Watanabe T; Murase N; Kime R; Kurosawa Y; Fuse S; Hamaoka T;

Advances in experimental medicine and biology [Adv Exp Med Biol] 2021; Vol. 1269, pp. 101-105.

The primary symptom in patients with chronic heart failure (CHF) is exercise intolerance. Previous studies have reported that reduced exercise tolerance in CHF can be explained not only by cardiac output (a central factor) but also by reduced skeletal muscle aerobic capacity (a peripheral factor). Although exercise training in CHF improves exercise tolerance, few studies have evaluated the effects of exercise training on each specific central and peripheral factor in CHF. The aim of this study was to investigate the central and peripheral aerobic functions in CHF and the effects of exercise training in CHF on cardiac output and skeletal muscle deoxygenation during exercise. We assessed peak oxygen uptake (VO ₂ ) during cardiopulmonary exercise testing, peak cardiac output (CO) using noninvasive hemodynamic monitoring, and muscle oxygen saturation (SmO ₂ ) using near-infrared spectroscopy (NIRS). Patients with CHF were trained for 12 weeks and performed ramp cycling exercise until exhaustion before and after the exercise training. Peak VO ₂ , peak CO, and SmO ₂ changes from rest to peak exercise (ΔSmO ₂ ) were significantly lower in CHF than those in healthy subjects. As a result of exercise training, peak oxygen uptake in patients with CHF was improved and positively associated with change in ΔSmO ₂ . In contrast, there was no change in peak cardiac output. The results of this study indicate that both cardiac and skeletal muscle functions in patients with CHF were lower than those in healthy subjects. Further, the results suggest that the improvement of exercise capacity in patients with CHF by exercise training was related to the improved utilization of oxygen (a peripheral factor) in skeletal muscle.

McNeill JN; Lau ES; Zern EK; Nayor M; Malhotra R; Liu EE; Bhat RR; Brooks LC; Farrell R; Sbarbaro JA;
Schoenike MW; Medoff BD; Lewis GD; Ho JE;

Respiratory medicine [Respir Med] 2021 Apr 30; Vol. 183, pp. 106434. Date of Electronic Publication: 2021 Apr 30.

Background: Obesity has multifactorial effects on lung function and exercise capacity. The contributions of obesity-related inflammatory pathways to alterations in lung function remain unclear.
Research Question: To examine the association of obesity-related inflammatory pathways with pulmonary function, exercise capacity, and pulmonary-specific contributors to exercise intolerance.
Method: We examined 695 patients who underwent cardiopulmonary exercise testing (CPET) with invasive hemodynamic monitoring at Massachusetts General Hospital between December 2006-June 2017. We investigated the association of adiponectin, leptin, resistin, IL-6, CRP, and insulin resistance (HOMA-IR) with pulmonary function and exercise parameters using multivariable linear regression.
Results: Obesity-related inflammatory pathways were associated with worse lung function. Specifically, higher CRP, IL-6, and HOMA-IR were associated with lower percent predicted FEV ₁ and FVC with a preserved FEV ₁ /FVC ratio suggesting a restrictive physiology pattern (P ≤ 0.001 for all). For example, a 1-SD higher natural-logged CRP level was associated with a nearly 5% lower percent predicted FEV ₁ and FVC (beta -4.8, s.e. 0.9 for FEV1; beta -4.9, s.e. 0.8 for FVC; P < 0.0001 for both). Obesity-related inflammatory pathways were associated with worse pulmonary vascular distensibility (adiponectin, IL-6, and CRP, P < 0.05 for all), as well as lower pulmonary artery compliance (IL-6 and CRP, P ≤ 0.01 for both).
Interpretation: Our findings highlight the importance of obesity-related inflammatory pathways including inflammation and insulin resistance on pulmonary spirometry and pulmonary vascular function. Specifically, systemic inflammation as ascertained by CRP, IL-6 and insulin resistance are associated with restrictive pulmonary physiology independent of BMI. In addition, inflammatory markers were associated with lower exercise capacity and pulmonary vascular dysfunction.

Mihalick VL; Canada JM; Arena R; Abbate A; Kirkman DL;

Progress in cardiovascular diseases [Prog Cardiovasc Dis] 2021 May 06.
Date of Electronic Publication: 2021 May 06.

The outbreak of the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has presented a global public health emergency. Although predominantly a pandemic of acute respiratory disease, corona virus infectious disease-19 (COVID-19) results in multi-organ damage that impairs cardiopulmonary (CP) function and reduces cardiorespiratory fitness. Superimposed on the CP consequences of COVID-19 is a marked reduction in physical activity that exacerbates CP disease (CPD) risk. CP exercise testing (CPET) is routinely used in clinical practice to diagnose CPD and assess prognosis; assess cardiovascular safety for rehabilitation; and delineate the physiological contributors to exercise intolerance and exertional fatigue. As such, CPET plays an important role in clinical assessments of convalescent COVID-19 patients as well as research aimed at understanding the long-term health effects of SARS-CoV-2 infection. However, due to the ventilatory expired gas analysis involved with CPET, the procedure is considered an aerosol generating procedure. Therefore, extra precautions should be taken by health care providers and exercise physiologists performing these tests. This paper provides recommendations for CPET testing during the COVID-19 pandemic. These recommendations include indications for CPET; pre-screening assessments; precautions required for testing; and suggested decontamination protocols. These safety recommendations are aimed at preventing SARS-CoV-2 transmission during CPET.

Arena R; Myers J; Kaminsky LA

Journal of cardiopulmonary rehabilitation and prevention [J Cardiopulm Rehabil Prev] 2021 May 11. Date of Electronic Publication: 2021 May 11.

No abstract available

Whittle J; San-Millán I

Current opinion in critical care [Curr Opin Crit Care] 2021 May 11. Date of Electronic Publication: 2021 May 11.

Purpose of Review: Addressing the reduced quality of life that affects ICU survivors is the most pressing challenge in critical care medicine. In order to meet this challenge, we must translate lessons learnt from assessing and training athletes to the clinical population, utilizing measurable and targeted parameters obtained during cardiopulmonary exercise testing (CPET).
Recent Findings: Critical illness survivors demonstrate a persistent reduction in their physical and metabolic function. This manifests in reduced aerobic exercise capacity and metabolic inflexibility. CPET-guided targeted metabolic conditioning has proved beneficial in several clinical populations, including those undergoing high-risk surgery, and could be successfully applied to the rehabilitation of ICU survivors.
Summary: CPET shows great promise in the guidance of rehabilitation in functionally limited ICU survivors. Parallels in the physiological response to exercise in athletes and clinical populations with the stress and consequences of critical illness must be investigated and ultimately applied to the burgeoning population of ICU survivors in order to treat the consequences of survival from critical illness.

Element K; Asher V; Bali A; Abdul S; Gomez D; Tou S; Curtis R; Low J; Phillips A;

Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology [J Obstet Gynaecol] 2021 May 02, pp. 1-7. Date of Electronic Publication: 2021 May 02.

This study assessed Cardiopulmonary Exercise Testing (CPET) in predicting oncological outcomes, post-operative recovery and complications in advanced ovarian cancer (AOC) cytoreductive surgery. We reviewed all patients who had CPET prior to AOC cytoreductive surgery with evidence of upper abdominal disease on preoperative imaging at the University Hospitals of Derby and Burton (UHDB) between August 2016 and July 2019. Patients were stratified by AT and maximum VO ₂ levels. 43 patients were identified. AT showed no relationship with major complications. 100% of patients in the AT ≥11 group received R0 ( n  = 21, 91.30%), or R1 ( n  = 2, 8.70%) cytoreduction, whereas in the AT <11 group, only 75.00% achieved and R0 or R1 resection ( p  = .02). Surgical complexity was higher in the AT ≥11 group ( p  = .001) and the VO ₂ ≥15 group ( p  = .0006). No other correlations were seen between AT or VO ₂ max and complications or readmissions. No difference in overall survival was seen if R0 resection was achieved.IMPACT STATEMENT
What is already known on this subject? CPET testing allows pre-operative assessment of functional capacity to generate variables that can be used as a risk-stratification tool for major surgery. Whilst CPET testing has been shown to predict morbidity in non-gynaecological surgery, it remains unproven in cytoreductive surgery for ovarian cancer surgery despite being increasingly utilised.
What do the results of study add? Our data suggest that CPET testing does not predict complication rates or survival in AOC. Patients with poor CPET performance are more likely to receive suboptimal cytoreductive outcomes from surgery.
What are the implications of these findings for clinical practice and/or further research? CPET results should not be used to discount patients from cytoreductive surgery further research should address the interplay with nutrition, haematological markers, neoadjuvant chemotherapy and CPET performance.

Boutou AK; Dipla K; Zafeiridis A; Markopoulou A; Papadopoulos S; Kritikou S; Panagiotidou E; Stanopoulos I;
Pitsiou G;

Respiratory physiology & neurobiology [Respir Physiol Neurobiol] 2021 May 03, pp. 103677. Date of Electronic Publication: 2021 May 03.

Background: The integrative physiological effects of O ₂ treatment on patients with pulmonary hypertension (PH) during exercise, have not been fully investigated. We simultaneously evaluated, for the first time, the effect of oxygen supplementation on hemodynamic responses, autonomic modulation, tissue oxygenation, and exercise performance in patients with pulmonary arterial hypertension (PAH)/Chronic Thromboembolic PH(CTEPH).
Material-Methods: In this randomized, cross-over, placebo-controlled trial, stable outpatients with PAH/CTEPH underwent maximal cardiopulmonary exercise testing, followed by two submaximal trials, during which they received supplementary oxygen (O ₂ ) or medical-air. Continuous, non-invasive hemodynamics were monitored via photophlythesmography. Cerebral and quadriceps muscle oxygenation were recorded via near-infrared spectroscopy. Autonomic function was assessed by heart rate variability; root mean square of successive differences (RMSSD) and standard-deviation-Poincare-plot (SD1) were used as indices of parasympathetic output. Baroreceptor sensitivity (BRS) was assessed throughout the protocols.
Results: Nine patients (51.4 ± 9.4 years) were included. With O ₂ -supplementation patients exercised for longer (p = 0.01), maintained higher cerebral oxygenated hemoglobin (O ₂ Hb;p = 0.02) levels, exhibited an amelioration in cortical deoxygenation (HHb;p = 0.02), and had higher average cardiac output (CO) during exercise (p < 0.05), compared to medical air; with no differences in muscle oxygenation. With O ₂ -supplementation patients exhibited higher BRS and sample-entropy throughout the protocol (p < 0.05) vs. medical air, and improved the blunted RMSSD, SD1 responses during exercise (p = 0.024).
Conclusion: We show that O ₂ administration improves BRS and autonomic function during submaximal exercise in PAH/CTEPH, without significantly affecting muscle oxygenation. The improved autonomic function, along with enhancements in cardiovascular function and cerebral oxygenation, probably contributes to increased exercise tolerance with O ₂ -supplementation in PH patients.

Bittencourt L; Javaheri S; Servantes DM; Pelissari Kravchychyn AC; Almeida DR; Tufik S;

Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine [J Clin Sleep Med] 2021 May 05. Date of Electronic Publication: 2021 May 05.

Study Objectives: Patients with chronic heart failure (CHF) while undergoing exercise test, frequently exhibit elevated ratio of minute ventilation over CO₂ output (VE/VCO₂ slope). One of the factors contributing to this elevated slope is increased chemosensitivity to CO₂, as this slope significantly correlates with the slope of the ventilatory response to CO₂ rebreathing at rest. A previous study in patients with CHF and central sleep apnea (CSA) has shown the highest VE/VCO2 slope during exercise was associated with the most severe CSA. In the current study, we tested the hypothesis that in patients with CHF and obstructive sleep apnea (OSA), the highest VE/VCO₂ slope is also associated with most severe OSA. If correct, it implies that in CHF, augmented instability in the negative feedback system controlling breathing predisposes to both OSA and CSA.
Methods: This preliminary study involved 70 patients with stable CHF and spectrum of OSA severity who underwent full night polysomnography, echocardiography, and cardiopulmonary exercise testing. Peak oxygen consumption (VO₂ max) and VE/VCO₂ slope were calculated.
Results: There were significant positive correlations between apnea hypopnea index (AHI) and VE/VCO₂ slope (r= 0.359; p=0.002). In the regression model, involving relevant variable, age, body mass index, gender, VE/VCO₂ slope, VO₂, and left ventricular ejection fraction, AHI retained significance with VE/VCO₂.
Conclusions: In patients with CHF, the VE/VCO₂ slope obtained during exercise correlates significantly to the severity of OSA suggesting that an elevated CO₂ response should increase suspicion for presence of severe OSA, a treatable disorder that is potentially associated with excess mortality.

Meucci M; Nandagiri VKavirayuni VS; Whang A; Collier SR;

Pediatric exercise science [Pediatr Exerc Sci] 2021 May 06, pp. 1-5. Date of Electronic Publication: 2021 May 06.

Purpose: To investigate the association between the heart rate (HR) at maximal fat oxidation (MFO) and the HR at the aerobic threshold (AerT) in adolescent boys and girls, and to identify sex differences in the intensity that elicits MFO (Fatmax) as a percentage of HR peak (HRpeak).
Methods: Fifty-eight healthy adolescents participated in this study (29 boys and 29 girls). Participants performed a cardiopulmonary exercise test on a cycle ergometer. MFO was calculated using a stoichiometric equation, and the AerT was identified using gas exchange parameters.
Results: A strong correlation between HR at Fatmax and HR at AerT was found in both boys and girls (r = .96 and .94, respectively). Fatmax as a percentage of HRpeak occurred at 61.0% (4.9%) of HRpeak and 66.8% (6.9%) of HRpeak in adolescent boys and girls (P = .001, F = 13.6), respectively. MFO was higher in boys compared with girls (324 [150] and 240 [95] mg/min, respectively), and no sex differences were observed in the relative contribution of fat to energy expenditure at Fatmax.
Conclusions: HR at Fatmax and HR at AerT were highly correlated in adolescent boys and girls. Girls obtained Fatmax at a higher percentage of HRpeak than boys.

Hanley C; Wijeysundera DN;

Current opinion in anaesthesiology [Curr Opin Anaesthesiol] 2021 Jun 01; Vol. 34 (3), pp. 309-316.

Purpose of Review: This review examines how functional capacity informs preoperative risk stratification, as well as strengths and limitations of options for estimating functional capacity.
Recent Findings: Functional capacity (or cardiopulmonary fitness) overlaps with other important characteristics, including muscular strength, balance, and frailty. Poor functional capacity is associated with postoperative morbidity, especially noncardiovascular complications. Both patient interviews and exercise tests are used to assess functional capacity. The usual approach of an unstructured patient interview does not predict outcomes. Structured interviews that incorporate validated questionnaires (Duke Activity Status Index) or standardized questions about physical activity (ability to climb stairs) do predict moderate-or-severe complications and cardiovascular complications. Among exercise tests, cardiopulmonary exercise testing (CPET) has shown the most consistent association with risks of complications. Other tests (6-min walk test, incremental shuttle walk test, stair climbing) might predict complications, but still require further high-quality evaluation.
Summary: A straightforward way to better assess functional capacity is a structured interview with validated questionnaires or standardized questions about physical activities. Functional capacity can also be assessed by exercise tests, with the strongest evidence supporting CPET. Although some simpler exercise tests have shown promise, more research remains needed to better define their role in preoperative evaluation.