VE/VCO2 slope and its prognostic value in patients with chronic heart failure

Physical Fitness Is Directly Related to Exercise Capacity and Ventilatory Response to Exercise in Men with HFrEF

Background: Heart failure (HF) patients experience reduced functional fitness level (determining the performance of routine, daily activities) and diminished exercise capacity (linked to more effortful activities). Aim: The aim of the study is to assess this relationship using functional fitness tests compared to peak VO2 and VE/VCO2 slope in the context of exercise capacity and ventilatory response to exercise. Methods: A total of 382 men with stable HFrEF (age: 61 ± 10, NYHA class I/II/III/IV: 16/50/32/2%, LVEF: 30.5 ± 8.3%) underwent cardiopulmonary exercise testing (CPX) and a Senior Fitness Test (SFT). Afterwards, the patients were divided according to the 2capacity with peak VO2 ≥ 18 mL/kg/min, those with higher or lower ventilatory responses (VE/VCO2 slope ≥ 35 vs. <35) to the exercise were compared. Results: Patients who covered shorter distances in the 6 min walking test showed worse results in the functional tests ('stand up and go', 'chair stand' and 'arm curl') and CPX (lower peak VO2, shorter exercise time and higher VE/VCO2 slope). Subjects classified into Class D demonstrated the worst results in all elements of SFT; those in Class A demonstrated the best results. Significant differences that were analogous occurred also between classes B and C. Among the participants who reached peak VO2 ≥ 18 mL/kg/min (n = 170), those with VE/VCO2 slope ≥ 35 were characterized by worse physical fitness as compared to those with VE/VCO2 < 35. Conclusion: Reduced exercise tolerance led to worsening physical function in patients with HFrEF. Moreover, limitations in physical fitness seem to be distinctive for those patients showing excessive ventilatory response to exercise slope VE/VCO2 (≥35). The Senior Fitness Test may be considered as a useful tool for assessing comprehensive functional and clinical status and risk stratification in patients with HFrEF, especially those with extremely low exercise capacity.

Determinants of V̇+O2peak Changes After Aerobic Training in Coronary Heart Disease Patients

This study aimed to highlight the ventilatory and circulatory determinants of changes in ˙VO2peak after exercise-based cardiac rehabilitation (ECR) in patients with coronary heart disease (CHD). Eighty-two CHD patients performed, before and after a 3-month ECR, a cardiopulmonary exercise testing (CPET) on a bike with gas exchanges measurements (˙VO2peak, minute ventilation, i. e., ˙VE), and cardiac output (Q˙c). The arteriovenous difference in O2 (C(a-v¯)O2) and the alveolar capillary gradient in O2 (PAi-aO2) were calculated using Fick's laws. Oxygen uptake efficiency slope (OUES) was calculated. A 5.0% cut off was applied for differentiating non- (NR: ˙VO2<0.0%), low (LR: 0.0≤ ∆˙VO2<5.0%), moderate (MR: 5.0≤∆˙VO2 < 10.0%), and high responders (HR: ∆˙VO2≥10.0%) to ECR. A total of 44% of patients were HR (n=36), 20% MR (n=16), 23% LR (n=19), and 13% NR (n=11). For HR, the ˙VO2peak increase (p<0.01) was associated with increases in ˙VE (+12.8±13.0 L/min, p<0.01), (+1.0±0.9 L/min, p<0.01), and C(a-v¯)O2 (+2.3±2.5 mLO2/100 mL, p<0.01). MR patients were characterized by+6.7±19.7 L/min increase in ˙VE (p=0.04) and+0.7±1.0 L/min of Q˙c (p<0.01). ECR induced decreases in ˙VE (p=0.04) and C(a-v¯)O2 (p<0.01) and a Q˙c increase in LR and NR patients (p<0.01). Peripheral and ventilatory responses more than central adaptations could be responsible for the ˙VO2peak change with ECR in CHD patients.

Prognostic Value of Body Surface Area-Adjusted Oxygen Uptake Efficiency Slope in Heart Failure Patients

Background

COVID-19 has been associated with a higher risk of developing heart failure (HF). Among the parameters derived from cardiopulmonary exercise testing (CPET), oxygen uptake efficiency slope (OUES) has become one of the most important parameters for predicting the prognosis of HF patients. However, the clinical utilization of OUES is limited owing to its variation with patient height and weight. This study aimed to evaluate the prognostic value of body surface area-adjusted OUES (OUES/BSA) in adults with HF.

Methods

Thirty-six HF patients (mean age, 57 ± 12 years; 30 men) undergoing CPET between July 2019 and May 2020 who were followed up for 12 months were enrolled. The endpoints were major cardiovascular (CV) events, including hospitalization due to acute decompensated HF, left ventricular assist device implantation, heart transplantation, and cardiovascular-related death. We analyzed the correlations between clinical/CPET variables and major CV events.

Results

Among the analyzed CPET variables, OUES/BSA had better correlation with maximal oxygen uptake (VO2max) than other variables. In univariate Cox proportional analysis, OUES/BSA and peak VO2 were both significant independent prognostic factors. The cutoff value of OUES/BSA was 595 ml/min/m2 with an area under the curve of 0.929. The patients with OUES/BSA < 595 ml/min/m2 had a lower CV event-free survival rate at 12 months of follow-up compared with the other group (33.3% and 100%, respectively; log-rank test, p < 0.001).

Conclusions

BSA-adjusted OUES is an effective independent predictor for prognosis in HF patients and can be an alternative to peak VO2 for risk stratification in HF patients, regardless of exercise intensity. However, further large-scale studies are required to validate our findings.

Insulin Resistance/Hyperinsulinemia, Neglected Risk Factor for the Development and Worsening of Heart Failure with Preserved Ejection Fraction

Heart failure (HF) has become a subject of continuous interest since it was declared a new pandemic in 1997 because of the exponential increase in hospitalizations for HF in the latest years. HF is the final state to which all heart diseases of different etiologies lead if not adequately treated. It is highly prevalent worldwide, with a progressive increase with age, reaching a prevalence of 10% in subjects over the age of 65 years. During the last two decades, it was possible to see that the prevalence of heart failure with preserved ejection fraction (HFpEF) was increasing while that of heart failure with reduced ejection fraction (HFrEF) was decreasing. HFpEF is typically characterized by concentric remodeling of the left ventricle (LV) with impaired diastolic function and increased filling pressures. Over the years, also the prevalence of insulin resistance (IR)/hyperinsulinemia (Hyperins) in the general adult population has progressively increased, primarily due to lifestyle changes, particularly in developed and developing countries, with a range that globally ranges between 15.5% and 46.5%. Notably, over 50% of patients with HF also have IR/Hyperins, and the percentage is even higher in those with HFpEF. In the scientific literature, it has been well highlighted that the increased circulating levels of insulin, associated with conditions of insulin resistance, are responsible for progressive cardiovascular alterations over the years that could stimulate the development and/or the worsening of HFpEF. The aim of this manuscript was to review the scientific literature that supports a pathophysiologic connection between IR/Hyperins and HFpEF to stimulate the scientific community toward the identification of hyperinsulinemia associated with insulin resistance as an independent cardiovascular risk factor in the development and worsening of HF, believing that its adequate screening in the general population and an appropriate treatment could reduce the prevalence of HFpEF and improve its progression.

The association between cardiopulmonary exercise testing and postoperative outcomes in patients with lung cancer undergoing lung resection surgery: A systematic review and meta-analysis

BACKGROUND

Exercise capacity should be determined in all patients undergoing lung resection for lung cancer surgery and cardiopulmonary exercise testing (CPET) remains the gold standard. The purpose of this study was to investigate associations between preoperative CPET and postoperative outcomes in patients undergoing lung resection surgery for lung cancer through a review of the existing literature.

METHODS

A search was conducted on PubMed, Scopus, Cochrane Library and CINAHL from inception until December 2022. Studies investigating associations between preoperative CPET and postoperative outcomes were included. Risk of bias was assessed using the QUIPS tool. A random effect model meta-analysis was performed. I2 > 40% indicated a high level of heterogeneity.

RESULTS

Thirty-seven studies were included with 6450 patients. Twenty-eight studies had low risk of bias. [Formula: see text] peak is the oxygen consumption at peak exercise and serves as a marker of cardiopulmonary fitness. Higher estimates of [Formula: see text] peak, measured and as a percentagege of predicted, showed significant associations with a lower risk of mortality [MD: 3.66, 95% CI: 0.88; 6.43 and MD: 16.49, 95% CI: 6.92; 26.07] and fewer complications [MD: 2.06, 95% CI: 1.12; 3.00 and MD: 9.82, 95% CI: 5.88; 13.76]. Using a previously defined cutoff value of > 15mL/kg/min for [Formula: see text] peak, showed evidence of decreased odds of mortality [OR: 0.55, 95% CI: 0.28-0.81] and but not decreased odds of postoperative morbidity [OR: 0.82, 95% CI: 0.64-1.00]. There was no relationship between [Formula: see text] slope, which depicts ventilatory efficiency, with mortality [MD: -9.60, 95% CI: -27.74; 8.54] however, patients without postoperative complications had a lower preoperative [Formula: see text] [MD: -2.36, 95% CI: -3.01; -1.71]. Exercise load and anaerobic threshold did not correlate with morbidity or mortality. There was significant heterogeneity between studies.

CONCLUSIONS

Estimates of cardiopulmonary fitness as evidenced by higher [Formula: see text] peak, measured and as a percentage of predicted, were associated with decreased morbidity and mortality. A cutoff value of [Formula: see text] peak > 15mL/kg/min was consistent with improved survival but not with fewer complications. Ventilatory efficiency was associated with decreased postoperative morbidity but not with improved survival. The heterogeneity in literature could be remedied with large scale, prospective, blinded, standardised research to improve preoperative risk stratification in patients with lung cancer scheduled for lung resection surgery.

The Negative Impact of Insulin Resistance/Hyperinsulinemia on Chronic Heart Failure and the Potential Benefits of Its Screening and Treatment

This opinion article highlights the potential alterations caused by insulin resistance and hyperinsulinemia on the cardiovascular system and their negative impact on heart failure (HF), and describes the potential benefits of an early screening with consequent prompt treatment. HF is the final event of several different cardiovascular diseases. Its incidence has been increasing over the last decades because of increased survival from ischemic heart disease thanks to improvements in its treatment (including myocardial revascularization interventions) and the increase in life span. In particular, incidence of HF with preserved ejection fraction (HFpEF) is significantly increasing, and patients with HFpEF often are also affected by diabetes mellitus and insulin resistance (IR), with a prevalence > 45%. Concentric left ventricular (LV) remodeling and diastolic dysfunction are the main structural abnormalities that characterize HFpEF. It is well documented in the literature that IR with chronic hyperinsulinemia, besides causing type 2 diabetes mellitus, can cause numerous cardiovascular alterations, including endothelial dysfunction and increased wall thicknesses of the left ventricle with concentric remodeling and diastolic dysfunction. Therefore, it is conceivable that IR might play a major role in the pathophysiology and the progressive worsening of HF. To date, several substances have been shown to reduce IR/hyperinsulinemia and have beneficial clinical effects in patients with HF, including SGLT2 inhibitors, metformin, and berberine. For this reason, an early screening of IR could be advisable in subjects at risk and in patients with heart failure, to promptly intervene with appropriate therapy. Future studies aimed at comparing the efficacy of the substances used both alone and in association are needed.

Surrogates of Muscle Mass on Cardiac MRI Correlate with Exercise Capacity in Patients with Fontan Circulation

BACKGROUND

Sarcopenia is an increasingly recognized marker of frailty in cardiac patients. Patients with a history of congenital heart disease and Fontan procedure have a higher risk of developing progressive muscle wasting. Our objective was to determine if we could use routine cardiac MRI (CMR) for the surveillance of muscle wasting.

METHODS

A retrospective study of all Fontan patients (n = 75) was conducted at our institution, with CMR performed from 2010 to 2022 and exercise stress testing performed within 12 months (4.3 ± 4.2 months). The skeletal muscle area (SMA) for the posterior paraspinal and anterior thoracic muscles were traced and indexed for body surface area (BSA). Patients were stratified by percentile into the upper and lower quartiles, and the two groups were compared. Multivariable regression was performed to control for sex and age.

RESULTS

There was a significant positive association of both anterior (r = 0.34, p = 0.039) and paraspinal (r = 0.43, p = 0.007) SMA to peak VO2. Similarly, paraspinal but not anterior SMA was negatively associated with the VE/VCO2 (r = -0.45, p = 0.006). The upper quartile group had significantly more males (18/19 vs. 8/20; p = 0.0003) and demonstrated a significantly higher peak VO2 (32.2 ± 8.5 vs. 23.8 ± 4.7, p = 0.009), a higher peak RER (1.2 ± 0.1 vs. 1.1 ± 0.04, p = 0.007), and a significantly lower VE/VCO2 (32.9 ± 3.6 vs. 40.2 ± 6.2, p = 0.006) compared to the lowest quartile. The association of SMA to VO2 peak and VE/VCO2 was redemonstrated after controlling for sex and age.

CONCLUSION

Thoracic skeletal muscle area may be an effective surrogate of muscle mass and is correlated to several measures of cardiorespiratory fitness post-Fontan. CMR would be an effective tool for the surveillance of sarcopenia in post-Fontan patients given its accessibility and routine use in these patients.

Do cardiopulmonary exercise tests predict summit success and acute mountain sickness? A prospective observational field study at extreme altitude

OBJECTIVE

During a high-altitude expedition, the association of cardiopulmonary exercise testing (CPET) parameters with the risk of developing acute mountain sickness (AMS) and the chance of reaching the summit were investigated.

METHODS

Thirty-nine subjects underwent maximal CPET at lowlands and during ascent to Mount Himlung Himal (7126 m) at 4844 m, before and after 12 days of acclimatisation, and at 6022 m. Daily records of Lake-Louise-Score (LLS) determined AMS. Participants were categorised as AMS+ if moderate to severe AMS occurred.

RESULTS

Maximal oxygen uptake (V̇O_2max) decreased by 40.5%±13.7% at 6022 m and improved after acclimatisation (all p<0.001). Ventilation at maximal exercise (VE_max) was reduced at 6022 m, but higher VE_max was related to summit success (p=0.031). In the 23 AMS+ subjects (mean LLS 7.4±2.4), a pronounced exercise-induced oxygen desaturation (ΔSpO_2exercise) was found after arrival at 4844 m (p=0.005). ΔSpO_2exercise >-14.0% identified 74% of participants correctly with a sensitivity of 70% and specificity of 81% for predicting moderate to severe AMS. All 15 summiteers showed higher V̇O_2max (p<0.001), and a higher risk of AMS in non-summiteers was suggested but did not reach statistical significance (OR: 3.64 (95% CI: 0.78 to 17.58), p=0.057). V̇O_2max ≥49.0 mL/min/kg at lowlands and ≥35.0 mL/min/kg at 4844 m predicted summit success with a sensitivity of 46.7% and 53.3%, and specificity of 83.3% and 91.3%, respectively.

CONCLUSION

Summiteers were able to sustain higher VE_max throughout the expedition. Baseline V̇O_2max below 49.0 mL/min/kg was associated with a high chance of 83.3% for summit failure, when climbing without supplemental oxygen. A pronounced drop of SpO_2exercise at 4844 m may identify climbers at higher risk of AMS.

Correlation between acylcarnitine/free carnitine ratio and cardiopulmonary exercise test parameters in patients with incident dialysis

Objective: Diminished physical capacity is common and progressive in patients undergoing dialysis, who are also prone to deficiency in carnitine, which plays a pivotal role in maintaining skeletal muscle and cardiac function. The present study aimed to evaluate the association of carnitine profile with exercise parameters in patients with incident dialysis. Design and Methods: This was a single-center cross-sectional study including 87 consecutive patients aged 20-90 years who were initiated on dialysis in Keio University Hospital between December 2019 and December 2022 and fulfilled the eligibility criteria. Exercise parameters were evaluated via cardiopulmonary testing (CPX) using the electronically braked STRENGTH ERGO 8 ergometer, whereas the carnitine profile was assessed by determining serum free carnitine (FC), acylcarnitine (AC) levels and AC/FC ratio. Results: The mean cohort age was 62.1 ± 15.2 years, with male and hemodialysis predominance (70% and 73%, respectively). AC/FC was 0.46 ± 0.15, and CPX revealed peak oxygen consumption (VO₂) of 13.9 ± 3.7 (mL/kg/min) with percent-predicted peak VO₂ of 53.6% ± 14.7% and minute ventilation (VE)/carbon dioxide output (VCO₂) slope of 35.1 ± 8.0. Fully-adjusted multivariate linear regression analysis showed that AC/FC was significantly associated with decreased peak VO₂ (β, -5.43 [95% confidence interval (CI), -10.15 to -0.70]) and percent-predicted peak VO₂ (β, -19.98 [95% CI, -38.43 to -1.52]) and with increased VE/VCO₂ slope (β, 13.76 [95% CI, 3.78-23.75]); FC and AC did not exhibit similar associations with these parameters. Moreover, only AC/FC was associated with a decreased peak work rate (WR), percent-predicted WR, anaerobic threshold, delta VO₂/delta WR, and chronotropic index. Conclusion: In patients on incident dialysis, exercise parameters, including those related to both skeletal muscle and cardiac function, were strongly associated with AC/FC, a marker of carnitine deficiency indicating altered fatty acid metabolism. Further studies are warranted to determine whether carnitine supplementation can improve exercise capacity in patients on incident dialysis.

Average and Interindividual Effects to a Comprehensive Cardiovascular Rehabilitation Program

Background: To describe the average effects and the interindividual variability after a comprehensive outpatient cardiovascular rehabilitation (CCR) program using concurrent exercise training prescribed according to cardiovascular risk stratification on cardiorespiratory fitness (CRF), anthropometric/body composition, quality of life and emotional health in patients of four cardiovascular disease profiles. Methods: CRF, anthropometric/body composition, quality of life, and emotional health were measured before and after a CCR and analyzed in heart valve surgery (HVS), heart failure with reduced ejection fraction (HFrEF), post-acute myocardial infarction (post-AMI), and in coronary artery disease (CAD) patients. Twenty, twenty-four, and thirty-two exercise sessions were prescribed according to mild, moderate, and severe baseline cardiovascular risk, respectively. In addition to concurrent exercise training, nutritional counseling, psychological support, and lifestyle education programs were performed. Results: The main outcomes by delta changes comparisons (Δ) revealed no significant differences at anthropometric/body composition as ΔBody fat decreases (HVS Δ−1.1, HFrEF Δ−1.0, post-AMI Δ−1.4, CAD Δ−1.2 kg) and ΔSkeletal muscle mass increases (HVS Δ+1.4, HFrEF Δ+0.8, post-AMI Δ+0.9, CAD Δ+0.9 kg), and CRF performance as ΔVO2peak increases (HVS Δ+4.3, HFrEF Δ+4.8, post-AMI Δ+4.1, CAD Δ+5.1 mL/kg/min) outcomes among HVS, HFrEF, post-AMI, and CAD (p > 0.05). Secondary outcomes showed significant pre-post delta changes in METs (HVS Δ+1.8, HFrEF Δ+0.7, post-AMI Δ+1.4, CAD Δ+1.4), and maximal O2pulse (HVS Δ+3.1, post-AMI Δ+2.1, CAD Δ+1.9). In addition, quality of life had a significant improvement in physical functioning (HVS Δ+17.0, HFrEF Δ+12.1, post-AMI Δ+9.8, CAD Δ+11.2), physical role (HVS Δ+28.4, HFrEF Δ+26.8, post-AMI Δ+25.6, CAD Δ+25.3), vitality (HVS Δ+18.4, HFrEF Δ+14.3, post-AMI Δ+14.2, CAD Δ+10.6) and social functioning (HVS Δ+20.4, HFrEF Δ+25.3, post-AMI Δ+20.4, CAD Δ+14.8) in all cardiovascular disease. For anxiety (HVS Δ−3.6, HFrEF Δ−2.3, post-AMI Δ−3.0, CAD Δ−3.1) and depression (HVS Δ−2.8, HFrEF Δ−3.4, post-AMI Δ−3.2, CAD Δ−2.3) significant changes were also observed. Conclusions: A CCR program that prescribes the number of exercise sessions using a cardiovascular risk stratification improves CRF, QoL, and emotional health, and the average results show a wide interindividual variability (~25% of non-responders) in this sample of four CVD profile of patients.

Effects of Home-Based Electrical Stimulation on Plasma Cytokines Profile, Redox Biomarkers, and Metalloproteinases in the Heart Failure with Reduced Ejection Fraction: A Randomized Trial

Background: Low-frequency electrical stimulation (LFES) is an adjuvant method for heart failure (HF) patients with restrictions to start an exercise. However, the impact on molecular changes in circulating is unknown. We investigated the effects of 10 weeks of home-based LFES on plasma cytokines profile, redox biomarkers, metalloproteinases (MMPs) activity, and exercise performance in HF patients. Methods: Twenty-four HF patients (52.45 ± 9.15 years) with reduced ejection fraction (HFrEF) (EF < 40%), were randomly assigned to a home-based LFES or sham protocol. Plasma cytokines profile was assessed through interleukins, interferon-gamma, and tumor necrosis factor levels. Oxidative stress was evaluated through ferric reducing antioxidant power, thiobarbituric acid-reactive substances, and inducible nitric oxide synthase. The MMPs activity were analyzed by zymography. Cardiorespiratory capacity and muscle strength were evaluated by cardiopulmonary test and isokinetic. Results: LFES was able to increase the active-MMP2 activity post compared to pre-training (0.057 to 0.163, p = 0.0001), while it decreased the active-MMP9 (0.135 to 0.093, p = 0.02). However, it did not elicit changes in cytokines, redox biomarkers, or exercise performance (p > 0.05). Conclusion: LFES protocol is a promising intervention to modulate MMPs activity in HFrEF patients, although with limited functional effects. These preliminary responses may help the muscle to adapt to future mechanical demands dynamically.

The prognostic value of the Incremental Shuttle Walk Test in Chagas cardiomyopathy

PURPOSE

To verify the value of the Incremental Shuttle Walk Test (ISWT) distance to identify patients with Chagas cardiomyopathy (ChC) at risk of adverse cardiovascular events.

METHODS

Fifty-two patients with ChC (51 ± 6 years) were evaluated by ISWT, echocardiography, Cardiopulmonary Exercise Testing, and Human Activity Profile (HAP) Questionnaire. Patients were prospectively followed for 44 ± 10 months. The combined endpoint was cardiac death/heart transplant/stroke. The prognostic value of ISWT was verified by the Cox regression, and the ISWT was adjusted for age, sex, left ventricular ejection fraction (LVEF), and minute ventilation/carbon dioxide production relationship (VE/VCO₂ slope).

RESULTS

At the final follow-up, 11 patients (21%) had experienced the endpoint event. When adjusted for age, sex, LVEF, and VE/VCO₂ slope, only ISWT distance (HR 0.99, 95% confidence interval (CI): 0.98-0.99; p = 0.026) and VE/VCO₂ slope (HR 0.93, 95% CI: 0.87-0.99; p = 0.044) remained as independent predictors of adverse cardiovascular events in patients with ChC. The optimal cutoff point for identifying poor prognosis was the ISWT distance less than 440 m (AUC = 0.72). There was a significant difference (p = 0.032) in the number of events between the groups with low ISWT distance (≤440 m) and high (>440 m) ISWT distance.

CONCLUSIONS

The ISWT is a valuable tool with potential value in the prognostic evaluation of patients with ChC.Implications for rehabilitationPatients with Chagas cardiomyopathy showed functional impairment since the early stages of heart disease.The Incremental Shuttle Walk Test (ISWT) can be a valuable and inexpensive tool in the risk stratification of the patients.The ISWT distance is an independent predictor of adverse cardiovascular event.The ISWT distance of 440m is the optimal cut-off point in the identification of patients at risk for adverse cardiovascular events.

Clinical outcomes of opioid administration in acute and chronic heart failure: A meta-analysis

BACKGROUND AND AIMS

Opioid use in heart failure (HF) management is controversial, and whether rapid symptomatic relief outweighs the risks of opioid use in HF remains unknown. This study aimed to explore the clinical outcomes of opioid administration in patients with acute or chronic HF.

METHODS

A systematic search for eligible studies was conducted in databases (MEDLINE, Scopus, Web of Science, EBSCO) and registries (ClinicalTrials.gov, WHO Clinical Trial Registry) until June 8, 2022. Odds ratios (ORs) or adjusted OR (aORs) and mean difference (MD) or standardized MD were quantified for binary and continuous outcomes, respectively. Meta-regression was performed using the restricted maximum likelihood method.

RESULTS

A total of 20 studies (154,736 participants) were included. In acute HF, opioid use presented a high risk for in-hospital mortality (OR = 2.35; 95% confidence interval (CI): 1.03-5.38; I² = 97%), invasive (OR = 2.78; 95%CI: 1.17-6.61; I² = 93%) and noninvasive (OR = 2.97; 95%CI: 1.06-8.28; I² = 95%) ventilations, intensive care unit admission (OR = 3.62; 95%CI: 3.11-4.21; I² = 6%), and inotrope use (OR = 2.54; 95%CI: 1.94-3.32; I² = 63%). In chronic HF New York Heart Association (NYHA) Class II/III, opioid use improved ventilatory efficiency (MD = -3.16; 95%CI: (-4.78)-(-1.54); I² = 0%), and exercise test duration (MD = 69.24; 95%CI: 10.11-128.37; I² = 89%).

CONCLUSIONS

Opioids are not recommended for acute HF management; however, they showed an advantage in exercise testing by improving ventilatory efficiency, chemosensitivity, and exercise test duration in stable patients with chronic HF NYHA Class II/III. Nonetheless, larger randomized controlled trials and individual patient-level data meta-analyses are warranted.

Inhibition of peripheral chemoreceptors improves ventilatory efficiency during exercise in heart failure with preserved ejection fraction − a role of tonic activity and acute reflex response

Peripheral chemoreceptors (PChRs) play a significant role in maintaining adequate oxygenation in the bloodstream. PChRs functionality comprises two components: tonic activity (PChT) which regulates ventilation during normoxia and acute reflex response (peripheral chemosensitivity, PChS), which increases ventilation following a specific stimulus. There is a clear link between augmented PChS and exercise intolerance in patients with heart failure with reduced ejection fraction. It has been also shown that inhibition of PChRs leads to the improvement in exercise capacity. However, it has not been established yet: 1) whether similar mechanisms take part in heart failure with preserved ejection fraction (HFpEF) and 2) which component of PChRs functionality (PChT vs. PChS) is responsible for the benefit seen after the acute experimental blockade. To answer those questions we enrolled 12 stable patients with HFpEF. All participants underwent an assessment of PChT (attenuation of minute ventilation in response to low-dose dopamine infusion), PChS (enhancement of minute ventilation in response to hypoxia) and a symptom-limited cardiopulmonary exercise test on cycle ergometer. All tests were placebo-controlled, double-blinded and performed in a randomized order. Under resting conditions and at normoxia dopamine attenuated minute ventilation and systemic vascular resistance (p = 0.03 for both). These changes were not seen with placebo. Dopamine also decreased ventilatory and mean arterial pressure responses to hypoxia (p < 0.05 for both). Inhibition of PChRs led to a decrease in V˙E/V˙CO₂ comparing to placebo (36 ± 3.6 vs. 34.3 ± 3.7, p = 0.04), with no effect on peak oxygen consumption. We found a significant relationship between PChT and the relative decrement of V˙E/V˙CO₂ on dopamine comparing to placebo (R = 0.76, p = 0.005). There was a trend for correlation between PChS (on placebo) and V˙E/V˙CO₂ during placebo infusion (R = 0.56, p = 0.059), but the relative improvement in V˙E/V˙CO₂ was not related to the change in PChS (dopamine vs. placebo). We did not find a significant relationship between PChT and PChS. In conclusion, inhibition of PChRs in HFpEF population improves ventilatory efficiency during exercise. Increased PChS is associated with worse (higher) V˙E/V˙CO₂, whereas PChT predicts an improvement in V˙E/V˙CO₂ after PChRs inhibition. This results may be meaningful for patient selection in further clinical trials involving PChRs modulation.

Exercise Intolerance in Post-Acute Sequelae of COVID-19 and the Value of Cardiopulmonary Exercise Testing- a Mini-Review

Coronavirus disease (COVID-19) is an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with systemic organ damage in the most severe forms. Long-term complications of SARS-CoV-2 appear to be restricted to severe presentations of COVID-19, but many patients with persistent symptoms have never been hospitalized. Post-acute sequelae of COVID-19 (PASC) represents a heterogeneous group of symptoms characterized by cardiovascular, general, respiratory, and neuropsychiatric sequelae. The pace of evidence acquisition with PASC has been rapid, but the mechanisms behind it are complex and not yet fully understood. In particular, exercise intolerance shares some features with other classic respiratory and cardiac disorders. However, cardiopulmonary exercise testing (CPET) provides a comprehensive assessment and can unmask the pathophysiological mechanism behind exercise intolerance in gray-zone PASC. This mini-review explores the utility of CPET and aims to provide a comprehensive assessment of PASC by summarizing the current evidence.

Prediction of Postoperative Complications: Ventilatory Efficiency and Rest End-tidal Carbon Dioxide

BACKGROUND

Cardiopulmonary exercise testing parameters including ventilatory efficiency (V_E/VCO₂ slope) are used for risk assessment of lung resection candidates. However, many patients are unable or unwilling to undergo exercise. V_E/VCO₂ slope is closely related to the partial pressure of end-tidal carbon dioxide (P_ETCO₂). We hypothesized P_ETCO₂ at rest predicts postoperative pulmonary complications.

METHODS

Consecutive lung resection candidates were included in this prospective multicenter study. Postoperative respiratory complications were assessed from the first 30 postoperative days or from the hospital stay. Student t test or Mann-Whitney U test was used for comparison. Multivariate stepwise logistic regression analysis was used to analyze association with the development of postoperative pulmonary complications. The De Long test was used to compare area under the curve (AUC). Data are summarized as median (interquartile range).

RESULTS

Three hundred fifty-three patients were analyzed, of which 59 (17%) developed postoperative pulmonary complications. P_ETCO₂ at rest was significantly lower (27 [24-30] vs 29 [26-32] mm Hg; P < .01) and V_E/VCO₂ slope during exercise significantly higher (35 [30-40] vs 29 [25-33]; P < .01) in patients who developed postoperative pulmonary complications. Both rest P_ETCO₂ with odds ratio 0.90 (95% confidence interval [CI] 0.83-0.97); P = .01 and V_E/VCO₂ slope with odds ratio 1.10 (95% CI 1.05-1.16); P < .01 were independently associated with postoperative pulmonary complications by multivariate stepwise logistic regression analysis. There was no significant difference between AUC of both models (rest P_ETCO₂: AUC = 0.79 (95% CI 0.74-0.85); V_E/VCO₂ slope: AUC = 0.81 (95% CI 0.75-0.86); P = .48).

CONCLUSIONS

P_ETCO₂ at rest has similar prognostic utility as V_E/VCO₂ slope, suggesting rest P_ETCO₂ may be used for postoperative pulmonary complications prediction in lung resection candidates.

Outcomes of adults with repaired tetralogy of Fallot from the national Scottish Cohort

BACKGROUND

The adult population of repaired tetralogy of Fallot is increasing and at risk of pre-mature death and arrhythmia. This study evaluates risk factors for adverse outcome and the effect of pulmonary valve replacement within a national cohort.

METHODS

A retrospective cohort study of 341 adult repaired tetralogy of Fallot (16-72 years) managed through a single national service was undertaken incorporating over 1200 patient-years of follow-up. Demographics, cardiopulmonary exercise testing, cardiac magnetic resonance, reintervention (including pulmonary valve replacement), and clinical events were analysed. The influence of these parameters on a primary outcome (death or arrhythmia) was evaluated.

RESULTS

Compared with an age-/gender-matched population, patients experienced a reduced survival, particularly males over 55 years (standardised mortality ratio : 6.12, 95% CI: 1.64-15.66, p = 0.004). Cox proportional hazards modelling identified increased indexed right ventricle (RV) end-diastolic volume (hazard ratio (HR): 2.86, 95% CI: 1.4-5.85, p = 0.004) and female gender (HR (male): 0.37, 95% CI: 0.14-0.98, p = 0.045) to be predictors significantly associated with the primary outcome. Pulmonary valve replacement undertaken at indexed RV end-diastolic volume = 145 ml/m2 reduced RV volumes and QRS duration but did not improve cardiopulmonary exercise testing nor NYHA class. Pulmonary valve replacement during cohort period was associated with increased risk of primary outcome (HR: 2.82, 95% CI: 1.36-5.86, p = 0.005).

CONCLUSIONS

Although the majority of adult tetralogy of Fallot were asymptomatic in NYHA 1, cardiopulmonary exercise testing revealed important deficits. Tetralogy of Fallot survival was reduced compared to the general population. Female gender and increasing RV end-diastolic volume predicted adverse events. Pulmonary valve replacement reduced RV volumes and QRS duration but did not improve primary outcome.

Effect of induced acute metabolic alkalosis on the V̇E/V̇CO2 response to exercise in healthy adults

We tested the hypothesis that increasing the respiratory control systems' arterial PCO₂ equilibrium point via induced acute metabolic alkalosis by ingestion of sodium bicarbonate (NaHCO₃, 0.3 g/kg) would decrease the ventilatory equivalent for CO₂ (V̇_E/V̇CO₂) at its lowest point ("nadir") during constant-load cycle exercise testing performed at 80 % of peak power output in 18 healthy young adults. Compared to the sodium chloride (4 g) control condition, ingestion of NaHCO₃: increased arterialized venous pH, HCO₃- and PCO₂ at rest by 0.05 ± 0.01 units (mean ± SE), 6.4 ± 0.4 mEq/L and 4.3 ± 0.7 mmHg, respectively (all p < 0.0001); and decreased the V̇_E/V̇CO₂ nadir during exercise by 9.4 % (p < 0.0001) secondary to a 4.7 ± 1.8 L/min decrease in V̇_E (p = 0.019). In conclusion, induced acute metabolic alkalosis by ingestion of NaHCO₃ decreased the V̇_E/V̇CO₂ response to strenuous exercise in healthy adults.

Inflammation in Heart Failure: JACC State-of-the-Art Review

It has long been observed that heart failure (HF) is associated with measures of systemic inflammation. In recent years, there have been significant advancements in our understanding of how inflammation contributes to the pathogenesis and progression of HF. However, although numerous studies have validated the association between measures of inflammation and HF severity and prognosis, clinical trials of anti-inflammatory therapies have proven mostly unsuccessful. On this backdrop emerges the yet unmet goal of targeting precise phenotypes within the syndrome of HF; if such precise definitions can be realized, and with better understanding of the roles played by specific inflammatory mediators, the expectation is that targeted anti-inflammatory therapies may improve prognosis in patients whose HF is driven by inflammatory pathobiology. Here, the authors describe mechanistic links between inflammation and HF, discuss traditional and novel inflammatory biomarkers, and summarize the latest evidence from clinical trials of anti-inflammatory therapies.

The Effects of Aerobic Exercise on N-terminal Pro-B-type Natriuretic Peptide and Cardiopulmonary Function in Patients With Heart Failure: A Meta-Analysis of Randomised Clinical Trials

BACKGROUND

Aerobic exercise (AEx) improves outcomes in heart failure (HF). N-terminal pro B-type natriuretic peptide (NT-pro-BNP) is a prognosticator in HF. There are few data on the association of AEx, NT-pro-BNP, and cardiopulmonary function; hence, robust evidence is needed. The aim of this study was to measure the effects of AEx on NT-pro-BNP levels and cardiopulmonary function in HF.

METHOD

Databases (Pubmed, EMBASE, Medline, Cochrane Central Registry, and Scopus) were systematically searched for randomised controlled trials (RCTs) that assessed the association of AEx with NT-pro-BNP and cardiopulmonary function (VE/VCO₂ slope, peak VO₂, maximal workload, and left ventricular ejection fraction [LVEF]) in HF. RevMan 5.3 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen, 2014) was used to produce forest plots, and the random-effect model was applied with the effects measure of weighted mean differences (WMD) and 95% confidence interval (CI).

RESULTS

Thirteen (13) RCTs recruited 1,503 patients and 1,494 controls. Aerobic exercise was significant in lowering NT-pro-BNP (pg/mL) compared with control group (WMD=-741.69, 95% CI -993.10 to -490.27 [p<0.00001; I²=63%]). VE/VCO₂ slope was also significantly reduced (WMD=-3.57, 95% CI -6.48 to -0.67 [p=0.02; I²=97%]). Peak VO₂ (mL/kg/min) significantly improved (WMD=3.68, 95% CI 2.39-4.96 [p<0.00001; I²=96%]). Maximal workload (watt) significantly increased following AEx (WMD=22.80, 95% CI 18.44-27.17 [p<0.00001; I²=78%]). Furthermore, there was a significant enhancement of LVEF (%) in the AEx group (WMD=2.42, 95% CI 0.64-4.19 [p=0.008; I²=71%]).

CONCLUSIONS

Aerobic exercise improves the NT-pro-BNP, ventilatory efficiency, aerobic capacity, maximal workload, and the left ventricular function in patients with HF.

The hemodynamic effects of a central iliac arteriovenous anastomosis at 6 months in patients with resistant and uncontrolled hypertension

A central iliac arteriovenous anastomosis, termed the "coupler" (ROX Medical), results in a significant reduction in blood pressure (BP) in hypertensive patients. This study assessed functional and hemodynamic changes induced by the device. Twenty-one patients with resistant and/or uncontrolled hypertension underwent stress echocardiography and cardiopulmonary exercise testing (CPET) at baseline and 6 months post-coupler implantation. End points were selected to best evaluate cardiac function including Doppler stroke volume (SV), septal and lateral E/E', and right ventricular systolic velocity S' (RV S'). CPET VO₂ peak demonstrated total cardiopulmonary performance. SV increased from 76.4 SD12.2 mL to 92.1 SD22.7 mL 6 months post-coupler insertion; P = .002. No changes in RV S', septal or lateral E/E', or VO₂ peak were observed. Five patients experienced increased diuretic requirement ≥3 times baseline. RV S' fell from 19.0 SD1.87 cm/s to 16.80 SD3.43 cm/s in these patients (P > .05). A significant increase in SV 6 months post-coupler insertion was observed. In patients with increased diuretic requirement, the device was associated with a lower RV S' suggesting occult RV dysfunction as the mechanism of this pre-specified adverse outcome.

Cardiopulmonary exercise testing for identification of patients with hyperventilation syndrome

Introduction

Measurement of ventilatory efficiency, defined as minute ventilation per unit carbon dioxide production (V_E/VCO₂), by cardiopulmonary exercise testing (CPET) has been proposed as a screen for hyperventilation syndrome (HVS). However, increased V_E/VCO₂ may be associated with other disorders which need to be distinguished from HVS. A more specific marker of HVS by CPET would be clinically useful. We hypothesized ventilatory control during exercise is abnormal in patients with HVS.

Methods

Patients who underwent CPET from years 2015 through 2017 were retrospectively identified and formed the study group. HVS was defined as dyspnea with respiratory alkalosis (pH >7.45) at peak exercise with absence of acute or chronic respiratory, heart or psychiatric disease. Healthy patients were selected as controls. For comparison the Student t-test or Mann-Whitney U test were used. Data are summarized as mean ± SD or median (IQR); p<0.05 was considered significant.

Results

Twenty-nine patients with HVS were identified and 29 control subjects were selected. At rest, end-tidal carbon dioxide (P_ETCO₂) was 27 mmHg (25–30) for HVS patients vs. 30 mmHg (28–32); in controls (p = 0.05). At peak exercise P_ETCO₂ was also significantly lower (27 ± 4 mmHg vs. 35 ± 4 mmHg; p<0.01) and V_E/VCO₂ higher ((38 (35–43) vs. 31 (27–34); p<0.01)) in patients with HVS. In contrast to controls, there were minimal changes of P_ETCO₂ (0.50 ± 5.26 mmHg vs. 6.2 ± 4.6 mmHg; p<0.01) and V_E/VCO₂ ((0.17 (-4.24–6.02) vs. -6.6 (-11.4-(-2.8)); p<0.01)) during exercise in patients with HVS. The absence of V_E/VCO₂ and P_ETCO₂ change during exercise was specific for HVS (83% and 93%, respectively).

Conclusion

Absence of V_E/VCO₂ and P_ETCO₂ change during exercise may identify patients with HVS.

Relationship of ventilatory inefficiency and low cardiorespiratory fitness in the elderly: a retrospective observational study

Abstract Objectives : To check if ventilatory inefficiency is related to low cardiorespiratory fitness in the elderly and to identify the variable(s) of the cardiopulmonary exercise test (CPET) best suited to determining this relationship. Methods : A retrospective analysis of 1357 CPETs was performed. Sixty-one subjects over 60 years old with a ventilatory efficiency slope (VE/VCO2) index >35 were selected and divided into two groups: low cardiorespiratory fitness (VO2<80% predicted) (n=22) and normal cardiorespiratory fitness (VO2>80% predicted) (n=39) and were compared with a control group of healthy elderly persons with normal cardiorespiratory fitness and VE/VCO2 slope index <35 (n=16), matched by gender, weight, height, and age. Results : Oxygen consumption had a low correlation with VE/VCO2 slope (r= -0.35, p<0.01), a moderate correlation with the cardiorespiratory optimal point (COP) (r= -0.59, p<0.001) and a strong correlation with oxygen uptake efficiency Slope (OUES) =0.92, p<0.0001). In relation to the ROC curve, the VE/VCO2 slope presented an area under the curve of 0.65, but without statistical significance (p> 0.05); the COP showed an area under the curve of 0.84 (p <0.0001) and the OUES presented an area under the curve of 0.81 (p<0.0001). Conclusion : Ventilatory inefficiency is related to poor cardiorespiratory fitness in the elderly. The COP and OUES were more accurate at predicting low cardiorespiratory fitness.

Minute ventilation-to-carbon dioxide slope is associated with postoperative survival after anatomical lung resection

OBJECTIVES

The aim of the study was to identify whether ventilation-to-carbon dioxide output (V_E/V _CO2) slope obtained from cardiopulmonary exercise test (CPET) as part of the preoperative functional workup was an independent prognostic factor for short and long-term survival after major lung resection.

PATIENTS AND METHODS

974 consecutive patients undergoing lobectomy (n = 887) or segmentectomy (n = 87) between April 2014 to March 2018 were included. 209 (22%) underwent CPET, and pulmonary function tests and several clinical factors including age, sex, performance status and comorbidities were retrospectively investigated to identify the prognostic factors with a multivariable Cox regression analysis.

RESULTS

Among the patients with measured V_E/V _CO2, the incidence of cardiopulmonary complications in patients with high V_E/V _CO2 slope (>40) was 37% (19 of 51) vs. 27% (33 of 121) in those with lower slope values (p = 0.19). The 90-day mortality in patients with high V_E/V _CO2 slope (n = 8) was 16% vs. 5% (n = 6) in those with lower slope values (p = 0.03). No overall difference in 2-year mortality was identified between the two groups (VE/VCO2 > 40: 70% (54-80) vs. VE/VCO2 ≤ 40: 72% (63-80), log-rank test, p = 0.39). In a Cox regression analysis V_E/V_CO2 values were associated with poorer 2-year survival (HR 1.05, 95% CI 1.01-1.10, p = 0.030).

CONCLUSIONS

We found that V_E/V _CO2 slope was an independent prognostic factor for the 90-day mortality and 2-year survival after anatomic pulmonary resection. This finding may assist during the multidisciplinary treatment decision-making process in high-risk patients with lung cancer.

Clinical significance of respiratory compensation during exercise testing in cardiac patients

Ventilation (VE) increases linearly with the increase of carbon dioxide output (VCO2) during cardiopulmonary exercise testing. VE-VCO2 slope rises in parallel with exercise intensity, reaches a turning point (called the RC point), then steepens because of respiratory compensation for lactic acidosis. While this RC point can be identified universally, it is undetectable in some patients. In this study we evaluated whether the respiratory compensation during exercise testing has clinical significance in cardiac patients. In total, 152 cardiac patients with a respiratory exchange ratio at peak exercise (peak R) of between 1.10 and 1.20 were enrolled. Cardiopulmonary parameters were compared between patients who manifested the RC point (n = 118) and those who did not (n = 34). The peak R did not significantly differ between these two groups. Compared to the patients without the RC point, those with the RC point had a higher oxygen uptake at peak exercise (peak VO2) (20.2 ± 5.3 vs 13.6 ± 3.4 mL/min/kg, p < 0.001), higher anaerobic threshold (AT) (12.4 ± 3.2 vs 9.2 ± 2.3 mL/min/kg, p < 0.001), and lower VE-VCO2 slope (31.7 ± 5.8 vs 37.8 ± 9.6, p = 0.001). Brain natriuretic peptide (BNP) tended to be lower in the patients with the RC point (175.4 ± 364.7 vs 327.9 ± 381.1 pg/mL, p = 0.067). Peak VO2, the marker of cardiopulmonary function, was found to be the independent predictor of the presence of the RC point. The present findings suggest that the phenomenon of respiratory compensation during heavy exercise indicates better cardiopulmonary function in cardiac patients within a prescribed range of effort.

Cerebral desaturation in heart failure: Potential prognostic value and physiologic basis

Cerebral tissue oxygen saturation (SctO₂) reflects cerebral perfusion and tissue oxygen consumption, which decline in some patients with heart failure with reduced ejection fraction (HFrEF) or stroke, especially during exercise. Its physiologic basis and clinical significance remain unclear. We aimed to investigate the association of SctO₂ with oxygen transport physiology and known prognostic factors during both rest and exercise in patients with HFrEF or stroke. Thirty-four HFrEF patients, 26 stroke patients, and 17 healthy controls performed an incremental cardiopulmonary exercise test using a bicycle ergometer. Integrated near-infrared spectroscopy and automatic gas analysis were used to measure cerebral tissue oxygenation and cardiac and ventilatory parameters. We found that SctO₂ (rest; peak) were significantly lower in the HFrEF (66.3±13.3%; 63.4±13.8%,) than in the stroke (72.1±4.2%; 72.7±4.5%) and control (73.1±2.8%; 72±3.2%) groups. In the HFrEF group, SctO₂ at rest (SctO_2rest) and peak SctO₂ (SctO_2peak) were linearly correlated with brain natriuretic peptide (BNP), peak oxygen consumption (V˙O2peak), and oxygen uptake efficiency slope (r between -0.561 and 0.677, p < 0.001). Stepwise linear regression showed that SctO_2rest was determined by partial pressure of end-tidal carbon dioxide at rest (P_ETCO_2rest), hemoglobin, and mean arterial pressure at rest (MAP_rest) (adjusted R = 0.681, p < 0.05), while SctO_2peak was mainly affected by peak carbon dioxide production (V˙CO2peak) (adjusted R = 0.653, p < 0.05) in patients with HFrEF. In conclusion, the study delineates the relationship of cerebral saturation and parameters associated with oxygen delivery. Moreover, SctO_2peak and SctO_2rest are correlated with some well-recognized prognostic factors in HFrEF, suggesting its potential prognostic value.

Effect of exercise training on ventilatory efficiency in patients with heart disease: a review

The analysis of ventilatory efficiency in cardiopulmonary exercise testing has proven useful for assessing the presence and severity of cardiorespiratory diseases. During exercise, efficient pulmonary gas exchange is characterized by uniform matching of lung ventilation with perfusion. By contrast, mismatching is marked by inefficient pulmonary gas exchange, requiring increased ventilation for a given CO2 production. The etiology of increased and inefficient ventilatory response to exercise in heart disease is multifactorial, involving both peripheral and central mechanisms. Exercise training has been recommended as non-pharmacological treatment for patients with different chronic cardiopulmonary diseases. In this respect, previous studies have reported improvements in ventilatory efficiency after aerobic exercise training in patients with heart disease. Against this background, the primary objective of the present review was to discuss the pathophysiological mechanisms involved in abnormal ventilatory response to exercise, with an emphasis on both patients with heart failure syndrome and coronary artery disease. Secondly, special focus was dedicated to the role of aerobic exercise training in improving indices of ventilatory efficiency among these patients, as well as to the underlying mechanisms involved.