Prognostic value of cardiopulmonary exercise testing in a European cohort with cardiovascular risk factors absent of a cardiovascular disease diagnosis

Validity and reliability of the 6-min stepper test in hypertensive individuals

BACKGROUND

Hypertension is a common public health problem characterized by high blood pressure (BP) and associated with complications such as coronary artery disease, stroke, and renal failure. Physical activity and exercise regulate BP, and assessment of exercise capacity is a cornerstone of exercise training.

OBJECTIVE

The aims of this study were to evaluate the validity and reliability of the 6-min stepper test (6MST) in hypertensive individuals and compare their physiological responses during the 6MST and 6-min walk test (6MWT).

METHODS

Forty individuals with hypertension were included. Participants performed the 6MWT and 6MST in separate morning and afternoon sessions. In each session, the test was repeated twice with a 30-min rest interval. Heart rate (HR), BP, perceived dyspnea, general fatigue, and leg fatigue were measured pre and posttest. Intraclass correlation coefficient (ICC), Bland-Altman plots, and standard error of measurement (SEM) were used to assess reliability. Pearson correlation analysis was used for convergent validity.

RESULTS

There was a strong and significant correlation between 6MWT distance and 6MST score ( r  = 0.689, P  < 0.001). Physiological responses during the 6MST had ICC values ranging from 0.70 to 0.89, suggesting good to excellent test-retest reliability. The SEM and minimum detectable difference (MDD) indicated the 6MST had low measurement error and high sensitivity.

CONCLUSION

The 6MST is a valid and reliable tool for assessing exercise capacity in people with HTN. Its practicality and ease of use make it a suitable alternative to the 6MWT for this population.

The prognostic role of cardiopulmonary exercise testing in obesity

AIM

Poor cardiorespiratory fitness has been suggested to increase the risk of chronic diseases in obesity. We investigated the ability of key variables from cardiopulmonary exercise testing (CPET) to predict all-cause mortality in an obese cohort.

METHODS

The sample included 469 participants of both sexes (mean age 40 ± 13 years) who underwent a CPET for clinical reasons between 1 March 2009 and 1 December 2023. All-cause mortality was the prognostic endpoint. A receiver operating characteristic analysis was performed to establish optimal cut-points for CPET variables. Kaplan-Meier and Cox regression analyses were used to determine the association between CPET variables and all-cause mortality.

RESULTS

There were 46 deaths during a mean follow-up period of 69 ± 48 months, resulting in an annual mortality rate of 2%. Despite the sample being made up of mostly women (70%), there were more deaths in men (18 vs. 6%, p < 0.001).The optimal thresholds for discrimination of survival were as follows: (a) peak oxygen uptake (pVO2) ≤16 mL/kg/min; (b) minute ventilation/carbon dioxide production (VE/VCO2) slope ≥31; (c) ventilatory power ≤5.8 mmHg; and (d) circulatory power ≤2980 mmHg/mL O2/min. Kaplan-Meier survival plots revealed a significant positive association between lower pVO2, circulatory power and ventilatory power values and survival (log-rank, p < 0.001) and higher mortality for men than women. Adjusted Cox regression models showed that a pVO2 ≤16 mL/kg/min had a 20-fold higher risk of mortality when compared with >16 mL/kg/min.

CONCLUSION

Given the strong association of VO2, ventilatory efficiency, circulatory and ventilatory power with all-cause mortality, our findings support the notion that poorer cardiorespiratory fitness is associated with a poor prognosis in patients with obesity.

Improving cardiovascular risk stratification through multivariate time-series analysis of cardiopulmonary exercise test data

Nowadays cardiorespiratory fitness (CRF) is assessed using summary indexes of cardiopulmonary exercise tests (CPETs). Yet, raw time-series CPET recordings may hold additional information with clinical relevance. Therefore, we investigated whether analysis of raw CPET data using dynamic time warping combined with k-medoids could identify distinct CRF phenogroups and improve cardiovascular (CV) risk stratification. CPET recordings from 1,399 participants (mean age, 56.4 years; 37.7% women) were separated into 5 groups with distinct patterns. Cluster 5 was associated with the worst CV profile with higher use of antihypertensive medication and a history of CV disease, while cluster 1 represented the most favorable CV profile. Clusters 4 (hazard ratio: 1.30; p = 0.033) and 5 (hazard ratio: 1.36; p = 0.0088) had a significantly higher risk of incident adverse events compared to clusters 1 and 2. The model evaluation in the external validation cohort revealed similar patterns. Therefore, an integrative CRF profiling might facilitate CV risk stratification and management.

Serum Follistatin Levels are Independently Associated with Exercise Tolerance in Patients with Obesity

OBJECTIVE

Follistatin (FST)/myostatin (MST) myokine-signaling axis is important for muscle metabolism and pathogenesis of obesity. FST, mainly secreted by skeletal muscle and liver, inhibits MST and affects skeletal muscle synthesis. This study aimed to identify the characteristics of myokines and independent predictors of serum FST levels in patients with obesity.

METHODS

In this retrospective cross-sectional study, 226 patients (mean age, 46.6 years; men, 35.4%) with obesity who initially visited an outpatient clinic between June 2014 and September 2020, were included and classified into obesity (25.0 ≤ body mass index (BMI) < 35.0 kg/m2) and severe obesity (BMI ≥35 kg/m2) groups based on the guidelines of the Japan Society for the Study of Obesity. Body composition was measured using bioelectrical impedance analysis and computed tomography. Muscle strength, exercise tolerance, metabolic parameters, and myokines were measured, including serum levels of FST, MST, irisin, and brain-derived neurotrophic factor.

RESULTS

Serum FST levels were significantly higher in the severe obesity group than in the obesity group (median: 768.4 vs. 895.1 pg/mL, P = 0.020). However, the levels of other myokines showed no significant differences between the groups. In Model 1, which included factors that significantly correlated with FST levels, stepwise multivariate regression analysis revealed peak oxygen uptake (VO2) as an independent predictor of FST levels based on the significance of the univariate analysis. Additionally, Model 2 was analyzed by adding myokine level to Model 1, revealing that peak VO2, MST, and irisin levels were independent predictors of FST levels.

CONCLUSION

Serum FST levels were higher in patients in the severe obesity group compared to those in the obesity group. There was an independent association between low exercise tolerance and elevated serum FST levels.

Limosilactobacillus reuteri consumption significantly reduces the total cholesterol concentration without affecting other cardiovascular disease risk factors in adults: A systematic review and meta-analysis

As one of the most significant probiotics, Limosilactobacillus reuteri (L. reuteri) has been exploited as a nutritional supplement. We hypothesized that L. reuteri consumption might improve the significant risk factors of cardiovascular disease, including blood pressure, blood lipid, and blood glucose. However, previous clinical studies have shown controversial results. This study aims to explore the effect of L. reuteri consumption on these risk factors. PubMed, Embase, Scopus, the Cochrane Library, and Web of Science were searched for eligible randomized controlled trials published before May 2022. A total of 6 studies with 4 different L. reuteri strains and including 512 participants were included. The results showed that L. reuteri consumption significantly reduced total cholesterol (TC) by -0.26 mmol/L compared with the control group. In contrast, it did not affect systolic blood pressure, diastolic blood pressure, fasting blood glucose, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), or triglycerides. Subgroup analysis showed a significant reduction in TC when participants were <55 years old, had a body mass index between 25 and 30, or had hypercholesterolemia. In addition, TC decreased significantly when L. reuteri supplementation was >5 × 109 colony-forming unit or the length of the intervention was <12 weeks. Strain subgroup analysis showed that L. reuteri NCIMB 30242 significantly reduced TC and LDL-C. In conclusion, L. reuteri consumption has a significant TC-lowering effect, which can effectively reduce the risks of cardiovascular disease associated with hypercholesterolemia. However, the results do not support the effectiveness of L. reuteri consumption on other metabolic outcomes. Further examination of larger sample sizes is needed to confirm these findings.

Prognostic role of minute ventilation/carbon dioxide production slope for perioperative morbidity and long-term survival in resectable patients with nonsmall-cell lung cancer: a prospective study using propensity score overlap weighting

BACKGROUND

The role of minute ventilation/carbon dioxide production ( / CO 2 ) slope, a ventilation efficiency marker, in predicting short-term and long-term health outcomes for patients with nonsmall-cell lung cancer (NSCLC) undergoing lung resection has not been well investigated.

MATERIAL AND METHODS

This prospective cohort study consecutively enrolled NSCLC patients who underwent a presurgical cardiopulmonary exercise test from November 2014 to December 2019. The association of / CO 2 slope with relapse-free survival (RFS), overall survival (OS), and perioperative mortality was evaluated using the Cox proportional hazards and logistic models. Covariates were adjusted using propensity score overlap weighting. The optimal cut-off point of the E/ CO 2 slope was estimated using the receiver operating characteristics curve. Internal validation was completed through bootstrap resampling.

RESULTS

A cohort of 895 patients [median age (interquartile range), 59 (13) years; 62.5% male] was followed for a median of 40 (range, 1-85) months. Throughout the study, there were 247 relapses or deaths and 156 perioperative complications. The incidence rates per 1000 person-years for relapses or deaths were 108.8 and 79.6 among patients with high and low E/ CO 2 slopes, respectively [weighted incidence rate difference per 1000 person-years, 29.21 (95% CI, 7.30-51.12)]. A E/ CO 2 slope of greater than or equal to 31 was associated with shorter RFS [hazard ratio for relapse or death, 1.38 (95% CI, 1.02-1.88), P =0.04] and poorer OS [hazard ratio for death, 1.69 (1.15-2.48), P =0.02] compared to a lower / CO 2 slope. A high E/ CO 2 slope increased the risk of perioperative morbidity compared with a low E/ CO 2 slope [odds ratio, 2.32 (1.54-3.49), P <0.001].

CONCLUSIONS

In patients with operable NSCLC, a high E/ CO 2 slope was significantly associated with elevated risks of poorer RFS, OS, and perioperative morbidity.