Exercise-Induced Pulmonary Hypertension in Long-Term Survivors of Congenital Diaphragmatic Hernia.

OBJECTIVE: To determine the prevalence of exercise-induced pulmonary hypertension (PH) among long-survivors of congenital diaphragmatic hernia repair. STUDY DESIGN: This is a single-center, retrospective cohort study of CDH survivors who underwent exercise stress echocardiography (ESE) at Boston Children's Hospital from January 2006 to June 2020. PH severity was assessed by echocardiogram at baseline and after exercise. Patients were categorized by right ventricular systolic pressure (RVSP) after exercise: Group 1 - no or mild PH; and Group 2 - moderate or severe PH (RVSP ≥ 60 mmHg or ≥ ½ systemic blood pressure). RESULTS: Eighty-four patients with CDH underwent 173 ESE with median age 8.1 (4.8 - 19.1) years at first ESE. Sixty-four patients were classified as Group 1, 11 as Group 2, and 9 had indeterminate RVSP with ESE. Moderate to severe PH after exercise was found in 8 (10%) patients with no or mild PH at rest. Exercise-induced PH was associated with larger CDH defect size, patch repair, use of ECMO, supplemental oxygen at discharge, and higher WHO functional class. Higher VE/VCO2 slope, lower peak oxygen saturation, and lower percent predicted FEV1, and FEV1/FVC ratio were associated with Group 2 classification. ESE changed management in 9/11 Group 2 patients. PH was confirmed in all 5 Group 2 patients undergoing cardiac catheterization after ESE. CONCLUSIONS: Among long-term CDH survivors, 10% had moderate-severe exercise-induced PH on ESE, indicating ongoing pulmonary vascular abnormalities. Further studies are needed to optimally define PH screening and treatment for patients with repaired CDH.

The Child Opportunity Index 2.0 and Disparities in Pediatric Cardiorespiratory Fitness.

OBJECTIVE: To evaluate the effect of neighborhood-level characteristics on cardiorespiratory fitness (CRF) via peak oxygen consumption (VO2peak) for healthy pediatric patients. STUDY DESIGN: The institutional cardiopulmonary exercise testing (CPET) database was analyzed retrospectively. All patients aged ≤ 18 years without a diagnosis of cardiac disease and with a maximal effort CPET were included. Patients were divided into three self-identified racial categories: White, Black, and Latinx. The Child Opportunity Index (COI) 2.0 was used to analyze social determinants of health. CRF was evaluated based on COI quintiles and race. Assessment of the effect of COI on racial disparities in CRF was performed using ANCOVA. RESULTS: A total of 1753 CPETs met inclusion criteria. The mean VO2peak was 42.1 ± 9.8 mL/kg/min. The VO2peak increased from 39.1 ± 9.6 mL/kg/min for patients in the very low opportunity cohort to 43.9 ± 9.4 mL/kg/min for patients in the very high opportunity cohort. White patients had higher percent predicted VO2peak compared with both Black and Latinx patients (P < .01 for both comparisons). The racial differences in CRF were no longer significant when adjusting for COI. CONCLUSION: In a large pediatric cohort, COI was associated with CRF. Racial disparities in CRF are reduced when accounting for modifiable risk factors.

Reference Values for Cardiorespiratory Fitness in Patients Aged 6 to 18 Years.

OBJECTIVE: To develop reference values for cardiorespiratory fitness, as quantified by peak oxygen uptake (VO2peak) and treadmill time, in patients aged 6 through 18 years referred for cardiopulmonary exercise testing (CPET). STUDY DESIGN: We reviewed a clinical pediatric CPET database for fitness data in children aged 6-18 years with no underlying heart disease. CPET was obtained via the Bruce protocol utilizing objectively confirmed maximal effort via respiratory exchange ratio. Fitness data (VO2peak and treadmill test duration) were analyzed to determine age- and sex-specific reference values for this pediatric cohort. RESULTS: Data from 2025 pediatric CPETs (53.2% female) were included in the analyses. VO2peak increased with age in males, but not females. Treadmill test duration increased with age in both males and females. Fitness was generally higher in males when compared with females in the same age groups. CONCLUSIONS: Our study provides extensive reference values for both VO2peak and total treadmill test time via the Bruce protocol for a pediatric population without known cardiac disease. Furthermore, the inclusion of objectively confirmed maximal exercise effort increases confidence in these findings compared with prior studies in this area. Clinicians performing CPET in pediatric populations can utilize these reference values to characterize test results according to representative peer data.

A Cardiopulmonary Exercise Testing for Prescribing High-Intensity Interval Training Sessions with Elastic Resistance.

This study aims to analyze the agreement of cardiopulmonary variables between a cardiopulmonary exercise test with elastic resistance (CPxEL) and high-intensity interval exercise with elastic resistance (EL-HIIE). METHODS: Twenty-two physically independent participants were recruited. Visit one consisted of conducting a health survey and anthropometric assessment. On visit two, the participants performed CPxEL. After seven days, on visit three, the participants performed EL-HIIE. The CPxEL was carried out on a rubber mat demarcated by lines representing eight stages. The test consisted of alternating back and forth steps against elastic resistance. The increments were performed at a rate of one stage per minute, following a cadence controlled by a metronome calibrated by beats per minute (bpm). The EL-HIIE was performed at the stage corresponding to an intensity of ~85% VO2max, as determined by CPxEL. The EL-HIIE consisted of 10 × 1 min (work):1 min (passive rest), with a cadence of 200 bpm. Cardiopulmonary parameters, heart rate (HR), and oxygen consumption (VO2) were measured during exercise. Bland-Altman was applied to analyze the agreement between the HR and VO2 found in EL-HIIE and the values prescribed by CPxEL (~85-90% VO2max). RESULTS: The HRpeak and VO2peak in the EL-HIIE showed good agreement with the VO2CPxEL and HRCPxEL values, showing an average difference of (-1.7 mL·kg-1·min-1) and (0.3 bpm). CONCLUSIONS: The results of the present study demonstrate the agreement of cardiopulmonary variables between the CPxEL and the EL-HIIE. Therefore, for a more specific prescription of EL-HIIE intensity, CPxEL can be used.

Dynamic Ventilatory Reserve During Incremental Exercise: Reference Values and Clinical Validation in Chronic Obstructive Pulmonary Disease.

Rationale: Ventilatory demand-capacity imbalance, as inferred based on a low ventilatory reserve, is currently assessed only at peak cardiopulmonary exercise testing (CPET). Peak ventilatory reserve, however, is poorly sensitive to the submaximal, dynamic mechanical ventilatory abnormalities that are key to dyspnea genesis and exercise intolerance. Objectives: After establishing sex- and age-corrected norms for dynamic ventilatory reserve at progressively higher work rates, we compared peak and dynamic ventilatory reserve for their ability to expose increased exertional dyspnea and poor exercise tolerance in mild to very severe chronic obstructive pulmonary disease (COPD). Methods: We analyzed resting functional and incremental CPET data from 275 controls (130 men, aged 19-85 yr) and 359 Global Initiative for Chronic Obstructive Lung Disease patients with stage 1-4 obstruction (203 men) who were prospectively recruited for previous ethically approved studies in three research centers. In addition to peak and dynamic ventilatory reserve (1 - [ventilation / estimated maximal voluntary ventilation] × 100), operating lung volumes and dyspnea scores (0-10 on the Borg scale) were obtained. Results: Dynamic ventilatory reserve was asymmetrically distributed in controls; thus, we calculated its centile distribution at every 20 W. The lower limit of normal (lower than the fifth centile) was consistently lower in women and older subjects. Peak and dynamic ventilatory reserve disagreed significantly in indicating an abnormally low test result in patients: whereas approximately 50% of those with a normal peak ventilatory reserve showed a reduced dynamic ventilatory reserve, the opposite was found in approximately 15% (P < 0.001). Irrespective of peak ventilatory reserve and COPD severity, patients who had a dynamic ventilatory reserve below the lower limit of normal at an isowork rate of 40 W had greater ventilatory requirements, prompting earlier attainment of critically low inspiratory reserve. Consequently, they reported higher dyspnea scores, showing poorer exercise tolerance compared with those with preserved dynamic ventilatory reserve. Conversely, patients with preserved dynamic ventilatory reserve but reduced peak ventilatory reserve reported the lowest dyspnea scores, showing the best exercise tolerance. Conclusions: Reduced submaximal dynamic ventilatory reserve, even in the setting of preserved peak ventilatory reserve, is a powerful predictor of exertional dyspnea and exercise intolerance in COPD. This new parameter of ventilatory demand-capacity mismatch may enhance the yield of clinical CPET in the investigation of activity-related breathlessness in individual patients with COPD and other prevalent cardiopulmonary diseases.

Respiratory gas kinetics in patients with congestive heart failure during recovery from peak exercise.

BACKGROUND: Cardiopulmonary Exercise Testing (CPX) is essential for the assessment of exercise capacity for patients with Chronic Heart Failure (CHF). Respiratory gas and hemodynamic parameters such as Ventilatory Efficiency (VE/VCO2 slope), peak oxygen uptake (peak VO2), and heart rate recovery are established diagnostic and prognostic markers for clinical populations. Previous studies have suggested the clinical value of metrics related to respiratory gas collected during recovery from peak exercise, particularly recovery time to 50% (T1/2) of peak VO2. The current study explores these metrics in detail during recovery from peak exercise in CHF. METHODS: Patients with CHF who were referred for CPX and healthy individuals without formal diagnoses were assessed for inclusion. All subjects performed CPX on cycle ergometers to volitional exhaustion and were monitored for at least five minutes of recovery. CPX data were analyzed for overshoot of respiratory exchange ratio (RER=VCO2/VO2), ventilatory equivalent for oxygen (VE/VO2), end-tidal partial pressure of oxygen (PETO2), and T1/2 of peak VO2 and VCO2. RESULTS: Thirty-two patients with CHF and 30 controls were included. Peak VO2 differed significantly between patients and controls (13.5 ± 3.8 vs. 32.5 ± 9.8 mL/Kg*min-1, p < 0.001). Mean Left Ventricular Ejection Fraction (LVEF) was 35.9 ± 9.8% for patients with CHF compared to 61.1 ± 8.2% in the control group. The T1/2 of VO2, VCO2 and VE was significantly higher in patients (111.3 ± 51.0, 132.0 ± 38.8 and 155.6 ± 45.5s) than in controls (58.08 ± 13.2, 74.3 ± 21.1, 96.7 ± 36.8s; p < 0.001) while the overshoot of PETO2, VE/VO2 and RER was significantly lower in patients (7.2 ± 3.3, 41.9 ± 29.1 and 25.0 ± 13.6%) than in controls (10.1 ± 4.6, 62.1 ± 17.7 and 38.7 ± 15.1%; all p < 0.01). Most of the recovery metrics were significantly correlated with peak VO2 in CHF patients, but not with LVEF. CONCLUSIONS: Patients with CHF have a significantly blunted recovery from peak exercise. This is reflected in delays of VO2, VCO2, VE, PETO2, RER and VE/VO2, reflecting a greater energy required to return to baseline. Abnormal respiratory gas kinetics in CHF was negatively correlated with peak VO2 but not baseline LVEF.

High Cardiorespiratory Optimal Point Values Are Related to Cardiovascular Mortality in Men Aged 46 to 70 Years: a Prospective Cohort Study

Abstract Background: Several hemodynamic and respiratory variables measured during cardiopulmonary exercise testing (CPX) have been shown to predict survival. One such measure is the cardiorespiratory optimal point (COP) that reflects the best possible circulation-respiration interaction, but there are still limited data on its relationship with adverse outcomes. Objective: To assess the association between COP and cardiovascular mortality in men aged 46 to 70 years. Methods: A sample of 2201 men who had anthropometric, clinical, and COP data obtained during cycling CPX between 1995 and 2022 was extracted from the CLINIMEX Exercise cohort. COP was identified as the minimal minute-to-minute VE/VO2 during CPX. Vital data were censored on October 31, 2022 for ICD-10-identified cardiovascular deaths. Cox proportional hazard models were used to estimate hazard ratios (HRs) with 95% confidence intervals (95% CIs). Results: The mean ± standard deviation age was 57 ± 6 years and the median COP value was 24 (interquartile range = 21.2 to 27.4). During a mean follow-up of 4688 ± 2416 days, 129 (5.6%) patients died from cardiovascular causes. The death rates for low (< 28), high (28 to 30), and very high (> 30) categories of COP were 3.2%, 9.6%, and 18.7%, respectively. Following adjustment for age, history of myocardial infarction, diagnosis of coronary artery disease, and diabetes mellitus, the HR (95% CI) for cardiovascular mortality comparing very high versus low COP was 2.76 (1.87 to 4.07; p < 0.001). Conclusions: Our data indicate that, for a general population-based sample of men, COP > 30 represents a considerably higher risk for cardiovascular death. Information on COP could assist cardiovascular risk assessment in men.

Prognostic value of right ventricular strain and peak oxygen consumption in heart failure with reduced ejection fraction.

Our purpose is to evaluate the combined predictive value of cardiopulmonary exercise testing (CPET) and echocardiographic evidence of left ventricular (LV) and right ventricular (RV) strain in predicting mortality and heart transplant (HTx) in a series of outpatients with heart failure with reduced ejection fraction (HFrEF). A retrospective cohort study of 66 patients with HFrEF (median age, 57 years; 51% women) who underwent CPET and echocardiography (up to 90 days apart) to assess prognosis. The primary outcome was a composite of death and need for HTx. At a median follow-up of 27 [20-39] months, 19 patients (29%) experienced the primary outcome. In unadjusted analysis, most echocardiographic and CPET parameters were associated with the primary outcome, including percentage of predicted peak oxygen consumption (ppVO2), VE/VCO2 slope, LV ejection fraction, and LV and RV longitudinal strain. After adjusting for other clinical, echocardiographic and CPET variables, RV free wall longitudinal strain and ppVO2 remained significantly associated with the primary outcome. Kaplan-Meier survival curves for death and HTx, based on the best cutoff values, showed lower survival rates in patients with impairment in both ppVO2 and RV FW-LS than in those with one or neither parameter impaired (p < 0.001). RV dysfunction and low cardiorespiratory fitness were independent markers of death and need for HTx. Impairment of both ppVO2 and RV FW-LS had a strong additive impact on prognostic assessment in this cohort of patients with HFrEF.

Long-term reduced functional capacity and quality of life in hospitalized COVID-19 patients.

Background: Persistent symptoms and exercise intolerance have been reported after COVID-19, even months after the acute disease. Although, the long-term impact on exercise capacity and health-related quality of life (HRQoL) is still unclear. Research question: To assess the long-term functional capacity and HRQoL in patients hospitalized due to COVID-19. Study design and methods: This is a prospective cohort study, conducted at two centers in Brazil, that included post-discharge COVID-19 patients and paired controls. The cohort was paired by age, sex, body mass index and comorbidities, using propensity score matching in a 1:3 ratio. Patients were eligible if signs or symptoms suggestive of COVID-19 and pulmonary involvement on chest computed tomography. All patients underwent cardiopulmonary exercise testing (CPET) and a HRQoL questionnaire (SF-36) 6 months after the COVID-19. The main outcome was the percentage of predicted peak oxygen consumption (ppVO2). Secondary outcomes included other CPET measures and HRQoL. Results: The study sample comprised 47 post-discharge COVID-19 patients and 141 healthy controls. The mean age of COVID-19 patients was 54 ± 14 years, with 19 (40%) females, and a mean body mass index of 31 kg/m2 (SD, 6). The median follow-up was 7 months (IQR, 6.5-8.0) after hospital discharge. PpVO2 in COVID-19 patients was lower than in controls (83% vs. 95%, p = 0.002) with an effect size of 0.38 ([95%CI], 0.04-0.70). Mean peak VO2 (22 vs. 25 mL/kg/min, p = 0.04) and OUES (2,122 vs. 2,380, p = 0.027) were also reduced in the COVID-19 patients in comparison to controls. Dysfunctional breathing (DB) was present in 51%. HRQoL was significantly reduced in post COVID patients and positively correlated to peak exercise capacity. Interpretation: Hospitalized COVID-19 patients presented, 7 months after discharge, with a reduction in functional capacity and HRQoL when compared to historical controls. HRQoL were reduced and correlated with the reduced peak VO2 in our population.

Respiratory gas kinetics in patients with congestive heart failure during recovery from peak exercise

Abstract Background Cardiopulmonary Exercise Testing (CPX) is essential for the assessment of exercise capacity for patients with Chronic Heart Failure (CHF). Respiratory gas and hemodynamic parameters such as Ventilatory Efficiency (VE/VCO2 slope), peak oxygen uptake (peak VO2), and heart rate recovery are established diagnostic and prognostic markers for clinical populations. Previous studies have suggested the clinical value of metrics related to respiratory gas collected during recovery from peak exercise, particularly recovery time to 50% (T1/2) of peak VO2. The current study explores these metrics in detail during recovery from peak exercise in CHF. Methods Patients with CHF who were referred for CPX and healthy individuals without formal diagnoses were assessed for inclusion. All subjects performed CPX on cycle ergometers to volitional exhaustion and were monitored for at least five minutes of recovery. CPX data were analyzed for overshoot of respiratory exchange ratio (RER=VCO2/VO2), ventilatory equivalent for oxygen (VE/VO2), end-tidal partial pressure of oxygen (PETO2), and T1/2 of peak VO2 and VCO2. Results Thirty-two patients with CHF and 30 controls were included. Peak VO2 differed significantly between patients and controls (13.5 ± 3.8 vs. 32.5 ± 9.8 mL/Kg*min−1, p < 0.001). Mean Left Ventricular Ejection Fraction (LVEF) was 35.9 ± 9.8% for patients with CHF compared to 61.1 ± 8.2% in the control group. The T1/2 of VO2, VCO2 and VE was significantly higher in patients (111.3 ± 51.0, 132.0 ± 38.8 and 155.6 ± 45.5s) than in controls (58.08 ± 13.2, 74.3 ± 21.1, 96.7 ± 36.8s; p < 0.001) while the overshoot of PETO2, VE/VO2 and RER was significantly lower in patients (7.2 ± 3.3, 41.9 ± 29.1 and 25.0 ± 13.6%) than in controls (10.1 ± 4.6, 62.1 ± 17.7 and 38.7 ± 15.1%; all p < 0.01). Most of the recovery metrics were significantly correlated with peak VO2 in CHF patients, but not with LVEF. Conclusions Patients with CHF have a significantly blunted recovery from peak exercise. This is reflected in delays of VO2, VCO2, VE, PETO2, RER and VE/VO2, reflecting a greater energy required to return to baseline. Abnormal respiratory gas kinetics in CHF was negatively correlated with peak VO2 but not baseline LVEF.

Cardiopulmonary Exercise Testing in Patients with Post-COVID-19 Syndrome.

Background and aim: Several reports have shown the persistence of long term symptoms after the initial COVID-19 infection (post-COVID-19 syndrome). The objective of this study was to analyze the characteristics of cardiopulmonary exercise testing (CPET) performed in patients with a history of COVID-19, comparing subjects according to the presence of post-COVID-19 syndrome. Methods: A cross-sectional study was performed. Consecutive patients >18 years with history of SARS-CoV-2 infection confirmed by polymerase chain reaction test and a CPET performed between 45 and 120 days after the viral episode were included. The association between variables related to CPET and post-COVID-19 syndrome was assessed using univariate and multivariate analysis. Results: A total of 200 patients (mean age 48.8 ± 14.3 years, 51% men) were included. Patients with post-COVID-19 syndrome showed significantly lower main peak VO2 (25.8 ± 8.1 mL/min/kg vs. 28.8 ± 9.6 mL/min/kg, p = 0.017) as compared to asymptomatic subjects. Moreover, patients with post-COVID-19 syndrome developed symptoms more frequently during CPET (52.7% vs. 13.7%, p < 0.001) and were less likely to reach the anaerobic threshold (50.9% vs. 72.7%, p = 0.002) when compared to asymptomatic subjects. These findings were not modified when adjusting for confounders. Conclusion: Our data suggest that post-COVID-19 syndrome was associated with less peak VO2, a lower probability of achieving the anaerobic threshold and a higher probability of presenting symptoms during the CPET. Future studies are needed to determine if these abnormalities during CPET would have prognostic value.

Antecedentes y objetivo: Varios informes han demostrado la persistencia de síntomas a largo plazo luego de la infección inicial por COVID-19 (síndrome post-COVID-19). El objetivo de este estudio fue analizar las características de la prueba de esfuerzo cardiopulmonar (PECP) realizada en pacientes con antecedentes de infección por COVID-19, comparando sujetos según la presencia de síndrome post-COVID-19. Métodos: se realizó un estudio transversal. Se incluyeron pacientes consecutivos >18 años con antecedentes de infección por SARS-CoV-2 confirmada por la prueba de reacción en cadena de la polimerasa y una PECP realizada entre 45 y 120 días luego del episodio viral. Se evaluó la asociación entre variables relacionadas con la PECP y síndrome post-COVID-19 mediante análisis univariante y multivariado. Resultados: Se incluyeron 200 pacientes (edad media 48,8 ± 14,3 años, 51% hombres). Los pacientes con síndrome post-COVID-19 mostraron un VO2 pico significativamente menor (25,8 ± 8,1 mL/min/kg frente a 28,8 ± 9,6 mL/min/kg, p = 0,017) en comparación con los sujetos asintomáticos. Además, los pacientes con síndrome post-COVID-19 desarrollaron síntomas con mayor frecuencia durante la PECP (52,7% vs. 13,7%, p < 0,001) y tenían menos probabilidades de alcanzar el umbral anaeróbico (50,9% vs. 72,7%, p = 0,002) en comparación con sujetos asintomáticos. Estos hallazgos no se modificaron al ajustar por factores de confusión. Conclusión: Nuestros datos sugieren que el síndrome post-COVID-19 se asoció con un menor VO2 pico, una menor probabilidad de alcanzar el umbral anaeróbico y una mayor probabilidad de presentar síntomas durante la PECP. Se necesitan estudios futuros para determinar si estas anomalías durante la PECP tendrían valor pronóstico.

Prognostic role of cardiopulmonary exercise testing in pulmonary hypertension: a systematic review and meta-analysis.

INTRODUCTION: Several studies have evaluated the relation between variables of cardiopulmonary exercise testing (CPET) and major clinical events in pulmonary hypertension (PH) patients, although the results were conflicting. The main objective of this study was to investigate the prognostic value of the CPET derived parameters on all-cause mortality or urgent transplantation in PH patients. MATERIAL AND METHODS: A meta-analysis of time-to-event outcomes were performed from observational studies that evaluated the predictive value of CEPT-related variables [peak oxygen uptake (VO2) and the ventilation to CO2 production slope (VE/VCO2)] in PH patients, reporting data from mortality or urgent transplantation, after searching the PubMed/MEDLINE, Embase, Science Direct, Scopus, Google Scholar, and Cochrane databases. A random-effects meta-analysis model was then applied. RESULTS: Nine eligible studies, including 986 patients, were identified and considered eligible for the quantitative analyses. This meta-analysis showed that high peak VO2 was associated with a lower mortality or transplant occurrence (HR: 0.81; 95% CI: 0.78-0.85, I2 = 29%). In addition, high VE/VCO2 slope was associated with a higher incidence of the primary endpoint (HR: 1.04; 95% CI: 1.02-1.06, I2 = 78%). The sensitivity analysis showed that the results were robust. CONCLUSIONS: Our data suggest that in a population with PH the CPET-related variables have predictive capacity regarding mortality and the risk of transplantation. Future studies should establish the best cut-off points for these CPET-related variables.

Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation.

OBJECTIVES: Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O2 pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE). METHODS: Thirty-one patients of both sexes, aged 45 to 75 years, with symptomatic (Canadian Cardiovascular Society class II to IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov: NCT03218891. RESULTS: The patients had low cardiorespiratory capacity (OUES of 1.74 ± 0.4 L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O2 pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R = 0.48; p = 0.019). CONCLUSION: Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O2 pulse response during CEPT and contractile alterations detected by exercise stress echocardiography.

The Association of Field Test Outcomes with Peak Oxygen Uptake in Patients with Cystic Fibrosis: A Systematic Review.

The purpose of the study was to evaluate the association of field test outcomes with peak oxygen uptake (VO2peak) in patients with cystic fibrosis (CF) and to describe the main prediction equations available. Data searches were performed in five databases (Pubmed, Embase, LILACs, Scopus and Web of Science) and also in the reference lists of articles included. The following inclusion criteria were used: studies including individuals with CF, presenting both a field test and a cardiopulmonary exercise testing (CPET), and describing a predictive equation or coefficient of correlation/determination. Case studies, abstracts, letters of reply, editorials and duplicate publications were excluded. The methodological quality analysis was performed using the JBI Critical Appraisal Checklist for Analytical Cross-Sectional Studies scale. Protocol registration number: CRD42020148363. Ten studies were eligible. Five equations were found to predict VO2peak. Equations derived from the shuttle tests (ST) showed strong correlations with VO2peak (r = 0.79 to 0.95). The six-minute walk test (6MWT) showed moderate associations with VO2peak in participants with moderate disease severity (r = 0.53 to 0.65). Furthermore, patients with lower maximum heart rate on the three-minute step test tended to have a higher percent predicted VO2peak (r = -0.40), and the one-minute sit-to-stand test demonstrated moderate correlations between VO2peak and the number of repetitions (r = 0.52 to 0.66). In conclusion, field test outcomes correlate with oxygen consumption assessed through CPET, although only the ST seems to be valid as a predictor of VO2peak in patients with CF.

Assessment of Cardiorespiratory and Metabolic Responses in Women with Obesity After Surgically Induced Weight Loss: Results from a Pilot Study.

PURPOSE: Bariatric surgery is effective in controlling severe obesity. However, studies investigating the impact of surgically induced weight loss on cardiorespiratory and metabolic responses during maximal effort are controversial. The aim of this study was to assess cardiorespiratory and metabolic responses in women with obesity after bariatric surgery. MATERIALS AND METHODS: We performed a secondary analysis on data from a pilot study with women with obesity submitted to bariatric surgery and who did not participate in a controlled physical training program. Anthropometry, pulmonary function (spirometry), and cardiorespiratory fitness (cardiopulmonary exercise testing [CPX]) were assessed before and after bariatric surgery. RESULTS: Thirty-four women were included (38.7 ± 9.6 years, body mass index = 44.1 ± 6.3 kg/m2). Postoperative assessment was conducted 9.4 ± 2.7 months after surgery. After surgery, we observed a reduction in all anthropometric measurements (mean loss of 28.6 kg, p < 0.001), and improvement in spirometry values (p < 0.001). Relative VO2peak (mL/kg/min) increased slightly (Δ = 1.7; p = 0.06); however, absolute VO2peak (L/min) reduced significantly (Δ = - 0.398; p < 0.001). We also observed an increase of 1.3 min (p < 0.001) in CPX duration, a reduction of 11.3 bpm (p < 0.001) in resting heart rate, and a decrease of systolic (p = 0.02) and diastolic (p < 0.001) blood pressures at peak effort. CONCLUSION: Surgically induced weight loss without exercise training improved cardiac reserve, ventilatory response, blood pressure, and resting heart rate. Cardiorespiratory fitness reflected by relative VO2peak increased slightly, despite increased tolerance to CPX.

Determinants of exercise capacity in children and adolescents with severe therapy-resistant asthma.

OBJECTIVE: To evaluate the exercise capacity of children and adolescents with severe therapy resistant asthma (STRA) aiming to identify its main determinants. METHODS: Cross-sectional study including individuals aged 6-18 years with a diagnosis of STRA. Clinical (age and gender), anthropometric (weight, height and body mass index) and disease control data were collected. Lung function (spirometry), cardiopulmonary exercise testing (CPET) and exercise-induced bronchoconstriction (EIB) test were performed. RESULTS: Twenty-four patients aged 11.5 ± 2.6 years were included. The mean forced expiratory volume in one second (FEV1) was 91.3 ± 9.2%. EIB occurred in 54.2% of patients. In CPET, the peak oxygen uptake (VO2peak) was 34.1 ± 7.8 mL kg-1 min-1. A significant correlation between ventilatory reserve and FEV1 (r = 0.57; p = 0.003) was found. Similarly, there was a significant correlation between CPET and percent of FEV1 fall in the EIB test for both VE/VO2 (r = 0.47; p = 0.02) and VE/VCO2 (r = 0.46; p = 0.02). Patients with FEV1<80% had lower ventilatory reserve (p = 0.009). In addition, resting heart rate correlated with VO2peak (r=-0.40; p = 0.04), VE/VO2 (r = 0.46; p = 0.02) and VE/VCO2 (r = 0.48; p = 0.01). CONCLUSIONS: Exercise capacity is impaired in approximately 30% of children and adolescents with STRA. The results indicate that different aspects of aerobic fitness are influenced by distinct determinants, including lung function and EIB.

Cardiopulmonary exercise test in patients with refractory angina: functional and ischemic evaluation

Abstract Objectives Refractory angina (RA) is a chronic condition clinically characterized by low effort tolerance; therefore, physical stress testing is not usually requested for these patients. Cardiopulmonary exercise testing (CPET) is considered a gold standard examination for functional capacity evaluation, even in submaximal tests, and it has gained great prominence in detecting ischemia. The authors aimed to determine cardiorespiratory capacity by using the oxygen consumption efficiency slope (OUES) in patients with refractory angina. The authors also studied the O2 pulse response by CPET and the association of ischemic changes with contractile modifications by exercise stress echocardiography (ESE). Methods Thirty-one patients of both sexes, aged 45 to 75 years, with symptomatic (Canadian Cardiovascular Society class II to IV) angina who underwent CPET on a treadmill and exercise stress echocardiography on a lower limb cycle ergometer were studied. ClinicalTrials.gov: NCT03218891. Results The patients had low cardiorespiratory capacity (OUES of 1.74 ± 0.4 L/min; 63.9±14.7% of predicted), and 77% of patients had a flattening or drop in O2 pulse response. There was a direct association between Heart Rate (HR) at the onset of myocardial ischemia detected by ESE and HR at the onset of flattening or drop in oxygen pulse response detected by CPET (R = 0.48; p = 0.019). Conclusion Patients with refractory angina demonstrate low cardiorespiratory capacity. CPET shows good sensitivity for detecting abnormal cardiovascular response in these patients with a significant relationship between flattening O2 pulse response during CEPT and contractile alterations detected by exercise stress echocardiography. Highlights OUES analysis is useful for assessing functional capacity in refractory angina. O2 pulse curve is correlated with contractile alterations in exercise echocardiogram. Cardiopulmonary exercise test is useful toll in patients with refractory angina.

Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude.

BACKGROUND: Exercise intolerance, desaturation, and dyspnea are common features in patients with chronic obstructive pulmonary disease (COPD). At altitude, the barometric pressure (BP) decreases, and therefore the inspired oxygen pressure and the partial pressure of arterial oxygen (PaO2) also decrease in healthy subjects and even more in patients with COPD. Most of the studies evaluating ventilation and arterial blood gas (ABG) during exercise in COPD patients have been conducted at sea level and in small populations of people ascending to high altitudes. Our objective was to compare exercise capacity, gas exchange, ventilatory alterations, and symptoms in COPD patients at the altitude of Bogotá (2,640 m), of all degrees of severity. METHODS: Measurement during a cardiopulmonary exercise test of oxygen consumption (VO2), minute ventilation (VE), tidal volume (VT), heart rate (HR), ventilatory equivalents of CO2 (VE/VCO2), inspiratory capacity (IC), end-tidal carbon dioxide tension (PETCO2), and ABG. For the comparison of the variables between the control subjects and the patients according to the GOLD stages, the non-parametric Kruskal-Wallis test or the one-way analysis of variance test was used. RESULTS: Eighty-one controls and 525 patients with COPD aged 67.5 ± 9.1 years were included. Compared with controls, COPD patients had lower VO2 and VE (p < 0.001) and higher VE/VCO2 (p = 0.001), A-aPO2, and V D /V T (p < 0.001). In COPD patients, PaO2 and saturation decreased, and delta IC (p = 0.004) and VT/IC increased (p = 0.002). These alterations were also seen in mild COPD and progressed with increasing severity of the obstruction. CONCLUSION: The main findings of this study in COPD patients residing at high altitude were a progressive decrease in exercise capacity, increased dyspnea, dynamic hyperinflation, restrictive mechanical constraints, and gas exchange abnormalities during exercise, across GOLD stages 1-4. In patients with mild COPD, there were also lower exercise capacity and gas exchange alterations, with significant differences from controls. Compared with studies at sea level, because of the lower inspired oxygen pressure and the compensatory increase in ventilation, hypoxemia at rest and during exercise was more severe; PaCO2 and PETCO2 were lower; and VE/VO2 was higher.