition-derived bias in the estimation of CRF in people with obesity.

METHODS

Two hundred eleven participants (58.8% women; mean BMI 35.7 kg/m² [± 6.94; 20.7-58.6]) were clinically examined, and body composition (InBody720; InBody Co., Ltd., Seoul, South Korea) and spiroergometrical peak oxygen consumption (VO₂ peak) were assessed. The impacts of TBM, lean body mass (LBM), and skeletal muscle mass (SMM) on CRF estimates were analyzed by the application of respective weight models. Linear regression and plotting of residuals against BMI were performed on the whole study population and two subgroups (BMI < 30 kg/m² and BMI ≥ 30 kg/m² ).

RESULTS

For every weight model, Δmean VO₂ peak (expected - measured) was positive. LBM and SMM had a considerable impact on VO₂ peak demand (P = 0.001; ΔR²  = 2.3%; adjusted R²  = 56% and P = 0.001; ΔR² = 2.7%; adjusted R²  = 56%), whereas TBM did not. Confounding of body composition on VO₂ peak did not differ in LBM and SMM.

CONCLUSIONS

TBM-adjusted overestimation of relative VO₂ demand is much higher in people with obesity than in those without. LBM or SMM adjustment may be superior alternatives, although small residual body composition-derived bias remains.

Heart failure with preserved vs reduced ejection fraction following cardiac rehabilitation: impact of endothelial function

There is no proven therapy for heart failure with preserved ejection fraction (HFpEF). Research has shown beneficial responses to cardiac rehabilitation (CR) among HF patients. To date, there are no reports comparing those responses between patients with HFpEF and those with reduced ejection fraction (HFrEF). The purpose of this study was to compare responses to CR in patients with HFpEF versus those with HFrEF. We included 78 consecutive patients (mean age 69 ± 15 years; 80% male) with HF in our CR unit who underwent cardiopulmonary exercise testing and brachial artery flow-mediated dilation (FMD) testing pre- and 5 months post-CR. Patients were judged as HFpEF (n = 40) or HFrEF (n = 38) using a left ventricular ejection fraction (LVEF) cut-off of 50%, and endothelial dysfunction was defined as FMD ≤ 5.0%. Following 155 ± 11 days and 44 ± 8 sessions, peak oxygen uptake ([Formula: see text]) and plasma B-type natriuretic peptide concentrations improved significantly in both groups. The percentage change in peak [Formula: see text] of HFrEF patients was significantly greater than compared with the HFpEF patients (P < 0.01). To further investigate whether a combination of LVEF and FMD values predicts the effect of CR, we divided patients into four groups according to LVEF of 50% and FMD of 50%. Post hoc analysis showed a significant difference between HFrEF patients without endothelial dysfunction and HFpEF patients with endothelial dysfunction (P = 0.01). In conclusion, although CR improves prognosis in HF patients, a larger effect can be expected in HFrEF patients than in HFpEF patients, and endothelial function may enhance the effect.

Development of an exercise intervention as part of rehabilitation in a glioblastoma multiforme survivor during irradiation treatment: a case report

INTRODUCTION

This case report describes the rationale and development of an exercise intervention in a patient with glioblastoma multiforme (GBM ) and discusses potential relations of observed effects in functional performance and quality of life (QOL).

METHODS

A 54-year-old GBM survivor completed a supervised six-week exercise intervention during irradiation treatment beginning 42 d after resection. Exercise modalities of cardiorespiratory, resistance, and balance training were designed on generic recommendations of various cancer populations and literature review.

RESULTS

Our case attended all possible sessions without experiencing adverse effects, and improved in aerobe power (24%), muscle strength (0-38%), standing balance (71%), walking ability (9%), and QOL domains of "Global Health Status/QoL" and "Physical functioning."

CONCLUSIONS

Based on this single case, exercise rehabilitation has the ability to maintain or improve functional performance and QOL domains even during heavy treatments. It also implies that patients with GBM are capable and may be willing to participate in exercise rehabilitation if supervised by physical therapists. Implications for rehabilitation The use of exercise as part of rehabilitation still needs attention in strong methodology studies of patients with gliomas. Exercise rehabilitation may maintain or even improve functional performance and QOL domains during medical treatment regimens. Functional independent patients with GBM are capable to comply with generic exercise recommendations and may be willing to participate in exercise rehabilitation if supervised by physical therapists.

Role of cardiopulmonary exercise testing in clinical stratification in heart failure. A position paper from the Committee on Exercise Physiology and Training of the Heart Failure Association of the European Society of Cardiology

Traditionally, the main indication for cardiopulmonary exercise testing (CPET) in heart failure (HF) was for the selection of candidates to heart transplantation: CPET was mainly performed in middle-aged male patients with HF and reduced left ventricular ejection fraction. Today, CPET is used in broader patients' populations, including women, elderly, patients with co-morbidities, those with preserved ejection fraction, or left ventricular assistance device recipients, i.e. individuals with different responses to incremental exercise and markedly different prognosis. Moreover, the diagnostic and prognostic utility of symptom-limited CPET parameters derived from submaximal tests is more and more considered, since many patients are unable to achieve maximal aerobic power. Repeated tests are also being used for risk stratification and evaluation of intervention, so that these data are now available. Finally, patients, physicians and healthcare decision makers are increasingly considering how treatments might impact morbidity and quality of life rather than focusing more exclusively on hard endpoints (such as mortality) as was often the case in the past. Innovative prognostic flowcharts, with CPET at their core, that help optimize risk stratification and the selection of management options in HF patients, have been developed.

Obesity, body composition and cardiorespiratory fitness in heart failure with preserved ejection fraction

Obesity is defined as an excess body fat that impairs health and is associated with increased risk of heart failure (HF), particularly HF with preserved ejection fraction (HFpEF), evolving into a ‘HFpEF obesity phenotype’. The interplay between obesity and cardiorespiratory fitness, primary clinical parameters in HF, requires further exploration. The contribution of body composition compartments in the development and progress of HF has been the object of numerous studies. Here we focus on how fat mass and lean tissues affect cardiorespiratory fitness, with emphasis on their effects on peak oxygen consumption. Moreover, while several studies have focused on characterization of body composition compartments, here we describe also recent findings related to abnormal and/or dysfunctional lean mass, especially in HFpEF.

Obesity and Heart Failure: Focus on the Obesity Paradox

The escalating prevalence of obesity has been linked to substantial increases in both metabolic and cardiovascular disease. Nevertheless, the direct effects of obesity on cardiovascular health and function require further exploration. In particular, the relationship between obesity and cardiac function has received intense scrutiny. Although obesity increases the risk for development of heart failure (HF), it appears to exert a protective effect in patients in whom HF has already been diagnosed (the "obesity paradox"). The protective effects of obesity in patients with previously diagnosed HF are the focus of particularly intense research. Several explanations have been proposed, but most studies are limited by the use of body mass index to classify obesity. Because body mass index does not distinguish between fat mass, fat-free mass, and lean mass, individuals with similar body mass indices may have vastly different body composition. This article discusses the roles of body composition, diet, cardiorespiratory fitness, and weight loss in the development of cardiac dysfunction and HF and the potential protective role that body composition compartments might play in improving HF prognosis. Based on an intensive literature search (Pubmed, Google Scholar) and critical review of the literature, we also discuss how a multidisciplinary approach including a nutritional intervention targeted to reduce systemic inflammation and lean mass-targeted exercise training could potentially exert beneficial effects for patients with HF.

Statement on cardiopulmonary exercise testing in chronic heart failure due to left ventricular dysfunction: recommendations for performance and interpretation Part III: Interpretation of cardiopulmonary exercise testing in chronic heart failure and future applications: Task Force of the Italian Working Group on Cardiac Rehabilitation and Prevention (Gruppo Italiano di Cardiologia Riabilitativa e Prevenzione, GICR), endorsed by Working Group on Cardiac Rehabilitation and Exercise Physiology of the European Society of Cardiology

Optimal use of cardiopulmonary exercise testing (CPET) in clinical practice and chronic heart failure (CHF) requires appropriate data presentation and a flexible interpretative strategy. The greatest potential impact on the decision-making process may rest not on the value of any individual measurement, although some are obviously more important than others, but rather on their integrative use. Such an integrative approach relies on interrelationship, trending phenomena and patterns of key gas exchange variable responses. An multiparametric approach will be discussed in different clinical applications, for exercise prescription and monitoring, functional evaluation of drug therapy or cardiac resynchronisation therapy efficacy, and risk stratification. The role of CPET in the daily clinical decision-making process will be underscored. Future indications of CPET will be addressed, suggesting and promoting an extended candidacy either to all CHF patients, including those at high risk or most vulnerable, such as female, elderly patients, and patients with implantable cardioverter defibrillator or in every clinical setting where objective definition of exercise capacity provides implications for medical, surgical, and social decision making.

Cardiopulmonary Exercise Testing in Heart Failure

Exercise intolerance, indicated by dyspnea and fatigue during exertion, is a cardinal manifestation of heart failure (HF). Cardiopulmonary exercise testing (CPET) precisely defines maximum exercise capacity through measurement of peak oxygen uptake (VO2). Peak VO2 values have a critical role in informing patient selection for advanced HF interventions such as heart transplantation and ventricular assist devices. Oxygen uptake and ventilatory patterns obtained during the submaximal portion of CPET are also valuable to recognize because of their ease of ascertainment during low-level exercise, relevance to ability to perform activities of daily living, independence from volitional effort, and strong relationship to prognosis in HF. The ability of peak VO2 and other CPET variables to be measured reproducibly and to accurately reflect HF severity is increasingly recognized and endorsed by scientific statements. Integration of CPET with invasive hemodynamic monitoring and cardiac imaging during exercise provides comprehensive characterization of multisystem reserve capacity that can inform prognosis and the need for cardiac interventions. Here, we review both practical aspects of conducting CPETs in patients with HF for clinical and research purposes as well as interpretation of gas exchange patterns across the spectrum of preclinical HF to advanced HF.