Peak ventilation during treadmill cardiopulmonary exercise testing: applicability analysis of the FRIEND registry prediction equation in a Brazilian healthy sample

Background

Peak ventilation (VEpeak) measured by cardiopulmonary exercise testing (CPX) is a valuable clinical information, especially in patients with pulmonary diseases. Measured values can be compared to maximal voluntary ventilation or to predicted VEpeak calculated by nonexercise equations. However, the FRIEND Registry prediction equation has never been assessed for portability in a Brazilian population sample.

Purpose

To analyze the applicability of the FRIEND registry prediction equation for VEpeak during treadmill CPX in a Brazilian healthy sample.

Methods

Cross-sectional study of subjects assessed by CPX in the Brazilian Midwest region between January/2011 to March/2020. The inclusion criteria were CPX performed on treadmill in healthy individuals aged 20 years or older, and with respiratory exchange ratio ≥1.0. The exclusion criteria were any history of cardiovascular or pulmonary disease, presence of cardiovascular risk factors (such as hypertension, diabetes mellitus, current smoking, and obesity) and abnormalities on CPX. Measured VEpeak values were compared with predicted values calculated using age, sex, and height, according to the FRIEND Registry prediction equation. Variables were described as median and interquartile range. Statistical comparisons between measured and predicted VEpeak were performed using Spearman correlation test, Wilcoxon signed rank test, and Blant-Altman agreement analysis.

Results

During the study period 7,843 CPX were performed and included for study eligibility. After the inclusion and exclusion criteria were applied, 3,544 healthy individuals' assessments were included [1,574 females and 1,970 males, age 39 (33, 47) years]. The measured and predicted VEpeak were, respectively, 76.8 (66.7, 87.4) and 76.2 (68.5, 83.0) L min–1 in females, with significant difference (p=0.004). In males, the measured and predicted VEpeak were, respectively, 123.0 (107.3, 137.3) and 114.8 (107.5, 120.7) L min–1, also with statistical difference (p<0.001). Correlations were significant (p<0.001) for both sexes (r2=0.424 for females and .421 for males) (Figure 1). Average error was lower for females than males, with bias of 1.22 L min–1 (95% limits of agreement: - 26.95 to 29.39) in females and bias of 8.41 L min–1 (95% limits of agreement: −33.04 to 49.87) in males (Figure 2).

Conclusion

Measured VEpeak median values were greater than predicted median values for both sexes, with lower average error in females than in males. The significant average error in males limits the prediction equation applicability in the Brazilian population. Thus, the development of a new Brazilian prediction equation is necessary to better evaluate the variable response during CPX in Brazil.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).

Exercise intensity domains determined by heart rate at ventilatory threshold: a comparison of the guideline-directed exercise intensity domains for cardiovascular rehabilitation prescription

Background

Appropriate exercise prescription for cardiovascular diseases patients is a keystone for efficient and safe cardiovascular rehabilitation (CR). Exercise intensity prescribed according to the first and second ventilatory threshold (VT1 and VT2), identified by cardiopulmonary exercise testing (CPET), is considered the gold-standard method. However, because CPET is often not available, percentages of peak heart rate (%HRpeak) or heart rate reserve (%HRR), according to heart rate (HR) response during a conventional exercise test, are very commonly used.

Purpose

To compare the HR at VT1 and VT2 identified by CPET with the recommended exercise intensity prescription domains according to the Brazilian, American, and European CR guidelines/recommendations.

Methods

This retrospective cohort study assessed 1,465 treadmill CPETs from adult patients with stable cardiovascular diseases. Inclusion criteria were available VT1 and VT2 identification, sinus rhythm during exercise, and had reached maximal effort (respiratory exchange rate ≥1.10). HR at VT1 and VT2 were compared with the exercise intensity prescription domains recommended by Brazilian CR Guideline 2020, European Position Statement 2022, and the American College of Sports Medicine Guideline 2017, according to the obtained %HRpeak and %HRR.

Results

After applying the inclusions criteria, a sample of 972 CPETs were included (mean age 57.7±12.0 years, 80.8% males, 81.4% with coronary artery disease, and 26.6% with heart failure). VT1 and VT2 were identified, respectively, at 68.8% (63.8, 74.7) and 89.1 (85.8, 92.2) of the peak HR, and 39.0 (32.9, 45.8) and 78.0 (71.6, 84.5) of the HR reserve, indicating a greater heterogeneity of the latter (Figure 1). We found substantial heterogeneity between the measured %HRpeak and %HRR correspondent to the VT1 and VT2 and the estimated HR exercise intensity domains by compared international recommendations (Figure 2).

Conclusion

The disparities among currently established guideline-directed exercise domains limits the clinical validity of the use of %HRR and %HRpeak, and further strengthens the importance of performing CPET for an accurate exercise intensity prescription in CR. In the absence of CPET, HR values identified in our study at VT1 and VT2 could be used for guiding moderate-intensity exercise prescription for CVD patients, and the suggested range would be 69 to 89% of %HRpeak or 40 to 78% of %HRR. Current established exercise domains limits should be revised to improve HR-based prescription efficiency and safety.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).Conselho Nacional de Desenvolvimento Científico e Tecnolόgico (CNPq).

Cardiopulmonary exercise testing in post-COVID-19 patients: Where does exercise intolerance come from?

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES). Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq).

Background

Post-COVID-19 persistent symptoms and exercise intolerance are poorly understood. Cardiopulmonary exercise testing (CPET) assessment is important to address the sources of the underlying symptoms and limitations.

Purpose

To evaluate the source and magnitude of exercise intolerance in post-COVID-19 subjects via CPET.

Methods

This cohort study assessed subjects with different SARS-CoV-2 illness severities. The propensity score matching method was used to select the control group. Patients with available CPET prior to SARS-CoV-2 infection were compared before and after COVID-19.

Results

288 subjects (144 post-COVID-19 and 144 matched-controls) were assessed. The median age was 43.0 years, and 57% were male, with different illness severity (60.4% mild, 20.8% moderate, 18.8% severe). Residual symptoms were reported in 41% of the sample. CPET was performed 14.4±9.4 weeks after disease onset, with exercise limitations being attributed to the peripheral muscle (91.7%), pulmonary (6.3%), and cardiovascular (2.1%) systems. Lower median percent-predicted peak oxygen consumption was observed in the severe subgroup (72.2%) compared to both mild (98.5%) and control subgroups (91.6%). Peak oxygen consumption (peakVO2), VO2 at the ventilatory thresholds (VO2 at VT), and heart rate differed among illnesses, severities, and controls. Conversely, ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse were similar (Figure 1). Additional subgroup analysis of 42 subjects with prior CPET revealed changes only on peak treadmill speed in the mild subgroup and additional reductions on peakVO2 and VO2 at VT in the moderate/severe subgroup (Figure 2), while ventilatory equivalents, oxygen uptake efficiency slope, and peak oxygen pulse remained unchanged.

Conclusions

Peripheral muscle fatigue was the most common etiology of exercise limitation in post-COVID-19 patients regardless of the SARS-CoV-2 illness severity. Our data suggest that treatment should emphasize comprehensive rehabilitation programs, including aerobic and muscle strengthening components.

Heterogeneity of cardiorespiratory fitness among Brazilian regions and comparison with Norwegian values

Introduction

Cardiorespiratory fitness (CRF) is an important component of health-related physical fitness, and its reduction is associated with a higher risk of cardiovascular disease and increased mortality. Maximal oxygen consumption (VO2 max) measured in the Cardiopulmonary Exercise Test (CPET) is the gold standard for CRF evaluation. The measured VO2 max is compared to predicted normal reference values to provide an accurate and individualized evaluation and classification. However, predicted values have gender and age differences, and data from different regions and countries can be heterogenous due to different demographic and biopsychosocial characteristics.

Purpose

To compare reference values of VO2 max in Brazilian and Norwegian population samples do analyze geographical CRF differences.

Method

Brazilian reference values for CRF were compared within each other and with Norwegian values. The included studies evaluated healthy individual with CPET and direct measurement of VO2 max on a treadmill. Mean, standard deviation and sample size were obtained from the published articles in the last decade, and and standard error of mean (SEM) were calculated. The differences on CRF between studies were analyzed using SEM and the 95% confidence interval.

Results

Brazilian reference values for CRF were different between each other, with lower values at Northeast region and higher values at Southeast for all age groups and both genders. Midwest region showed CRF with intermediate values between these two regions. Comparisons also revealed different values from Norway, which presented the highest CRF for all age groups and both genders (Pictures 1 and 2). Observed heterogeneity in CRF may be explained by anthropometric differences, as Northeast individuals had lower height than the other Brazilian samples, and the Norwegians were the tallest. Other demographic and biopsychosocial characteristics may also play a role.

Conclusion

The present study revealed differences on CRF between countries and within Brazilian population, with a negative gradient from southern to northern regions of Brazil. This finding reinforces the appropriateness of adequate use of regional and country specific reference values for VO2 max to ensure a correct CRF evaluation and classification.

Funding Acknowledgement

Type of funding sources: None.

Obstructive and restrictive ventilatory patterns are differentially associated with cardiac structure and function in late-life

Background

Pulmonary and cardiac function both decline with age. However, few data exist regarding the associations of obstructive and restrictive spirometric patterns with cardiac structure and function in late-life.

Purpose

Determine the associations of reduced percent predicted forced vital capacity (ppFVC) and forced expired volume in 1 second (FEV1)/FVC with cardiac structure and function in late life.

Methods

In the Atherosclerosis Risk in Communities longitudinal cohort study, 3,854 heart failure free participants underwent echocardiography and spirometry at the fifth study visit (2011–2013). Relationships were examined using multivariable linear regression. Models adjusted for demographics and clinical risk factors (Table legend).

Results

Mean age was 75±5 years, 40% were male, 19% black, and 6% current smokers. Mean FEV1/FVC was 72±8, and ppFVC was 98±17%. In adjusted analyses, lower FEV1/FVC was associated with higher pulmonary arterial pressure (PASP) but not with measures of left ventricular (LV) structure or function (Table). In contrast, lower ppFVC, was associated with greater LV mass, worse LV strain, higher E/e' ratio, greater left atrial volume index, and higher PASP (all p<0.01; Table).

Conclusion

In late life, reductions in both FEV1/FVC and ppFVC are associated with higher pulmonary pressure, but only ppFVC was associated with worse LV structure and function.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services

Differential impact of obstructive and restrictive ventilatory patterns on incident heart failure with preserved versus reduced ejection fraction in late-life

Background

Subclinical pulmonary dysfunction predicts cardiovascular (CV) outcomes, especially heart failure (HF). However, the impact of reduced percent predicted forced vital capacity (ppFVC) and forced expired volume in 1 second (FEV1)/FVC on different incident HF phenotypes in late-life is unclear.

Purpose

Determine the associations of FEV1/FVC and ppFVC with incident HF with preserved (HFpEF) and reduced (HFrEF) ejection fraction in late-life.

Methods

In the Atherosclerosis Risk in Communities longitudinal cohort study, 3,854 HF-free participants who underwent echocardiography and spirometry at the fifth study visit (2011–2013). The relation between pulmonary function and incident adjudicated HFpEF and HFrEF were examined using multivariable Cox proportional hazards models adjusted for demographics, body mass index, coronary artery disease, atrial fibrillation, hypertension, diabetes, and NT-proBNP.

Results

Mean age was 75±5 years, 40% were male, 19% black, and 6% current smokers. Mean FEV1/FVC was 72±8, and ppFVC was 98±17%. At a median follow-up of 5.6 years, lower ppFVC was independently associated with incident HFpEF, but not HFrEF (Table). Lower FEV1/FVC ratio was associated with higher risk of incident HFrEF but not HFpEF in models adjusted for demographics, which did not persist after further adjustment for clinical risk factors.

Conclusion

The relationships of reduced ppFVC and FEV1/FVC with incident HF differ significantly by HF phenotype.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services

Pulmonary and cardiac cysticercosis: helical CT findings

The authors aim to report the chest CT findings of a patient with disseminated cysticercosis, emphasising the pulmonary and cardiac features. The main finding consisted of multiple pulmonary, cardiac and chest wall nodules. The present case demonstrates that cysticercosis should be considered in the differential diagnosis of multiple pulmonary nodules, mainly in those patients with similar lesions in the cardiac muscle and/or in the chest wall.